usa battery chargers

Know nothing about them. But what is a little concerning is that their website has no real deep information.

Does not STATE that these are VOLTAGE REGULATED. I would assume they are not

(Such terms as "automatically tapers charge" are meaningless and have been used for years)

Nothing on site about parts, repair, or circuit diagrams.

The vast majority of home chargers in the 1/2--20 or so amp range are nothing more than a transformer and rectifiers, sometimes the older selenium, sometimes silicone diodes.

Some have decent current protection, but most just have a simple automotive auto-reset breaker

Some have charging rate switches, but most in the 20A and less class only have 6/ 12 volt selection

Frankly, for the typical unregulated batch of home chargers, there isn't 10 cents of difference in the whole tub full. There is only so much that goes wrong

1--If severely overloaded or abused, the rectifiers burn up. You can replace these yourself

2--Sometimes the breaker gives up from too much cycling. Cheap at any parts store

3--Sometimes the transformer appears to be bad, and many times this is a bad thermal element which is buried in the top few layers of paper on the transformer. I've "fixed" countless transformers by cutting into the paper and either bypassing, or installing a fuse

4--Most destructive is the rare cases where the transformer is actually burned up, and which you have an effective anchor for a very small boat.

One type of thermal fuse. Most I've seen are a little glass capsule