Battery charger

[jstafford]

My 42 grand banks has an old outdated 30 amp charger that I think I should replace. I have 3 wet batteries. A 4d for the generator starting and two 8d that are engine start and house. I'm thinking I need a 3 bank smart charger but no clue from there. I'm in a slip with power. Need to keep costs down.

[Thorne]

So you have three separately-wired battery systems?

Lots of different smart chargers out there, but I'm not sure which would be best for your setup.

12 Amp 3-bank smart charger $150
https://www.amazon.com/NOCO-GENM3-Wa...attery+charger

$130 4-bank
https://www.amazon.com/Battery-Tende...attery+charger

$230 3-bank 20 amp -
https://www.amazon.com/Powermania-M3...ger+waterproof

[jstafford]

I wouldn't say 3 separately wired systems. The 4d is starting for the generator, the two 8d go through a selector switch. In the engine room is a box with a disconnect for each battery. I saw a disclaimer on a NOCO that stated it was not comparable with a 4d that I found odd.

[Breakaway]

Don't overthink it. Get a three-bank, 50 amp smart charger. Get one UL-rated marine.

If you start using gel or AGM batteries, you'll need to do some more homework.


Kevin


Sent from my iPhone using Tapatalk Pro

[jstafford]

Ouch, my planned expenditure of $150 just went to $400??? Is there a cheaper viable option than the ProMariner ProNautic 1250P? I want to replace the current 30amp buzz box because as a maintenance charger it is junk. I get the charge time calculations for my three batteries pushing up the size of the charger. The reality is though that I don't think, for at least the short term, I am going to use up my batteries. Remember, I'm trying to get an old girl back up and working after being on the hard for 5 years. Like me she is going to take things slow to begin with. Most of her days will be sleeping in the slip plugged in to a nice warm shore power. I think as of today I need a bigger version of a battery tender. The 4D only does generator start and as of right now the generator has control issues and is not running. I do plan to hopefully get it fixed next month but even then that battery is going to start the generator and then get charged right back up. So it should never get drained low. The two 8D are switched to act as engine start and house. Once the motor starts it is feeding back into the battery. For house draw all I have is electronics and lights. With the switch I can ensure that at most I only kill one of the batteries. So for the short term anyway can't I get away with a $150 3 bank smart charger? Or is this just another bigger boat bigger bills suck it up and pay the piper thing?

[Thorne]

Jstafford -

I was wondering the same thing myself as to why folks were recommending such high amperage chargers. I could see that for an electric motor house bank, but not for something with minimal use like yours.

[Breakaway]

^ I recommended a 50 A charger based on the size of his boat, and a guesstimate of the electrical demands the systems of such a boat demand. I based this on my experience running 40- and 50-foot powerboats. I like to be able to bring drawn down batteries up even while simultaneously supplying a full suite of 12-volt gizmos.

But certainly, as long as the limitations are acceptable to you, a charger with smaller output can be used.

Kevin

[jstafford]

I get, a 50 amp charger is what this battery capacity needs and I appreciate Breakaway's recommendation. It is spot on. I'm just wondering 2 things. Is there a good choice other than the ProMariner ProNautic that may be cheaper? I am not seen any competition for them. Secondly, in my situation would it be smart at all to kick the can down the road a bit. Get a cheaper charger today that will keep batteries up to snuff as they are not getting used hard and then once I get the old girl up and running and my battery usage becomes greater then upgrade?

[Favorite]

Is there a good choice other than the ProMariner ProNautic that may be cheaper? I am not seen any competition for them.

Don't know if they are any hceaper but the Victrons do multiple batteries and have a good reputation. Craigslist time ?

[Thorne]

I'd confirm that the NOCO won't work with the 4d before eliminating that brand. This $99 NOCO 8 amp 2-bank might work as an interim charger that could then be deployed elsewhere later.
https://www.amazon.com/NOCO-GENM3-Wa...2Bcharger&th=1

[jstafford]

Went and worked on the boat today. I took with a small smart charger i narrowed from work. I replaced the 4d about 6 weeks ago and wanted to check it and charge it since its been out there in the bitter cold. Hooked up that little charger and let it do its thing. After it ran all its tests it shows a 75% charge. Let it run while I worked the fuel polishing project. Checked it an hour or so later and it was 100%. I looked over the existing charger set up and came to a conclusion. Until the old girl is up and running i need to pick my battles carefully. I'm going to pick up a charger like I used for checking status and small amounts of charging. I can use one like that around the garage and at the boat. Use the current big buzz box for when they get real low, it's good at that I think. Hold off on the upgrade for now.

[jstafford]

Holy moly, that charger was like $200. I thought the young engineer that bought it said is was like $50.

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[Puttputt]

It looks as if you’ve found a decent temporary solution but you may want to take Kevin’s advice to heart.
I believe you’ve mentioned you won’t be splashing the boat for awhile...but it’s not too early too figure out your battery load for the day you leave the dock.
When you combine running lights, cabin lights, anchor lights, the fridge(s), bilge pumps, and all your electronics you could easily go through 120 amp hours in a 24 hour period. And that’s without an inverter.
42 feet is a lot of boat. If it was me, i’d want at least 4 deep cycle and 2 starting batteries. Pro mariner chargers aren’t cheap but they have a good reputation. Sometimes you can find somewhat discounted prices on eBay or an online marine chanderly.