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Powering bench/lab power supply off cig socket

Joined
Jul 6, 2020
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Hi all,
Doing a small trip in a car and want to run some equipment while I'm moving around and I want to charge my lifepo4 battery while I'm driving.
I don't have a DC to DC charger spare.

Would it be okay to run a bench power supply off a 24v cig socket in the truck and charge the 12v lithium with it?
Or is the alternator power too "dirty" for the electronics?

I would be using a RD6012 lab power supply
 
It depends on the amp draw and circuit capacity. Alternator is straight DC power, but how do you get 24V to a cigar lighter plug?
 
I would say no, but if you try it, I'd like to hear the results, hopefully not in the up in smoke section.

You have a DC to DC converter not just to match voltages, but to limit amps. Potential is there to suck too many unregulated amps through the cigarette lighter and pop the fuse. That and the voltages would be way unmatched, with the real potential to swell cells if it truly is a 24 volt socket.

I've seen people charge 12 volt lead acid batteries from a socket by doing what you say, and I consider that very unwise. If it 12 volts for the socket, the low resistance of lithium does have the potential just like mentioned before of overamping the socket and blowing the fuse. Depending on your alternator and charge profile, you could provide too much voltage to the lithium batteries and cause the cells to swell.

If you're talking using a inverter to power the bench supply or maybe the bench power supply has a DC input, then you'd have to see. I have not had luck at using the cigarette socket to power anything higher wattage, which I think is 100 watts. There's the fuse its attached to and also the skinny wiring as a limitation. If its a 10 amp fuse, you could get 120 watts (10 amps x 120 Volts) before the fuse pops, but probably would be less than that with any surge.
 
Thanks for the reply guys,
So the vehicle is a heavy truck which has a high current 24v DC alternator.

The RD6012 lab power supply takes a DC INPUT of 6-70 volts and has a max output current of 12 amps.

I was just hoping to run the power supply at the 14.5 volts to get 12amps and 174 Watts. Being that that is only just over 7amps the truck infrastructure will be fine.

My biggest concern is just considering, what could try the supply.

Charging at that 12amps in to the battery will provide good charge for my creature comforts for the drive.
 
For a fixed volt output - CV - and variable current, I would set it for 13.6V to float it. Should work fine.
The 24v input doubles your converted output amps, less any efficiency losses.
 
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