Hey y’all,

One of the charging ports on my three bank charger failed. Two still work, I’m going to hook up the two that work to my two trolling motor batteries.

Before, one of the working ports was hooked to my cranking battery. My question is, will my alternator be enough to charge up that battery?

It’s a 60 HP Mercury 4 stroke.

I also have a small trickle charger I may hook up to the cranking battery if it’s sitting in the garage for a period of time. Will also check it with my multimeter.

Thanks

If you very much motoring and don’t have a bunch of electronics pulling on it your alternator will probably do the job.

Is this your model? https://www.mercurymarine.com/us/en/engines/outboard/fourstroke/fourstroke-40-60hp

18 amp hour alternator. Does your cranking battery power anything else?

Per the internet,

40 minutes ago, Junger said:

Is this your model? https://www.mercurymarine.com/us/en/engines/outboard/fourstroke/fourstroke-40-60hp

18 amp hour alternator. Does your cranking battery power anything else?

per the internet, yes.

It powers 2 fish finders, which I only have 1 on at a time. That would be the only extra stuff.

Depending on your graphing unit, let's say a Helix 10, it draws about 2.5 amps/hr, and you can manage that by turning down the screen brightness. Your alternator should be able to charge the battery pretty quickly. Like you said earlier, just keep that battery tender handy when your boat isn't in use.

7 minutes ago, Junger said:

Depending on your graphing unit, let's say a Helix 10, it draws about 2.5 amps/hr, and you can manage that by turning down the screen brightness. Your alternator should be able to charge the battery pretty quickly. Like you said earlier, just keep that battery tender handy when your boat isn't in use.

Yeah I have a Lowrance hds gen touch 2 at the console and a garmin striker 7sv at the bow, both pretty low in drawing amps.

I think that’s the route I’m gonna go for now, doesn’t make too much sense to me to blow 300 bucks on a new three bank charger if I have other free options at my disposal to remedy the issue.

I would hook it up to the trickle charger when it's not being used.

You don't want to get to the lake and have the starter battery partially drained to the point where it might not start your outboard.

Also, you might want to consider a boost pack or jumper cables. Just in case.