Solar Install; the on-going saga

paddyp

I recently negative bell curve lost about 160ah through negligence and mismanagement of batteries, all the while I thought I was doing the right things. Before I decided to replace the bank I had I've been doing some serious research on how to prevent this from happening again.


Most of this install I can attribute to Handybob http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/ [re-post]


It was not my intention to blatantly copy his system downspec'ed until I tried to find a better or similar one where none could be had as far as I could tell...and I've been looking for a month.
If you can make it to the end of that link I recommend the rest of the blog, particularly his meter rants.
I've been gauging my battery condition subconsciously for years and I have gotten rather good at estimating a state of charge, despite having two conflicting voltmeters.


After watching the voltmeter today running the module for the first time I'm glad I ordered the Trimetric. It's one thing to estimate the actual voltage while there's a load on the batteries. It's an entirely different story trying to do it when there's a load and a low current generator at the same time.




I also owe thanks to PaddyP for straightening my expectations out with his indispensable formula,
indispensable because after one month looking I have yet to find a site that makes the same comprehensive list of hidden losses.

paddyp wrote: »

Total annual solar insolation ireland - 900-1200 kwh/m2

100w panel = approx 0.5m2

450 - 600k kwh total to be captured

Panel efficiency 12-14% say 14%

63 - 80kwh per year

Lead acid charging efficiency 70%

44kwh - 56kwh = 10 - 12.8Ah per day annual average.

May/June/July Dublin 5kwh/m2/day

5 x .5 x .14 x .7 = 0.245kwh


245watts / 12 volts = 20.5Ah per day summer average.

Also there's high temperature inefficiencies to be considered (abroad) and I'm looking at a 40% output reduction for mounting the module flat.


Being the optimist that I am I up-spec'ed the module and cracked on. I'm going to install a shunt driven ammeter later so hopefully in a few weeks I can get back with some numbers.


I'm intending to retrofit adjustable tilting brackets (tiltable both sides) eventually but I daresay it'll be rare I use them as I don't often stay put very long so not a priority. In this case I think it's more practical to get 40% more panels to offset the loss.


Also on the long-finger agenda is a wind deflector because perhaps the best solution for too much ballast on the roof is more ballast on the roof.

I looked around and found all those “camper solar kits” were bundled with low end controllers;
I found a not bad one with a steca controller that has a built in ammeter until I did some more research and learned these are not accurate, nor are the solar charge controller remotes.
If you want to read amps you need a shunt or a clamp meter and a calculator.
I read of one customer complaining to Steca that the ah readouts were misleading and the reply received was that this feature was inaccurate, simply that it would be far more expensive for that feature to work correctly.?!


I settled on a 150watt Chinese panel with a decent warranty that came in at the right price and suited my roof dimensions. I had a look at european panels and speculated that they won't honour their warranties soon as China puts them out of business. Bosch are pullling out of the market, Q cells are being outsourced etc.


First agenda I had is to disguise it. My camper lives in the wild and urban, so I need a way to hide it from prying fingers and gobsh1teology.
Simpliest solution I had was make an unassuming roof box and paint it black outside (stealth) and yellow inside (reflective....white would be more reflective but I like yellow so meh!)


2 Mock up side .JPG


I mounted the box onto an existing roof rack with clamped U-brackets.
I secured the module to the box with adapted domestic solar PV brackets, this required a little angle grinding of the brackets and some padding of the panel. I'm not too fond of the extra ballast on the back of the module but it may be useful later for the tilting mounts.
I put a layer of road noise reducing rubber between the backboard and the module more to meet the bracket requirements than the sound ones.
This was cut from an old inner tube...if you want straight pieces cut from the center not the sides...



Road noise reducing filler.JPG
Back board.JPG
Scaffolding solution.JPG
Rack Box.JPG

Wiring;


Wiring diagram.JPG

{EDIT; I just spotted this: the 20 amp fuse on the starter +ve is after the split to the automotive electrics and before the battery link switch. The diagram implies all the automotive electrics are off a single 20amp...in reality it's on it's own core independant of the auto-electric loom...thus the oversight}

I didn't use 4mm solar cable for a few reasons many I grew to regret.
I went with 4.5mm automotive cable single insulated...so I heat shrank 10 metres of it (one of the regrets).
It was easier and quicker for me to get thicker (so better) wire with no UV protection which works for my setup because I've no UV exposure.
I couldn't find a cable entry box quick enough either so I just plugged a cable entry gland straight into the roof, chased it with some sealant and doubled up on rubbers. It's covered by the roof box so I'm not concerned with a leak appearing. Besides the gland is one hole, a glanded box is 5 holes. I prefer the gland even vertical as it is.


Cable entry gland.JPG



There's a few lines on the wiring diagram with two fuses or a fuse and circuit breaker here's the logic. The solar module is rated for < 10amps. However fuses increase resistance and cause voltage drop so I put a 15amp fuse on the module to try to offset this and a 10 amp DC circuit-breaker beside the charge controller. It needs a fuse on the generator side before the risk of it grounding off the body...but hopefully the circuit breaker goes first if there's any other issue (lower rating) so I don't have to climb out on the roof to replace a bloody awkward fuse. Also it allows me to turn off the module from inside for whatever reason...like protecting the controller from open circuit voltage when I want to reset the controller.



Module fuse.JPG
Sealed module fuse.JPG


There's two fuses on the starter to leisure battery link (for switched alternator charge) the reason for this is there's two positives on opposite sides of a switch that is usually open.

