Harrop 2300 supercharger to Optimiser 6500

[PeeBee]

I have had Optima Yellows go to Zero and have been able to pull them back up to charge. They are a very hardy battery.

Have done it twice now, dead zero, battery chargers wont even look at them. Car alternator/jumo start the only way forward when it gets to that level. Anyway the new buzzer should suffice until my brain finds a way to null it from the picture!