Operating fish finder using lithium battery

[BearLakeFishGuy]

Wiperhunter, Why not take the Li batteries to a battery store and have them tested? It might be that one is bad and is draining the other one. Or both might be bad (having been put on an improper charger prior to you buying your boat. Something isn't right. That set up should last at minimum a LONG day (8+hours) or even two days. You need to get the batteries load-tested. Voltage might be fine, but under a load they could be bad. Also I looked up your brand of Li battery and that company went out of business in Jan 2025 according to their Facebook page.