The reason for the master breaker is it's handy to have a kill-everything switch, as well as this every live is fused, but some run several meters from the battery before it gets to that fuse. The master can thus detect a ground fault that fuses might not.


In my war on voltage drop I removed the MC4 connecting leads from the module (regret number 2)
Turns out the back of the module has non-standard crimp connections. I attempted to salvage the old crimps off the MC4 leads I removed and made a bags of it giving up after an hour or more. I didn't want to tail in on bare wires here because there was bad connectivity so I tried to order more and nobody had them, ordered the wrong ones from china and “made” them fit after 2 fun hours of crimping.

I decided to spec. the new system to the alternator because that's the hardest component to change, which means getting flooded deep cycle batteries that can take 14.7volts. However I have a sealed battery now I want to make use of it for the time being.


Wiring mess.JPG


Given this I wanted a versatile solar controller, then I decided I wanted a programmable controller because well that's pretty versatile. I went for the Morningstar Tristar 45 because of this and also because it is the only solar controller that can run wind/hydro and hybrid systems too which I plan on using down the line for other projects.

Tristar patch.JPG


The leads from the controller to the battery are 8mm cores from stranded 125amp single phase TRS cable I got through work. I re-used the rubber shielding after wiring everything as cable trunking wrapped in electricians tape...does the job.


Tidied Cables...ish.JPG


The controller has separate battery sense leads (to avoid reading voltage from a load carrying wire), and remote temperature sensor connected to the battery negative terminal for temperature compensation.

Installed.JPG

As far as I can see PWM charging plays havoc with cheap voltmeters. For accurate readings I think you need an RMS meter. I've observed a 0.5v difference between the two after a minor fluster.

CBI DC Breaker box.JPG


10 amp; solar module 150watts / 18volts = 8.3amps
16amp ; solar controller 150watts / 12volts = 12.5amps
35amp; in the post
10amp; temporary master DC breaker




oops forgot to post this one earlier
Fixed flat mount.JPG




TBC

Retail blade fuse holder.JPG: €3 - €5 aprox.
Home made blade fuse holder.JPG: €0.30 aprox.

Fairly simple to install and program this unit. Wired it to the shunt and two battery +ives. It monitors the amps in/out off the leisure batteries and displays an accurate percentage charge via a series shunt. It also displays voltages for two separate battery banks (with a common ground) so I can monitor my starter battery with the same unit. I'm guessing it's RMS because it's verifying my multimeter and shaming my cheapo Chinese joby.

This requires 5 core cable (one twisted pair semi-recommended) on fairly small cable (0.5mm...depending on distance of course). I just used 7 core trailer cable for convenience because I had enough lying around for the job, the core set twists 360° every meter and two spare cores could eventually come in handy.
It's quite useful to compare ah to % charge to calculate what the current rating of your batteries are too (%Dod).

1 amp fast blow fuses on both +ives on battery side.

I have to admit although this is a very handy gizmo, I'm not entirely sure I need it now, as so far, since I installed the panel I've been fully charged everyday. ...time will tell, I may start running the fridge on 12volt and see how well that works. Besides it's always there now should I want to up-rate or salvage the system.




%charge.JPG
Absorption Amps in.JPG

Goes in series with all negative returns to the leisure batteries and the chassis ground is to be connected to the shunt and not the -ive battery terminal . There's smaller kelvin connections on the sides to take voltage sensing wires, where the main current carrying wires are sent to the main lugs on the top. I wired the -ive solar controller battery sense lead onto the kelvin connection, I'm not entirely sure if this is right but it's made little difference.

Shunt Nearside.JPG
Shunt Farside.JPG


The saga isn't going to be as ongoing as I first predicted because, I had intended to do another few posts on refitting my sealed battery for 2 x 6volt flooded golf cart batteries in series, that weren't going to fit where I wanted them, but a few things have transpired since to make me re-evaluate.
I was going to up-rate my mains charger too for one that conforms to the battery manufacturer's spec.



A: My lone battered and bruised battery with solar is outperforming what two new of it's kind were doing with an alternator subsidised weekly mains charge. Oh I don't have to use the alternator anymore to top up the leisure batteries...but I still use the link switch to top up the starter off solar now.
B: I want to see if Morningstar's claims that PWM charging can recover lost battery capacity is true.
C: I don't want to throw out a working battery albeit it working very badly as a simple ecological issue.
I bought a car with my new battery budget and still have €40 change. :cool:
E: Winter will be the true teller if I need to invest given the less light more demand equation but I've already done three Winters in a camper so I'm kinda determined to go bricks and mortar next one.


I'll post some definitive figures where I get them but it might be a while.

dfbemt

Limalot - have followed your thread with interest. Am a keen supporter of solar in my home environment and would be interested in the merits of it for my camper.

Always hook up while away but there are those rare times when this is not possible. Any views on these as a top up when required? Intend to connect direct to battery and put back in box when not required.

http://www.sealey.co.uk/PLPageBuilder.asp?id=20&method=mViewProduct&productid=12095

Can pick them up here for €70 - €80

tehehe yeah I just put one on a car today to save another starter from the recycle heap. They're fairly rubbish. All it'll do is prevent a battery from self-discharge in the height of summer. We had it tilted 40° directed at the mid-day sun today at 20° Celcius and it took a battery from 12.5volts to 12.9volts producing < 100mA.

