V-Balancers are not very good imop

[TomC]

I have not had a lot of luck with my 2x V-balancers (VB) over the last 6 months.

My normal proceedure has been to balance the cells (stand-alone mode) after a discharge, which I try to keep ~75% at most. I then hook up the VB's with my charger (Schultze 330-d w/ latest chipset) and charge at 3.5A (~0.9C) and change the VB mode to charge through it.

This is all with 5s1p 3700 Evo20 packs with some old and some new formulation ones. I've got 12 of these, which I mainly use in series as 10s packs.

With the VB's sometimes this works well and the cells charge to full capacity no problem with an end voltage (measured) of ~20.96v. The majority of the time (~60-70%) the VB cuts the charger off and the cells only reach ~ 20.80v. I also notice at these times that the VB is working pretty hard and getting pretty hot as well.

If I let the VB's cool down, standalone balance the pack while discharging them about 100-150 mah's I can then recharge them and get another 3-350 mah into them and the final measured voltage is 20.96v.

While I sometimes charge these packs as 5s I also charge them in series as 10s packs at 2.5A, my charger max. Before I do so I check that their voltages are +/0.03v. I also do not use them in series under load unless their voltages are +/-0.01v and do not mix new and old formula packs.

Charging them as balanced 10s packs does not make any difference, I get the same results.

Previously I have used 2x FP 2-6s staybalance (SB) modules to do my balancing. Based on FP advice, after a discharge I would let the cells cool to body temp, balance them, and then charge them without the SB's. Occasionally, I would also re-balance them after a charge in which case most lights would flash and the pack would be balanced very quickly (~30-60 sec).

My current procedure is to use the SB modules to balance the packs prior to charging, charge them untill the charger amps goes below 1A, re-hook the SB's untill the pack is balanced (often this is immediate, and at most takes a couple of minutes), remove them and continue to charge the pack until it's full. I almost always get a pack that measures 20.96v.

Also, I've noticed that if I balance a pack with a VB in standalone mode and then put it on a SB module, it takes a while (1-5 min) to balance. If I take another pack and balance it with a SB and then put it on a VB it balances immediately. I can only assume that the SB's are more accurate than the VB's.

Also, if your cell voltages have gone even slightly above 4.21v/cell then the VB's will not standalone balance them and will just shut off. The SB's will however handle this, no problem.

In short, I do not even use the VB's anymore. I have over 200 cycles with my old formula packs and they are still working great. I can only imagine that if I had used these partially charged packs from the VB's and taken them to 80-85% capacity, they would not have lasted 50 cycles.

Imop I think that the current VB's are a waste of money and do not do as good a job as the old SB's. Maybe the new ones with a heatsink work better.

In the meantime, I've gone to 2 x E-station PB6 Balancers (with FP/TP conversion boards) and they work great. They seem to be more accurate than the SB's (that is, they will rebalance SB's but SB's wil not rebalance them) and work a lot quicker since they will draw 0.5A, more than double SB's. The PB6's are in an Al case and seem to dissipate the heat quickly.

I sent Jullian (Mr FP) a note a couple of months ago stating that these VB's were overheating and not working very well but I never got a reply. Just like this forum, any FP balancer issues do not seem to get answered.

Too bad since their batteries, and battery customer service are the best imop!

Cheers,
Tom C

[TomC]

I've never heard back from FP regarding these crappy V-balancers, what a surprise eh!

I added heatsinks to mine but this only helped a little bit. I have also tried hooking up 2x VB's in parallel, to do 2x5s=10s but this does not work very well since either since the VB's do not talk to each other anyway so one just cuts off the charge early anyway. I see that FP have deleted this parallel setup from their tech notes now.

I've tried 2 other balancers that hook up together to properly balance 10-12s packs, E-station pb-6's and hyperion lba10's. Both of these, with the right inter-connect cables, seem to balance my 2x5s packs perfectly and cost the same, or less, than FP V-balancers as well. I'm sure that the TP 201v balancers would work fine as well for packs up to 10s.

I'm sure that FP will come out with better balancers soon, but for now, I'd avoid buying these, esp if you want to balance +6s packs imop.

Cheers,
Tom C

[Clintstone]

Tom please call FlightPower USA and we will be happy to help you. Thanks Tom we are looking forward to helping you.

[Jafa]

We've encountered the overheating also,
there is a newer version with a small but still inadequate heat sink

The LBA6 and TP210 does seem balance better that the VB
I thought they balanced to a lower volatage tollerance
but reading your description it may be the absolute voltage level

[TomC]

Jafa,

I agree with you. I met a guy at our field (with a 10s heli) last week with the new heatsink v-balancers, and he was having similar problems.

I've retired my v-balancers. If FP comes out with a better version, I might try them.

Cheers,
Tom C