I have a battery issue in my 36 V system. I have 3 Group 27s, and 1 will not take a charge. I have elimintaed the bank charger, as I have swapped leads to verify that is not an issue. I have cleaned all the connections and the battery posts. The chargers still has an error on 1 battery stating check connections, on that battery. So that battery will not take a charge.
So my main question is I have a spare Group 24 (and it will take a charge off the same charger lead), if I place that with the other 2 Group 27s... Will that harm the system in any way, as it is still a 36 V, just unbalenced batteries? I guess I am asking this because I would prefer to make it a few more months, and purchase a set 3 new batteries for the trolling motors in the spring, and not an add one this fall. The current batteries are 40 months old.