Electrical Problem - Newbie Not Sure Where to Start

[wolfmt]

All,

I have an electrical issue on my new-to-us good old boat, which is powered by an Atomic 4. I'm new to the idiosyncrasies of the Atomic 4 as well as the electrical system on our boat, which appears to have 30 years of DIY ad-hoc modifications.

Last weekend, we motored for 6+ hours on a return trip on account of weather. About 4 hours into the trip, the engine started to run rough. The problem continued for a few minutes and then I decided to drop the throttle down at which point the engine stalled. I attempted to restart the engine without success (the starter didn't move). I opened the engine compartment and didn't notice anything abnormal. I happened to look at the battery switch indicator and noticed that it was set to BATTERY#1, which is not my ususal protocol when motoring (we usually have the switch set to BOTH when motoring). I also noticed that the blower was still slowly turning (we usually switch that off following a successful engine start). It is probably also useful to mention that we overnighted on the boat the night before and, while we weren't heavy users of electrical power, we probably had some lighting on for part of the evening. I then set the battery switch to BOTH and tried the engine, which promptly started, and we motored for another 3 hours without incident. I arrived on the boat last night to find that the engine wouldn't start. When the battery switch was set to BOTH or BATTERY #2, I heard something going when attempting to start the engine but it didn't turn over. When the battery switch was set to BATTERY #1, I heard nothing. I pulled both batteries last night to check the charge and recharge them if necessary. Battery #1 showed 10 and change volts and Battery #2 showed 11 and change volts. I hooked them up to a charger to top them off. By the way, both batteries are 2 months old.

The question is, what's going on? My ignorance of basic electrical systems is killing me and I've committed to learning everything I can before the winter in order to undertake a complete overhaul of my electrical system. That being said, I need to function the rest of the summer.

Could it possibly be that the blower, which is wired directly to the batteries, was pulling more power off the batteries that they were receiving in the way of a charge while the engine was running? Could it be that another 2-3 hours of motoring was not sufficient to charge both batteries? Does this sound like an alternator problem? Any direction would be helpful.

Many thanks,

Mike
s/v Liberty

[speciald]

Sounds like there may be no alternator output. Start the engine and check the voltage at the alternator - should be about 14v. Good book to get is Nigel Calder's book on boat mechanical and electrical systems.

[negrini]

Your engine is not charging, its a failure on your alternator system. Check it all over for disconections, loose bolts, rusted connectins, fuses, switches, etc ... Volts on your battery terminals should read about 14 during engine charging operation. If, after you recharged batts and fired the engine, you don't read that, take your alternator for repair.

[chucklesR]

I'd guess alternator as well. When motoring along it should be putting out 13-14v depending on it's setting and that should be both recharging the battery and providing the spark to the engine and power for whatever else is running.

Unfortunately if the engine died when the battery got below 10v that means the alternator isn't providing spark for your plugs.

what you heard when you tried to start with the low voltage on battery two was the solenoid clicking, it was clicking because there was not enough voltage to disengage it.

If it wasn't providing spark your batteries would be dead rather quickly.

Here's a nice link for starting troubleshooting, but I second that you should have Nigel's book in hand.
Troubleshooting the Alternator System

It might be as simple as loose belts, or a wire being loose, don't despair and call a mechanic just yet.

[djodenda]

You are getting good, consistent information here.
( except that there should be no apostrophe in a possessive "its")

A question to our Sailnet experts.... Would this boat have an external regulator, or would it be integral to the alternator? If so, then can the OP be guided to a method to test/isolate the regulator?

David

[wolfmt]

Thank you all for your prompt feedback. I have a couple of follow-up questions.

First, assuming the alternator is the problem, which seems to be the initial consensus here, is it possible that the alternator is providing some power but an insufficient amount to continue to run the engine, and that the batteries have been filling the gap? In other words, is there a mechanism by which the power received from both sources (alternator and battery) are balanced to achieve the desired power input to the engine?

Second, assuming the alternator is the problem, for how long do you believe a fully charged battery can continue to start and run and engine (and various other electrical devices) without receiving a full or partial charge back from the alternator?

