How to charge/balance two TrakPower's

Hello,

I'm hoping that 2008 brings all kinds of great changes in the land of LiPo however to prepare I want to buy a new charger. My main goal is to buy something which can charge and balance up to 5s LiPo. I think I know which charger I want but what I can't figure out is...is there any way to charge and balance two TrakPower 4900's at the same time with one charger? I already have a V-Balance device however it seems to me that it will only hook up to one battery at a time. Do any of you guys know what I'd need to do this?

Thanks,

DM

[BrianG]

From the looks of things, you'd have to use two V-Balancer units and just hook the inputs in series like any normal Y adaptor. You could also make your own adaptor cable set to allow you to use any type of balancer unit which will allow you to balance both packs on one balancer.

[squeeforever]

Personally, I would go for the MRC 989 charger and simply get a LBA10 and make an adapter like Brian said. Its seems that either way, your gonna have to buy another balancer.

I'm with you guys...I certainly am open to loosing the V-Balance, the only thing I'd wonder is why it claims to handle up to 6s...perhaps there is an adapter cable which works with the V-B to charge two 2s packs? I think I will email FP...

DM

[squeeforever]

I know they have adapters to use 2 balancers and one pack, but not sure about the other way around. I'm pretty sure that if you make the right adapters, it would work just fine for balancing more than one pack.

I did get a reply from FP, they wrote:

You can use 2 Balancers in parallel to charge 2 packs at the same time
since you are using them together. This is not recommended however if
the packs are used separately.

So now my new question is...how exactly does one hook up two batteries each with their own V-Balance in "Parallel"...what does this mean?

Sorry for the low tech question but this is new territory for me.

Thanks,

DM

[BrianG]

Basically, you hook up a balancer to each pack, and then the inputs to the balancers are tied in parallel and then to the charger. Like FP said, you have to make SURE that each pack is at the same charge level, has seen the same number of cycles, etc. This is because if there is ANY difference in voltage between the two pack, you're gonna get a high current spark until they equalize to each other.

So, it would be MUCH better IMO to make a Y adaptor to charge both packs in series using a single 4s+ balancer.

Originally Posted by BrianG

Basically, you hook up a balancer to each pack, and then the inputs to the balancers are tied in parallel and then to the charger. Like FP said, you have to make SURE that each pack is at the same charge level, has seen the same number of cycles, etc. This is because if there is ANY difference in voltage between the two pack, you're gonna get a high current spark until they equalize to each other.

So, it would be MUCH better IMO to make a Y adaptor to charge both packs in series using a single 4s+ balancer.

Yeah, I like the idea of a single adapter using one balancer...While I use the packs togther with my own Y adapter on the ESC they are not identical always. Plus I have more than one "set" and sometimes intermix...

The V-Balance claims to support up to 6s - I wonder why they didn't suggest this...

Can you think of a way to make this Y adapter and which balancer would you pick if you had your choice?

Thanks,

DM

[squeeforever]

They didn't suggest it so they could sell another balancer most likely.

Ha...I would hope not. Heck I'd pay the $50 another VB would cost for the right cable harness...there must be some other reason...

DM

[BrianG]

Originally Posted by MacII

Yeah, I like the idea of a single adapter using one balancer...While I use the packs togther with my own Y adapter on the ESC they are not identical always. Plus I have more than one "set" and sometimes intermix...

The V-Balance claims to support up to 6s - I wonder why they didn't suggest this...

Can you think of a way to make this Y adapter and which balancer would you pick if you had your choice?

Thanks,

DM

Any balancer would work. The Y adaptors I made work with the LBA and the commonsenserc balancers. Since the lipo connections are different for the TPs, it would just be a matter of finding the right connectors that will fit and wiring them up. Pretty simple really. But then you'd have to make SURE you hook them up right or bad stuff could happen since there is no keyed plug like you have with most other lipo packs.

FP sent me a reply today with a photo...it seems that the idea of hooking up the balancers in parallel is much simpler than I though it was. All you need is a simple Y adapter! Very easy. Attached is the photo they sent...those are two 5s packs.

If all it takes is a simple Y, another VB and making darn sure I hook it all up properly, I think I may just go for that as a solution.

I don't quite understand how the charger will know when to stop...does the balancer prevent the charge from coming through once it's cells are fully charged? (I know that's a dumb question, mainly because I've been using an FMA Scorpion charger which charges and balances, I've not even used the one VB I have!)

Thanks guys,

DM

[BrianG]

Hmm, I was thinking you had two 2s TP packs (the ones in the cases). If you have that balancer and two 2s packs, you can use one balancer on both packs just like the diagrams on my lipo web page. Or, you can do the diagram they show in that pic, but that requires another balancer unit. If charging two 5s packs, you'd almost HAVE to charge them in parallel or you'd need a 10s capable charger if done in series.

Either way, you should still charge packs like this if they both have always been used together, seen the same number of cycles, have the same charge level, and seen the same usage.

Originally Posted by BrianG

Hmm, I was thinking you had two 2s TP packs (the ones in the cases).

Oh, yes, I do have two of the TrakPower Gold packs (2s) - the photo was sent to me by FP showing a demo of the config I'd have...their photo shows 5s packs but mine are 2s...

They did send another reply today answering the question of why not build a super adapter for the one VB do do it all, it explains it quite nicely...here is that reply:

--FP--
It would be possible to use one balancer with a special harness but the
balancer is designed to shut off if it detects to great of an in balance
& wont turn back on until the balance is within tolerance. SO with your
situation 2 would almost be a must unless the voltages on the cells in
both packs were very close.
--FP--


DM

[Patrick]

Do they know that you use both packs at the same time in the same vehicle, so they shouldn't get too out of balance?