For that sort of money you should be considering something like this http://www.hollybrookps.co.uk/pv_modules/80w-solar-panel-monocrystalline.html

That Sealy link is just a trickle charger, it might give you enough for a mobile phone charge. Aside from this the wires are too small and it's unregulated. Not that 100mA could harm a leisure battery at all but the principle of unbridled charge upsets me.

dfbemt

Link looks like a fairly top end product that is a permanent connection. I am looking at the portable the better.

Would this product from Maplins be an improvement? It is just top up that I am looking for? Self contained closing case is of interest as it should protect the panel when not being used.

http://www.maplin.co.uk/13w-solar-briefcase-99760#overview

So for portable, protectable, top up is this value for money?

Ah..no, my link is low end, it's a Chinese job...but value for money.

I try to avoid Maplins, they're rip-off merchants. Even though I post lots of links to them. It's a convenience thing. Definitely for solar they're triple what you ought to be paying.

The competitive price per watt on solar modules today is about €1.20 You can go lower or higher for brands, guarantees and warranties.
Also a typical warranty on a solar module is 20 - 25 years...think economy of scale.

The link I posted is portable, there's also smaller ones on that web-site. They have connecting leads on the back you can mount them outside your camper on brackets or rocks or whatever and run a temporary lead to a cheap charge controller near your batteries. You can store them in the back of a wardrobe when you don't want them. They're quite durable.

I really wouldn't consider anything less than 50watts for light camper use. That briefcase will leave you high and dry on a cloudy day, actually at 13watts probably on a sunny day too.

Sorry I haven't posted any figures from my system to compare yet. I've not been using my camper much and won't be until next month. Mostly working on a car these days. I'll post what I can this week but daily averages could be mid July.

dfbemt

dfbemt wrote: »

It is just top up that I am looking for?

Any idea what this might be in terms of amp hours?

On a side note down the economy of scale road; is it worth factoring in the longevity of your leisure battery life on a maintained system relative to a depletive one? To me I estimate that's worth 4 times the value of batteries (half the bank I used to need giving me 6 years (at least) instead of 3)).
Although if you trickle charge in the down time then your result will be mute. ...mine rarely stays in dock more than two days.

dfbemt

Sir Liamalot wrote: »

Any idea what this might be in terms of amp hours?

Hard to know. Kids now have tablets. Will have to check the plugs to see what they need.

We tend to use EHU when away but last time in France we noticed that the battery was flat after a few days. Site had 10Amp hook up so was a bit surprised by this. Fridge was on all day (off main) and kids charged Nintendos overnight. Granted, within 12 months of minimal use we ended up needing a new battery

Aidan_M_M

10amp on mains is a lot more juice than on 12volt.

Any chance you have a clamp multi-meter?
Short of that if you can add up your ah usage, tell me your battery size and times between charges I can give you a guesstimate what you might need.

or you can take Aidan's word for it;

Aidan_M_M wrote: »

I fit the regulator beside the battery if at all possible. I dunno guys, it's easy get bogged down in the science of it, I just fit a decent wet battery, a good quality 75w panel with a decent non adjustae regulator , using high quality cabling. And I've never had an issue. In fact, I can't recall having to replace a battery for any customer that got a panel fitted once it was fitted as above.

If it was my choice, ALL MHs would have solar panels.

@17hr00

The Trimetric Rocks ,

Nominal system voltage 12.6volts (lower the voltage = higher the amperage), with solar module and controller off (night-mode)

• System idle self-consumption (ghost loads & Trimetric); 300mA

(all further figures are compensated for this load)

• 60litre Dometic Fridge with mini freezer switched to 12v : 9.5A
• Fridge cooing fans x2 : 300mA

• LED RGB strip-lights lighting controller: 100mA
• 7metre LED strip-lights set to 100% red: 1.4A
• 7metre LED strip-lights set to 100% red, 100% Green & 100% Blue (ie. full white-ish) :3.5A

• Overhead 12volt LED dichroics (6watt total): bow pair: 500mA
• Stern pair: 700mA (voltage drop on longer cable)
• Mid tungsten pair (40watt total): 3.3A

• Phone charger 5volt USB port: 300mA

• Water pump (continuous) 1.7A

• 600watt Modulated inverter idle (ridiculously over-spec.ed): 400mA
• Inverter: running 30watt 5.1 surround sound 1.0A
• Inverter: running aux. computer monitor: 2.9A
• Inverter: with mains laptop charger idle: 600mA
• Inverter: laptop battery charge only: 4.3A
• Inverter: laptop on (CPUs @ 10%) with laptop battery charging: 6.5A
• Inverter: laptop on (CPUs @ 10%) without laptop battery/fully charged laptop battery: 2.8A

• DC Laptop charger: 19volt 120watt (running @ 90watts max) idle:100mA (ish)
• DC Laptop charger: laptop battery charge only: 3.4A
• DC Laptop charger: laptop on (CPUs @ 10%) with laptop battery charging: 5.7A
• DC Laptop charger: laptop on (CPUs @ 10%) without laptop battery/fully charged laptop battery: 2.0A

Generation:

150watt solar module output absorption charge rate @17hr00, flat mount, covered in light road dirt/dust, sunny [EDIT: indirect ambient light (sun set behind house roof, but module yet unshaded)] 15°C: 4.8A

I can't stress this enough; if the intention is to put a camper exposed to as much sunlight as possible then take care of your tyres!
Direct sunlight will rot the sidewalls making them flakey and dangerous.

