Voltage and Controller Caps.

cannonball2 · Apr 29, 2014

Am adding another cell(15s total) to my latest battery to get to 60v(actually 55.5v nominal) It comes off the charger @ 63.5v and settles there The cap in the controller is 63v and the fets(6) are 75v. I can replace the cap with a 100v cap of the same uf but don't want to if really not necessary. Gut says it will be ok. Thoughts?

Iceboy · Apr 29, 2014

I think I would replace the cap. While it may never go while running it at its maximum rating if it does it could potentially take out other components in the controller. A higher voltage capacitor is cheap insurance in this case.

cannonball2 · Apr 29, 2014

Good advise, better safe as they say.

cannonball2 · May 9, 2014

Well having a back up controller, I went ahead and used the battery at 63.2v static. The cheapy 48v controller with the 63v cap as well as the (6) 63v caps in the battery+ input lead survived. I noticed no heating of the external caps. We will see how long it lasts. Got a 60v controller on the way, but wont change until(if) the old one fails, just to see how long it lasts.

Iceboy · May 13, 2014

Glad to hear it lasted for you. Just to let you know, caps do not get very hot before failure. They just kind of bulge and then let go. Most will take about 10% over voltage but it is not recommended. Thanks for posting all of this info. It is helpful for some of us contemplating e builds.

cannonball2 · May 13, 2014

I know Its pushing the limits, but sometimes I just have to see what will happen. Actually am now charging to 4.15v/cell which works out to about 62v, at least thats under the 63v max. See what happens long term.

Glad some of what I have posted is useful.

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Voltage and Controller Caps.

cannonball2

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Iceboy

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cannonball2

Well-Known Member

cannonball2

Well-Known Member

Iceboy

New Member

cannonball2

Well-Known Member