What capasitor to run on a 150v circut?

[verytricky]

OK, getting there.....

Am I correct in thinking that charging the capacitor uses up some of the voltage?

So that if we have your saw-toothed graph, the peaks are chopped off ( ie the Green areas) as the power is used to load the capacitor, and then the valleys are filled by the capacitor unloading power? - So there is no voltage above the Blue line, as this is used up loading the capacitor?

 

[verytricky]

The optimum voltage is probably more like 13.8V.

Not that it is completely relevent, but I wired up the batteries in series, so the battery set should have been able to manage 70 volts? Interestingly only the first and the last battery heated up and burst. The middle batteries were fine.....

 

[Hero999]

It's just lucky/unlucky that the first and last battery burst, it sould have been any of the batteries.

I thought you said that the maximum voltage was 150V which whould have killed the batteries for sure.

 

[verytricky]

Hi,

I thought it was interesting that it was the two batteries I had connected directly to the power, and none of the middle three. Random chance I guess. Thought it could mean something.

Yes, the maximum charge is 150 volts. That is why the batteries popped. I thought I could run it like that for a while to test. I guess not!

I now calculate the maximum voltage I could have put into those batteries is 69 volts, being 13.8 x 5.

When I rebuild the bank, I will set the charge limiter at around 69 volts.

 

[Hero999]

The batteries are in series therefore the current through them is the same.

Before you connect it, I suggest you check that all the batteries are good and there aren't any shorted cells which could result in destruction of the other batteries.

69V is a good voltage to limit it, 75V is probably safe but 69V is safer still.