lipo balancer q? - Page 2 - RC-Monster Forums

MetalMan · 11.18.2005, 09:52 PM

The PCM will cut the charge as soon as a cell gets to 4.25v, and that's it. It will monitor each cell independently to see if any get to 4.25v, but it certainely won't balance the battery (which is what individual cell charging would do). When the PCM cuts the battery off, that means that you need to balance the pack.

Serum · 11.19.2005, 05:04 AM

Here is what the PCM guard does;

it cuts of the pack when 1 cell reached the 4,25 volts. it simple doesn't balance the cells, it's just a warning device, that tells you when the pack is in unbalance. nothing more...

Here is what a proper balancer does;

during the charge proces it monitors and adjusts the charging proces of each cell, not only at 4.25 volts, like the polyquest PCM, but continuesly, thru the whole charging proces

You need to balance the cells at some point. discharging or charging. imo it is the best to do it at charging, because only then, you know that all the are equal when you give them the big load or torsing a monster truck thru the fields..

MetalMan · 11.19.2005, 04:47 PM

Balancing during charge really is the only way to balance a Lipo. Balancing at discharge would be pointless because of the slight variations of resistance between cells. Also, constant voltage during charging is much easier than it would be for discharging.

stampy · 11.21.2005, 12:03 AM

back to me you tread jackers:p. hey i just wont to know
how a balancer hooks up? im thinking that the chargers out put goes in to the balancer and then the pack connects to the balancer :C: . im cornfuzed can any buddy draw up somthin for my simple brain

MetalMan · 11.21.2005, 10:20 AM

A balancer can be hooked up like that, if that is how a particular balancer works.

Ususally, you plug the battery into the charger like you normally would, and then you would plug the battery's multi-pin connector into the mating port on the balancer.

If you still need explanation in the form of a picture, just ask :).

Serum · 11.21.2005, 02:16 PM

Normally, you don't use the wires that power up your speedo, those are left untouched in the charging process (normally)

MetalMan · 11.21.2005, 08:08 PM

Usually I see Lipo being charged through the main leads, and if balancing is done, then a balancer is hooked up to the multi-pin connector. What I do is charge to ~4.15v/cell or higher, depending upon how well the cells are balanced. Then I individually charge each cell, just to make sure that they are all well balanced. I do this manually because I don't have a balancer, and I use male JST connectors as taps.

stampy · 11.21.2005, 08:21 PM

do i have to balance cells that are in parallel or just the ones in series, like if i had a 3s2p pack would a 3s balancer work on it?

MetalMan · 11.21.2005, 08:56 PM

You would only balance the cells in series, unless it is 2 3s packs put in parallel. But if it is 3 groups of 2 parallel cells, that are then put in series, then it would be fine. IE, if 2 cells in parallel, they will always remain in balance with each other because they have to remain at the same voltage. The only downside is that if one cell goes bad between these 2, then the other will go down with it (this has happened to me with 2 different packs).

stampy · 11.23.2005, 02:12 AM

ok last q? now on my big truck the one right <- there i plan in building my lipo packs for it to save money. how would i go about wiring up balacing taps for it? my guess is this

MetalMan · 11.23.2005, 09:33 AM

What you have there is a parallel connection. You don't need balancing for a parallel connection. Here is a drawing of a 4s2p pack wired with Polyquest-type balancing leads:

Serum · 11.23.2005, 01:40 PM

here is an article about them (pcm guards)

MetalMan · 11.23.2005, 05:09 PM

The PCM wiring explanation can be confusing for those that don't recognize what the cells are.

11.23.2005, 08:33 PM

Taken from Serum's link in his post (under "Metering And Balancing")...

"If you have any doubts of your ability to meter and re-balance cells then locate someone who can do it for you. "

hmmmm - how often does balancing need to be done, and what is needed to be known by a user, to go about balancing a pack??

Is there much difference in balancing nimh and lipo cells? I assume the balancer is just a plug in feature kinda similar to the PCM?
Any pics of a pack being balanced by chance? (i wasn't sure on the PCM till i saw the diagram in the linked article - so this pic couldn't hurt for explanations sake i guess? -lol-)

Sorry for all the questions - newbie needs help - at least i was on topic? -lol-

MetalMan · 11.23.2005, 11:07 PM

How often you should balance cells depends upon the differences between the cells themselves, and how hard the cells are pushed. You would be fine if you did it every 3 cells or so. If you have a balancer, then all you need to know is how to plug the battery into it.

You don't really "balance" NiMh cells, you more of equalize them. Besides, NiMh is done during discharge, and Lipo balancing is done at the end of a charge. The balancer would plug into the battery just like a PCM guard would.
There is nothing special that could be gained from seeing a pack being balanced, except for the flashing LEDs indicating the condition of each cell.