"Tony Hwang" wrote in message
news:3tRPj.87705$rd2.70935@pd7urf3no...
Hi,
Battery can be tested with meter and a 12V light bulbs.
Are brushes worn out? Is the commutator show a sign of groove?

Well, brushes seems still quite a bit left. But if I know where to get new
ones, I would easily replace it.
The motor commuatator looks OK. I know of wipe and clean it a bit.
Meter measurement of batteries seems OK. But cannot test how strong is the
charged current.