So far I've found two methods of doing this:

• Make solar shades from towels or wood or anything you deem not translucent. Personally I recommend making two tyre frames from this and some gaffa tape for portability sakes (or make four if you think that's necessary).
• Otherwise spray the sidewalls only with silicone spray periodically.

Some generation figures in;
(compensated for ghost loads)

Average overnight consumption:
12Ah - 20Ah

Daily generation figures are capped at what I use the previous night as the solar controller stops charging as the battery fills up.
I will have to run deeper discharges to get max. possible daily generation figures.


Days #1 & #2
12°-16° C
Sunny morning (direct sunlight) 09hr00: 3.3A
Cloudy morning (diffused sunlight) 09hr30: 2.6A

Midday sun through cloud (possible edging) 11:30: 5.0A

Overcast midday (Heavy rain-cloud): 1.8A
Bright Midday: 3.0A

Raining afternoon: 1.2A
Sunny evening 17hr10: 5.4A

Daily generation 20Ah.
Float Charge by 14:00 - 17:00

Day #3
max 20°C

Bulk Charge:

07hr00: 1.4A
Overcast cloudy 10hr00: 2.6A
Sun through light cloud (edging) 10hr30: 4.8A > 7.8A
Sun through cloud 11hr40: 4.0A
Sun through light cloud, (edging) 12hr05: 5.8A > 9.8A
Direct sunlight 12hr30: 7.5A
Direct sunlight 13hr40: 5.6A

Absorption:
Sun through light cloud 15hr30: 1.3A
Direct sun 19hr40: 200mA

No Float.
Aprox. Generation 22.5Ah

Day #4
17°C

Bulk Charge:

Sun through light cloud 11hr30: 5.5A
Sun through light cloud 11hr50: 4.1A

Absorption:
Sun through light cloud 13hr05: 1.3A
14hr25: 400mA

Fully charged - Float Charge @ 17hr00

Aprox. Generation 18Ah


I'm not using the batteries during the daytime at the moment, I'm preoccupied subjugating the tin worm.

The module I'm using is a monocrystalline as these outperform the polycrystallines in diffused light conditions, ie. cloudy weather. So are best suited to our climate.

The first two days of figures I used were when the module was covered in a light layer of road filth.
So just to satisfy my curiosity I climbed up the roof with some Jif Universal spray and gave the module a good seeing to. After it was clean and dry I re-checked the meter in what i reckoned was the same light conditions and I had gained 100mA > 200mA.

Normally I tend to charge all battery operated devices during the evening, after letting the leisure battery recharge to midday from the previous night. This means excess bulk charge is being directed and there's enough sunlight afterwards to complete an absorption charge cycle after my dry cell devices are charged. Also it means that the leisure battery is not being unnecessarily run down overnight for want of better organisation.

One of the experiments I was hoping to shed light on was Morningstar's bold claim that their PWM chargers can recover stratified batteries. I speculated in April that my last remaining battery was at 65% DOD after 2.5 years almost daily use up to 50% depletion (mostly) and weekly charging.
In early July after one month of PWM charge constant float I've calculated the same battery at 77% DOD
Now some of this I can attribute to the benefit of a temperature compensating charger but I'm still quite impressed
As of last night this seems to be on the rise again possibly from cycling the battery. Meter was showing 12.7v for 3 hours longer than the previous night with the same discharge.

As for my hopes of running the fridge on 12volt during the daytime I realised this was highly ambitious and impractical as the module will only ever produce 7.5A max in optimal conditions with a flat mount and the fridge consumes 9.5A. Compounding this, optimal conditions for a solar module are the least efficient for a fridge in which case I would have to use gas anyway.

Meanwhile in another corner of the yard, I've had my 5½ cell battery on charge with the 5watt panel similar to the link in post #9 for two days undisturbed and it's moved from 12.1v to 12.2v.

Before anyone harps onto me about the dangers of trickle charging a battery with a damaged cell, bare in mind I have set up a 15 metre perimeter with flashing hazard warning signs and trenches and I only approach the battery fully clad in bomb disposal gear with a gas mask and riot visor!

paddyp

Sir Liamalot wrote: »

Meanwhile in another corner of the yard, I've had my 5½ cell battery on charge with the 5watt panel similar to the link in post #9 for two days undisturbed and it's moved from 12.1v to 12.2v.

Before anyone harps onto me about the dangers of trickle charging a battery with a damaged cell, bare in mind I have set up a 15 metre perimeter with flashing hazard warning signs and trenches and I only approach the battery fully clad in bomb disposal gear with a gas mask and riot visor!

Ahh its only the escaped vapours that explode in a confined space.

Witnessed it once from about 20-30 feet away where someone had left a battery on fast charger for 24 hours instead of 1.5hours needless to say the poor sod that took off the crocodile clip was a bit deaf afterwards and was the first man unlucky enough to have to use the eyewash/chemical shower.:o

Why didn't the charger cut out at completion?

I tried a deeper discharge last night but hit 12.3v on a 125Ah battery after 22.5Ah so I curtailed the endeavor. This likely means my DOD figures are way off...which is exactly what I should expect from using battery voltage to indicate % charge. I'll recalculate where I'm at using specific gravity instead one of these days...as I should have in the beginning :rolleyes:
The TriMetric does display % charge calculated by cumulative/subtractive amps in/out but as I set this to an optimistic 125Ah I don't deem this accurate either.

