Recommendations for 100w Solar Panel

huddlejonny

As the title suggests I am looking at buying a 100w Solar Panel.

Could anyone point me in the right direction?

I have been looking at this on Amazon but I am wondering if it is good enough for the job. I would be looking to keep 1 x leisure battery topped up.

https://www.amazon.co.uk/d/Electronics-Photo/Photonic-Universe-monocrystalline-controller-overcharge/B00S1H81L4/ref=sr_1_3?ie=UTF8&qid=1487685504&sr=8-3&keywords=motorhome+solar+panel+kit

Any help appreciated.

spaceHopper

When you say topped up do you mean to charge it while you are way or keep it from going flat while parked up at home?
How big is the battery in AH and how much power will you use. How long will you be away for or between trips.

100 W(17V panel ) x 50% efficency x 8 hours of sunlight = 23.5 AH so it will charge a battery in about 3 to 4 days.

For your money you may be better off with a good battery charger at home and adding second battery if you have space.

If you want to stop a battery from going flat between trips a 10 to 20 W pannel might do.

crabbypaddy

That one on amazon doesn't ship to ireland, you'd have to use parcel wizard / parcel motel and may be an oversize charge on it.

Controller looks like a rebadged epsolar ls1024b which should actually be ok they are about €20 from china.

I paid £103 for a 140w polycrystalline panel delivered to my door in Cork from this guy, careful if ordering as some of the listings have ireland as £20 shipping and some as £10:
http://www.ebay.co.uk/sch/friendly-green-giant/m.html?_nkw=&_armrs=1&_ipg=&_from=

No point in buying anything less than 25w in ireland even for trickle charging.

I'd go for solar before anything else. I use my mains battery charger maybe 10 times a year. It's cheaper to run solar and way more convenient if you live in a city and can't run cables. Plus the right solar controller, does a far superior job of charging a battery than a mains charger.

PV pays for itself by offsetting extortionate campsite lecky costs.
In reduced battery replacement costs.
Reduced engine wear if used just for the alternator.
Better fuel efficiency (less alternator load).
Power on demand, no battery cycling.
No drain on house lecky running chargers inefficiently at minimal load.
Save yourself the price of a fridge every 5 months by switching to electric instead of gas...and enjoy the benefits of an automatic thermostat.


It's not just the replacement battery cost that is a nuisance, it's the diminishing returns and the annoying journey to the threshold of usefulness before replacing it. ie. using a 100Ah rated battery that holds 75Ah and self-discharges but isn't worth replacing quite yet because it's still serviceable.

Personally I can't see the sense in buying a second battery that will last 3-5 years when you can get PV that will last 30+

As regards what panel to get I honestly believe it doesn't matter I've never had an issue with any of them. As long as it's €1.20 per watt or lower it's as good a deal as you'll find.
Depending on what you want to run 50W to 350W will cover most requirements.

Space your calculation is a mite simplified but not terribly off the mark. For one thing the 50% efficient thing quoted is 50% reduced input compared to optimal angle all year round. Given most campers don't need power in the Winter we could use the 20% figure given the higher solar azimuth in the Summer.

I prefer the 3.5x / 7x formula myself I'd found to fairly accurate (instead of factoring temperature, angle of incidence, system losses, battery losses, input...etc) which means on average from mid Spring to late Autumn 100W will produce 350Wh to 700Wh or 27Ah to 54Ah.

spaceHopper

Sir Liamalot wrote: »

Space your calculation is a mite simplified but not terribly off the mark. For one thing the 50% efficient thing quoted is 50% reduced input compared to optimal angle all year round. Given most campers don't need power in the Winter we could use the 20% figure given the higher solar azimuth in the Summer.

I prefer the 3.5x / 7x formula myself I'd found to fairly accurate (instead of factoring temperature, angle of incidence, system losses, battery losses, input...etc) which means on average from mid Spring to late Autumn 100W will produce 350Wh to 700Wh or 27Ah to 54Ah.

