# Connectors for Thundersky Lifepo4 cells



## gss99 (Dec 31, 2009)

Hi. I'm buying some TS-LP20AHA lifepo4. These are for my electric bike. I'd like to find some connectors for the cells that could easily come off so I can charge the cells individually with a 3.2v lifepo4 charger. I don't have the lifepo4 charger yet. I'm planning on using a 12v black and decker charger for each 4-pack. Do you think that will work okay? I plan on monitoring the usage with a watt meter and only using 60 % capacity and just praying that no cells go below 2.5v. 

What I'd like to do is charge them individually to about 3.8v each so it will be far away from the 2.5v cut off. I thought about using anderson powerpoles. I'd like to find something locally that I can use if possible. I'm not sure Home Depot or BatteryPlus carries the anderson powerpoles.


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## JRP3 (Mar 7, 2008)

You don't need to disconnect the cells to charge them one at a time, if that's what you're talking about. Even charging to 3.8 volts the cells will drop down to around 3.4 once they are off the charger for a while and will drop to around 3.2 under load. If you are only planning to use 60% of capacity you should not see under 3 volts, maybe an occasional sag under heavy amp draw.


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## gss99 (Dec 31, 2009)

oh. I know the 20ah come in packs of 4. I was planning on removing the top and charging all 4 cells individually. Are you saying that I don't have to disconnect the cells to charge them individually? I'm planning on using a 3.2v lifepo4 charger so if the cells are still connected in a series and I hook one positve and one negative of one cell up to the charger, what would that do? Wouldn't that short it out or something?


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## JRP3 (Mar 7, 2008)

You can charge an individual cell in a series pack by just connecting the charger to that cell's terminals.


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## gss99 (Dec 31, 2009)

JRP3 said:


> You can charge an individual cell in a series pack by just connecting the charger to that cell's terminals.


While it's still hooked up to other cells?


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## JRP3 (Mar 7, 2008)

Yup, you got it. Remember, if you put a voltmeter on an individual cell hooked up in series you only see the voltage of that cell.


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## racunniff (Jan 14, 2009)

JRP3 said:


> Yup, you got it. Remember, if you put a voltmeter on an individual cell hooked up in series you only see the voltage of that cell.


Just be careful to hook up to the correct terminals so you don't let the smoke out of your charger.


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## gss99 (Dec 31, 2009)

racunniff said:


> Just be careful to hook up to the correct terminals so you don't let the smoke out of your charger.


wow, I didn't know that I could charge them that way. You mean don't accidentally connect the alligator clip to the bracket connecting the batteries but rather the actual terminals. Right ?


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## JRP3 (Mar 7, 2008)

Well it's effectively the same thing, but yeah to be safe just connect to the cell terminals of the cell you are trying to charge.


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## Harold in CR (Sep 8, 2008)

Just to be sure, put POS to POS from charger to battery. In series the batteries could be turned one way, then the other, then the other.

Just to be sure you understand.


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## racunniff (Jan 14, 2009)

gss99 said:


> wow, I didn't know that I could charge them that way. You mean don't accidentally connect the alligator clip to the bracket connecting the batteries but rather the actual terminals. Right ?


That's part of it, but the real thing I was trying to say was - detach *both* charger leads from one battery before attaching them to the next (otherwise, you'll be exposing your charger to a larger voltage potential than it is designed for), and pay close attention to + and -


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## Coulomb (Apr 22, 2009)

gss99 said:


> Hi. I'm buying some TS-LP20AHA lifepo4. These are for my electric bike.


Um, are you aware that these are likely not LiFePO4? Thunder Sky give LiFePO4 a LFP part number, at least for single cells. If you look at the data sheet for the LP20AHA, it doesn't mention either of the words "iron" or "phosphate".

These batteries are designed for "automotive use", which I think means they are designed for high discharge for short time (starter motor use), not long life or safety, which you get with LiFePO4. 

I've been looking at these too, but I don't think they are what you would want for an EV's traction battery. I could be wrong.

Note that Elite Power Systems has a TS-LFP20AHA battery that looks rather different, and I get the impression that it really is LiFePO4 inside.

See also the end of this thread.


