Battery replaced - H300 won't boot

[colo]

Hi! I replaced the old battery of my H360 yesterday according to denny how-to-thread (this is the replacement battery: http://www.akkushop.de/product_info....oducts_id=1343 ). I then charged it, but it was never completely charged. Instead it shows the "charging"-logo all the time. I can turn it on when it is plugged in, but only the original FW boots. As soon as I disconnect the H360, the display turns black and it won't boot - neither the original FW nor Rockbox.
What might be the reason? Could it be the wire that might have slipped out or the wire changing wasn't necessary when using this particular battery?
P.S. No offense to denny's guide, of course.
EDIT: Problem solved! It was due to the wires. Thanks!

[shadesbass]

Sounds like the polarity might be wrong. I'd suggest opening it up and checking that the wires are secure (as you suggested). If they are then try swapping them round and try booting up again before closing it.

Although that still doesn't explain why RB won't boot when plugged in... Try the above and let us know how you get on and we'll take it from there. It may be that one of the RB files happened to get corrupted at the same time you changed the battery or something.

[colo]

@shadesbass: Thanks so far. I'll try what you suggested.
looks like the connection between the battery and the rest is broken, so when plugged in Rockbox can't boot (because the original FW is being used) and when not plugged it the H360 has no power at all...