I konw was jus trying to get across that you have to know why you want solar and what it's limitations are.

huddlejonny

spaceHopper wrote: »

When you say topped up do you mean to charge it while you are way or keep it from going flat while parked up at home?
How big is the battery in AH and how much power will you use. How long will you be away for or between trips.

100 W(17V panel ) x 50% efficency x 8 hours of sunlight = 23.5 AH so it will charge a battery in about 3 to 4 days.

For your money you may be better off with a good battery charger at home and adding second battery if you have space.

If you want to stop a battery from going flat between trips a 10 to 20 W pannel might do.

When at home we usually have the van charging 1-2 days a week.

Bought a new 110ah Halfords leisure battery last summer but on weekends away ( off-grid ) it drained very quickly. So much so that we had to turn on the engine to top up the leisure battery.

There is something in the background drawing off the leisure battery when the van is idle and so I have the van booked in with an auto-electrician type who also fits solar panels.

While the van is in for repair I thought I might as well get the solar panel installed as well and hopefully have enough power between 1 x 110ah leisure battery and 100w solar panel to keep us ticking over for 2-3 days.

The leisure battery would mainly be used for lights at night and the odd bit of tv, maybe 1 hour a day. Our fridge and heating run off gas. I don't know how much this would draw from the leisure battery but I would hope it is minimal.

crabbypaddy

huddlejonny wrote: »

When at home we usually have the van charging 1-2 days a week.

Bought a new 110ah Halfords leisure battery last summer but on weekends away ( off-grid ) it drained very quickly. So much so that we had to turn on the engine to top up the leisure battery.

There is something in the background drawing off the leisure battery when the van is idle and so I have the van booked in with an auto-electrician type who also fits solar panels.

While the van is in for repair I thought I might as well get the solar panel installed as well and hopefully have enough power between 1 x 110ah leisure battery and 100w solar panel to keep us ticking over for 2-3 days.

The leisure battery would mainly be used for lights at night and the odd bit of tv, maybe 1 hour a day. Our fridge and heating run off gas. I don't know how much this would draw from the leisure battery but I would hope it is minimal.

Change the lights to led for a start, is the tv running off an inverter?

spaceHopper

spaceHopper wrote: »

I konw was jus trying to get across that you have to know why you want solar and what it's limitations are.

Sun's gonna last another 5 billion years give or take.

huddlejonny wrote: »

There is something in the background drawing off the leisure battery when the van is idle

huddlejonny wrote: »

I don't know how much this would draw from the leisure battery but I would hope it is minimal.

Both those problems could be addressed with a zero centre ammeter.

huddlejonny

Just a quick update on this, I have gone for a 150W solar panel and dual controller.

https://www.amazon.co.uk/d/Electronics-Photo/Photonic-Universe-monocrystalline-charging-automatic-controller-overcharge/B00S1H89SY/ref=sr_1_11?ie=UTF8&qid=1490006385&sr=8-11&keywords=150W+SOLAR+PANEL

The solar panel has 5 metres of cabling attached, just wondering what type of lead should I be getting to attach the charge controller to the leisure battery?

crabbypaddy

huddlejonny wrote: »

The solar panel has 5 metres of cabling attached, just wondering what type of lead should I be getting to attach the charge controller to the leisure battery?

Depends on the length of the cable run. Ideally keep the cables as short as possible to reduce losses. Looks like an epsolar controller the terminals on those controllers only accept 4mm2 cable which is fine a for a run of a few feet. You could fit 6mm2 with a yellow pin crimp.

+



I fit panel->isolator (can be a fuse, >15A DC Switch, PV Switch-Disconnect or DC MCB) -> solar controller -> (DC MCB/Fuse -> Battery) x 2.

Always turn solar off first before controller and controller on first before solar to keep all your magic smoke inside the controller.

