Battery Voltage...Which Meter

[Dick Simonis]

OK, now that I have the Magnum Inverter I have two meter that display battery voltage...the inverter  remote and the CMPII meter.  I am finding that there is a slightly differant reading between them.  I.e. while in float, the inverter show 13.4 and the CMP 13.2.  Under moderatly heavy discharge ~18A the inverter reads 12.3 and the CMP 12.0 so it appears that the CMP is fairly consistantly a bit low.

Any thoughts about which would be more accurate???

The old Xantrex remote didn't have this degree of resolution so the question never came up.   Or, am I just obsessing?

[Karl Welhart]

Dick,

Your obsessing.  Do not worry about that small a difference.  The gauges are not that accurate....

[Gerald Farris]

Dick,
I agree with Karl that you obsessing slightly. The meters are probably pretty accurate, however they are measuring the voltage at two different locations in the system, so wiring resistance can account for the difference. If you are going to use one as a guideline to manage your batteries, I would use the voltage readings on the inverter control panel because the inverter is tied to the batteries with the largest cables and therefore it will have the least resistance drop.

Gerald

[Edward Buker]

Dick,

Depending on where the DC voltage is beng sensed there can be differences in the results. These are voltage losses that take place in the harnesses and because we cannot increase the voltages usually the higher value is correct. The Magnum may also have a sense wire at the battery which provides an accurate value that has no losses. If not the Magnum has a very large gauge wire feeding it with little loss at those current levels.

It is a small difference but useful in determining how discharged the battery bank might be when the load is light.

Later Ed