Batteries for home solar/wind system

jomag45

Hi,

Where can I get batteries in Ireland suitable for a home solar PV/wind generating system. I currently use standard high capacity car batteries, but these are not suitable as they cannot be discharged fully and expected to maintain their life. (In fact after using them for over a year, they are failing to hold any decent charge now). I'm looking for deep-cycle batteries, perferably the sealed gel type, as I don't want to do any maintenance on them. The total capacity should be in the order of 400Ah. I'm happy to start small and build the battery bank over time, so I don't need individual batteries with large capacities.

Any pointers appreciated.

Thanks,

Belfast

My Grandfather had a wind turbine on his house back in the 1930s charging car batterys and supplying power to the house before the rural rural electrification came in. He had a socket and a light bulb in very room in the house.
All sound very back to the future to me. Cool.

http://www.affordable-solar.com/surrette.battery.2v.1700.ah.2-ks-33ps.htm

http://www.affordable-solar.com/solar.batteries.htm

in the UK
http://www.barden-uk.com/renewable-energy-batteries.html

Belfast

"How to build a wind turbine"
Workshop course
with Hugh Piggott
Crann Og, Gort, Co Galway, 8th - 13th September 2008
http://eirbyte.com/gort/

doubledecker

You can get deep cycle batteries through marine stores, at least 200 Euro for a 100 amp hour. Thou also saw in Halfords, in Cork a deep cycle 70amp hour for 135 Euro.........

Belfast

This one seems cheaper

http://www.barden-ukshop.com/rb24ht80-911-p.asp
RB/24HT80

Rolls Deep Cycle 12V 80Ah Battery

Our Price: £119.66

jobrok1

Belfast wrote: »

This one seems cheaper

http://www.barden-ukshop.com/rb24ht80-911-p.asp
RB/24HT80

Rolls Deep Cycle 12V 80Ah Battery

Our Price: £119.66

It may seem cheaper!

But it isn't...

derry

Your making the typical mistake that every non tecky person makes when it comes to lead acid batteries be they car type or deep cycle

If you deep cycle a typical car battery 10 to 20 times that will destroy it with whats called sulfation of the plates


If you deep cycle a typical deep cycle battery 100 to 200 times that will destroy it with whats called sulfation of the plates

Now if we take 10% out of a car battery and then recharge it we can expect a ~1000 cycle life

Now if we take 10% out of a deep cyle battery and then recharge it we can expect a ~1000 cycle life


Now we can see that 100 cycles is to low a life time to accept

However to get 1000 cycle life we need ten times as many batteries so we are back to square one roughly

Its when we compare the 20% to 50% discharge capasity of the battery we miight find a suitable ratio that suits the budget

We can expect ~500 cycle life for a deep cycle if we always deep cycle it 50%

We might get ~1000 cycles from a deep cycle if we discharge it 20%

If you go to most good solar power battery sites they will suggest to only take 10% of the capasity out from the batteries deep cycle type lead acid

Now lots of the guys figure that well the car battery is often half the price and can do 10% often just as well so they opt to use car batteries
How that works out I don't know

Really the problem is in terms of power 100KG of battery equals ~1Kgs of petrol

That shows that if 1KG (~1 liter) of fuel costs 1.50 euro and 100 kgs of battery costs probably 2000 euro we start to see battery power is very very expensive
Also it very fragile can short circuit and be wrecked and requires lots of specialist knowlege to use properly lots of maintance and TLC and requires deeeeep pockets

Really if you are going to do batteries then buy a bucket load of them direct from China or USA and save 50% of the cost as even with shipping cost equal to the cost of the batteries ( lead is really heavy crap ) and import tax it will still be much cheaper than buying from local rip off battery suppliers here

When I was in Spain I could buy a 60 Amp car battery in the Carrefour supermarket for 30 euros
Here often it s 120 euros and best prices are maybe 60 euros if you scour Ireland

The deep cycle are even more mad money

It probably still cheaper to go to Spain buy the batteries and ship them out from Spain than buy them here
or even go online and source them from Germany Holland Spain France Italy

Forget the UK they are another rip off SOB


But no matter what price those bandits in ESB charges it still wicked cheap compared to storing power in batteries

Thats why wind and solar power try to hook into the local electric power stations grid
They put power into the elctric grid and gain units and when wind or solar is low they draw the power back from the grid and hopefully they use less than they take out


The only way batteries can be made to half way economic is to try to get hold of the big huge batteries they use in the telecom exchanges

These are huge big banks of these big batteries they use to cover the power failure from ESB and can run the telephone network for several days if the power goes down that long

These are 1/2 ton batteries each one with two volts so you need 6 of them
Even though it big money to get each battery they seem to last for ten years and don't seem to break so easy like the small batteries

Might be able to get them second hand
I think telcoms opertors replace them every 8 years so there is still a fe years left in it

I think they are built from type glass so its bad story if one of them cracks as they got gallons of acid

Might also be issue to have a chemical polution certificate to own and store them in a normal house

But years later they would still be working when you sitting in front of the computer listining to sob stories from other guys why thier 10 batteries of deep cycle all clapped out so soon

sorry lead acid is so fragile and so expensive but the deep cycle sales rep will promise you the sun the moon and the stars and then sub section 5 cluase 3 is the reason why there is no refunds for faulty batteries

good luck with your choises

Derry

jomag45

ok, I understand that the level of discharge of the battery determines how many cycles you get before sulfation of the places occurs.

And so increasing the number of batteries for a given load will reduce the amount of discharge.

But which is better: buy less batteries and take the lower number of cycles replacing the batteries more often, or buy more batteries, and get more cycles. I can't figure out what I should go for.

I've had a look around at the Trojan batteries. They seem to be a leader in the field. The prices are astronomical though, especially for the hobbyist. 2-300 euro a pop (from an Irish distributor). A lot cheaper in France as you suggest - but when shipping costs are added for very heavy items, would I really save?

I don't expect to save any money by generating my own electricity. But I'd like to minimise the costs as much as possible.

Thanks for the detailed responses.

derry

For a hobbiest wishing to get longest life cycle ratio the more batteries the better
For a hobbiest wishing to get cheapest cost the less batteries the better

catch 22
very hard to figure the facts without info on the input power from wind and solar

Often shipping costs from France are a lot less than from rip off UK

However if the batteries are in the north of Ireland then driving up and collectting them might be cheaper

Swings and roundabouts

I would just go aound to every car and truck place dumping old batteries and collect as many as you can for free or low costs

When some dont work or some wear out there is no dumping costs as dumps dont charge for batteries

Once you have lots of cheap batteries you can learn how to service them and you can be suprised how many fairly new batteries are dumped

Best sources of info for battery service solutions are the old fashoned ships radio training manuals which needed to service these batterries to send out SOS signals

Then with fact a few years later you can estimate the best solution better


My guess if the wind system is good and proves itself over a few years then going as foot passenger with suitable push cart or bike trailers to carry bateries off the ship or small car to France and buying a whack of the good batteries and comming back would still save you thosands compared to buying in Irealnd

Good quality batterris properly serviced can last sometimes 4 plus years


Also in a few years we might start to see carbon foam lead acid SLA AGB batteries for a good price and being much lighter could be much cheaper to ship than wet lead acid types

How many amps peak and average do you get from the wind power and from the solar power whats the peak and the average???

Derry

jomag45

Wind (Marlec Furlmatic 910-3)
Peak: 8A
Average: 3A

Solar (80W panel)
Peak: 6A
Average: 2A

So you see, I've a small scale operation. I use it to power my office computer and some outside lights. I'm not expecting to save money, but batteries are the pain point at the moment.

parsi

jomag45 wrote: »

Wind (Marlec Furlmatic 910-3)
Peak: 8A
Average: 3A

Solar (80W panel)
Peak: 6A
Average: 2A

So you see, I've a small scale operation. I use it to power my office computer and some outside lights. I'm not expecting to save money, but batteries are the pain point at the moment.

Hoppecke do a range for solar panels I think. They should be fairly widely available.

derry

jomag45 wrote: »

Wind (Marlec Furlmatic 910-3)
Peak: 8A
Average: 3A

Solar (80W panel)
Peak: 6A
Average: 2A

So you see, I've a small scale operation. I use it to power my office computer and some outside lights. I'm not expecting to save money, but batteries are the pain point at the moment.

Respectable amounts of power for the equipment you have

Ireland is the second most windy country in the world after Malvinas Islas
( Faulklands Isalnds for Brit types ) so the most potensial to get power for the best price for power seems to be wind with repayments fully cleared in three years everage

Solar expensive as it is it is still factored to repay itself in the Irish climate after 10 years which is on power with many other viable alternitive power sources such as solar water heaters

I would personnaly just opt for going to suitable junk yards and getting a whole stack of batteries cheap or for free and aim for 30% are useble for two years

Try Gumtree.ie or Adverts.ie or Jumbletown.ie asking for old useable scrap bateries in the freebee section where people are throwing out stuff

Then get all the stuff for servicing batteries like acid and pure water and hydrometers and big chargers with high amps

A blast from a high amp charger can rescue a weak battery and kick off the sulfates from lead plates


Also consider to get friendly with truck fleets or fork lift operators and try to get their batteries

Its no harm to have these power sources in case of bad weather or stirkes chops of the ESB power source

I have a few car batteries I get from places for free as useless for car use and most last a few years on low useage they will power me for days


i can rechage my umteen packs nicads from them in 20 minutes
my many NiMH in 45 minutes
and my lipos in 1 hour or some in 30 minutes

So I can run lots of lights in a power cut senario or fly my radio control electric model planes if the ESB is working properly


Derry

derekohara

derry wrote: »

Respectable amounts of power for the equipment you have

Ireland is the second most windy country in the world after Malvinas Islas
( Faulklands Isalnds for Brit types ) so the most potensial to get power for the best price for power seems to be wind with repayments fully cleared in three years everage

Solar expensive as it is it is still factored to repay itself in the Irish climate after 10 years which is on power with many other viable alternitive power sources such as solar water heaters

