deep cycle Batteries

[Augusta08]

I'm thinking of beefing up the batteries on my solar power system. Which batteries are best? AGM or something similar? I'm not in the market for Lithium (too expensive) but I am looking for 3000ah plus if possible.

 

[funflair]

Is this for home? or did you mean 300ah as 3000ah would be a big chunk out of your payload.

 

[Augusta08]

For home array

 

[Raul]

For that amount of storage best bet is forklift battery configured to your system voltage. If you have the cash and buy new, I would go Rolls surrette or Trojan flooded, either 2v cells or 6v blocks.
Are you sure you need 36kwh battery?

 

[Augusta08]

My house has 8x6 mtr south facing sloping roof i reckon it's a potential power house

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[Raul]

Not quite, 8x6m would give you max 6 panels(4 portrait 2 landscape) of 360-400w tops. The bigger panels will not fit. That’s a max 2,4kwp array. 2400kwh per year in Uk from Birmingham down. Any extra is a bonus.

 

[autorouter]

Maybe the house is in France, as in the OP's avatar.

 

[Augusta08]

Not quite, 8x6m would give you max 6 panels(4 portrait 2 landscape) of 360-400w tops. The bigger panels will not fit. That’s a max 2,4kwp array. 2400kwh per year in Uk from Birmingham down. Any extra is a bonus.

I'm about 400 miles south of Birmingham

N47'42'44.59 W3'20'1.14

 

[CuckooChaser]

I did see this house in Germany a couple of weeks ago - too much?

 

[Raul]

Fair enough stil 47 north dough, I would add a optimistic additional 500-800kwh per year to what I previously said. It’s worth it if you use it.

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[autorouter]

House solar arrays and storage systems are a different ballgame, you need to rethink the whole system. If you are thinking of 36kWh of battery storage (= 3000Ah at 12V) you should be using 48V battery banks, not 12V. It's not a big deal, you just arrange the batteries in groups of 4 when you are connecting them up.

But it means that from the beginning you use a 48V solar controller, 48V inverter and 48V battery charger. Or a 'hybrid' inverter that incorporates all three devices in one box.

A 36kWh battery bank is definitely on the large side. I'm sure these things will go like computer memory, in ten years time we'll think it's small, but right now it's bigger than normal. If it's lead-acid-based, it will need to be completely filled to 100% every couple of weeks at least, to avoid sulfation problems. In the winter you may need to top up the batteries from the mains grid, to keep them healthy, so you should consider choosing a system that has that facility built-in for when you need it.

48V systems are not necessarily more expensive than 12V systems. In fact, they can be cheaper, because they use a smaller transformer and thinner copper windings because the amps is 4 times less for the same wattage.