Hi Joe,
Thanks for that info. I bought four used batteries of that size, not Gill brand, and none of them were usable, so beware. These are starting batteries, designed for high current for a few seconds, then recharge at high current but from a voltage regulated source, just like a vehicle system treats them. I eventually recycled them (recycle just like lead acid battery, which they are). These also have a limited shelf life. They have to be topped up every few months or they go bad.
What I am saying is, if these are take-out batteries, they were probably taken out for a reason. My guess is they were not maintained and/or just one attempted aircraft start with the battery low caused cell damage.
But, if these are newish batteries, maybe rejected due to long shelf life, even if they have not had recommended maintenance charges, WOW, you have a great source there. The MFG date should be stamped into them. Those larger batteries would be great in a smaller 24 v vehicle. I thought about using them in my U-1300 Diesel but would need higher CCA, and these batteries don't parallel well without discharging each other. Would need relays to parallel them only while starting and running.
I bought another four Concorde aircraft AGM's (smaller batteries) model RG24-15 (about 15 AH) that had 'expired' with no maintenance charge, and they still work great. Even with the low 15 AH rating (meaning not too good for solar storage), they have relatively high CCA.
I have used these smaller AGM batteries for about 3 years now for starting 404 Unimogs (rather low current requirements) but mainly for 24 v radio use. I have run my Lube and Service trailer off them, and they would be adequate for most any 24 v generator. I have just bought a 40 ft light tower trailer with 5 kW generator and will put a Concorde battery in it.
I charge these with a voltage regulated power supply with current limiting. Again, charging is critical so don't try the normal cheap charger with simple transformer and diode innards. In my experience, don't float charge them. Get a manual and heed it.
Thanks for the offer but transport cost is prohibitive. If I ever get up the 81 slab to your vicinity (I am near Knoxville) I'll be looking you up!
[edit: what type connector? If the aircraft type, some aircraft salvage yards have them. New ones are expensive! Are they like this?
http://www.concordebattery.com/accessories.php?id=51 ]
Bob
WB4ETT
Bob, just got the batteries in. They are the concord type, made by Gill. 24V, sealed,88.5 pounds, 600 CCA. Let me know if you have a need for them or if you have any ideas for their use. Joe