Alternator problem on Sea Como No

[Sea Como No]

I've had 3 alternator failures, including one fire caused by a short that ignited the plastic case on the French alternator(Valero or Paris-Rhone, I think).
On my trip Monday to Catalina, the alternator failed to come up to charge voltage. Previously, it had been requiring a "fast idle" to get going, but this time, nothing doing. I have it in the shop being checked out now but I determined that it would kick in OK with a direct connection to the batteries, but not with the voltage available from the instrument panel. This is from a brown wire that comes out of the back of the warning panel on my 1999 with a A41 diesel, but is only about 3 volts??? Does anyone know if this is normal?
Also, has anyone had success adding a second alternator to the port side? I have tried to replace the Valero with a Prestolite or equivalent but it looks too difficult to make it fit onto the Volvo mounting locations.
Dave, on Sea Como No

[Wizard]

NoSlack (Mike) has all the answers, including how to replace the stock alternator which is only 55-65amps (depending on year), with a one-wire 105-110amp-er. I have plans to pick Mike's brain and do this myself on my KAD42 setup that is only running a 55Amp and could be better at providing power to everything I run at night.

When he gets a chance to read this, maybe he can start describing what we need to be doing to plan for this upgrade.

[NoSlack]

See the post on this subject over at the AllCoast board, we had a few months ago. My comments are 4th or 5th down the tread. Most everything you need to know about upgrading the altenator will be covered there.
http://www.allcoastsportfishing.com/forum/dcboard.php?az=show_topic&forum=316&topic_id=141557&mesg_id=141557&listing_type=search

After reading that info, fire away with some questions and we'll do our best to hook you up.

Mike

[Sea Como No]

Many thanks guys. The Allcoast info is a big help. I'll check out the Balmar alternator with a 3 stage reg. My only remaining concern is: "Will the alarm still work?"
Dave, on Sea Como No.

[NoSlack]

Wiring on the alternator,

The red wire on terminal B+ is the hot output wire that carries the current to the batteries. You should find the other end of this wire at the starter matted up to the large battery cable. Make sure you upgrade this wire if you go with a bigger unit or it will be your next fire.

Terminal D will have all your negatives on it. You may want to upgrade the wire that goes back to the block to support the upgraded red wire. Don't count on the mounting bolt to carry the current back to the block(-).

Terminal W will have a gray wire on it, and that is your tach signal. For the boats that use the alternator for the tach signal, it's very important to keep the pulley ratio the same(use your old pulley). You will never notice a 3% difference in size with your eye, but that comes out to be 100 RPM at 3300.

Terminal B1 has a brown wire on it and goes to the alarm panel it should be on pin 5 in the main wiring harness and pin 1 at the alarm panel. I've never had the opportunity to play with the alarm panel on a 41, but it looks like the alarm comes on if that wire goes negative. That's just a guess on my part looking at the wiring diagram I got from Rich last year.


Last but not least, don't go overboard with a monster alternator. 85-90 amps is a lot of output. I'll take 50 amps of charging capacity with 4 batteries over 100 amp and 2 batteries any day. Its all about how much you can store, not how fast you can store it.

Mike

[Wizard]

Ok, I need more explanation about the number of batteries vs. number of amps. Also need to understand belt size more. I don't have a choice on the belt, since it runs off the front groove of 3, from the big engine pulley.

Also, I have one standard starting battery, and one 8D house battery. Should I go to 4 standards or something? I'm having some minor flickering on lights at night and fishfinder/GPS resetting on occasion when running all lights and instruments at night.

[NoSlack]

Glen, hang onto that 8D, that's a good house battery.

Let me give two examples of battery and alternator use.(my opinion)

Most guys that own a gas boat shut down the engine when they pull up to a kelp or get into a nice bait bite. You might drift for 20 or 30 minutes then fire back up for 10 and move to the next kelp. With short runs of the engine you need to charge up the batteries a much as possible between stops. Larger alternators and good battery capacity.

Most of us diesel guys never shut the boat off until we set anchor for the night or return home. You have all day to get those batteries charged at a slower rate. Why zap your batteries and stress your belts with a heavy charge if you don't need to. A slower trickle charge is better for the batteries than a heavy fast rate charge. On a heavy charge the batteries will get warm and bubble more. This is were the phrase boiling your batteries comes from.

If you have 15 amps worth of load on while at anchor for 4 hours, you pulled 60 amp/hours (15X4)out of the battery. With a stock 50 amp alternator, you can fully recharge that battery in just over an hour with the motor running at trolling speed. After the batteries charge, the alternator basically unloads and maintain the charge on the battery while supplying the house load.

Quick explanation on volts and amps for those of you that think electricity is still some form of black magic.

Volts in the battery would be like water pressure at the house. If the pressure is down, it's harder to blast the dirt off the driveway with a hose. If the volts are down to 11(not charged) your pumps and motors run slower and do less work.

Amps are like water flow. amp/hour = gallons per hour. You can fill a bucket with a garden hose or a fire hose, both get the job done. Sooner or later your going to bust the sides out of the bucket with the fire hose.house load.

I Run 2, 1000 CCA group 24 starting batteries and 1 group 24 deep cycle for the house load. I don't do any overnighting so the one house battery gets me by. The only thing on the starting batteries should be the engine and the instrument panel. Everything else should be on the deep cycle house battery.

Mike

[Wizard]

I think I may just need to tear out some garbage old wiring and redo my main grounds to the breaker panel then. I can run my bait tank and lighting on the hook for several hours, but am fearful of doing so all night without starting up the motor. My breaker panel guage never shows my starting battery or house battery low, so the flickering is probably an indicator I just need to upgrade 20 year old wiring to handle the increase in electronics and lighting. Hate to do all the conversion to new alternator and find out it's no help.

Thanks for the feedback, I like what I have setup, and think it works. Gut feeling is not a problem with charging, nor battery health, given what I said.

[NoSlack]

The way Don set up the batteries on our boat is great. The silver Cole Hersee solenoid that's in the battery box or behind the breaker panel takes care of separating the battery banks when you turn the key off. When you sit all night with the bait pump running, the only battery you will draw down will be the house battery.

Test it out in the slip some night with the shore power unplugged. You'll be surprised how long that 8D will run the pump and a few lights. If you run the pump(4 amps) and the anchor light(2 amps) for 12 hours you only draw 72 amp/hours off the batteries. Most of the 8D batteries are rated well over 200 amp/hours with a huge reserve.

Mike

[Wizard]

I knew my house battery was isolated, but never done such a test to build up the confidence. All my overnight on-the-hook trips have been at Catalina or drifting out 100 miles, not a good place to find out that all my bait rolled because house battery died, even though I knew it would start on the other battery. My former boat killed the bait once, didn't think this setup was any better. Now you got me thinking.

[Dos Pelones]

Dave,

If you have any questions on the Balmar upgrade and/or want to see some pictures, let me know. We did it and are very happy with the results.
Jorge