55A power supply, PL6 charger, only 21A output...why?

[dendenyc]

I have a 1200W, 24v power supply capable of 55A output. I have a PL6 connected to it charging 6 x 6S Lipo's. All Lipo's are 2600mAh. I chose a high power preset and set the charge Amps to 40A in the preset and hit start. The charge cycle has been going for about 30min now however the charger never seem to go over 21.5amps. I know the charger is capable of doing 40A. Where am I going wrong here? Where is the rest of the juice, it would be nice to be able to balance charge these cells faster. Anyone know why I cant charge at full capacity of the charger?

[Gregor99]

Two things. Increase the supply current limit and use the high power preset. More info here.

FAQ - Powerlab Quick Start Guide - Wiring modes, Supply Limits and 1s charging

[jchen]

Hi Gregor,

I set it to 40 amps. My psu is suppose to output max 47 amps
at 12V but when para charging two 5000 mah 6s lipos, it will
go only to 16amps max. Since the voltage is step up in the
the charger, I should at least see 20amps during charging
right ?


Thanks

[yhchoong]

Jaff, if you don't mind me answering here's what I think it is.

The power supplied by the HP unit is 12V x 40A (since you set the cap to 40A) which gives 480W.

I assume a typical efficiency of 80% at 12V for the PL8 (it's more efficient as voltage increases so 24V will yield perhaps 85%).

So at 12V that means the PL8 is only able to utilise 80% of that 480W supplied by the power supply which = 384W. This 384W is the real-world current amount that makes it to your packs.

So 384W / 22.2V (for 2 6S pack in parallel) = 17A, which is approximately what you are getting.. (if you divide 384 by (6 x 4.2V) at the end of charge you get 15.3A) so 16A that you get sounds about right.

You should be able to get *fingers crossed* your 20A if you set the current cap to around 45A or 46A. (The HP unit has been tested around the forums to be stable up up 50A without breaking a sweat so its 47A rating is actually conservative - I set mine to 45A on my PL8).

[Gregor99]

Higher input voltage is required for 6s high current charging.

[jchen]

Hi YL will give it a shot & thks again Gregor