www.iFourWinns.com

We spent the last 2 days on the hook, changing location every day.

Normally per my Garmin, when underway we are at 14volts. I noticed yesterday after leaving anchorage it was only 10.8 and kept going down as we drove I finally stopped, shut the engines off, and switched to the other battery. Same results. The battery alarm went off on our GPS too, while underway. Its obvious the power being produced by the alternators arent getting to the batteries.

I have twin 4.3l Volvos. Before this issue, I noticed the port side volt gauge was always showing a good charge (14v) but the starboard was always 1-2 volts less, on the gauge. Now both gauges read less than/around 10v when underway. I have 2 new AGM batteries that are about 3 months old and a new Mastervolt battery charger (2 months old).

Where can I start troubleshooting this? Was is the purpose of the isolator and could that have gone bad? Is there any kind of fuse between the alternators and the batteries?

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

Here is a link to the wiring schematics from the FW site.

http://www.fourwinns.com/past_product/o ... attery.pdf

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2008 210SS 6.2L DTS Bravo 1 Now featuring MercMonitor w/SmartTow

I have had a similar problem, I've bypassed the isolator and now I am getting 13.5 - 14v on each engine. I tested the isolator according to the Guest procedure and it supposedly checked out good but I'm pretty sure it is the culprit. I have 70 amp breakers between the alternators and batteries.

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2004 Vista 298
Twin 5.7L Volvo Penta GXi-E

Ok does this have anything to do with it?

I was watching tv on a 200w inverter down in the cabin while it was raining. I put he battery switch (Engine systems - Emergency Start - House systems) on Emergency Start, assuming they worded it in a fancy way and emergency start meant putting both batteries in parallel. I only watched tv for 5 minutes after that.

Thats the only thing I can think of that might have precipitated this.

Also, how would I bypass the isolator?

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

EDIT: Thank You for that tip. I went out and checked and BOTH of the breakers were popped. I pushed them in and reset them and now Im back to 12+ volts!! Thanks!!

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

Do not bypass the isolator! It's a very important piece of equipment and it's not costly.

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1981 Columbia 8.7
2015 Yamaha FZR - 87mph - sold
2006 Yamaha GP1300R - sold
2003 Chaparral 215 SSI - sold
2009 Stingray 195CS - sold
2000 Four Winns H180 - sold
1976 O'day Daysailer II - sold
Rick's Four Winns H180 Mods/Upgrade Thread

If I would bypass the isolator, it would be determine if it was defective or not. However, after resetting the two 60 amp breakers in the bilge, Im good to go now

Dont know what exactly was the catalyst for the breakers to pop, but Im grateful it was a cheap fix and will keep an eye on it!

_________________
1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

Did you flip any batteries off while an engine was running?

_________________
1981 Columbia 8.7
2015 Yamaha FZR - 87mph - sold
2006 Yamaha GP1300R - sold
2003 Chaparral 215 SSI - sold
2009 Stingray 195CS - sold
2000 Four Winns H180 - sold
1976 O'day Daysailer II - sold
Rick's Four Winns H180 Mods/Upgrade Thread

Never. I know much better than that!!

I did however start the generator the other morning while the Kohler switch was set to shore. We were in a big lightning storm on the lake. And I ran the inverter for the tv. Those are the only things I can even remotely think of causing any breakers to pop.

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

What are the adverse affects of running without an isolator, besides not allowing a weak battery draining a strong battery and not being able to charge the house battery while underway?

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2004 Vista 298
Twin 5.7L Volvo Penta GXi-E

Jerry rigging the system, risking fire if not done right, and voiding any kind of insurance claim for any reason if that's noticed.

_________________
1981 Columbia 8.7
2015 Yamaha FZR - 87mph - sold
2006 Yamaha GP1300R - sold
2003 Chaparral 215 SSI - sold
2009 Stingray 195CS - sold
2000 Four Winns H180 - sold
1976 O'day Daysailer II - sold
Rick's Four Winns H180 Mods/Upgrade Thread

I don't think Ric understands what an isolator is used for?

Not true! Or I will say, anything will can catch on fire if wired wrong, but not bypassing the isolators. Now it would be a like a dual battery setup. But in your case you have the 3 batterys, one for each engine and one for the genset.

On Ricks "Did you flip any batteries off while an engine was running?" Again, not ture or better, it won't matter! With isolators, you can trun the battery switch to off. The reason being is that the charging circuit (alternator output circuit) is not wired to the battery switch, but to the battery isolator which distributed the charge to both batteries through a diode. BUT I would read the manual on yours, if somthing were to happen I would not want it over my head.

What I'm trying to say is, it's an important part of the boat's wiring and it's really freaking cheap. You risk voiding any insurance claims by bypassing it if you ever have a boat fire and the adjuster see's the wires bolted together.

_________________
1981 Columbia 8.7
2015 Yamaha FZR - 87mph - sold
2006 Yamaha GP1300R - sold
2003 Chaparral 215 SSI - sold
2009 Stingray 195CS - sold
2000 Four Winns H180 - sold
1976 O'day Daysailer II - sold
Rick's Four Winns H180 Mods/Upgrade Thread

Disconnecting the battery isolator has corrected my alternator charging problem. I've checked the isolator according to Guest instructions and it appears to be working correctly. I reviewed the Guest isolator installation instructions and I found a note under the wire guage selection chart. "Note: The input wiring must match the respective alternator input current rating. The output wiring must match the sum of both alternator input ratings." Using the wire guage chart, the minimum guage wire would be 2wg on the output side (two 70 amp alternators). My output wiring is 4wg. I've also reviewed the manual for ProMariner's battery isolator, the installation instructions show that with a 70 amp alternator the breakers should be 100 amps, I only have 70 amp breakers. Could these two items be creating excessive voltage drop?

As far as bypassing the isolator, I intend on using a terminal block in lieu of the isolator to connect the wires together for a permanent solution. From a safety standpoint I don't see anything wrong with this type of wiring setup.

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2004 Vista 298
Twin 5.7L Volvo Penta GXi-E

Yes, it "could". What you also need to account for is distance. The greater the distance, the heaver the wire will be needed.

http://www.engineeringtoolbox.com/amps- ... d_730.html

The chart is showing, that at 70amps with #2 wire, total run should not be over 30' feet. With #4, 20 feet.

What most of us don't get, total length of the wire from the source to the device and back again. = Total feet of wire.