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-   -   Weird LIPO question (https://www.rc-monster.com/forum/showthread.php?t=6058)

elegal 03.15.2007 09:17 AM

Weird LIPO question
 
1. I have a RC18 with a mamba 6800 and 2S and 3S Apogee 20C LIPO battery packs. I talked to the owner (i think)(of pfm distribution) and he said that the apogee packs did not need to be balanced since they were matched when they were made. I thought that everyone balanced their LIPO packs, and these batteries even have voltage ports. Should I begin balancing them, or just check the voltage of each cell to see if they are still in balance (I have about 10 runs through each)?
My main question is: is this guy serious?
He also does not endorse the use of MRC 989 on his products (which I have heard is a fine product).

2. I am almost done converting a LSP-R to brushless, and am going to get two trakpower 4900 batteries. Can I stack these in the same mount on top of each other, or will I have overheating issues with the packs? Also, does anyone have a pic of the setup to use when balancing these packs?

3. Assuming I buy two trakpowers, can I use the Flightpower V-Balancer to balance both trakpowers at the same time (would be like one 4S pack)? I also want to be able to balance the Apogee packs, so would it be easier to use the trakpower adaptor for the V-balancer (to balance the trakpowers) and use the taps that come with the V-Balance to balance the apogee packs?

Thanks in advance.

BrianG 03.15.2007 10:53 AM

1: If a pack was made of perfectly matched cell, then it wouldn't need balancing. The reality is that nothing is perfect and an imbalance can occur. I always use a balancer as it can't hurt.

2: Depends on how hot the packs get now. If they are barely warm, then stacking them shouldn't be an issue. If they are quite warm after a run, the stacking isn't a good idea IMO.

3: Don't know. Someone else can answer that one... :)

jollyjumper 03.15.2007 11:01 AM

i'd get one 4s 4900 flighpower pach instead of stacking 2 trakpower's.
also, the plug go in on topside of the trakpower, so how would you plug in the bottom battery?
also, the trakpower use tiny 2mm gold plugs to balance, one would need a wiring harness to balance 2 at the same time.

skellyo 03.15.2007 11:06 AM

Quote:

Originally Posted by elegal
2. I am almost done converting a LSP-R to brushless, and am going to get two trakpower 4900 batteries. Can I stack these in the same mount on top of each other, or will I have overheating issues with the packs? Also, does anyone have a pic of the setup to use when balancing these packs?

No, they can't be stacked because the connector terminals are located on top of the packs. You'd have to have them offset by about 1/2" to be able to plug the 4mm connectors in both.

Quote:

Originally Posted by elegal
3. Assuming I buy two trakpowers, can I use the Flightpower V-Balancer to balance both trakpowers at the same time (would be like one 4S pack)? I also want to be able to balance the Apogee packs, so would it be easier to use the trakpower adaptor for the V-balancer (to balance the trakpowers) and use the taps that come with the V-Balance to balance the apogee packs?

No, you need an adapter specific to the Trakpowers. If you don't have a V-Balance already, you can buy a version that comes with the Trakpower adapter included. It will also charge their standard Flightpower Lipos with the proper harnesses. Also, it's $5 cheaper than the standard V-Balance and then you don't need the $7 adapter harness for the Trakpowers. If you plan to order Trakpowers, speak with a gentleman named Jack at Duralite...very helpful guy and will make sure you get what you need.

skellyo 03.15.2007 11:07 AM

Quote:

Originally Posted by jollyjumper
i'd get one 4s 4900 flighpower pach instead of stacking 2 trakpower's.

I agree. If you're wanting to stack the packs, a single 4S 4900 pack is the way to go. I bought the Trakpowers because I plan to run one pack on each side in my LSP-R.

elegal 03.15.2007 11:09 AM

I want to be able to use them in an emaxx a well, plus I like the extra protection provided by the trakpowers.
They would be staggered enough to allow the bottom battery to be plugged in.
I would wire the harnesses together just like one big pack, the balancer and charger should see them as one large pack, and i shouldnt have any voltage problems if i discharge them at the same time in the same car.
I would just need another balancing cable to balance my other batteries.

skellyo 03.15.2007 11:21 AM

Quote:

Originally Posted by elegal
I want to be able to use them in an emaxx a well, plus I like the extra protection provided by the trakpowers.
They would be staggered enough to allow the bottom battery to be plugged in.
I would wire the harnesses together just like one big pack, the balancer and charger should see them as one large pack, and i shouldnt have any voltage problems if i discharge them at the same time in the same car.
I would just need another balancing cable to balance my other batteries.

Sounds logical to me. The only thing you should need is an extra Trakpower balancing harness so you can custom make an adapter for the V-Balance for 4S. For me, since I have two ICE chargers, I just ended up buying two of the V-Balancers that included the Trakpower harness.

pinolelst 03.16.2007 04:40 PM

I've read somewhere a manufacturer saying 2 cell packs are less problematic as far as imbalances go than 3 cell and above but I think that's not really entirely true.An imbalance between 3 cells can happen just as easily with 2 IMHO.
I added balance taps to all my older packs and was surprised how hard the balancers were working the first time.Looked like christmas tree lights blinking on and off :005: Far more than a new pack put on the same balancer so I have to assume they were pretty far out 20 or so cycles into their lifespan.
I balance about every couple 3 cycles now and find that works about right for me .

hope this helps
Steve

crazyjr 03.17.2007 10:18 AM

Quote:

Originally Posted by pinolelst
I've read somewhere a manufacturer saying 2 cell packs are less problematic as far as imbalances go than 3 cell and above but I think that's not really entirely true.An imbalance between 3 cells can happen just as easily with 2 IMHO.
I added balance taps to all my older packs and was surprised how hard the balancers were working the first time.Looked like christmas tree lights blinking on and off :005: Far more than a new pack put on the same balancer so I have to assume they were pretty far out 20 or so cycles into their lifespan.
I balance about every couple 3 cycles now and find that works about right for me .

hope this helps
Steve

I always thought that was on the parallel side, but i guess anytime you put an extra cell in a pack it makes ot more complicated and more liable to possible problems

glassdoctor 03.17.2007 10:32 AM

Apogee is not the only mfg to claim their packs don't need balanced. For a long time ThunderPower refused to put taps on their packs and kept saying that they never or rarely go out of balance, etc etc..

Now all TP have taps and TP sells a chanrger/balancer system.

I don't think TP would have ever done that without all the heat from the consumers...


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