More Numbers


18°C - 25°C

Bulk Charge

Moderate Cloud 09hr00: 2.0A
Cloud Edging 09hr45: 3.3A > 5.3A
Direct Sun 10hr25: 5.8A
Direct Sun 10hr45: 6.2A
Heavy Cloud 11hr00: 1.6A
Heavy Cloud 12hr05: 2.8A

Absorption Charge

Direct Sun 12hr40: 3.0A
Applied load (fridge) 12:40: 7.9A

Direct Sun 13hr30: 1.5A
with load: 7.6A

Direct Sun 15hr00: 500mA
with load 7.2A

Light cloud & edging 15hr45: 400mA
with load 4.8A > 6.8A

Direct Sun 16hr30: 300mA
with load: 6.5A

Direct Sun 18hr00: 200ma
with load 5.0A

Overcast 18:50: 200mA
with load 1.5A

Direct Sun 19:55: 200mA
with load 1.3A

No Float...mostly because I kept switching loads on/off all day

Approx. Generation: 22.5Ah
Potential Max Generation (very rough approximation from above figures): 60Ah

Had a look at my sticky skylights :eek:.
Silicone Paste is the business for this kind of problem. [re-post from Aidan's top tips]

• Stops rubbers from sticking & tearing.
• Prevents sun damage, weather stripping and flaking.
• Makes windows run like be-jaysus (apply in vertical channels) and therefore de-stresses electric window motors.
• Apply to O-rings to stop them twisting on installation.
• Safely lubricates brake caliper slides and pad slides (high temp resistant).
• Shuts up squeaky bushings.
• Doesn't harm metal, rubber or paint.
• Weather-resistant.

paddyp

Fast charger was an accident waiting to happen the battery was used to blow 300a fuses to configure sealed military spec gear someone overrode the timer as the battery lost capacity with age.

Voltage.as a measure of battery capacity is only possible on a rested battery depending on the rate of discharge it could take hours for the voltage to stabilise.

That silicone paste looks great I.was using small tubes of Dow corning stuff that costs a fortune.

paddyp

paddyp wrote: »

Fast charger was an accident waiting to happen the battery was used to blow 300a fuses to configure sealed military spec gear someone overrode the timer as the battery lost capacity with age.

Cowboys! :rolleyes:
Sher he won't do it again I suppose...

paddyp wrote: »

Voltage.as a measure of battery capacity is only possible on a rested battery depending on the rate of discharge it could take hours for the voltage to stabilise.

I had thought of that but even compensating 0.2v the numbers are still v. low. I was running 3Ah discharge, reading 12.2v loaded 12.3v after 30mins rest. I'm going to idle the system 24hrs and stick a hydrometer on the one cell I can get to. Need to know myself to set the Trimetric.

paddyp wrote: »

That silicone paste looks great I.was using small tubes of Dow corning stuff that costs a fortune.

Cost me more in postage than unit price. Well worth it though IMO.

Aidan_M_M

what temp will it go to?

The module? 85°C external.
20°C outside the module equates to 50°C behind the glass.

Efficiency reduction of -0.031A per °C after internal temp of 45°C

I got the module here. From Quentin Gargin who I later found out is quite the legend over in boards.ie renewables. His Ebay price is almost half his listed web-price.

Silicone paste works safely to 200°C

My VRLA sealed batteries aren't sealed any more . Bye bye warranty.

Battery Surgery.JPG

The 5watt solar charger has charged my "bad" battery up to 12.3v one week later...in this weather:rolleyes:.

Turns out none of the cells are bad. Not even considerably weak given that the battery was sitting flat for months. The electrolyte was below the plates on one cell and almost on a second.

I have the Tristar equalising it at the moment :eek:.

Agenda #1: does PWM recover lost capacity (good battery....also equalised :eek: is testing close to new).

Agenda #2: Can Elecsol Batteries be left depleted and not get damaged as the manufacturers claim (haha...I seriously doubt it).

I'm re-instating my bank :) and I'll see how they do for a while.

If I stop posting soon it might have something to do with hydrogen and cigarettes :pac:.

This is as far as I've got today.
Please let me know if anyone spots any glaring mistakes.

Battery #1 Status
Temperature 29°C
24 hours resting after full charge and watering followed by 4 hour equalisation charge.
Battery Voltage 13.0v


__________Specific Gravity_____S.G. @ 20°C_____Voltage
____________(± 0.010)______________________________
Cell #1________1.200____________1.202___________1.9v
Cell #2________1.230____________1.232___________2.2v
Cell #3________1.225____________1.227___________2.1v
Cell #4________1.200____________1.202___________2.2v
Cell #5________1.225____________1.227___________2.1v
Cell #6________1.210____________1.212___________2.4v

S/G at new 1.250 per cell (Elecsol just have to be different..)

Average Cell S.G. = 1.217
20% DOD

20% of 125Ah = 25Ah
Present Capacity = 100Ah

Battery #2 isn't looking so hopeful.
It's on it's second equalisation cycle now...5½ cells seems about right for what it is, from preliminary results. I ran out of photons to get it above 14.6v yesterday.
Probably not worth reinstating...hmmm...

paddyp

Sir Liamalot wrote: »

This is as far as I've got today.
Please let me know if anyone spots any glaring mistakes.

