lipo balancer q? - RC-Monster Forums

stampy · **lipo balancer q? -** 11.16.2005, 02:13 AM

i plan on getting the new mrc 977 charger, and it can charge 2 3s lipo packs independently so i shouldent need a balancer right?
also i plan on wiring them in perallel in my truck so i can get longer run times do i need some kind of balancer for in the truck?
1 more thing will 1 3s low voltage cut off thing work on 2 3s packs (3s3p total) or do i need 2 of them?

coolhandcountry · 11.16.2005, 09:11 AM

If I got it right the 2 packs are going in parrellal. They are 3s 3p each pack so that make you running 3s6p. The 3s low volatage cut off should work with this set up. A balance equalizes each cell in the pack to make sure the voltage is equal in all the cells.

MetalMan · 11.16.2005, 10:00 AM

You will still need a balancer if you want the packs to stay in balance during the charge.
There is no balance device for parallel packs. As long as the voltage of the two packs is very similar, then you are good to go.

crazyjr · 11.16.2005, 03:42 PM

So your saying that you need a balancer for each pack while charging, or that you need to charge each pack seperately.

Sorry for the hijack, but i'm curious to.

stampy · 11.16.2005, 04:04 PM

sorry for the confusing post :o i posted it when i was half a asleep lol. ok so each pack is just a 3s pack, 3 cells in series to get 11.1 volts. i plan in wireing the two packs togeather with a y splitter so i can run them at 11.1 volts but get incressed run times. do i need to run a balancer on board the truck to keep both packs voltage the same or? now the charger it as to charging ports im going to charge 1 pack on one charging port and the other pack on the other do i need a balancer for the 2 packs even though they are charging basicly on to diff chargers. now the low voltage cutoff should work them sence it is 3s3p total right? one thing i know is that i need a balancer for each pack to keep the cells in the pack th same but, im just trying to save as much money as posable dont wont to have to buy like 6 of them.

Serum · 11.16.2005, 07:13 PM

Charging them ballanced is more criticall. just get a voltage cutoff.

MetalMan · 11.16.2005, 07:42 PM

If you were to charge both packs on different channels, you would still need one balancer per pack. If you were to charge both packs in parallel, you would still need two balancers. Any 3s cutoff will work with any 3s Lipo battery. Parallel has nothing to do with the number of cells in series. No balancer on the truck, as balancing is only done during charging (or right after a charge).

crazyjr · 11.16.2005, 09:34 PM

So the balancer works without the charger?

MetalMan · 11.16.2005, 09:47 PM

The balancer is used in conjunction with a charger. The balancer balances a pack during charging (usually at the end of the charge is when it will kick in).

crazyjr · 11.16.2005, 11:28 PM

Ok, i understand now

coolhandcountry · 11.17.2005, 08:24 AM

Do you run the charger threw the balancer? Or do you hook it up like normal and the balancer to the other balancer connector?

MetalMan · 11.17.2005, 09:35 AM

Usually you plug the balancer into the charger, and the charger into the battery. I have seen some rare cases where you can plug the charger into the balancer, and the balancer into the battery, but they are uncommon.

11.17.2005, 11:06 AM

ok, metalman, my head's spinning.. I've got 2s 3100mah polyquest packs.. and AF109d chargers (i know you've already said that that charger isn't recomended w/ balancers..)

now, I've got PCM's, which you said were not balancers.. so the PCM makes sure that the packs are not over charged correct?
and a balancer would make sure that both cells charge equally..

so if I were to use a balancer, would I use the pcm as well? the pcm plugs into the pcm jack on the packs, and then into the charger.. is there a way to put a balancer between the pcm and battery or charger? or... gimme a hint.. I havn't tried charging the packs yet, so don't want to mess it up..
btw, what balancers would work with my cells?

thanks for any help in advance.
-nick

MetalMan · 11.17.2005, 05:54 PM

Quote:

Originally posted by A4DTM
ok, metalman, my head's spinning.. I've got 2s 3100mah polyquest packs.. and AF109d chargers (i know you've already said that that charger isn't recomended w/ balancers..)

now, I've got PCM's, which you said were not balancers.. so the PCM makes sure that the packs are not over charged correct?
and a balancer would make sure that both cells charge equally..

The PCM guards make sure that no cell in a pack is charged to over 4.25v (or somewhere around there). If a cell does reach 4.25v, the PCM guard will terminate the charge by creating an open circuit between the charger and battery. It is able to do this since it connects directly to the battery and the charger plugs into it. A balancer will do what its name says.

Quote:

Originally posted by A4DTM
so if I were to use a balancer, would I use the pcm as well? the pcm plugs into the pcm jack on the packs, and then into the charger.. is there a way to put a balancer between the pcm and battery or charger? or... gimme a hint.. I havn't tried charging the packs yet, so don't want to mess it up..
btw, what balancers would work with my cells?

thanks for any help in advance.
-nick

Generally you wouldn't use the PCM guard and a balancer at the same time because Lipo packs only have one set of balancing leads (and 1 connector). A balancer would plug into the "PCM jack" on a battery. This "PCM jack" is merely a plug that provides a direct connection to each internal cell of a pack.
Balancers work with any Lipo cells, as long as there are taps (direct connection to internal cells via a connector).

11.17.2005, 07:02 PM

thanks a ton for replies metalman. now.. this is what I have:
http://www.starluckrc.com/catalog/pr...products_id=72

says that it monitors individual cell voltage.. if I used this every time I charged the packs, wouldn't that "balance" the cells? it'd charge each cell to the maximum voltage independently correct?
so if for whatever reason the cells became unbalanced durring discharge, when I went to charge it again using the PCM, it would charge each cell to the maximum voltage again, and therefore re-balance them.. correct?