XPS External Battery Charger

I have a XPS Gen2 M170

Like so many others my laptop will not charge my battery.

(My battery and charge works fine when connected to another XPS system)

I've replaced the DC power jack, but that did not help, so it has to be the mother board that need to be replaced or repaired. I don't want to spend the hundreds of dollars to repair a problem that will most like just happen again, so I'm thinking of try one of the many external battery chargers that are on the market.

Has anyone tried one of these?

Is there a brand out there that works better then any others?

I don't want to get something that's not going to charge my battery or one that will fry it either.

Anyone use one of these with success?