I bought an AGM battery 2 years ago and now it's dropping down to under 12 volts with only after only an hour of fishing. So while checking the battery, I decided to check my battery charger. No voltage output from the leads to the cranking battery. Just great, had to order a new charger but I did run the boat quite a bit after turning all electronics off Saturday so the battery shows fully charged on my load tester. Here's the deal... I can fish for one hour with my LS, Helix 10 and Solix 12 on and the voltage on the batteries drops down below 12 volts. These are the exact same issues I had with the lead acid battery that I replaced with the current AGM.

On the load tester that I have you are supposed to hold the switch down for 10 seconds. That engages a heating element of sorts. It got hot and the batteries amps didn't drop. I then waited about 30 seconds and load tested it again. This time I held the switch engaged for about 20 seconds. The element was glowing red. It looked like a branding iron. The amperage didn't drop.

So, if my battery load tests good, why is it draining so fast?

If my battery is bad, I'm considering replacing it with a Lithium. If any of you are running Lithium batteries, how large would I need to power the 3 afore mentioned units and crank my battery? I'm either going to do that, or replace it with a cheap Lead Acid battery and just swap them every year.