[johnogbirk]

Hello group. Im working on a small farm tractor, for weeding in rows. Have found a Fiat 211 with the hoe underneath. Really nice. Motor is 36volts. Rated at 3hp continuous. 80Amps.
Instead of buying a 36v charger, or 3 12 v chargers, would it be possinble to use a car type alternator (lying on my shelf), 12v 80 Amps. It will be driven by an AC motor (also on the shelf) from the outlet in the barn.
The plan is to get a cheap and reliable charger. That will give the right charging pattern.
Also from the shelf, a 100A fuse and an on-off switch, which will have to substitute a controller for the testing.
Another 100A on-off as emergency switch, in case the stop-go switch should weld stuck...

About Amps. Will a 100Amp fuse work equally well with any DC voltage; 12, 24, 36 and so on? It will still burn at 100 Amps?

Cheers from John in Denmark

 

[cricketo]

I would suggest not to monkey around and get a used 36v Golf Cart charger - those often go for under $100 on Ebay.

Yes, a fuse will work across a range of voltages and up to its maximum rated voltage. Maximum rated voltage is a product of insulation/arcing limitations.

 

[remy_martian]

Do not use a fuse, a SAFETY device, beyond its rated voltage. Do not use an AC-rated fuse for DC circuit protection.

 

[piotrsko]

Do not use a fuse, a SAFETY device, beyond its rated voltage. Do not use an AC-rated fuse for DC circuit protection.

Other than IR2T conversion issues, why not Ac fuse on Dc? Been doing this 60 years wrong I guess.

 

[cricketo]

Other than IR2T conversion issues, why not Ac fuse on Dc? Been doing this 60 years wrong I guess.

Yeah, I don't know either. Seems like the common practice is to derate them - a 600V AC fuse is good for up to 300V DC. Breakers and similar devices may be a different story due to their more sophisticated nature, but I see a lot of those double rated too, with both DC and AC ratings specified on the package.