I want to charge a 12 volt lead acid battery from another DC source but keep the charging amperage between 5 to 10 amps
Should I use a DC to DC converter, a regulator or what
What is the best way to do this

 

What's the "another DC source"?

 

What's the "another DC source"?

The other DC source is another 12 volt lead acid battery

 

DC to DC converter with current limiter.

But why use one 12V battery to charge another? Why not just swap batteries?

 

The other DC source is another 12 volt lead acid battery

The source battery is connected in-place and receives an intermittent charge from a generator that we dont have access to
So i would like to draw a low amperage charge from the source battery so that we dont flatten it

 

Why not put a small solar panel and charge controller on it?

 

To charge one 12V battery from another, you would need a DC-DC boost converter to up the voltage to about 15V.
That would then go to a constant-current charging circuit to the battery.

 

Directly connecting two batteries will result in one battery gaining some charge, but not nearly a complete charge. So it depends on what you need. Of course, when the source battery is being charged the voltage will be higher and the second battery will gain some more charge than when no charging is happening.

 

Why not put a small solar panel and charge controller on it?

That would work for some but in my case the battery is in a location where we dont have permission to install any hardware like that

 

Can you provide some more details so that we can have a better idea of what sort of things could possibly work. Presently my best suggestion is to periodicaly exchange the one battery for a similar sized one that is fully charged. THAT would certainly work. Probably heavy and expensive, but very effective. With the totall lack of any information except for the voltage that is the best I can offer, and I KNOW that it works.