Help with Venom Pro Charger (displaying wrong voltage?)
 

Just bought a Venom Pro Charger per LHS recommendation. I'm trying to figure out how to use it and have some questions (the manual isn't exactly comprehensive...)

I'm trying to charge a new Orion 3500 25C lipo. When I set all the parameters (lipo mode, 3.5A, 7.4V 2S, 3500mAh) and start charging, the display shows the battery voltage going beyond 7.4V (like up to 7.5V) and when I hit the "status" button, it says "end voltage 8.4V". That can't be right, can it?? Can I charge it to 8.4V?

Also, it seems to charge very quickly. It went from about 6.4V to 7.5V in a couple minutes. That can't be right either....can it??? I thought lipos were supposed to take a long time to charge.

Thanks in advance. I really want to get this figured out without blowing anything up....

Maximum safe voltage for a 2S lipo is 8.4v.

A 2S lipo should charge to 8.4volts since cell maximum voltage is 4.2v/cell. Don't confuse the "nominal" lipo voltage of 3.7v/cell (7.4v for a 2S) with the max voltage. Nominal voltage is jsupposed to be the voltage under load, it has nothing to do with what the charged voltage.

The charge routine for lipo is 2 steps - CC/CV. Lipo charges at constant current (usually 1C, but sometimes its higher, depends on the lipo) until teh max cell voltage of 4.2v/cell is reached. Then the charger switches to constant voltage, holding the max voltage on teh lipo as it tops off. In this stage you can watch current fall off to zero or close to zero as the charge finishes.

Sounds like charger is doing exactly what its supposed to and everything is fine.

That's the best answer you're gonna get. It would seem to me that your LHS should really have explained this to you. Doesn't sound like a very helpful shop to me. I'm bashing your LHS not you.;)

Cool, thanks for the quick and thorough answer. The charger is working as it should.