PDA

View Full Version : Charger question


JLK
10-01-2005, 06:53 PM
What is the difference between a charger and a balancer?
Thanks!
JLK

flyranger
10-01-2005, 10:17 PM
A balancer allows the individual LiPoly cells to be charged to the required voltage independently. In other words, if a two cell pack has one cell at 2.9 volts and the other cell at 3.0 volts, only the lower volt cell would continue to charge.

Red Scholefield
10-02-2005, 06:12 PM
A balancer allows the individual LiPoly cells to be charged to the required voltage independently. In other words, if a two cell pack has one cell at 2.9 volts and the other cell at 3.0 volts, only the lower volt cell would continue to charge.

Actually a well designed charger with balancing will sense each of the cell voltages and charge them individually until full charge as indicated by reaching 4.2 volts on each cell. There are some systems being offered that will actually discharge the pack down to the lowest cell voltage and then start the charge from that point. Not a good system, if you have one bad cell that falls below the recommended 2.5 volts for any reason this type of charging will take the other cells down to that level also, rendering them useless. This approach also assumes that the charge acceptance is the same for each cell.

Unbalanced prop
10-03-2005, 04:07 PM
A balancer will try to get all the cells in a pack to the same voltage. If you have a three cell pack with say 4.16, 4.17 and 4.20 volts, the balancer will drain voltage out of the highest cells to try and get them all to say 4.16 volts.

A charger set to three cells will try and charge the "pack" to 12.6 volts regardless of the voltage of each cell so some cells could be under 4.2 volts and some could be over. This could be dangerous and could damage cells that get charged too high. Some lipol companies such as TP and Kokam are just now releasing chargers that balance and charge at the same time.

Keeping the cells balanced prevents some cells from being over charged. This makes charging safer and helps the packs to last longer and perform better.

Doug

Red Scholefield
10-03-2005, 08:20 PM
A balancer will try to get all the cells in a pack to the same voltage. If you have a three cell pack with say 4.16, 4.17 and 4.20 volts, the balancer will drain voltage out of the highest cells to try and get them all to say 4.16 volts.

And here lies the problem. If one cell is really bad for any reason and the voltage is in the danger zone, this technique will drag the good cells down to this level also.

Charging the pack while monitoring each cell and terminating the charge to that cell when it reaches 4.2 volts is a much more desireable approach.

A charger set to three cells will try and charge the "pack" to 12.6 volts regardless of the voltage of each cell so some cells could be under 4.2 volts and some could be over. This could be dangerous and could damage cells that get charged too high. Some lipol companies such as TP and Kokam are just now releasing chargers that balance and charge at the same time.

Keeping the cells balanced prevents some cells from being over charged. This makes charging safer and helps the packs to last longer and perform better.

Doug

Red S. The Battery Clinic

N3CLI
10-04-2005, 12:30 AM
Thinking of the Thunder Power TP 205 which does 2 to 5 cells with a center tap pack.

Have you looked at this setup yet?

I want to charge with My Astro 109 using the tp205 balancer
Is that the proper technology that you spoke of?

Thanks Fred AMA68196:)

Red Scholefield
10-04-2005, 12:42 AM
Thinking of the Thunder Power TP 205 which does 2 to 5 cells with a center tap pack.

Have you looked at this setup yet?

I want to charge with My Astro 109 using the tp205 balancer
Is that the proper technology that you spoke of?

Thanks Fred AMA68196:)

I can't speak with any authority on the TP205 balancer as I have not seen a description of how it works posted, nor have I had a sample to examine.

Unbalanced prop
10-04-2005, 02:21 AM
Fred...........I use the 205 with an AF109 (and three other chargers) all the time. The 205 is very flexible, you can charge then balance, you can balance while charging or you can start charging and hook the balancer up any time during the charge cycle. I find that once balanced a pack will stay balanced for a while. The better cells seem to stay balanced longer. I usually check the balance every ten cycles or so. I just hook up the 205 and it will signal if any balancing needs done.

Doug

Unbalanced prop
10-04-2005, 02:32 AM
Red..........in answer to your comment:

And here lies the problem. If one cell is really bad for any reason and the voltage is in the danger zone, this technique will drag the good cells down to this level also.

Charging the pack while monitoring each cell and terminating the charge to that cell when it reaches 4.2 volts is a much more desireable approach.

IMHO.......I agree so if the cells are that far out of balance, I can just top off the pack after balancing to get the cells back up to 4.2 volts, but that amount of capacity is really meaningless in flight time so I seldom bother. Or the balancer can be used for the entire charge cycle which will get each cell to 4.2 or as close as the charger or cells will allow. Some chargers do not charge all the way to 4.2volts, and as cells age, they will not get to 4.2 volts and stay there. At least this is what I have found from many charges of many different brands of lipolys.

Doug