My choice has been Concorde for the last 20 years. I have paid the extra for the platinum series and haven't been disappointed.

I change my battery every 3 years no questions asked. A lot of guys say if it starts it's good but that is not true. I am a serious flyer and routinely fly IFR, over lakes (big ones) and night so I have no problem with buying new and staying fresh. It's the one time you loose charging that will make a believer out of you.

I also use a Battery Minder made specifically for the Concorde battery. It stays on my plane whenever it's in the hangar

That can't be right. I must have linked to the wrong product. I'll check in the Bonanza forum I belong to and get the right info. The cheap Bonanza owners I know that have LI batteries would never spend that kind of money on a battery!

How are you connecting your battery minder? Are you popping the cowl off and opening up the battery box to attach alligator clips, or is it possible to hook something like this up to the GPU port?

https://www.aircraftspruce.ca/pages/...jumperplug.php

Mine is in the GPU door. Works great

Battery Minder
 

I installed the interface kit on my engine baffle - accessible through the oil dipstick door on the front engine. Simple log book entry.

https://www.batteryminders.com/batte...fied-aircraft/

Jeff