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## gss99 (Dec 31, 2009)

Coulomb said:


> Um, are you aware that these are likely not LiFePO4? Thunder Sky give LiFePO4 a LFP part number, at least for single cells. If you look at the data sheet for the LP20AHA, it doesn't mention either of the words "iron" or "phosphate".
> 
> These batteries are designed for "automotive use", which I think means they are designed for high discharge for short time (starter motor use), not long life or safety, which you get with LiFePO4.
> 
> ...


Strange. I didn't notice that. I know a guy who ordered from Elite Power solutions. He sent me pictures of the silver case opened up. Inside is 4 Thundersky yellow cells. They look like Thundersky Cells to me. In that thread, it was suggested that the cells could be Lithium Polymer. Is there any way to prove that it's lifepo4 ?


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## gss99 (Dec 31, 2009)

wow, you are probably right. I didn't realize that. If you go to the Thundersky website. They have these:

LFP Battery LCP Battery LMP Battery LP Battery 
Probably Lifepo4
then Lithium cobalt
then lithium manganese ?
then Lithium polymer


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## Coulomb (Apr 22, 2009)

gss99 said:


> Strange. I didn't notice that. I know a guy who ordered from Elite Power solutions. He sent me pictures of the silver case opened up. Inside is 4 Thundersky yellow cells. They look like Thundersky Cells to me. In that thread, it was suggested that the cells could be Lithium Polymer. Is there any way to prove that it's lifepo4 ?


The 4 yellow Thunder Sky Cells are probably LiFePO4. It's just weird that TS don't seem to sell the individual 20 Ah cells to other than OEMs, and don't have a data sheet on them. I believe that the Elite Power product with the shiny silver case has an F in the part number. As far as I can tell, it's not the same thing as EV Components sell, and has a datasheet on the TS Web site, and (now) has no F in the part number. It's this latter one that is probably not LiFePO4, possibly LiPo.

BTW with the Elite Power product, is it easy to get at the individual cells (or is there breaking involved)?
Is there a BMS integrated with the Elite Power 4-cell pack?
Would you be able to publish the picture of the pack opened up?


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## gss99 (Dec 31, 2009)

Even if they are lithium poly, for a noob like me, I think it's probably a decent deal. I just didn't want to have to wire up 15 different Zippy Flightmax's . This way, I'd only have to wire up 3 packs. Even for lithium poly, I'm still getting my money's worth.


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## gss99 (Dec 31, 2009)

BTW, I'm pretty sure it's lithium polymer because I saw these exact cells advertised as lithium polymer on alibaba.


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## MN Driver (Sep 29, 2009)

The Elite Power Solutions pack looks different than the Thunder Sky site shows their 20Ah cells that have the LP designation. They are likely different, they could have produced 20Ah cells and been selling them to Elite Power. Thunder Sky could have discontinued those and are now selling the ones you see on the Thunder Sky site, with Elite Power selling discontinued cells that they have in inventory. ...but I'm just thinking out loud.


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## gss99 (Dec 31, 2009)

Does everyone like Elite Power Solutions? I put in my order on Dec 31st and it's Jan 2nd and they have yet to get back to me. You'd think that they'd want to get your money but they don't seem to be too motivated. If they take time off the holidays, a nice message like, "won't be back until Jan 10th" would be nice so I'd know not to place my order until then.


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## JRP3 (Mar 7, 2008)

I think their prices are high, but as far as getting back to you, you've got a holiday and a weekend, so that doesn't really surprise me too much. I expect you'll hear something on Monday.


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## gss99 (Dec 31, 2009)

Screw Elite Power Solutions. They take 5 days to get back to me. Then they just tell me to "send them a check" . That's not a problem but they didn't even give me a total yet !!! What a bunch of idiots. I think I'm going to look elsewhere for my batteries.


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## JRP3 (Mar 7, 2008)

I would suggest www.evcomponents.com


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## s2156945 (Apr 15, 2009)

gss99 said:


> Is there any way to prove that it's lifepo4 ?


LiPo should have a voltage around 3.7 (x4 = 14.8) for most of their charge, LiFePO4 around 3.2 (x4 = 12.8).


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## gss99 (Dec 31, 2009)

if anyone is curious, I e-mailed Thundersky and they said that the TS-LP20AH cells are indeed Lifepo4.


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## s2156945 (Apr 15, 2009)

gss99 said:


> if anyone is curious, I e-mailed Thundersky and they said that the TS-LP20AH cells are indeed Lifepo4.


Aha - a "social engineering" solution was probably the best way!


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