Thread: A Battery that can Handle high current draw for long periods?

20 amps for 40 mins will generate a fair amount in the battery.

me thinks dissipating that heat will be the key to acceptable battery life

Best bet would be to go to a battery outlet, and see what they recommend, as that way if it doesn't work out you can blame them and not a suggestion by a forumite. What are you running to draw 800 + amp hrs. ?
Kryn

Originally Posted by KBs PensNmore

Best bet would be to go to a battery outlet, and see what they recommend, as that way if it doesn't work out you can blame them and not a suggestion by a forumite. What are you running to draw 800 + amp hrs. ?
Kryn

How do you get 800 Amp hrs?

New technology is quite amazing, it just costs. Vanadium Redox Flow batteries are being tested as I write this in Canberra, roughly the size of a vertical cylinder gas HWS and on the outside of a house. I think there are about 6-7 units in the study, which is in it's final stages.

http://www.extremetech.com/electroni...energy-storage

With my limited understanding of flow batteries, I believe these will be a better bet than what most are proposing for houses and residential solar systems. My understanding is that Tesla will be building up to a 10kWh battery bank, but it is effectively a large bank of telephone type batteries.

The Vanadium Redox Flow battery is unique in that you can completely exhaust the battery without ill effect, than you just recharge it.

Mick.

Look at the Supercharge Allrounder, they can be used for both deep cycle & cranking. Go for the biggest one you can, as the shallower the discharge the longer the battery will last, evn for deep cycle batteries. http://www.supercharge.com.au/others/allrounder
A good multi stage charger is also essential for long battery life, with an output of around 10% of the Ah capacity of the battery ie for a 100Ah battery, use a 10A charger.

Originally Posted by Optimark

New technology is quite amazing, it just costs. Vanadium Redox Flow batteries are being tested as I write this in Canberra, roughly the size of a vertical cylinder gas HWS and on the outside of a house. I think there are about 6-7 units in the study, which is in it's final stages.

http://www.extremetech.com/electroni...energy-storage

With my limited understanding of flow batteries, I believe these will be a better bet than what most are proposing for houses and residential solar systems. My understanding is that Tesla will be building up to a 10kWh battery bank, but it is effectively a large bank of telephone type batteries.

The Vanadium Redox Flow battery is unique in that you can completely exhaust the battery without ill effect, than you just recharge it.

Mick.

Tesla is making two Powerwall systems a 10kWh system that is designed to kick in when mains power fails and a 7kWh system that is designed to charge when there is excess power being generated by PV systems or similar. The Powerwalls use Lithium ion batteries and theyre encased in a gel to help prevent overheating of the batteries.

The Powerwall doesn't come with a battery inverter so you have to supply that yourself. Rough total cost for the 7kWh system has been estimated at around $Aus10,000 which makes for too long a pay back period to make it economical under current conditions. Note also that the Power Companies arent going to just sit and let half their customers fit these systems...they'll compensate by upping charges as they usually do. There's also the issue of managing a grid system when you have thousands of houses with PV and battery systems...if the utilities have no way of monitoring and predicting demand then it makes for a nightmare.

Originally Posted by BobL

How do you get 800 Amp hrs?

I'm no sparky, but isn't it, Amps drawn X time, 20 amps X 40 mins = 800 amp hrs. When I was looking at doing a motor home conversion, this is how I was told to work it out.
Kryn

Amps by time (in hours) = amp hrs

12v by 20A = 240W
Any decent 12v 100Ah battery would cope without a problem.

As it is stationary, why not go for 24V.

I have 4 by 6V 100ah batteries connected to a 24v 1500W inverter.

Originally Posted by KBs PensNmore

I'm no sparky, but isn't it, Amps drawn X time, 20 amps X 40 mins = 800 amp hrs. When I was looking at doing a motor home conversion, this is how I was told to work it out.
Kryn

Aren't you confusing mins and hours in your calculation?