Not all batteries are created equal. When using a series string or series/parallel bank to create differing voltages and Ah ratings from individual 12 Volt batteries, we can end up with a variance in terminal voltages on each battery, which causes the batteries to become unbalanced.
This situation is often made even worse by the seemingly ever increasing demands on batteries, to run power hungry equipment.
The consequence of all this is that an expensive string or bank can fail prematurely, which is costly in both time and money.
How to control battery imbalance?
Enter the new Victron Battery Balancer.
This recently launched product is the result of Victron’s extensive experience and the knowledge gained whilst working with both conventional and lithium batteries, in both series strings and series/parallel banks.
Earlier this year the new BMV 700 series of battery monitors were launched. Amongst the many new features is the ability, with the BMV-702 model, to monitor midpoint voltage deviation.
Clearly the next stage was not to simply monitor, but also to balance and actively correct any voltage deviation.
With the advent of the BMV-702 and the new Battery Balancer, there is now a comprehensive solution to monitoring and maintaining your batteries, in tip-top condition. Note that both products can be used individually if on a budget, however using both gives the most insight and control.
Technical Information
Here is a precis concerning mid-point voltage deviation and how that can create a battery string/bank imbalance.
Midpoint deviation may well be small when the battery bank is at rest, but will increase:
a) at the end of the bulk phase during charging (the voltage of well charged cells will increase rapidly while lagging cells still need more charging)
b) when discharging the battery bank until the voltage of the weakest cells starts to decrease rapidly, and
c) at high charge and discharge rates.
Note that, a midpoint deviation of only 2% will result in overcharging the top battery and undercharging the bottom battery.
This is why it is important to monitor midpoint voltages and correct any imbalance, to ensure the best performance and longevity of battery strings and banks; be they 24 V, 48 V or sometimes higher voltages.
For an in depth look at batteries and charging see the free book, Energy Unlimited at: https://www.victronenergy.com/orderbook