Battery #1 Status
Temperature 29°C
24 hours resting after full charge and watering followed by 4 hour equalisation charge.
Battery Voltage 13.0v


__________Specific Gravity_____S.G. @ 20°C_____Voltage
____________(± 0.010)______________________________
Cell #1________1.200____________1.202___________1.9v
Cell #2________1.230____________1.232___________2.2v
Cell #3________1.225____________1.227___________2.1v
Cell #4________1.200____________1.202___________2.2v
Cell #5________1.225____________1.227___________2.1v
Cell #6________1.210____________1.212___________2.4v

S/G at new 1.250 per cell (Elecsol just have to be different..)

Average Cell S.G. = 1.217
80% DOD

80% of 125Ah = 100Ah

Battery #2 isn't looking so hopeful.
It's on it's second equalisation cycle now...5½ cells seems about right for what it is, from preliminary results. I ran out of photons to get it above 14.6v yesterday.
Probably not worth reinstating...hmmm...

You can always put some epsom salt solution /edta into the dead cell if its sulfation it might limp along for another season. Still I'd scrap it and put the money towards new one.

paddyp

paddyp wrote: »

I'd scrap it and put the money towards new one.

I totally agree, I'm just experimenting really.
Everybody kills their first batteries not worth getting emotional about it.

Battery #2 Come out of equalisation a little better for wear albeit possibly only in the short term.


Temperature 21.5°C
13 hours resting after; full charge and watering followed by 3 hour aggressive charge, 10 hour rest, full charge, 4 hour equalisation charge.

Battery Voltage 12.8v


__________Specific Gravity @ 21.5°C_____Voltage

Cell #1________1.190____________________1.9v
Cell #2________1.205____________________2.1v
Cell #3________1.210____________________2.2v
Cell #4________1.200____________________2.1v
Cell #5________1.185____________________2.1v
Cell #6________1.210____________________2.2v



Average Cell S.G. = 1.2
30% DOD

70% of 125Ah = 87.5Ah

I found the cell voltage by metering protruding 6-inch nails I placed directly onto the plates in adjacent cells (plate and +ive battery post for the first one). This works great.
Zinc galvanised 6-inch screws however does not :eek: ...hmm...oops!

I'll make an update in a month or so and let yee know if either of these sick puppies have improved. I haven't decided to parallel them again yet. I'm wary of the detrimental effects the lesser will have on the stronger. Any thoughts?
I'm running on one this week because I haven't time to be dealing with explosions and such.
I may continue to do this and just swap them in the down time.

Re-instated and re-wired the bank today. Couldn't be bothered with the hydrometer but I will post comparative results in due time.
I've noticed definite improvement on the stronger battery (without giving Morningstar too much credit here I'm suspicious I ought to be reprimanding Halfords cheapo charger for an undercharging algorithm). I'd almost go so far as to say one battery on my current set-up is outperforming two at the end of my old (mains and alternator).
Bank is holding 12.9v after days charge.

I knocked 100mA off my ghost load by cleaning my battery terminals and terminal clamps. I thought the clamps were supposed to be grey because they were fully oxidised when I bought them. I was going to upgrade them for copper but seeing as it was a Sunday and I wasn't in the mood for a rip-off merchant, I just got the grinder out. Low and behold they're a shiney coppery/brass now and 0Ω.

I was getting 1Ω resistance across an inch of the clamp, this doesn't sound like a lot until you compare that to 0.3Ω from 20 metres of stranded 1.5mm copper cable. DC electrons travel across the surface area of the conductor so an oxidised surface is really killing it.

I know these numbers are very small but 100mA * 24 * 30 = dead battery at the end of a month without charge, before temperature induced loss and self-discharge.

I emailed Elecsol over a week ago requesting their recommended charge set-point voltages for their carbon fiber lead acids. They have not published this information anywhere I can find it. Nor can I find their charger algorithm set-points. No reply yet. :mad:

Morningstar on the other hand, you can email them a wiring diagram and they will get back to you in a few days with the pros and cons and practicalities.

Just to clarify something that's bothering me (and it's too late to edit my mistakes).
DOD means depth of discharge. I mistook this to be the inverse of what it is. I've corrected this from post #30 onwards (even though Paddyp has quoted me on the mistake :P).

This is the measure of percentage loss of a battery's capacity. I initially thought a battery at 80% capacity was 80% DOD. When in fact at 80% capacity it is 20% DOD.

Here's an idea I got indirectly from Morningstar that I have yet to implement, mostly because I thought I was going to soon be buying new batteries and I'm running low on 7mm cable. The Tristar controller has a 45A continuous rating (70A max for edging & spikes IIRC) I'm using ±9.5A from solar generation. If I was to link my alternator battery feed through the solar controller it will regulate the 14.7v (flooded battery set point) from the alternator to 14.4v (sealed battery set-point) for the leisure bank.

I wouldn't recommend this protocol on an automated relay charge set-up as it will always undercharge the starter. On a selective system this will work quite well.

[Edit:] Actually, second thought this could work on an automated system as second regulation is happening after the engine battery. This is not something I can speculate without measuring though. I wonder if there'd be back EMF issues? Might email Morningstar another diagram.

Any suggestions? Not looking in any particular direction Paddyp...{where's that innocent whistling smiley Peasant?...}

Ghost load is still 300mA.
Guess there was some ambient light when I checked 23hr00 - 00hr00.

Aidan_M_M

You're just a perfectionist!

