Wiring Idea Needed

[Offtwice]

I want to wire a 12 volt battery to power a fuse panel, but also want the ability to use a (72v to 12v) voltage reducer as a backup to power the fuse panel.

I can easily switch the power reducer to power on and off as necessary but am unsure if I need to switch off the battery power to the fuse panel.

Is there any harm to powering the fuse panel with the 12 volt battery and allowing feedback into the output side of the power reducer when it is powered off?

Would there be any issues if the power reducer were powering the fuse panel at the same time the 12 volt battery were providing power to it also?

Thanks for the feedback.

[DOOmsman]

Off, I can't answer your question, however a double throw double pole switch would work for isolating the supplies.

[TheWiltz]

12v from reducer and 12v from battery would produce 12v at fuse block. But your amperage at fuse block would be the total amperage of both supplies added together. You are running power sources in parallel.

In series you Add the volts together. In parallel you add the amperage.

As for as the back feeding I'm not sure.

[Hoof Hearted]

I would think that if your battery (12v) was lower than whatever the actual voltage supplied at the output side of the reducer was (say 13.1v) than your reducer would be "feeding" voltage to your battery reducing the available amperage when running accessories (and the reducers supply about 20 amps depending on model).

I would run a battery (switchable between two batteries) switch, many are available. You can get these at marine supply places or probably Amazon or Egay.

Just wire both supplies to the switch and then to the fuse block.

I am in the middle of becoming a distributor for a place that sells this type of electric supplies as well as LED lighting. If you are running lights remember for incandescent Watts devided by volts equals amp draw. An LED equal to the output of most of the incandescent driving lights only draws 2 to 3.5 amps. This will increase your battery run time 10 fold!

[sonicj]

Originally Posted by Offtwice

Is there any harm to powering the fuse panel with the 12 volt battery and allowing feedback into the output side of the power reducer when it is powered off?

Check the datasheet for your specific converter. I know this is not a problem with Sevcon DC/DC units. I can't speak for others.... If in doubt, you can use a diode.

Originally Posted by Offtwice

Would there be any issues if the power reducer were powering the fuse panel at the same time the 12 volt battery were providing power to it also?

No.

-sj

[Hoof Hearted]

Originally Posted by sonicj

If in doubt, you can use a diode.


-sj

This would be the simplest route (I overthunk it.......)

[Offtwice]

This is a great solution!! Thank you!

Now - I have never purchased a diode before - the reducer puts out 25 amps - is that how I determine the size to get? Any recommendations where to get one?

[Andy4639]

Something like this should work.




I have a singal one on my 2000 EZGO to turn the pack off with.

[TheWiltz]

Just remember that diodes Can get HOT. May require a heat sink.

[Offtwice]

Originally Posted by TheWiltz

Just remember that diodes Can get HOT. May require a heat sink.

Good suggestion - I need to research diodes and see what is available