Joined the club, killed my house batteries

[gregc]

Well, it was bound to happen.

Noticed online that the boat had stopped squawking AIS data. Very odd.

Took a drive up to the boat to investigate. The work crew that was working on my galvanic isolator must have switched everything off while working on mains (of course) but didn't remember to flip back on the house battery charger.

Alas, house batteries were dead. Got stuff up and running but I figure the AGM bats are damaged enough, and OLD enough to warrant a replacement.

Anyone have suggestions for marine batteries around Seattle/Everett, or is this just an Amazon situation?

 

[Submariner]

Well, it was bound to happen.

Noticed online that the boat had stopped squawking AIS data. Very odd.

Took a drive up to the boat to investigate. The work crew that was working on my galvanic isolator must have switched everything off while working on mains (of course) but didn't remember to flip back on the house battery charger.

Alas, house batteries were dead. Got stuff up and running but I figure the AGM bats are damaged enough, and OLD enough to warrant a replacement.

Anyone have suggestions for marine batteries around Seattle/Everett, or is this just an Amazon situation?

Make sure the lugs are 5/16" and not automotive clamp on posts.

 

[SKing]

Two seasons ago I replaced my AGMs with AGMs. I wasn't ready to change to lithium. If I was making the same decision today I would make the change to lithium instead of staying with agms.

 

[gregc]

Two seasons ago I replaced my AGMs with AGMs. I wasn't ready to change to lithium. If I was making the same decision today I would make the change to lithium instead of staying with agms.

It was/is an opportunity to jump to LiFePO4, but having seen and watched the videos from Submariner, I know I don't have the cash to do it properly this season. And truthfully, I rarely get the chance to anchor out. Dock to dock, always w/ a 30amp shore plug.

 

[gregc]

Oh, and now I have the excuse to mount the BMV-712 thats been sitting on the shelf. 🙂

 

[gswearin]

On your initial question, where to buy, figure out what type and brand and there are a lot of options. I went with the Victron Supercell last time and got them at Fisheries in Seattle. There are lots of opinions here on what to use for replacement batteries. If you are inclined to go with a cheaper battery, Costco sells Interstate marine.

 

[abastos]

Two seasons ago I replaced my AGMs with AGMs. I wasn't ready to change to lithium. If I was making the same decision today I would make the change to lithium instead of staying with agms.

That's interesting, thanks for sharing! I bought my boat last year, and according to the service records from the previous owner, the batteries were replaced in late 2022 with Discovery AGMs.

Before purchasing, I thought converting to LiFePO4 would be my first upgrade. Ten months later, I'm not so sure. I understand the value, but the biggest benefit seems to be when you're disconnected from shore power, like anchored in a bay, for example. So far, we've spent zero nights at anchor. I'm not sure if that will change with time, or if there's a subconscious blocker that will fade as we gain more confidence. Right now, we've anchored for 6-8 hours at a time on Lake Washington during the summer, and the AGM batteries have handled it just fine.

For those of you with AGM banks: have you stayed overnight at anchor? Did your AGM bank provide the power you needed comfortably, or did you have to be frugal? In terms of consumption, we're not particularly conservative and honestly, I don't want to worry about things like "I should turn this light off because it's been on for three hours." I estimate we'd run saloon lights for 4-5 hours, stateroom TV for 3-4 hours, plus two fridges and normal shower/head usage.

Using the Excel file Andrew provided in this thread, I roughly estimate 180 Amp-hours per day. How realistic is that? I have no idea. Assuming the batteries still have 90% efficiency, I could theoretically spend one night without shore power. I've never tested it because I haven't installed the SmartShunt yet, and I have no practical way to monitor consumption. I don't want to risk killing my batteries.

Sorry for this long message in your post, @gregc, but I think I can get some good takeaways from your decision and from others in this thread. I'm questioning whether the lithium investment would pay off in terms of actual benefits. Am I not staying overnight at anchor because I lack battery capacity, or because I lack interest/confidence. Might that change in the future? I honestly don't know.

Thanks and have a good weekend you'all