Battery capacity checks

[Will.iam]

Well i left my battery minder on my battery any time i parked it in the hanger as that is what the previous owner did and suggested that i get a battery minder as he wasn’t giving up his with the sell of the airplane  well one day last month my battery just died on starting. I first thought there might be a loose ground or corrosion on the battery connectors as i figured i would get an early warning like slower cranking before the battery died but after looking in the logbook at when the previous owner installed the new battery it lasted 13 + years. I ordered the exact same model and hope to get another long life span of use. RG24-16 even though concord list the RG24-15 they also say there can be fit problems with the RG24-15 and to call them about options. Probably to suggest the RG24-16 but if that original 16 battery worked that well and fit perfectly in the battery box who am i to argue with success. 

[Pinecone]

22 hours ago, PT20J said:

Agreed, but not that hard if you charge it immediately after the test. It’s a tradeoff. I wouldn’t do it monthly. But maybe 6 month intervals would make sense.

True.  

Maybe annual for the first 3 - 4, then more frequently

 

[PT20J]

It appears from the example in the Concorde document and Eric’s experience that these things go from good to bad rather rapidly. Maybe it’s just smart to just replace every 4 or 5 years if you fly IFR in a predominantly electric airplane. 

[Will.iam]

Mine happened to die when we had the first cold snap from summer temperatures. Seems that can set off the demise and i had no warning. In fact had flown just the week before and had done multiple stops. 
something i had noticed but could be just antidotal was that when i plugged in my battery minder it would go from 3/4 indicator to full in about 10 mins after plugging in the charger. With the new battery it takes longer than 20 mins before it goes to 100% maybe the new battery capacity just takes longer than a worn out battery but don’t know how that could be quantified into when the old battery will fail. 

[EricJ]

8 hours ago, PT20J said:

It appears from the example in the Concorde document and Eric’s experience that these things go from good to bad rather rapidly. Maybe it’s just smart to just replace every 4 or 5 years if you fly IFR in a predominantly electric airplane. 

AGMs in automobiles tend to do that...just suddenly quit.   In AZ it's usually associated with either the first hot weather in the spring or the first cold weather in the fall.    Maybe it's just what AGM technology does.    I did have some warning, but not much time from functional to sketchy.

[T. Peterson]

On 10/15/2024 at 11:14 PM, MikeOH said:

Hmm, maybe...I don't like 'not knowing' what my battery condition is until it fails.  As in, I doubt that any of my annuals have had a capacity check performed.  It was less than $200 for the equipment to perform the test myself.  Concorde has once a year in their manual, so I don't think it's all that hard on the battery.

I certainly respect that opinion. If I was more mechanically inclined with matching skills I may even share it.