My 45A solar controller accepts 150A cables...that's some commendable product design.

huddlejonny

crabbypaddy wrote: »

Depends on the length of the cable run. Ideally keep the cables as short as possible to reduce losses. Looks like an epsolar controller the terminals on those controllers only accept 4mm2 cable which is fine a for a run of a few feet. You could fit 6mm2 with a yellow pin crimp.

There is 5 metres of 4mm2 cable attached to the panel, presuming I have enough cable would it be possible to take some excess off the end of that cable and run it from the solar charger to the leisure battery? Alternatively is there anywhere in Ireland where I can pick up that particular cable?

crabbypaddy

huddlejonny wrote: »

There is 5 metres of 4mm2 cable attached to the panel, presuming I have enough cable would it be possible to take some excess off the end of that cable and run it from the solar charger to the leisure battery? Alternatively is there anywhere in Ireland where I can pick up that particular cable?

I doubt its 4mm2 I would suspect its 12awg which is about 2mm2. If the controller is close to the battery it would do.

At 10A 2mm2 tinned copper will drop something like 0.1V per meter of cable.

Its not that critical on the panel side with the lengths you'd usually have in a camper. On the battery side however it can be significant as the current increases the voltage drops at the battery so the battery may not accept the full current available - The longer the cables the larger the cable required.

Any electrical place will have 4mm2 cable a lot of the diy places would have 4mm2 earth wire you could use.
Don't forget a fuse near the battery http://www.halfords.ie/webapp/wcs/stores/servlet/SearchCmd?srch=fuse+holder&action=search&storeId=11101&catalogId=15551

Yellow crimp spades and ring terminals will fit 4mm2 cable.

crabbypaddy

MC4 connectors are probably what you are after but feel free to cut the ends off and butt crimp (with a ratcheting crimper) on any 4mm² stranded flex cable to make ends meet. You only need TUV for UV protection.

Traditionally the terminations are 1m from the panel so you can disconnect it locally.

Decent auto-electric suppliers will have thin wall 4mm², if you want to go the spendy route a chandlers will have marine tinned. Easy get solar flex on ebay and large electrical wholesalers will have single core stranded.

crabbypaddy wrote: »

I doubt its 4mm2 I would suspect its 12awg which is about 2mm2.

4mm² is standard min for PV. MC4s don't seal around thinner.

crabbypaddy wrote: »

Any electrical place will have 4mm2 cable a lot of the diy places would have 4mm2 earth wire you could use.

I wouldn't recommend earth cable, the strands aren't fine enough and it's too rigid to work. Doesn't crimp or terminate well & work hardens.

Halfords are an expensive choice. Besides it's an 8mm² cable rated 45A and holds a 100A fuse. :rolleyes:
So much vehicle electrics are regulated by user lack of imagination...:(



(not my drawing..circuit protection illustration purposes, you can ignore all the chassis grounds except the batteries)

crabbypaddy

Sir Liamalot wrote: »

4mm² is standard min for PV. MC4s don't seal around thinner.

I wouldn't recommend earth cable, the strands aren't fine enough and it's too rigid to work. Doesn't crimp or terminate well & work hardens.

The photonic universe crowd were using 2 or 2.5mm on the 100w panels on ebay when I was looking at them last year. Probably same outer diameter and tons of insulation like the chinese jump leads.

The earth wire hardens like feck alright but it does the job if you live in the sticks like I used to. For my main battery cable I had a bundle of 6mm earth wires in scavenged corrugated conduit soldered into DIY lugs made from off cuts of 10mm copper gas pipe flattened and drilled .. ghetto but low resistance.


@huddlejohnny

If you're in Cork theres a place out by MCK electrical in the togher industrial estate called OS Distributors that has everything you could want in terms of cable, fuses and crimps. I tried ever motorfactor in Cork for mega fuses and heavy cable until eventually Tadhg Hawe told me about the place.

jace_da_face

Has anybody tried flexible solar panels? Something like this?

https://www.amazon.com/dp/B01DXYNGA0?psc=1

I would imagine these could be mounted without drilling holes on your roof.

crabbypaddy

jace_da_face wrote: »

Has anybody tried flexible solar panels? Something like this?

https://www.amazon.com/dp/B01DXYNGA0?psc=1

I would imagine these could be mounted without drilling holes on your roof.

