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General Category => Magic Pie & Smart Pie Discussions => Topic started by: daggysheep on October 03, 2011, 11:28:11 AM

Title: 2x2amp Chargers in parallel?
Post by: daggysheep on October 03, 2011, 11:28:11 AM

Hi

I'd like to use 2x2amp GM chargers to speed up my GM 36V16Ah battery charge times.  Does anyone know if this is possible to do by connecting them in parallel?  I assume I will get 4amps charge and the battery bms will manage the rest?

Any words of caution before I blow something up??  Much appreciated!


ps: I bought a GM 36V16Ah battery last month....actually I note it's just been taken off the website now...maybe because it is old chemistry Li-Mn.. battery great so far, I like 42V off the charge! The addictive taste of pie power!

Title: Re: 2x2amp Chargers in parallel?
Post by: e-lmer on October 03, 2011, 12:13:19 PM

I am pretty sure that is a bad idea.
The chargers are (allegedly) smart.

They provide a voltage to push a current,
but they measure the current drop to
know when to stop charging.

Parallel chargers may stop this feedback
from happening

Title: Re: 2x2amp Chargers in parallel?
Post by: daggysheep on October 03, 2011, 01:00:17 PM

Ahh that kind of feedback would be a problem!  Thanks e-lmer!  From what I understand you're saying, even if I put in a diode between both the chargers the current drop would not be properly sensed by each charger for the cc to cv switch in charge mode....  Not such a great idea, I think I'll forget it then.

Title: Re: 2x2amp Chargers in parallel?
Post by: e-lmer on October 03, 2011, 10:14:41 PM

Having said that, some kind of switch to turn off one of the chargers
(relay disconnect from battery, not wall power)
Would let you ramp up the charge for half the cycle or so.