Third, let's assume I troubleshoot the alternator in accordance with the guidance you all have been kind enough to provide, and I can't identify the problem, what will it cost to replace, repair and/or rebuild an alternator, and can someone who is mechanically inclined but not experienced (i.e., me) install a new or repaired/rebuilt alternator? Would you recommend me doing so?

Thanks again. You all have been great.

Mike
s/v Liberty

[sailingdog]

It sounds like you fried the alternator by turning the main battery switch to the off position while the engine was still running. If that is the case, you should probably install a Zap-Stop when you get it repaired.

[SEMIJim]

Originally Posted by wolfmt

Thank you all for your prompt feedback. I have a couple of follow-up questions.

First, assuming the alternator is the problem, which seems to be the initial consensus here, is it possible that the alternator is providing some power but an insufficient amount to continue to run the engine, and that the batteries have been filling the gap?

Maybe. Or maybe the alternator's no longer doing anything at all.

Btw: Being as battery #1 died while the engine was running, switching to "both" was sub-optimal. You actually reduced your run-time that way, because now battery #2 was also trying to replenish battery #1.

Secondly: I wonder if it would've been a good idea to alert the CG of my situation and establish a check-in schedule, in case battery #2 bit the dust before I was able to complete my journey?

Originally Posted by wolfmt

Second, assuming the alternator is the problem, for how long do you believe a fully charged battery can continue to start and run and engine (and various other electrical devices) without receiving a full or partial charge back from the alternator?

There are so many variables there, I wouldn't even try to guess a time.

Originally Posted by wolfmt

Third, let's assume I troubleshoot the alternator in accordance with the guidance you all have been kind enough to provide, and I can't identify the problem, what will it cost to replace, repair and/or rebuild an alternator,

You're not going to try to repair your own alternator. Nobody does that. You're going to obtain a new or rebuilt replacement.

Originally Posted by wolfmt

and can someone who is mechanically inclined but not experienced (i.e., me) install a new or repaired/rebuilt alternator? Would you recommend me doing so?

Yes and yes. It's trivial.

I recommend you head on over to Moyer Marine and pick up the A4 Service and Overhaul manual. Indispensable.

Btw: It might be just the belt's off (broken). AutoZone carries the exact belt you need , if that's it .

Jim

[SteveInMD]

Volts give you some idea of what's happening, but it's not enough to give you the whole picture. One approach would be to pull the alternator off and take to AutoZone (or similar) and they can test it for you.

Volts don't tell you the whole story on batteries either. A full battery will rest at 12.7 volts. A dead battery will rest at 11.7 volts. Really the only way to know for sure is to install a battery monitoring system the counts every amp hour going out and every one going in to your battery. Then you can tell how many you have used and how many are left. However if the battery volts come up to 14 ish while running and rest at about 12.7 (with no load or charging for 24 hours) you are probably in good shape. You need leave your batteries on a good quality fully automatic charger for a few days to get them back up. It's hard a battery to run it down as far as you did. A few hours of running should help the batteries, but it wont get them back to max charge.

You need to check your electrical system carefully. You have to be systematic about it. Starting at the battery check the voltage, then to the switch, to the starting solenoid, to the alternator, checking each and every connection along the way. Check the voltage as you go (from the positive lead back the battery negative if possible). It should be very very close to the voltage you read directly off the battery. If any connections are loose or dirty take it apart clean it, re-assemble it, then move on down the line. Also start at the battery and follow the ground side doing the same for that. Again, voltage is only a trouble shooting aide. You could have fully voltage when testing with a meter, but it could dip way down under actual load if you have a bad connection or a bad cable. However, if you find a voltage drop with a meter under zero load you are sure have a problem under a load.

Trouble shooting is about being systematic, and eliminating items that work as you go. It would be nice to go straight to the problem, but that's usually not how it works.

[SteveInMD]

Battery switch...
Battery switches are "make before break" type switches. You can switch between 1, Both, and 2 while running as long as you don't go across the Off position. The switch should turn all the way around so you can avoid the Off position, or be setup so you don't have to cross it. If it doesn't do this the answer is no, you can't do it without destroying the alternator diodes even if you turn it really fast.