Boat battery charging time

Garcia · 06-05-2021, 06:52 AM

For the first time I can remember the battery in my boat drained. I am guessing it is due to the bilge running for the couple weeks the boat had been sitting at the slip. I used a jump pack to get it going, ran it over to the island (10 minutes) where it sat for the weekend. Dead again Monday. Jumped it, brought it back to the slip (10 minutes), left bilge and everything off and found it dead again on Friday.

The battery was new at the start of the season last year. It's on a trickle charger now. Battery seems to test OK.

Before I worry too much about something drawing power (I have checked all the usual suspects), adding a back up battery or solar charger, I started thinking - once a battery on a boat is drained, how long does the boat have to run to fully charge it back up? I am guessing it takes a long time and the 10 minutes it ran did basically nothing to recharge the battery; my hope is that using the battery charger and bringing it back up to 100% will resolve the issue.

Anyone know how long a 90 HP Mercury outboard needs to run to fully charge up the battery?

I have to say those little portable jump packs are great - I keep one in each of my vehicles.

06-05-2021, 06:52 AM	#1
Garcia Senior Member Join Date: Aug 2017 Posts: 578 Thanks: 130 Thanked 258 Times in 161 Posts	Boat battery charging time For the first time I can remember the battery in my boat drained. I am guessing it is due to the bilge running for the couple weeks the boat had been sitting at the slip. I used a jump pack to get it going, ran it over to the island (10 minutes) where it sat for the weekend. Dead again Monday. Jumped it, brought it back to the slip (10 minutes), left bilge and everything off and found it dead again on Friday. The battery was new at the start of the season last year. It's on a trickle charger now. Battery seems to test OK. Before I worry too much about something drawing power (I have checked all the usual suspects), adding a back up battery or solar charger, I started thinking - once a battery on a boat is drained, how long does the boat have to run to fully charge it back up? I am guessing it takes a long time and the 10 minutes it ran did basically nothing to recharge the battery; my hope is that using the battery charger and bringing it back up to 100% will resolve the issue. Anyone know how long a 90 HP Mercury outboard needs to run to fully charge up the battery? I have to say those little portable jump packs are great - I keep one in each of my vehicles.