# Battery Chargers for LiFePo4 (thunder sky)



## frk2 (Jan 2, 2009)

I'm thinking of purchasing LiFePo4 from everspring. My question is that I already have a Zivian NG1 72V charger in my car - I am thinking of building my 72V pack using 23 3.2v Nominal FePo4 cells.

Can I use the Zivian charger? Maximum Amp rating for my charger is around 20A. Is there a special way to charge these batteries?

Also- Since I probably will NOT have a balancer - Am I supposed to disconnect the batteries and check them individually for overcharge/undercharge? How would I top off the individual cell? (I cant use the 72v Zivian charger Im guessing! )


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## TexomaEV (Jul 26, 2007)

Zivan can reprogram your charger for LiFePO4 chemistry. They'll need some information regarding your particular LiFePO4 pack. I wouldn't ATTEMPT to go with LiFePO4 without using some sort of regulation on the individual cells, or a setup that individually charges each cell. Trust me, been there, don't EVER want to see that again. Look through the photos on my flickr site, they should shed some light on LiFePO4 usage/operation.


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## sailfish11 (Sep 15, 2007)

frk2 said:


> Also- Since I probably will NOT have a balancer - Am I supposed to disconnect the batteries and check them individually for overcharge/undercharge? How would I top off the individual cell? (I cant use the 72v Zivian charger Im guessing! )


Before shelling out the cash for LiFePo4 and foregoing a balancer, read this thread. You can pick up a decent BMS at EV-Power that won't break the bank -- and it will protect your LiFePo4 investment! Also look at Elite Power Solutions for your TS cells, they have pretty good prices and I've had good experiences working with them. Their biggest problem is they have trouble keeping their batteries in stock.


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## frk2 (Jan 2, 2009)

The BMS systems at elitepower say nothing about 'charging' - simply monitoring. Are there separate 'balancing' systems? which charger the individual batteries too? Thundersky apparently has their own balancing system which they also sell.Anybody has any experience with this?


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## frk2 (Jan 2, 2009)

Also, with the batteries + charger + BMS the total cost is hovering somewhere around $6000. That makes it roughly 3 times more expensive than a deep cycle battery solution. But I guess its worth it


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## frk2 (Jan 2, 2009)

I was able to ask the local manufacturer regarding their 'UPS' batteries. Here is the deal:

20hr rate: 200ah
10hr rate: 170ah

That does not look too bad, yeah? They dont have a 5hr or 1hr rate.


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## sailfish11 (Sep 15, 2007)

frk2 said:


> The BMS systems at elitepower say nothing about 'charging' - simply monitoring. Are there separate 'balancing' systems? which charger the individual batteries too?


Right -- that's why I went with the BMS from EV-Power. It's made for TS cells and the company has a good reputation.


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