Battery Power!

When you rev the engine up above idle does the voltage increase? I get about 14.2V at cruising speed and around 13.5 at idle. Is it possible that the depleted battery is so shot that it won't take a charge? It sounds like the good battery is trying to charge the depleted one.

--Andy

Maybe, but we just got back from 9 days of cruising and battery power wasn't an issue. We did do a lot of motoring though.

Thanks WB. I took some amp measurements and each circuit uses between .25 to 1.7 amps with the stereo being the biggest consumer. Then I measured the voltage as I add circuits. The voltage at the battery drops as I add circuits until it looks marginal whether the alternator is keeping up.
The spec on the alternator says 210 watts at 12 volts which apparently converts to 17 amps if I'm doing the conversion correctly. This should be plenty of current even with all the circuits on.
So I guess my alternator is marginal...
That said, a solar charger would be a good addition to get the batteries fully charged between race days. If I know I have a 100% battery then the 2nd can stay ashore.
Just for yucks, if you get a chance, take a voltage reading with all your circuits on and the engine idling and see what voltage you have at the battery. thx, john

Maybe it is not the regulator. Did you check some of this? You have three wires (two?) coming from under the fly wheel. Are they at (I have found) 12-18 vac while you run? Those wires go right intothe regulator. The wireout should be 13-13.8(14.2)v depending on revs. Are your grounds all good? That regulator is a pretty simple affair and I have seen some well abused units working fine . Your battery-engine ground cable has been sitting under the floor board for 25 years, check it carefully. Make sure your start switch wires and contacts are clean. The engine will run with the key in the "off" position so check that "on" position wiring is good, that is what enrgizes your charging system. Stuff get put back in that compartment and could knock that harness arround. Some of the multi-pin conectors on the engine/harness get moved arround while cleaning or maintenance is performed. Some pins push out of the connector body a little and don't make contact. Try pushing them in individually, gently with a dental pick . Wire arround the connector if pins are broke or wire has sepperated from the pin. There is 25 years of stereo, vhf and instrument wiring through that area. Focus onthe charging stuff and make sure you do not have old wiring (+12vdc) laying arround getting wet or shorting to metal. Good Luck

I've pasted my input there but check that thread briefly. You have 3-5 circuits, the largest being 1.7 amps. all things being equal, you have some connection/grounding issues. Swear to GOD this is a true story. For 1/2 a season I climbed behind the head and pull started the motor every race, day sail etc. because it only clicked and i was afraid of the repair cost.(It is hot and sweaty back there sometimes but I got good at 1-2 pull starting). The battery posts were snug but not tight. tightening the posts made everything was good but it was August at that point!!!! True story, I thought the connections were good, they were not.

I've been re-reading posts about charging cause my battery died (again) after an 8hr + 8hr road trip. Do I read your comment correct that you are supposed to leave the key in the 'on' position for charging? I was told, after she starts, to put the key back to the neutral position. thx, js

Making sure that the key was in the run position did not help deliver any extra voltage to the batteries. I checked the SA link that WB posted and they said their problem was the ignition switch. Not sure how they determined that.
The wiring diagram in the shop manual is a little hard to read. But tomorrow I'll check the wires from under the fly to see if they are delivering 12-18vac to the regulator. Looks like the bottom tab of the regulator is the battery feed.
And then what... its hard to see where the regulator activation lines are coming from but I'll try to trace them back.
js

Somewhat related but I've been having trouble starting the engine this year. Last year (my first year with the boat) it always fired up no problem.  Now, it needs to turn over for a good 5-10 seconds and a few times I've needed to select both batteries.  Once the engine is warm (i.e. after a sail when heading back to the dock) the engine always fires up right away.

I did voltage checks across the battery terminals and found:

engine off: 12.2/12.9
engine at idle: 14.6/14.3
1/2 throttle: 14.6/14.3

A quick check of the wiring and I really don't see any corrosion or anything but I'm completely unfamiliar with the electrical system on this boat...

These voltage values seem normal based on what I've read above but I'm kind of stumped here.  Do I need new batteries or is something else the problem and if so, what's the best way to find out?

Thanks in advance for the help.

Crinmar didn't have a regulator in stock so I did a little research over the weekend. I could see 'Saprisa' and '7172' stamped on the regulator. I found a cross reference/sub-up to a Saprisa 4172.
I found these available on the Italian ebay site and also Wood Auto distributor in the UK. So I spoke to a lovely lass at Wood Auto this morning. $50 for the regulator and $35 for 3-6 day shipping to New York.
Got my fingers crossed. js

fatjohnz wrote: problem fixed! js

That's weird. WE cruise Voila in the summer for 3 weeks at a time using whatever we want on the boat and never charge our 6 year old Category 24 AGM battery. All our lighting is LED. We carry a 14AMP lithium just in case, but have never had to use it. We race the Southern Straits race of 100 km taking nearly 24 hours with nav lights, instrument and radio and are still able to start the engine after finishing. Perhaps you are over using the air conditioner.