I would personnaly just opt for going to suitable junk yards and getting a whole stack of batteries cheap or for free and aim for 30% are useble for two years

Try Gumtree.ie or Adverts.ie or Jumbletown.ie asking for old useable scrap bateries in the freebee section where people are throwing out stuff

Then get all the stuff for servicing batteries like acid and pure water and hydrometers and big chargers with high amps

A blast from a high amp charger can rescue a weak battery and kick off the sulfates from lead plates


Also consider to get friendly with truck fleets or fork lift operators and try to get their batteries

Its no harm to have these power sources in case of bad weather or stirkes chops of the ESB power source

I have a few car batteries I get from places for free as useless for car use and most last a few years on low useage they will power me for days


i can rechage my umteen packs nicads from them in 20 minutes
my many NiMH in 45 minutes
and my lipos in 1 hour or some in 30 minutes

So I can run lots of lights in a power cut senario or fly my radio control electric model planes if the ESB is working properly


Derry

Hello there, You seem to know a decent amount about batteries and I will take your advice on the above posts. I was wondering if you had any experience dealing with ultra capacitors (12 volt packs) in parallel with a bank of 12 volt batteries to take the initial loads off of the batteries? Is it true that the ultra capacitors will prolong the life of the battery bank in this case? Just a thought!!

derekohara

derekohara wrote: »

You seem to know a decent amount about batteries and I will take your advice on the above posts.

derry wrote: »

If you deep cycle a typical car battery 10 to 20 times that will destroy it with whats called sulfation of the plates

This is more warping of the plates and over-shedding active material actually. Starter batteries have thin plates with high surface area to deliver cranking amps whereas semi-traction batteries have dense plates allowing deeper discharges.
Sulphation is a result of repeated under-charging, sitting below the sulphation threshold voltage and over-discharging.

derry wrote: »

If you go to most good solar power battery sites they will suggest to only take 10% of the capasity out from the batteries deep cycle type lead acid

The accepted standard is 50% discharge for cost versus return. You can do the maths on most cycle life graphs and it works out.

Discharging to less than 10% DOD is known as short-cycling and just as bad as discharging to 70% DOD. It's a little advertised phenomenon that causes the build up of hard lead on the positive. Manufacturers know about it and don't post information on the first 10% of their graphs to make a nice clean curve betting that if you use a battery this way you won't notice.

derry wrote: »

That shows that if 1KG (~1 liter) of fuel costs 1.50 euro and 100 kgs of battery costs probably 2000 euro we start to see battery power is very very expensive
Also it very fragile can short circuit and be wrecked and requires lots of specialist knowlege to use properly lots of maintance and TLC and requires deeeeep pockets

You can cycle a new traction battery for about 9c p kW/h over it's lifetime if you take care of it. However you still have to buy a charging system though.

derry wrote: »

When some dont work or some wear out there is no dumping costs as dumps dont charge for batteries

Lead acid scrap value is €0.50 per kilo.

derry wrote: »

Good quality batterris properly serviced can last sometimes 4 plus years

I'd give them 7-9 years for semi-traction OLA, I recently replaced low quality, badly maintained batteries after 4 years and they're still going at 50% DOD.
Maybe half that for "maintenance free" SLA as they'll probably have run out of electrolyte or sulphated from low charging voltages.

derry wrote: »

Respectable amounts of power for the equipment you have

Only on paper, I'd say 250W solar and a 20A windy would still struggle to maintain a 400Ah bank in daily use year round.

derry wrote: »

A blast from a high amp charger can rescue a weak battery and kick off the sulfates from lead plates

High voltage charger, it's called equalisation and don't expect miracles it doesn't replace lost electrolyte, active material or fix soft shorts and warped plates.

derekohara wrote: »

I was wondering if you had any experience dealing with ultra capacitors (12 volt packs) in parallel with a bank of 12 volt batteries to take the initial loads off of the batteries? Is it true that the ultra capacitors will prolong the life of the battery bank in this case? Just a thought!!

Can't see the point myself for storage, they self discharge much faster than lead acid and they're stupid expensive.
If you can afford them (I haven't done the figures but you'd get an awful lot of batteries for the same price of a bank of ultra-cap's) then they are beneficial in that they have a much lower resistance to charge acceptance, a far lower peukert exponent, they're lighter and they last 1000's more cycles to full discharge. I'd go for batteries or capacitors though not both. I'm waiting for cheap second hand ones outtov EV's though.

As a load buffer there's not much need it's usually the inverter you need to protect from hard starting not the battery. Depends on what you are running; anything with an intermittent load current higher than the C10 rate or constant load higher than the C20 I'd consider the need of more batteries to give you decent run-time and load balance, anything less they'll probably manage ok.

(OLA) Batteries are fairly durable, traditionally you'd have a starter battery for cranking amps, traction or semi traction batteries for medium to low loads and a soft starter on an inverter for high in-rush loads like compressor fridges, motors etc.
Simply having a bank with a high C20 rating would probably be a much cheaper solution.

The capacitors themselves will of course take a huge load out of the batteries every time you connect them from discharged.