Portable 12 Volt Power Supply

Oka · Post by **Oka** » 14 Dec 2019, 23:32

Sometimes I need a 12V DC power supply. When no fully charged car battery is laying around, I would have to charge one up.
I just searched and found some. One thing, I would not want to spend too much on one. What portable power unit would one recommend?
Thanks.

Post by **volvolugnut** » 15 Dec 2019, 10:35

First question is how much current do you need? Very low current could be supplied by two 6 volt flashlight batteries in series. Or do you want to plug a 12 volt power converter into wall outlet?

volvolugnut

Post by **cn90** » 15 Dec 2019, 11:38

Go to amazon and search "battery portable charger for car".
They can be bought for $45+.

Post by **abscate** » 15 Dec 2019, 12:58

A small 12 volt power supply will be about 1/4 the cost of a 12 V charger, for 5-10 amps

Oka · Post by **Oka** » 15 Dec 2019, 14:57

volvolugnut wrote: 15 Dec 2019, 10:35 First question is how much current do you need? Very low current could be supplied by two 6 volt flashlight batteries in series. Or do you want to plug a 12 volt power converter into wall outlet?

volvolugnut

Just like the car battery would - 12-Volts. The "12 Volt power converter" may be what I need than getting a portable rechargeable unit that would produce 12 Volts. Working on a car and need to test a relay with a 12V power source.

Oka · Post by **Oka** » 15 Dec 2019, 15:15

Oka wrote: 15 Dec 2019, 14:57
volvolugnut wrote: 15 Dec 2019, 10:35 First question is how much current do you need? Very low current could be supplied by two 6 volt flashlight batteries in series. Or do you want to plug a 12 volt power converter into wall outlet?

volvolugnut
Just like the car battery would - 12-Volts. The "12 Volt power converter" may be what I need than getting a portable rechargeable unit that would produce 12 Volts. Working on a car and need to test a relay with a 12V power source.

The AC to DC power converters I like has the cigarette lighter end adapter.

Just wondering. What if I connect a battery charger to a car battery as if am charging it, than tap from the battery connections?

Oka · Post by **Oka** » 15 Dec 2019, 20:03

cn90 wrote: 15 Dec 2019, 11:38 Go to amazon and search "battery portable charger for car".
They can be bought for $45+.

A battery charger did not give me what I need. I have a Schumacher SE50 I connected to a car battery, tested the connections and it was 15+ volts. I connected my 600A heavy duty jumper to the battery, it was twelve volts at the connections. I used the later to do a test on a fuel pump relay. So, battery charger does not do what I need. My setup was clunky but at least for now, it worked. Would really need a unit from AC to DC (12V).

Oka · Post by **Oka** » 15 Dec 2019, 20:04

abscate wrote: 15 Dec 2019, 12:58 A small 12 volt power supply will be about 1/4 the cost of a 12 V charger, for 5-10 amps

The 12 volt power supply I have been seeing are with cigarette lighter end for the 12 volt output.

Post by **cn90** » 15 Dec 2019, 20:35

I am confused.
The Schumacher SE50 does not provide what you need?
It is converting 120V AC to 12V DC.

Post by **cn90** » 15 Dec 2019, 20:37

Or install a brand-new battery in the car and keep the old battery as a "tester".

Of course, charge the old battery once every 2 months or so.