Onboard charger did the pop and fizzle...

Stickyskilet

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I bought a 16’ aluminum open boat last summer, with 2 Scotty 1106 electric downriggers, a bilge pump and a sounder. It was wired up with two group24 deep cycles through a 1/2/both/off switch with a guest onboard 2 bank charger and alternator module. Power is a 2005 Yamaha f25 manual start, that has a non OEM rectifier/regulator wired up to the chargers alternator module.




The batteries that were in it were pretty weak, with quick discharge, and incomplete charging towards the end of last summer. They limped through without major issue.




I recently replaced both batteries, and wired everything up exactly as it had been, and when I connected the positive leads between each battery and the switch(which was in the off position), the charger made a few “pop” sounds, until the positive leads were removed from the batteries. The charger was warm, and bulged... don’t know for sure whether it was that way prior to the “pops”, but I don’t think so.

I also have reservations about the rectifier, as at one point last summer, the finder was seeing a voltage of almost 17v.




So long term, I plan on getting a new onboard charger, and wiring it up as it should be, but I have a trip coming up next week that I need to have things working for.

My feeling is that I should be able to wire up the batteries with the positive lead from each to the corresponding input on the switch, the switch common output going through the 70A breaker to the loads at the rear of the boat, and negative leads both going to a ground post in the battery compartment, and then on to the ground post at the rear of the boat. I would also pull the fuse from the rectifier, taking that out of the picture along with the blown charger.




I’d be happy to hear from anyone about any issues with this plan, as well as any general thoughts about how you’d wire things up for two electric downriggers, a 55lb trolling motor, a small sounder, bilge pump and running lights.




Thanks.
 

alldodge

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Your drawing is missing some wires showing how everything is connected. You can use a 2 bank charger with separate connects (+ and -) for each bat.

Assumng everything runs off 12V, you can use the 1-2-Both switch to parallel the bats.

Power is a 2005 Yamaha f25 manual start, that has a non OEM rectifier/regulator wired up to the chargers alternator module.

Connection from the alternator can be connected to the main switch terminal but don't start the motor without at least one bat connected

wiring.jpg
 

Stickyskilet

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Thanks for the reply...
i got lazy with the drawing, and see now as well that the fuses shown between the batteries and the switch were actually between the switch and the charger. All loads are powered through the fuse box/dist. Bus at the top.

After removing the fried charger, and disconnecting both batteries fully, I took the boat to the lake to test a couple of hull patches that I’d done. Was happy to see a dry bilge, but you’ve got me thinking that as a result of running without the charging system connected to a battery, I may now have a legit reason to think there’s a problem with the rectifier/charging system?
 

alldodge

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Attach one bat and fire the motor up. Check with a voltmeter to see what it shows at idle to half throttle
 

Stickyskilet

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Will do in the next day or two... today I tested the rectifier and it is functioning as it should... put it back in line, and wired it to the common switch post. Bat 1 is wired to switch input 1, bat 2 to input 2, then common wired out to distribution through the 70A breaker. So will have to remember to make sure switch is on when starting engine, and not to switch bats while engine is running. We’ll see if I’m up to the task.😬

there was a 50A fuse in line between each charger bank and the switch... with the charger out of the loop now, I wanted to make sure that they don’t still need to be in there somewhere.
thanks for your help on this stuff.
 

Stickyskilet

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After testing rectifier as good, and wiring it to the common post on the switch, I hooked up the battery and tested it at 12.6v. Fired up the engine, and tested the leads at 15.5v at idle, and 15.75 at about half throttle.
 

alldodge

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If your meter is accurate, then that is a bit high if it stayed there
 

Stickyskilet

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I’ve read that over 14.5 or so, I’d be running the risk of cooking my batteries... that sound about right?
 

Stickyskilet

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From what I gather, my model of outboard was made and purchased without a rectifier, but with a flywheel magnet with the two leads to wire in a rectifier... should that not mean that those two leads could be capped off and the engine could be operated without risk to the outboard?

Edit: the model number by the way is f25 mlh (65w)
 
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GA_Boater

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Ahhh OB question, hey GA_Boater can you assist?

This one is a tweener, AD. The thread is covering a lot of bases between the broken onboard charger and now rectifier questions. I don't even have a clue about separating the two intertwined posts into another outboard thread.

My thoughts - If you have a simple rectifier and no regulator in the charging circuit, the battery(ies) act as the regulator. At higher RPMs, the rectifier can put out 16-17 volts and the battery acting as a regulator can cause the battery to possibly boil - It isn't really boiling, but if you look inside (only with eye protection) a battery being charged is giving off hydrogen gas bubbles and a high charge rate makes it look like a tea kettle. You must keep an eye on the electrolyte level and keep it topped up with distilled water.

The warning about a rectifier only system is do not used sealed batteries and to keep the batteries full. Only use plain old school lead/acid refillable batteries.

Sticky - You may want to consider starting a thread in the F25 motor section, whatever brand that is, about the rectifier and capping the stator wires.
 

Stickyskilet

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Thanks to both of you... appreciate your help.
I’ll head over to the outboard specific forum and poke around.
 
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