Cal,

to me it looks like it's designed that full amps would run through that, but it is limited to 10A.

I bet there is a low ohm resistor in there calibrated with a voltage gauge to display as current.
Not sure what your peak running amps is. You could bypass it with a switch for sure, then just switch the ammeter in when you want to check. That would prevent it having to tolerate all the current and heat.
Heat is a function of amps in a device like this, so it's limit is going to be heat dissipation and overheating, so if you only switch it in when needed, it will survive a lot more. Perhaps it will be willing to read higher amps, but if you put 20 amps through it I bet it will blow after a few mins. It's all about cooling and time. If the resistor is inside the plastic enclosure it will not get much cooling, you could cut the back open if you wanted to cool it more. even add a heat sink to that resistor.

If you're using up 4 of those full batteries in 8 hrs, that would be one per 2hrs, ~500Wh/ hr. at 24v. =20 Amps, does that sound right?

On Mon, Aug 31, 2020 at 7:50 AM Electri-Cal <calboats@...> wrote:

The volt/amp guage is from  ------ cosupower888 ------  item #  363000785546

Yep, just the gauge, the box, no install notes, or anything beyond the info. on the eBay web site.  No mention of any bridge, hole size or uses.   I did look up other eBay identical gauges, some with more info.  I did just find that my inside boat long term battery charger also as a side effect made the instruments, and 12 volt converter for that quite warm, huh !!  I disconnected that and will check it today, maybe put a switch right close to it.  Looks like I need to isolate the charge current from going there, and find out why it would.  Even with all accessories shut off, that makes me wonder if there is an accidental drain going on that I don't know about.  Will look at that today, while I'm doing more boat stuff. 

I haven't turned on the instrument lights while running before.  I just used them as charge checkers, and the depth finder as a battery drain, since that buzzes, and shuts down.  I will figure the actual cut off points and use the LED instruments more now, probably make indicators for amp power for best range on the dial face.  A few things I didn't get to (forgot or lazy) while I was having  hip operations, and recovery months without boat oriented movements. 

Later coots,  ---- Cal



Later,   Cal