robertsears1
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The airplane that I fly and manage uses a 24 V nicad battery made by Marathon. A new one was installed last year and should have lasted several years since you can replace any bad cells at a time up to 5 (it has 20). However, this year, I did something wrong while trying to get the right thrust reverser to stow on the ground that came unlocked (it isn't supposed to do that) before a start and got the battery too hot once. It seemed to work fine afterwards for the next 7 months until it was tested during an inspection in December and found to have 13 bad cells and would not pass. The replacement was $8400. The good news is that it now cranks over my MEPs like nobody's business. So far I have been using jumper cables to connect it to the generator being cranked since it uses a connector called a el conn and ones on ebay from old aircraft fetch over $150. I think I can figure a way to feed cables with lug ends into the connector hole on the side of the metal case since the cells have approximately 5/16" size machine screws holding everything together inside. It certainly spins up the generator being cranked much faster than lead acid batteries.
The battery had been shorted out by the maintenance folks before they gave it to me after I said I wanted the old one. I removed the lid and removed a bonding plate to make essentially two 12 volt batteries which I then used my battery charger to charge after testing if the cells would respond. Yes, I probably could have started a generator and then disconnected the cables from the generator batteries and clamped the jumper cables and used the 24 V system to charge it but at that point, I wasn't totally sure if it would blow up something. I now probably have the most expensive battery in the country starting MEP generators
Robert
The battery had been shorted out by the maintenance folks before they gave it to me after I said I wanted the old one. I removed the lid and removed a bonding plate to make essentially two 12 volt batteries which I then used my battery charger to charge after testing if the cells would respond. Yes, I probably could have started a generator and then disconnected the cables from the generator batteries and clamped the jumper cables and used the 24 V system to charge it but at that point, I wasn't totally sure if it would blow up something. I now probably have the most expensive battery in the country starting MEP generators
Robert
