What is Midpoint Voltage and it it important?

[bobcat22]

Originally Posted by Snore

Guys

Based on MaineSail's comments I am going to trust my "persnicketiness" to ensure all is wired correctly and remains so-- thereby negating the need for a smartguage.

Cheers!

Bill

Midpoint voltage measurement is an important feature when you have batteries wired in series. Cells in series may look all fine at rest, but with heavy charge or discharge the differences can turn up. The bad cell will cause an imbalance and this may result in some batteries getting overcharged and gased or undercharged. In either case lifespan is cut short.

With midpoint measurement you can tell if there is an imbalance between the two halfs. That doesn't tell you which cell or battery is bad, but it does give you a heads up so you can take remedial action.

With an even number of batteries connected in series (like two 6v golf cart batteries in series to make 12v) the normal measurement is the total voltage of the series. With the Victron BMV 702 or 712 it can measure each half of the string and give an alarm if they are out of whack by some degree. They should be about the same.

I have two 24v banks wired in parallel. Each bank is made up of four 6V batteries. I am using the BMV 702 to measure the midpoint voltage accordingly. The difference in cost over the 700 is nominal.