Discharging Batteries

[Burgerman]

There are occasions where we need to discharge a battery.

The PL8 is useful. It can graph and measure a battery accurately. But it cant do it fast. so we have to wait. But if you are prepared to fiddle with settings and voltages then we can do it fast. The PL8 can discharge at up to 40A. Into another battery. Or if you are prepared to play, into a load!

I use this.
Its a 24V 30A load. Thats better than the the 100W the PL8 allows alone.
It actually measures about 35A at out 26V battery voltage. But it used to get so hot it burned my bench. So I added an old PC memory fan unit out of my drawer. Now you can hold your hand on it. So not bad.

If you set your PL8 to think its running on a battery, then set to a sensible Amp level, and then set the power supply JUST BELOW this voltage, then the power supply runs the idle PL8, and the load. When you start a discharge it regeneratively takes over from the power supply, and tries to hold the "battery" it thinks its regeneratively charging to say 29.4V or whatever you set the regen to. So it allows you to discharge at a high rate.

RIGHT WAY UP!

[Burgerman]

This one takes a little understanding. So if you dont get it I dont really know how to explain it better! Its a workaround that allows the PL8 to discharge fast, that YOU must understand!!!

These are available as huge resistors, or as these as above - minus the fans - as dump loads for wind generators. I used this one for years. Works OK once you figure out the Amp, and volt settings on thje POWER supply and the PL8!

[Scooterman]

Remove the fan and chuck it in the bath. That way you can have a nice long soak for free

[Burgerman]

That would actually work.