2 x 3S in series

Hi Guys,

I've got a question about LiPo's. Ok, so I want to convert my LST to brushless, on 6S LiPo. I want to run 2 x 3S LiPo in series, so 22,2V.

My Problem: My charger can only charge up to 5S LiPo.
So I have to charge and balance the 2 LiPo's on their own. I can't balance and charge them in series.

Now my question: Will this damage for the LiPo's, if I charge them seperately, and discharge them in series?

Thanks,

Patrick

[BrianG]

No, that will be fine. The only bad thing is it will take a long time per charge since they must be charged individually.

Originally Posted by BrianG

No, that will be fine. The only bad thing is it will take a long time per charge since they must be charged individually.

Ok thanks! Now It is 1-1. Because my dad said it won't be good for the batteries.. But it is 40 years ago that he studied elektro

So I'll wait what other members will say...


Thanks for your comment!

Originally Posted by Byte

Ok thanks! Now It is 1-1. Because my dad said it won't be good for the batteries.. But it is 40 years ago that he studied elektro

So I'll wait what other members will say...


Thanks for your comment!

you can go with Brian said......and tell your dad he needs to get with technology.....lol

[BrianG]

Originally Posted by Byte

Ok thanks! Now It is 1-1. Because my dad said it won't be good for the batteries.. But it is 40 years ago that he studied elektro

So I'll wait what other members will say...


Thanks for your comment!

Did your dad explain why? As long as each pack is balanced before they reach their 4.2v/cell threshold, they will be fine.

But, you really should get an updated charger, unless you like waiting ~2 hours for them to charge. Just tell your dad that he was right and see if he'll get you a new charger. If he says no, just tell him that it is so unsafe that he risks a fire in his house/garage. Might as well play on his ignorance.

Originally Posted by BrianG

Did your dad explain why? As long as each pack is balanced before they reach their 4.2v/cell threshold, they will be fine.

But, you really should get an updated charger, unless you like waiting ~2 hours for them to charge. Just tell your dad that he was right and see if he'll get you a new charger. If he says no, just tell him that it is so unsafe that he risks a fire in his house/garage. Might as well play on his ignorance.

I won't do that, he pays enough for me, last time he paid my Traxxas Rustler VXL
( But the idea is good )

Anyway, thank you for your help! Now I've to search 2 good LiPos for in my LST. The LST is a huge car, but I can't find some space for the LiPos..
I'm thinking of buying Rhino 4000mAh 3S2P, for a long runtime, but I haven't got many space..

Again: Thank you!


- Patrick

[BP-Revo]

For something as large and heavy as a LST (high current) you are going to want very good cells (Nue or FlightPower) or another brand battery of similar spec. Anything else will struggle to dish out enough power and will suffer doing it. Better have too good of a battery sleep while you run your truck than a battery thats not good enough die trying (and take half your truck with it).

[webman405]

hey not looking to hijak the thread, butn just need to ask a quick question. so if you charge 2 3s packs in series, how would you balance them? do they make some sort of 6s to 2 3s adapter? thanks

[BrianG]

Go to the RC Calculations link in my sig, and click on the "lipo pack wiring" link in the menu. Scroll to the bottom and it will show you various ways to do make adaptors to do what you describe. Basically, you want something like this:

[webman405]

ok, so if i'm using neu packs, could i just put a kokam balance plug on the end going into the pack, and a hyperion plug on the other end?(getting the EOS0610i).

[suicideneil]

Assuming the order of the balance tap wires remains the same (+ - - - or whatever) at either end of the balancing harness, then it will be fine to have different brand taps as required to work with the lipos and charger/balancer. Just follow BrianG's diagrams carefully.

[webman405]

so most balancing taps just have one common positive and a negative for each cell? also, where do you guys recomend to buy the taps?

[hoober]

You may also charge them in parallel (still slow if charger rate is maxxed out) and balance however you wish.

Use in series, charge in parallel.

[suicideneil]

Originally Posted by webman405

so most balancing taps just have one common positive and a negative for each cell? also, where do you guys recomend to buy the taps?

Yep, or sometimes its - +++++, dont always trust the color of the wires as my charger uses 2 black and 5 red wires (voltmeter to be sure).

Anyway, maxamps, hobbycity or truerc are good places to just buy balance taps with wires attached, or there are plenty of other places too- basically any good retailer that sells lipos and chargers should have them.