xpc said:
Alan B said:
I have and use a Turnigy Accucel 8 charger, what exactly is your question?
Sorry for not making myself clearer.
If I'm using a Turnigy Accucel-8 charger, how long would it take me to charge 44.4 x 5000amh (3 x4s in parallel) ? There is a formula to work this out but I can't find it.
I intent to Parallel charge 3 packs using 3 chargers, giving me a total 44.4v 15000amh in series
That charger maxes at 150 watts or 7 amps, whichever is reached first. 6 cell packs are about 22 volts so at 7 amps that would be 154 watts, so the charger will start out just under 7 amps, and then the current will drop as the voltage rises. 25V is about the max voltage for a 6S pack so when it reaches 25V the max current this charger will put out is 6 amps. Then the voltage stays constant but the current drops as the battery fills up.
Each 5000 mAH brick will charge about 90% in an hour from this charger. So with one charger three bricks in parallel will take about 3 hours to get to 90%. The remainder takes awhile, not easy to predict how long.
I DON'T recommend reconfiguring battery packs to recharge them. This is how many battery accidents occur. Your pack is similar to the pack I use on my CroBorg. That pack has 12 Turnigy bricks, four in parallel in each of 3 series banks. So it is 18S4P 75Volts max 20 Amp Hours. To charge it with a single Accucel 8150 which is the way I first charged it, I would connect the Accucel to each bank and charge it, then move to the next bank. After doing this for awhile I moved to using a 75V bulk charger for awhile, then I moved to using three 25 Volt 13 Amp bulk chargers. I don't disconnect the pack, I just brought out three charge lines, one for each 6S bank. I monitor the cell voltages every few days through the JST-XH balance connections which are paralleled for each bank, but they are very boringly staying very well balanced.
The XT connections on the Multistars are much safer than the 4mm bullets on the Turnigy packs, so that helps keep things safe. There is still potential for fireworks if the XT main connector and JST balance connection are not routed to the same bank. So it is much safer to do this once, and then charge without reconfiguring the pack. I charge twice per day 5 days a week when the weather is good, so futzing around with a bunch of plugs is not fun.
I've mated the three PowerPole connector pairs into one connection for ease of charging. Here is a bulk charging connection from a single BMSBattery alloy charger, so only the two end connections are used:
In this image the charging setup is three 24V Meanwell LED supplies set for 25.0V, each charging a separate 6S bank at 12 amps (nearly 1KW charging), here at low current at the end of the charge cycle. Note that all three supplies are adjusted to 25.0V, the inexpensive ebae meters don't agree perfectly but I use a much more accurate meter for setting the supply voltages and currents. These Meanwell LED supplies are voltage and current limited, and UL rated and power factor corrected, so no hacking needed. The charging wires tuck into a compartment on the bike so they don't hang out during operation. In my next battery pack upgrade I'm going to move them up near the seat and away from the chain:
