Charging Issue - three battery system

[Nheels]

Hi everyone. I thought I would throw this issue out there to the masses, as it may be a common thing and someone will know exactly what to replace/fix. It is most likely an open connection somewhere perhaps, but anyway here it is.

Twin engine with two starter batteries and one house battery. Each battery has a switch. The two starter batteries have options of 1/2/1&2.

Battery 2 (second starter battery) will not charge unless it's switch is on 1&2.

Other batteries charge fine.

I should add, that I do not know if it is hurting anything by being on 1&2, but I don't believe that is desirable.

Any thoughts?

 

[sam am I]

When Battery 2 (engine 2) switch is set to 1&2, what is Battery 1 (engine 1) switch is set to?

Going to assume then engine 1 it is also set to 1&2?, therefor the alt on engine 1 is able to ALSO charge engine 2's batt as each engine can share the house (typically, see below) ............Check engine 2's alt, dead or loose wire!!

Perko Link

 

[poconojoe]

Something doesn't make sense.
If each engine only has one battery, why do they each have a 1/2/1&2 battery switch when there's no second battery? They should just be on or off.
You obviously could use the three position switches, but only wire it for one position.

Battery 2 just charges at position 1&2. That doesn't make sense. It should also charge at either 1 or 2.

Pull the covers off the switches and trace each wire. That would give you and us a better understanding of how it was wired. Then we can assess whether or not to rewire it.

I hope each battery is only wired to it's own engine.

 

[Bt Doctur]

a lot use the 3 position switch with twins and house. If 1 and 1 is normal,.
2 and 2 are jumped together. If both switches are on "both" the engine batteries are now combined
You need to find out how your switches are wired but is sounds like that the motor that will only charge on both has a bad alt

 

[Nheels]

When Battery 2 (engine 2) switch is set to 1&2, what is Battery 1 (engine 1) switch is set to?

Going to assume then engine 1 it is also set to 1&2?, therefor the alt on engine 1 is able to ALSO charge engine 2's batt as each engine can share the house (typically, see below) ............Check engine 2's alt, dead or loose wire!!

Perko Link

Hey, battery one switch is at one. House battery is just on or off, which I put to on.

Is it possible that engine one alternator charges both one and 2 and engine two only charges house battery?

 

[Nheels]

Something doesn't make sense.
If each engine only has one battery, why do they each have a 1/2/1&2 battery switch when there's no second battery? They should just be on or off.
You obviously could use the three position switches, but only wire it for one position.

Battery 2 just charges at position 1&2. That doesn't make sense. It should also charge at either 1 or 2.

Pull the covers off the switches and trace each wire. That would give you and us a better understanding of how it was wired. Then we can assess whether or not to rewire it.

I hope each battery is only wired to it's own engine.

can't they be wired together in the event one is dead, you can always start both engines?

From what I've been reading here, most likely a bad connnect from 2 or bad alternator though. I wonder what engine the house battery charges from then! Must be 1 I suppose..

 

[sam am I]

Hey, battery one switch is at one. House battery is just on or off, which I put to on.

Is it possible that engine one alternator charges both one and 2 and engine two only charges house battery?

I suppose it's possible.........Wondering however since in normal switch line-up (Port =1, Star = 2), then as wired and for simplicity, switches are lined up with their designation to the actual the batts ....(see below).

Think this is how your wired, Batt 2 is being charged with port alt when star engine switch is line-up to "1&2"........Thinking still your alt on star engine is bad/flaky.

 

[Nheels]

I suppose it's possible.........Wondering however since in normal switch line-up (Port =1, Star = 2), then as wired and for simplicity, switches are lined up with their designation to the actual the batts ....(see below).

Think this is how your wired, Batt 2 is being charged with port alt when star engine switch is line-up to "1&2"........Thinking still your alt on star engine is bad/flaky.
View attachment 339739

Yeah, good point on the simplicity. I can't see why they would have complicated things during initial wiring.

I'm heading out to the boat this week and will check that alternator. From reading all the comments, looks like everything is being charged with port alt..

 

[Nheels]

Something doesn't make sense.
If each engine only has one battery, why do they each have a 1/2/1&2 battery switch when there's no second battery? They should just be on or off.
You obviously could use the three position switches, but only wire it for one position.

Battery 2 just charges at position 1&2. That doesn't make sense. It should also charge at either 1 or 2.

Pull the covers off the switches and trace each wire. That would give you and us a better understanding of how it was wired. Then we can assess whether or not to rewire it.

I hope each battery is only wired to it's own engine.

Okay, so looks like when under engine if batteries are set to their respective number, they charge. It's when charging through shore there is an issue.

Loose wire probably?

 

[Nheels]

I suppose it's possible.........Wondering however since in normal switch line-up (Port =1, Star = 2), then as wired and for simplicity, switches are lined up with their designation to the actual the batts ....(see below).

Think this is how your wired, Batt 2 is being charged with port alt when star engine switch is line-up to "1&2"........Thinking still your alt on star engine is bad/flaky.
View attachment 339739

Okay, so looks like when under engine if batteries are set to their respective number, they charge. It's when charging through shore there is an issue.



Loose wire probably?

 

[dingbat]

Okay, so looks like when under engine if batteries are set to their respective number, they charge. It's when charging through shore there is an issue.



Loose wire probably?

The obvious answer is the battery charger.
Are they turned on, working?

 

[Nheels]

For anyone still following along, issue solved.
Checked alternators and all worked fine. Port engine charges battery 1 and the house battery. Starboard engine alt charges battery 2.

When on shore power, battery two wasn't getting charge unless it was set to 1&2. Checked voltage leaving charger to battery 2 and showed 7.5v.. odd.. lead goes to a 50amp push button reset fuse first before what I believe it then goes to the battery switch.

Jumped that fuse and voila, battery charges now. Issue was the reset circuit.

 

[poconojoe]

Glad you got it figured out!
Now go boating!