Solar voltage help...

Almot wrote:

Captain Obvious wrote:
In looking at it and reading through the engrish manual - it looks like it just dumps solar voltage onto the battery off and on until the battery looks charged around 14v, and then it stops dumping voltage until the battery voltage drops again. It's not a PWM and definitely not an MPPT charger.

They never put MPPT in those kits. And you wouldn't like el-cheapo MPPT if they did.

Even the most epxensive PWM works pretty much the same: voltage goes to pre-set point of 14-something (called Bulk), stays there for an hour, and then it tapers the current to let the voltage drop to 13-something (called Float). The biggest drawback of el-cheapo PWM I see in their inability to adjust those Bulk and Float setpoints - important because every battery has different setpoints, and also in lack of temperature compensation. Lead is getting more and more expensive, as all raw materials, so taking good care of your batteries makes sense. Low-current PWM with adjustable setpoints and temp-comp are not terribly expensive.

If you buy a $12 pwm charge controller like this on ebay ... Adjustable V + - 0.9V for bulk and float modes.

you can then choose your set points based on battery types. Anyone, before buying one of these units, should tie a watt meter charge controller, preferably a RC battery charger model, in line to see what actual voltage and amps are.

RC boat helicopter Watt/ Amp / volt meter for charging.

I can assure you, once you start paying attention to what this unit meters, as I have, you'll know for certain that even the stock PWM on that portable unit does indeed pulse charge at different volts and amps, constantly, in bulk mode.


A basic replacement model, if your original charge controller goes bad.

solar charge controller for Solar BLVD 120-160 watt panels.