[twnotter]

New to Lipos so I'm not sure what the charge time, cutoff voltage, or the charge current should be. Also the charger says parallel in the window and doesn't seem to be a way to switch to series, is this right? The charger is JB-1100

Thanks

[Oilsands]

What batteries are your charging? Looking for brand, mAh, C rating, Voltage and connection.

[twnotter]

Batteries are 1800mah, 11.1 V,C rating not too sure,brand is zippy

[Oilsands]

If it the ones I found at Hobby King, then they have a max charge rate of 2C and a max discharge rate of 20C. What this mean is the max you can charge the batteries through the main connections (not the smaller balancing wires) at 1800 mAh x 2 C = 3600 mA or 3.6 Amps. I usually charge at a less than 1 C rating, so that would be 1.8 Amp or 1800 mA, this will take 1800 mAh / 1800mA = 1 Hrs (60min) to fully charge from a fully empty battery. Note: never discharge so that the voltage of each cell is less than 3 volts, so in this case you have an 11.1 V pack so no less than 9 volts. If you charge at the 2C rate (which is ok some of the time but harder on the battery due to increased heat), but better for the battery if you charge at the 1C rate every 3 - 5 charges or all the time. So this means at the 2C charge rate: 1800 mAh / 3600 mA (2C) = 0.5 Hrs (30 min) to fully charge an empty pack.
The max discharge rate is 1800 x 20 = 36000 mA or 36 Amps at a constant rate. For the quick min burst of power it can go to a 25 to 30 C max discharge rate, I will let you do the math on that.
I recommend getting a lipo balancer, which at a min every 5 cycles I would check to make sure the pack is still balanced. I have a charger that can balance charge, so that is how I usually charge my packs all the time (but that is just the way I like to do it). You will find that usually the better quality packs do not go out of balance very often, while the less quality packgo out sooner.
So set your charger (if you can) so that the max mA before cutoff is around 1800 mA and the time around 60 min (1 hrs) or if charging at the 2C then 30 min (0.5 hrs). I would add a bit to each, so something like 2000 mA an 70 min or 40 min for a time out.
OH, you battery is 11.1 volt with 3s1p. This means that 3 cells are in series and 1 in pararell. The cells hooked up in series give you the 11.1 volts and the parrell give you the mAh. Not sure what your charge should read, other than there should be something about 11.1 volts.
Hope this helps.
My setup is:
Turnigy 4x6s charger (from Hobby King), also got more balance connections from them as well for my batteries (42 percent and now to Fromeco). This charger lets me monitor each cell (as long as hooked up to the balance wires), balance charge or regular charge, discharge, and store charge (which for storing a long time you do not want a fullly charged battery but one that is partialy charge around 3/4). I found the cooling fan to be noisey, but changed it out with another from The Source and it is quieter. I have used the Equinox balancer as well, which I found worked well.

Fixed up the incorrect calculations as mentioned in a below post, sorry for that.

[twnotter]

Thanks for the info, answers all the questions that I had, the charger I have, JB-1100 says it is a charger/balancer. After a charge the 3rd cell is at 4.03 on all 4 packs, the first being 4.17 the second 4.20, is this normal or should they be identical after the charge?

[russ]

Originally Posted by twnotter

Thanks for the info, answers all the questions that I had, the charger I have, JB-1100 says it is a charger/balancer. After a charge the 3rd cell is at 4.03 on all 4 packs, the first being 4.17 the second 4.20, is this normal or should they be identical after the charge?

did you charge in balance mode?

[Oilsands]

The third seems a little low, the other two are close which is what you want. No more than .03 volts difference is what I say is a balanced pack. Like was asked, did it charge in balance mode.

[twnotter]

I will have to check it out, thought it was automatic

[russ]

On my charger, it needs to be set to balance mode and both the JST-XH & main plug connected.

[RichT]

Originally Posted by Oilsands

...... What this mean is the max you can charge the batteries through the main connections (not the smaller balancing wires) at 1800 mAh / 2 C = 900 mA or 9 Amps. I usually charge at a 1C rating, so that would be 1.8 Amp or 180 mA, this will take 1800 mAh / 180mA = 10 Hrs to fully charge from a fully empty battery. .

Hi Oilsands,

You have your wires crossed on some of this....

A 2C max charging rate for a 1800mAh battery is 1800 x 2 (not divided by 2). So the max charging current at 2C would therefore be 1800 x 2 = 3600mA or 3.6A.

NOT 9A which would be a 5C charge.

Also, standard 20C zippy batteries are best charged at 1C, so 1800mA or 1.8A. It is the higher C rated batteries (30C and 40C) that allow higher charge currents. Generally it is best to stick with the 1C charge rate for safety and battery longevity.

A 1/10 C charge at 180mA or 0.18A would not do any harm but is really not necessary for a lipo and some chargers may time out before 10 hours. Save trickle charging for seriously out of balance batteries.

BTW 1A = 1000mA

Also check to cell balance every 5 charges (or more frequently) and use a cell balancer if necessary.


Safe charging.