Charger for my 24 volt set up

H@ystack

Petty Officer 2nd Class
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Apr 5, 2015
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101
Hey all. I think I know what I'm doing but checking one concern.

I have two 12 volts batteries for my trolling motor. I have the marinco receptacle with charging plug. Basically it comes with 2 plugs , one black for your trolling motor and one red for the charger.

Basically I need to buy a charger and wire it to the red plug which I can plug in to my boat and will charge the 2 batteries.

I am told by marinco that I can use a 2 bank , 20 amp charger, 10 amps each bank. Basically take the 2 bank wires and splice them in to the red plug. 2 positives from the charger to one pole in the plug and the same with negative making the total 20 amps.

With a trickle or float charge I'm concerned that it won't read the charge right or should those batteries deplete and charge evenly. Same batteries, same age.
 

fishrdan

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Jan 25, 2008
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Is this the Marinco 12/24 plug and receptacle set?

If so, the red plug (actually both) has 4 screw terminals internally, so you can take a 2 bank charger and connect the batteries independently, that's how I would do it, so each battery is being charged by it's own bank of the charger. You "could" combine the charger outputs (if the charger allows), but that defeats the purpose of the dual bank charger.

Actually, I would mount the charger in the boat and connect the charger leads directly to the batteries, permanently. Much easier to charge the batteries as you only need to drag an extension cord to the boat and plug it in.
 

H@ystack

Petty Officer 2nd Class
Joined
Apr 5, 2015
Messages
101
Is this the Marinco 12/24 plug and receptacle set?

If so, the red plug (actually both) has 4 screw terminals internally, so you can take a 2 bank charger and connect the batteries independently, that's how I would do it, so each battery is being charged by it's own bank of the charger. You "could" combine the charger outputs (if the charger allows), but that defeats the purpose of the dual bank charger.

Actually, I would mount the charger in the boat and connect the charger leads directly to the batteries, permanently. Much easier to charge the batteries as you only need to drag an extension cord to the boat and plug it in.
I considered mounting one but I already hate the limited room in this boat storage and there's no real good place to run screws through to hold it in place (it's a 2016 Carolina skiff jvx18)

I didn't realize the red had 4 leads too. That makes sense now. At least my concern was confirmed by their set up once again.

Correction: I cracked it open after this post. It has only 2 slots. 1 pos 1 neg in the plug.
 
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bruceb58

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Mar 5, 2006
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30,454
Actually, I would mount the charger in the boat and connect the charger leads directly to the batteries, permanently. Much easier to charge the batteries as you only need to drag an extension cord to the boat and plug it in.
I would do this way too. You must have some room to mount one right?
 

fishrdan

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I didn't realize the red had 4 leads too. That makes sense now. At least my concern was confirmed by their set up once again.

Correction: I cracked it open after this post. It has only 2 slots. 1 pos 1 neg in the plug.

Not sure if we are talking about the same thing or not (post up a pic of what you have, or link to it), but if it's what I think, both the red and black plugs have 4 external prongs. Same goes for their internal configuration, 4 screw terminals, with a clear disk that blocks some of the screw terminals.

Under the clear disk are (1 or 2) silver jumpers to make the serial and parallel connections for the batteries, parallel for the red charging plug. If you remove the clear disk and jumpers, and drill an extra set of holes through the clear disk, you can connect both sets of charger leads to the plug independently. I have done this on a couple of the plugs to get them connected the way I wanted. This takes reworking the plug a bit, but it's better to have the batteries separate when charging them. I mark the opaque colored plug body with red and black Sharpie markers, so I can tell at a glance which terminal is which. (You DON'T want to get them mixed up...)

"IF" the charger can combine it's outputs (some can't), you could simply wire the charger outputs to the existing 2 holes in the charging plug, but I would advise against doing it this way. Heck, I have a Schumacher 20 amp automotive smart charger I bought 10 years ago that would probably fit the bill of what you're trying to do with a portable charger and single output. It would be cheaper than a marine dual bank charger, but not waterproof.....
 

H@ystack

Petty Officer 2nd Class
Joined
Apr 5, 2015
Messages
101
Not sure if we are talking about the same thing or not (post up a pic of what you have, or link to it), but if it's what I think, both the red and black plugs have 4 external prongs. Same goes for their internal configuration, 4 screw terminals, with a clear disk that blocks some of the screw terminals.

Under the clear disk are (1 or 2) silver jumpers to make the serial and parallel connections for the batteries, parallel for the red charging plug. If you remove the clear disk and jumpers, and drill an extra set of holes through the clear disk, you can connect both sets of charger leads to the plug independently. I have done this on a couple of the plugs to get them connected the way I wanted. This takes reworking the plug a bit, but it's better to have the batteries separate when charging them. I mark the opaque colored plug body with red and black Sharpie markers, so I can tell at a glance which terminal is which. (You DON'T want to get them mixed up...)

"IF" the charger can combine it's outputs (some can't), you could simply wire the charger outputs to the existing 2 holes in the charging plug, but I would advise against doing it this way. Heck, I have a Schumacher 20 amp automotive smart charger I bought 10 years ago that would probably fit the bill of what you're trying to do with a portable charger and single output. It would be cheaper than a marine dual bank charger, but not waterproof.....
Yeah, waterproof isn't a concern. I only charge at the house. I ran the hell out of that motor Saturday, and didn't knock down those batteries much, so that's good.

It is 4 screws, with 2 holes that are jumped.

I called Marinco and the guy swears if you just drop the 2 pos in one hole and the 2 neg in one hole it will send the current through the plug appropriately. I was just concerned it wouldn't recognize the charge depth for the "smart" chips in the chargers, but he said the way the wires are run to the back of the receptacle it would be fine.
 

fishrdan

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+ and + are jumpered, then - and - are jumpered, so yes both batteries will receive charge. Your concern about the "smart" portion of the charger being thrown off by combining outputs is valid as it can's sense each battery. I just connected my Schumacher to the jon boat batteries, one at a time, and the charger was ramping up to sense state of charge, probably did this 30-40 times making sure the batteries were topped off, they were. IF... I had the batts combined and one of them was discharged, the other battery wouldn't be charged correctly. They both would have charged though.

My preference:
- If using a multi-back charger, mod the plug and connect each set of outputs to it's individual battery
- If using a single output charger just connect it to the plug as-is and go.

Charging both batteries from the same output is not optimal, but common.
 
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