Manual

www.enerdrive.com.au Page 39
13. APPENDIX 1
Measuring The Midpoint Voltage Of A 24V Or 48V Battery Bank
Being able to measure the midpoint (or center-) voltage of a battery bank that contains multiple
series connected batteries or cells, is an important feature that can save you a lot of money in
case one of the batteries or cells is dying. One bad battery or cell can for example show a high
internal leakage current, causing an excessive terminal voltage deviation compared to the other
batteries in the series string. During charging, the healthy batteries or cells are then exposed to a
too high charging voltage, causing damage to these batteries as well. When connecting several
series strings in parallel, a bad battery or cell can cause even more damage to the surrounding
healthy ones.
Wiring
When installing a series string of batteries or cells, please make sure to only use batteries
of the same age and with identical initial State of Charge (SoC). When you are not
certain if the SoC of each battery is equal, please perform a full charge cycle on each
battery individually before connecting these in series.
When using only one series string of batteries in a 24V or 48V setup, a midpoint voltage
measurement setup can be made easily. The +B1 input should be connected to the positive
terminal of the ‘upper’ battery and the +B2 input to the center connection between the batteries
(between battery 1 and 2 in a 24V system and battery 2 and 3 in a 48V system). Please see the
diagram below: