shunt precission question

[smilem]

Hello, I see there are panel meters like these nice ones

http://stores.ebay.com/Elite-element/Dual-Display-Combo-meter-/_i.html?_fsub=3083749012

Some are 100A some 20A same voltage and everything, the only difference is shunt used. What about if I use 100A version to measure only 10A Max would be less accurate than 20A version? Or perhaps the opposite?

 

[Bluejets]

Which one...there are quite a few on that page.

 

[smilem]

For example, note the

battery monitors are specified as:
Volt ± 1% + 2byte / Amp ± 2% + 5byte

wattmeters are specified as:
Volt ± 0.1% + 2byte / Amp ± 0.5% + 3byte

So in general I understand that typically you don't need 0.5% for battery measurements because of repeat-ability error.
But Victron Energy makes 300Eur meter 0.01%, maybe their stupid or make it because it's so expensive.

If measuring capacity of Lithium cells the 0.5% accuracy is more than needed I guess. The battery monitors and wattmeters by this seller are the same except the battery monitors can measure reverse current so no need to disconnect anything when charging and loading the battery for test. The wattmeters are more precise and will need to be rewired for each cycle.

50A
http://www.ebay.com/itm/DC-0-120V-0...313281?hash=item27dc9280c1:g:imAAAOSwHQ9WXb5G

100A
http://www.ebay.com/itm/DC-120V-100...294165?hash=item27b1989fd5:g:gWUAAOSwyQtVz1vp