Higher cost per watt and I can't see any benefit to the flexible panels on the roof of a camper. The rigid panels can be mounted without drilling, you still need to drill for the cables.

huddlejonny

@huddlejohnny

If you're in Cork theres a place out by MCK electrical in the togher industrial estate called OS Distributors that has everything you could want in terms of cable, fuses and crimps. I tried ever motorfactor in Cork for mega fuses and heavy cable until eventually Tadhg Hawe told me about the place.[/QUOTE]

I have heard of them Paddy, many thanks, will check them out.

jace_da_face

crabbypaddy wrote: »

Higher cost per watt and I can't see any benefit to the flexible panels on the roof of a camper. The rigid panels can be mounted without drilling, you still need to drill for the cables.

As in, just glue the mounts to the roof? Would these panels be flush with the roof or would there be a gap that could create air lift in windy conditions or when on the move?

JonMac

My problem is the algae growth under the fixed panel. I can't get it clean.

huddlejonny

JonMac wrote: »

My problem is the algae growth under the fixed panel. I can't get it clean.

Algae & moss remover diluted in a trigger spray bottle should do the trick.

crabbypaddy

crabbypaddy wrote: »

The photonic universe crowd were using 2 or 2.5mm on the 100w panels on ebay when I was looking at them last year. Probably same outer diameter and tons of insulation like the chinese jump leads.

Not just the Chinese who insinuate instantaneous loads are the same as continuous.

Photonic Universe wrote:

2x5m of high quality single core solar cable 4.0mm cross section

crabbypaddy wrote: »

.. ghetto but low resistance.

crabbypaddy wrote: »

@huddlejohnny

If you're in Cork...

Demesne in Tallaght will have all you need too.

jace_da_face

jace_da_face wrote: »

Has anybody tried flexible solar panels? Something like this?

Eh yeah I fit them on boats. Peel and stick onto polycarbonate. Works grand for neutral orientation on a moving foundation.

I don't recommend them for campers, more expensive and less output.
Due to the lack of a rear-side air gap they derate faster as the van roof heat sinks them.

My panel is on a roof rack. No holes and tilt adjustable with storage underneath.

crabbypaddy

Sir Liamalot wrote: »

Quote:
Originally Posted by Photonic Universe
2x5m of high quality single core solar cable 4.0mm cross section

Ah I didn't see the specifications tab on their site.

The 40-100w panels are 2.5mm and the 120w-280w panels are 4mm.

@huddlejohnny did you make any progress?

jace_da_face

Well if cost and output is an issue, it looks like rigid is the better choice.

huddlejonny

crabbypaddy wrote: »

Ah I didn't see the specifications tab on their site.

The 40-100w panels are 2.5mm and the 120w-280w panels are 4mm.

@huddlejohnny did you make any progress?

I am waiting on delivery of the following items

1 x 150w photonic universe panel inc 5m solar cable
1 x Dual Charge controller................€190

1 x Soudal Adhesive................€8

6pcs Mounting brackets + entry gland ... €29

1 x Fuse blade holder................€2

4 x MC4 Connectors.................€5

1 x LED Voltameter..................... €1.90

Total spent so far approx €235.00

I debated about getting a second leisure battery and decided against it due to wiring & space restrictions. The leisure battery i have is under the passenger seat and it's a bitch to get at.

All the items above were bought on Amazon, slightly cheaper too if you go through Flubit.

huddlejonny

huddlejonny wrote: »

1 x LED Voltameter..................... €1.90

Any links?

