Battery Charging: Marlin 280

[Candylane]

Hello,

I have a couple of novice questions regarding battery charging. I recently purchased a Marlin 280 with twin 2006 Yamaho 250's. My boat is stored on a lift (with power) and I have only taken it out for a few short trips while I get the hang of the boat.

I have four batteries:

• 1 Starboard Engine
• 1 Port Engine
• 2 for Accessories

I also have a Guest 15 Amp charger on board (see pic below).

A couple of silly questions:

• Do the accessory batteries charge while the engines are running?
• Or, do I need to plug my shore power into my lift and manually charge it at the end of each trip?

 

[Fishtales]

Looks like a two bank charger. Usually the batteries are wired in two banks, one bank per engine, two batteries in parallel per engine. Might want to chase down how the charger is wired. Sounds like it is connected to the two starting batteries only?

 

[Hookup1]

Three bank charger. Are the two accessory batteries wired in parallel? If that is the case then a 3-bank charger is fine although your existing charger is only a 15 amp charger 5/5/5. There are bank shifting battery chargers Like the ProMariner ProSportHD 20 that will shift a full 20 amps to charge a house battery If you decide to upgrade at some point.

You're motors have alternators that will charge their respective starting batteries. If your boat has a house battery (third battery) one of the motors has a charging shunt that will charge the house battery too. If you have a fourth battery (not paralleled) the other engine needs to have a charging shunt installed that will charge the fourth battery too.

This is what I had to install on my second motor. It was already installed on the first one.
I have 2006 F150 but its the same for F250's.

https://www.partsvu.com/13-5-isolat...MIxLylh_jS7wIVmgytBh1G6whQEAQYBSABEgIkrfD_BwE

 

[Candylane]

Thanks for the reply guys.

Hookup, when you installed the shunt your accessory batteries they are now all charging while the engines are running? Is there a downside to this configuration? If not, that seems like it would be a standard set up for everyone running twin engines?

If you have all your batteries getting charged by the engines what purpose does the charger serve?

 

[DennisG01]

Why is it labelled "5/5/5", which leads one to believe it's a 3-bank charger, yet there's only two positive leads coming out and only two sets of charging indicator lights?

As noted, that's a pretty light duty charger - but that's a discussion for another time. At this point - it's what you have and it will get the job done - just much slower.

Do this... with the engines running, advance the throttles to about 1,500RPM's. Use a voltmeter (they're cheap to buy) and check the voltage at each bank (the "house" batteries SHOULD be paralleled together). You should be seeing roughly 14V at each bank. Experiment with different battery switch positions, too. This will tell you, FOR SURE, what banks are being charged by the engines and when/how.

You can also simply trace the wires (both from the engine and the charger) to see where they are hooked up. The only way to know for sure is to physically check things out - you never know how a previous owner may have done things.

The idea of having a charger is to KEEP the batteries topped off - which extends their life. Plus, the house batteries may not get fully charged by the engines (if in fact, they are hooked up the engines) depending on engine run time.

If you do consder a new charger, definitely look at the ProMariner stuff. I had (and know of, literally, hundreds and hundreds of boats with the same thing) a ProNautic series (30 amp would be good for you) mounted in my Sea Ray bilge and was/is a great charger.

 

[Fishtales]

2 sets of leds and wires threw me off as well. It is technically a 3 bank charger, but ports (2 and 3) can be connected in parallel for 10A capability. It is only a two bank isolated charger. I'd want a charger with three isolated charging banks (would have 3 wires and 3 sets of status leds). I'd trace what you have and see if you have a 3 bank or 2 bank system. If factory, likely 2 but people do change things around.

 

[efx]

I went through a couple battery chargers on my Marlin. I have the same battery configuration as you. I highly suggest this charger in the photo. All my battery and electronics have appreciated it. It’s a 30 amp, 3 bank.

 

[efx]

Three bank charger. Are the two accessory batteries wired in parallel? If that is the case then a 3-bank charger is fine although your existing charger is only a 15 amp charger 5/5/5. There are bank shifting battery chargers Like the ProMariner ProSportHD 20 that will shift a full 20 amps to charge a house battery If you decide to upgrade at some point.

You're motors have alternators that will charge their respective starting batteries. If your boat has a house battery (third battery) one of the motors has a charging shunt that will charge the house battery too. If you have a fourth battery (not paralleled) the other engine needs to have a charging shunt installed that will charge the fourth battery too.

This is what I had to install on my second motor. It was already installed on the first one.
I have 2006 F150 but its the same for F250's.

https://www.partsvu.com/13-5-isolat...MIxLylh_jS7wIVmgytBh1G6whQEAQYBSABEgIkrfD_BwE

I never knew about the shunt option. Thank hookup!

 

[Hookup1]

Thanks for the reply guys.

Hookup, when you installed the shunt your accessory batteries they are now all charging while the engines are running? Is there a downside to this configuration? If not, that seems like it would be a standard set up for everyone running twin engines?

If you have all your batteries getting charged by the engines what purpose does the charger serve?

You need to inspect your wiring as stated above. I expect that the two house batteries are paralleled. Look at the wires coming out of the charger. I would expect three red positive leads - one to port battery, one to starboard battery and one to the the paralleled house batteries. All three batteries should have black jumpers to common all the grounds and the two or three battery charger black wires connected as well.

To answer your question about the second charger shunt charging a fourth battery - yes it can do that BUT if the two house batteries are paralleled it doesn’t do anything for you. The two paralleled batteries are considered one battery with double the amperage capacity.

if the two house batteries were NOT paralleled you would need a charging shunt to charge the second house battery. I have four batteries in my boat - port engine, starboard engine, house battery and second house battery for bait pumps, windlass and bow thruster.

This is my custom install driven by my installing a bow thruster and wanting a battery close to it (same compartment) and a new windlass. I bring charger line forward from the second engine to this compartment. Keeps runs short to bow thruster and windlass. Added a single bank battery charger in same compartment.

Your setup with parallel house batteries, three bank charger and one engine shunt is perfectly fine if that is how your boat is wired.

 

[dogdoc]

This is a good time to review exactly what you have back there and fully understand how it all functions. Ideally you have a 3 bank set up with a bank to start each engine and a bank for house equipment. Wired with battery switches in such a manner that each bank can perform the duties of the other 2 should the need arise. Each engines starting lead will charge the battery when running and one engines accessory lead will charge the house bank when running. Ideally you have a 3 bank distributive charger/maintainer with sufficient output to charge batteries in a timely fashion. I have the Pro Nautic 30 amp 3 bank installed on my boat. Most on board chargers are used mainly to maintain the batteries not charge them, so research that aspect of any charger you intend to buy. A well maintained battery will last much longer. I want my charger much smarter than my batteries. Adequate wire size and connections and fusing should be in place. Additionally a functional galvanic isolater should be inline with the ac input whenever plugged into power at the dock. Good luck