Tehehe..depends on what I'm doing...three years later and still no curtains.

Wasn't relying on the clouds to charge the bank yesterday so I turned off the module and solar controller and stuck my mains charger on it. If I left the solar running it's piffle of amps at 14v it would fool the charger into thinking the batteries were charged, 'nuff said.

So low and behold my mains charger signs off on a charged bank and has a nice cup of tea. I check the Trimetric and see that it's 92% charged (92% of a 180Ah bank not 250Ah as the combined battery labels might indicate).

wrote:

Lead Acid Batteries and Undercharging.

Undercharging of the battery occurs when 107% to 115% of the removed ampere hours are not provided during the recharge. When not fully recharged, the residual lead sulphate remains on the positive and negative plates and eventually 'hardens'. With successive cycles of undercharging the layer of residual lead sulphate becomes thicker, the electrolyte specific gravity decreases, and the battery cycles down in capacity. In the 'hardened' condition, it may not be possible to convert the residual lead sulphate back into the original lead dioxide, sponge lead and sulphur acid active materials, even with higher voltage charging efforts. In this case the battery will suffer a permanent loss in capacity.

The Tristar frequently carries on charging a few hours beyond 100% at an increasingly reduced amperage.

The very fact that Halfords state that a 9Amp charger is suitable for a 200Ah battery (4.5% charge rate) should say it all really. Battery manufacturers recommend a 10%- 13% charge rate of the C20 Ah rating. Reasons like this are why I have such low esteem in battery charger manufacturer claims.
I will not be buying another mains charger unless it's temperature compensating, and programmable or the algorithm matches the battery manufacturer's guidelines exactly. No fixed algorithm charger (non-programmable) is "suitable for all battery types".

Have I convinced anyone to get a TriMetric yet? Will this help?

My ghost load shot up to 1.1a :mad:
Much tinkering ensued as them escaping electrons are mighty trixy.
The problem with parallel battery banks is that one might forget that after disconnecting one negative terminal the bank is still live. :eek:

So low and behold in my pursuit I started an electrical fire with a spanner (...ah that olde chestnut ). So while I rummaged for an insulator to retrieve my spanner which was shorting off the chassis from the positive leisure battery B terminal, it was getting hot and smokey. By the time I retrieved it, the electrons had blown one ground lead off the chassis, melted another ground link cable to the starter battery and snapped a battery clamp.

Expired clamp.JPG

So for future endeavors I invented this.

High tech anti explosion do-fer.jpg

Hmmm insulation ...easier than fusing it too (which was actually my first idea )


In any case after a wee bit of ventilation, cable repairage and isolation, I found the trixy electrons escaping from the shunt via the kelvin connections.

My ghost load is now 0A.

System idle; 200mA
Tristar solar controller always on; 100mA
Trimetric battery monitor, mostly always on; 100mA

I started powering my fridge on photons, alternator and combined on the 12volt element, having never used it on 12v before.
The problem here is the engine battery isn't connected to the shunt (and that's unlikely to change soon) so the TriMetric tends to get befuddled from alternator charge as the electrons are skipping the turnstile and overestimates the used capacity. hmmm...maybe time to install an ammeter in the dash. In any case it self-resets when it detects a fully charged battery and in the short-term I just watch the volts instead.

Solar can power the fridge at about a 3A shortfall which works ok every second day to save the gas. How and ever my fridge has a 100watt element;
100wats /12.4 volts = 8A.

The TriMetric tells me it's running @ 9.2A @ > 13v.

Voltage drop methinks...there's 1.2A being used to heat cable back there. That'd be the 1.5mm cores I thought'll be grand a few years back then. So that's getting pulled out for 4mm then (2.5mm would be adequate on a run under 9metres but I'm a pedant when it comes to cable).

I read a suggestion which I think might be interesting to investigate. Which is that a 3-way absorption fridge works much better set to mains and powered off an inverter (modulated / RMS / pure sine wave...doesn't matter; it's a resistive element) than the 12volt setting as at 230V voltage drop is not an issue and the mains element has a thermostat. ...the thick plottens... once I have it asunder I'll see what the power consumption comparison is (+20% give or take I'm guessing...(inverter conversion loss and a 5watt stronger element) ...although not an issue with a large enough alternator).

Fridge Vent Fans;
Wonderful things! Fridge is way more efficient above 20°C with them running, for a humble 300mA (two fans).
Unfortunately my fans were 12volt. My nominal system voltage is now 13v, and usually 14v+ when I need them.
They have expired after putting up a good fight. I reckon I burnt the motor coils to bejaysus as at the end of their days I could hear them over-revving. It may just be a fried switch too but I've decided if I'm going in there then I might as well overhaul the lot (back of my fridge has access issues, if i knew when I was installing it what I know now then...ah..well...:rolleyes:).

I'm not a whole lot of upset about this because they were due and upgrade for brushless versions (quiet).

I had a notion of dual wiring them as generators (mmm permanent magnet motors:D) off the driving wind-speed with vent scoops but have abandoned the notion as a feeble return on investment and libelous over-engineering.

That just leaves me with the problem of running 12volt fans with a high voltage tolerance inexpensively on a 14volt variable system. Which I think I can solve simply with a strategic resistor.

Or running 24volt fans with a low tolerance at a significant reduction of torque.

There is a third option which is a Master Consumer Voltage Regulator,
Other versions of same.