My 150Wp flat mounted today, is powering this post with watts to spare.
Everything is fully charged I've been touring 17 days. Last plugged in 6 weeks ago. :cool:

huddlejonny

Sir Liamalot wrote: »

Any links?

My 150Wp flat mounted today, is powering this post with watts to spare.
Everything is fully charged I've been touring 17 days. Last plugged in 6 weeks ago. :cool:

https://www.amazon.co.uk/gp/aw/d/B008KY5ULW/ref=ya_st_dp_summary

Broke the bank with this one!!

Amazon

That voltmeter might not be as useful as you'd hoped.

Blue is quite hard to read in daylight and blue beside red makes your eyeballs go 3d vision and hard to focus..at least they do mine.

Amazon wrote:

Allowable error: 1% (+ /-1)

This means ± 0.12V ( plus or minus least significant digit) so if your voltmeter displays 12.4V (70% SOC at rest) your battery could be either 12.3V (60% SOC at rest) or 12.5V (80% SOC at rest).
Say you only use 50% of your battery as is normal accepted practice then this 20% disparity is amplified to 40% inaccuracy over operational range when using it as a state of charge meter.

Compounded by the fact solar means your battery is never at rest it's an altogether inaccurate way to measure capacity and merely the first third of the equation being pressure x rate x time = available power (Volts x amps x time). The other two missing ingredients are current (rate) and time (duration).

When you can read amps also, you see the current of your base load parasitics, your running appliances, your charge rate from PV and alternator and you can far more accurately dead reckon amp hours. Adding a ~250A shunted ammeter is a very inexpensive step to managing your available power. With both voltage and current you can see the watts in and out of the battery.
For calculated capacity over time or state of charge more sophisticated metering is required which start at the >€100 range. These are called battery monitors, while I recommend them as a precursor to any other electrical modification I don't think anyone has heeded me on that one. I think they are invaluable and worth the money..

To get the most outtov your voltmeter wire it through a switch on it's own dedicated conductor pair fused at the battery on the positive on 2 core 1.5mm² with a 100mA fuse.

If it has a trimmer you can adjust this with a plastic tool using a reference multimeter with better accuracy to calibrate the voltmeter to the same values. I find 1 in 2 cheap and cheerful Chinese jobs acceptably accurate after adjusting this.




Also available in these flavours;



I also find that switching supplies including ones integrated in LED MR16 lamps drive the Chinese Voltmeters crackt and they can be another volt or two out when the switching supply/light is running.

In any case I'd use a digital multimeter in the van for a few days to verify the fidelity of any cheap meter I install across it's operational range. Then I file it in the art basket if it's not up to tolerance, for a primary meter I deem that 0.3% accuracy @ 12V.

huddlejonny

Sir Liamalot wrote: »

That voltmeter might not be as useful as you'd hoped.

I have to say Liam your posts are very educational and interesting but quite honestly I don't have a clue what you mean by half of it..lol..

I'm learning though:)

William Thompson, Lord Kelvin

Maybe Bob can explain it better (and grumpier).

William Thompson, Lord Kelvin wrote:

If you can't measure it you can't improve it.

killalanerr

Have you anything to add to this one @Sir Liamalot , I have decided that the prices have reached the point that a 100w panel is now worth the investment , probably have been for quite a while now !!

100W panels are pretty expensive for what you get.

I use 300Watters + MPPT these days.

killalanerr

Yes I have been following your solar journey ,for starters we would not have the space for a 300 watter ,we are just tourists so really just hoping to extend the life of the batteries at avoid site fees , for around €200 a simple 100w set up seems like the way to go ?

100W is probably the minimum useful size for that, definitely lower than 80W is pointless and gets proportionately more expensive the smaller you go.

MorningStar make very good charge controllers that will actually maintain a battery properly. The cheaper ones not so much, they all produce similar output but it's the regulation, long term reliability and battery longevity yer paying for at the top.

Stay away from flexible solar unless you want to replace them every 5 years. They're not UV stable. They go yellow and die.