John Silverberg wrote on 5/8/2020 12:21 PM:
Hi,

I'm hoping someone with experience with K2 batteries can help determine if mine are due for replacement. I have dual K2 batteries wired in parallel to supply avionics power. I have an LX9000, S8 and V8 varios, trig transponder, FLARM core, and becker com radio running off them. I'm not sure how old they are but they're at least 3 years old as this is my 3rd season with the ship. Yesterday, after a little over 5 hours I got a low battery warning with the batteries at 11.3 volts. I had all the above avionics on but did virtually no transmitting on the com, just listening. They were fully charged at takeoff.

I'm not sure if this normal endurance for these batteries or not, any advice would be appreciated.


I recommend charging each battery separately and completely, then doing a
discharge test on each battery individually at it's 20 hour rate. For example,
discharge the 10 AH battery at 0.5 amps during the test.

While the test is under way, determine the current draw of your instruments. I'd
guess it's high, and over 1.5 amps at 12.8 volts.

Once you know your current draw and the capacity of each battery, you can consider
your options.

If you decide to replace them, try to use a single 20AH battery, instead of
paralleling two 10 AH units, or perhaps a single 15AH if size matters.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1