I'm reluctant to fork out for one of these though because a resistor is only €0.50:D and even though that's a quality product it's peak efficiency is 85%. Now after that my laptop charger is 80% efficient and everything else I run is regulated locally or easily replaced I'm disinclined to waste electrons on conformity without another 100Ah in the bank to support it, when I can just keep things exciting and working more "effectively" with a bittov me where-with-alls :rolleyes:.

Brushless Fans ; "4 of them please", they'll pay for themselves in the gas I save. 2 for the intake vent, 2 for the outlet vent.

4 fans in parallel = 640mA

Charging temperature compensation at 10°C = +0.27v
(fans not needed below 10°C)

Max System voltage = 14.4v + 0.27v temp. compensated = 14.67v (haha I'll regret this when I get flooded batteries)
Max Fan input = 13.8v

Min Fan input = 10.2v
Min System = 12.0v

Voltage = Current * Resistance
V=IR
V/I = R

I= 0.64A
V= 0.87v (required reduction for fan tolerance)

0.87v/0.64a = 1.36Ω

1.5Ω Resistor (nearest size available)
0.64a * 1.5Ω = 0.96V

System Max - voltage impedance = 14.67v- 0.96v = 13.7v
System Min - voltage impedance = 12.0v - 0.96v = 11.04v

-> DC System supply range with resistor = 13.7v -> 11.04v
-> Fan motor tolerance = 13.8v -> 10.2v



I²R = (0.64A)²(1.5Ω)= 0.61W


"an' a 0.6W 1.5Ω resistor. Cheers "

series resistor before parallel fans, Bob's yer Uncle!...I hope.

paddyp

"4 fans in parallel = 640mA"

What size fans did you get? 40mm? Thats an awful lot of noise and not an awful lof of air moving.

A 120mm silent design could move 9 time as much air with 4 times less noise at a similar current.

I reckoned brushless would be silent
Haven't bought them yet 4 x 120mm I'm thinking (that link just piles them all together, nothing I can do about that).
I'm comparing this to the former 2 x 80mm on the inlet vent only, giving me the same refrigeration abilities on one flame littler setting.

You think 4 x 35dB is noisy?

I'll have another look around and see what I find. It's taken two days so far to figure this much out. I've been looking at all sorts of madness like zener diode regulation, potentiometers (still thinking about that one), stepper motor fans as switchable generators, 24v set-up, etc.

Simple is often best.

Damn hard find decent fans with wide tolerences 'tis.

Ah cheap chineese kit
6 for the price of
¼ Quality made ones
tehehe...guess which ones I bought!

Sir Liamalot

Sir Liamalot wrote: »

I'm a pedant when it comes to cable

paddyp

The 120mm maplin ones are 380mA, 42dba four of which would be nearly 47dba skip to the end of this to hear what that might sound like unthrottled.#

http://www.youtube.com/watch?v=k5Y7S09sCKU

To be honest trying to push 4000 + liters per minute through there may cool the hot side or blow out the flame. a single fan with some kind of ducting to direct the flow through the coil may be more effective.

Tehehe wrong page Paddy I took your advice already .
And yup I was looking at the wrong spec myself!

The cheapy Chinese fans are ~22dBa (according to the manufacturer) and less than half the RPM.

Calculated load of 4 x Xinruilian fans is 720mA, which is kindov high but will hopefully complement the solar as I need them most when the sun's out so I'm not to worried about meeting the demand. In any case those fans were so cheap if they don't work and I have to get better ones then it's no big deal.

I'm putting a 50°C thermostatically controlled NC switch on the upper condenser heat sink on the far side from the gas exhaust to automate the fan control.

I've considered the possibility of inadvertently tampering with the flame and if I can't baffle it I'll just put two fans horizontally between the heat sinks blowing up and two on the outlet blowing out.

Also I'll be putting a thermostat bypass (off) on the old switch and a potentiometer for motor control (I can hear you tsk tsking already ). I know it's horribly inefficient but it's a 5Ω 100watt wire wound beast that'll happily take the heat. According to my calculations 5Ω shouldn't be enough to stall the motors because if I (hopefully) can't hear them I won't know if I am burning the rotor coils.


I spent a day trying to get my head around this;



Link here post #3


But given that I also need to regulate the input or it won't work and that I haven't much of a clue about electronics I had to resort to KISS (keep it simple stupid).


Incidentally I found this if anyone is interested;
Automatic temperature controlled fan speed regulator with 2 x fans + remote. <- that's either switch mode or PWM so it should be quiet and efficient.
Thought about buying it myself but the thermostatic switch was only €2 ...hard win 'em all.

paddyp

sure go the whole hog --

http://www.ebay.co.uk/itm/5-25-4-Channel-PC-Fan-Speed-Temperature-Controller-Manually-LCD-Front-Panel-/271271941250?pt=LH_DefaultDomain_0&hash=item3f29115482

You may need a 5 reg as it runs from standard drive connector.

paddyp

oooh, I dunno I think it might lower my street cred.; having something that cool and sophisticated lookin' for the sake of a few grams of propane.
It's way cheaper than the one's I was looking at before and I love that it has temp. readings.

Thanks but I think I'll pass, I'm looking for a fire and forget solution for this.

paddyp wrote: »

You may need a 5 reg as it runs from standard drive connector.

Do you mean a regulated 5VDC line for a Molex connector? (that took some googling...).
Easy enough to butcher a car USB charger for that.