Electrical gremlins on board

[JonnyQuest]

So for a couple of weeks the Quest sailboat has been experiencing electrical problems and I have commented in other threads about my progress. Since it is unfortunately ongoing, I am going to consolidate everything and post progress here.

To catch up somewhat...

About three or four weeks ago (just prior to when TS Karen came loitering along the Gulf Coast) everything was hunky dory. When resetting after the storm that wasn't, hitting the starter gave a clicking solenoid but nothing else. Batteries (at first) appeared to be charged, so I assumed that the solenoid was kaput. After replacing it and still having the same problem, I needed to step back and tackle this methodically. Batteries may not have been properly charged after all.

Specific gravity tested good in three of the four 6v golf cart batteries. 4th one showed slightly below the green zone on sp gravity tester.

Resting voltage at 12.5v on bank one, and 10.5v on bank two. One of the gc batteries on bank two is showing low charge. Same one with lower sp gravity.

Hitting the start button immediately drops voltage from 12.5v to a fluctuating low voltage like 4v.

1. Charger does not seem to be charging the batteries. Alternator too is not outputting charging voltage , though possibly not related.

So I have this evening isolated the batteries from everything but the charger and they are now showing a better charging voltage level of 14.x volts instead of 12.5 volts. Supports the theory that I have a short somewhere draining my batteries.

Hoping that by tomorrow afternoon the batteries will have recovered enough to actuate the starter. Currently used my car battery hooked directly to the solenoid and started without issue.

2. If batteries recovered tomorrow, then attempt to start first by existing wiring and then by bypassing wiring with jumper cables. That would suggest a short too.

Then continue to try to find any short by tracing wiring back from the batteries.

3. If batteries not recovered then try a remote heavy duty charger to help out charging.

4. If batteries still not charging then take then to get tested and possibly replaced.

Must Resolve the battery issue before tackling any possible shorts.

Stay tuned for more.

JQ

 

[kloudie1]

JQ, sounds a lot like bad battery connections instead of a short. A bad connection, at low/no ampere draw, will read kinda good volts but as soon as you ask it to transfer a lot of amperes, the volts will go very low because not enough current can get across. A battery with very high internal resistance (shot) will kinda look the same way to a voltmeter. You can see which by reading volts on the battery post itself and not a wire or the post clamp. If you hit the starter and the volts on the posts (both probes on the posts) go very low, the battery is shot. If it stays relatively high, then you have a bad connection.. Check both the hot and the grounds for bad connections.. Happy Hunting !

 

[JonnyQuest]

Hey Kloudie, that's some good advice to get me started. Later today, hopefully the batteries will have charged back up and I'll be able to test that way.

 

[Stu Jackson]

Jonny, good methodical approach you are taking.

Kloudie's right. You might be interested in this post, and also might want to noodle around the other posts on that topic which may be of help to you. Good luck.

http://c34.org/bbs/index.php/topic,5078.msg37179.html#msg37179

 

[JonnyQuest]

Hey Kloudie, that's some good advice to get me started. Later today, hopefully the batteries will have charged back up and I'll be able to test that way.

Kloudie and Stu,
Charging with inboard xantrex didn't work. Not much time today but cleaned terminals and added dielectric grease. Also got an external charger and isolated each bank for independent charging tonight. Will reassess tomorrow. Thanks for the suggestions here.

Oh, the batteries were installed just after the BP oil spill, making them under three years old after all.

 

[Stu Jackson]

Where and when did you install the grease?

 

[JonnyQuest]

Where and when did you install the grease?

I cleaned the battery terminals and wiring ring terminals with wire brush and then added dielectric grease to post and ring terminals at their mating surfaces. I did this this afternoon, after my night on xantrex charger and prior to placing each bank on separate charge sources for this evening.

I take it not a good idea after all?? Inhibiting good connection?

 

[JonnyQuest]

I didn't have any Vaseline and wasn't thinking at the moment it would kill the connection.

 

[Stu Jackson]

Yes. Maine Sail recommends Dioxit or something like that. One of these days I'll write it down. I suggest you just clean them up again, and if you want to use the grease, make the connections, then cover them.

 

[kenn]

I cleaned the battery terminals and wiring ring terminals with wire brush and then added dielectric grease to post and ring terminals at their mating surfaces. I did this this afternoon, after my night on xantrex charger and prior to placing each bank on separate charge sources for this evening.

I take it not a good idea after all?? Inhibiting good connection?

If you cleaned and tightened the connections, the grease shouldn't be a problem.

IN ANY CASE, as Kloudie mentioned, if the voltage at the starter solenoid still drops alot when the solenoid is activated, then you still have a path problem which still means there's a bad connection somewhere (or less likely the start wiring is inadequate). Assuming you can access every connection point between the battery and the starter, you can connect a voltmeter between the points and measure the voltage drop every time the starter is activated. Ideally you start from the farthest points (battery post and starter) then move one meter lead at a time towards each other, testing after each move, til you find where the vast majority of the v drop is occurring. Chances are you will find a slightly loose connection or a bad crimp.

A few years back I worked on a small hobby-tug that had chronic starting issues. They'd even doubled up the starting battery. After reviewing the wiring and making drop tests as described above, it became clear that there was simply too long a path and too light a wire gauge running from the batteries to the battery switch and then to the engine. I relocated the battery switch and rewired the much shorter path with a heavier gauge, and the engine started briskly, using just one battery.

 

[JonnyQuest]

...IN ANY CASE, as Kloudie mentioned, if the voltage at the starter solenoid still drops alot when the solenoid is activated, then you still have a path problem which still means there's a bad connection somewhere (or less likely the start wiring is inadequate).

What about when the solenoid is NOT activated? I'm seeing an instant and large drop merely by connecting the isolated battery to solenoid--before I even activated the solenoid with the starter button. I assume there shouldn't be any voltage draw unless the solenoid circuit is closed via hitting the starter button. Mine drops from 12.8v to 7v without even hitting the starter.
***Do I have that right?***

Hopefully Wednesday after work a friend is going to educate me on how to get started on tracing down a short-- checking for earth grounds (?) and then wiring and device shorts. Time for me to put on my Student Cap and learn how this is done. --reading it in books isn't sinking in for me, I need a hands on approach to learn it.

I still think my batteries are shot since charging with the batteries isolated hasn't helped. Touch jumper cable ends together and only get the faintest sparks. VERY faint.

More later.

 

[JonnyQuest]

...IN ANY CASE, as Kloudie mentioned, if the voltage at the starter solenoid still drops alot when the solenoid is activated, then you still have a path problem which still means there's a bad connection somewhere (or less likely the start wiring is inadequate).

What about when the solenoid is NOT activated? I'm seeing an instant and large drop merely by connecting the isolated battery to solenoid--before I even activated the solenoid with the starter button. I assume there shouldn't be any voltage draw unless the solenoid circuit is closed via hitting the starter button. Mine drops from 12.8v to 7v without even hitting the starter.
***Do I have that right?***

Hopefully Wednesday after work a friend is going to educate me on how to get started on tracing down a short-- checking for earth grounds (?) and then wiring and device shorts. Time for me to put on my Student Cap and learn how this is done. --reading it in books isn't sinking in for me, I need a hands on approach to learn it.

I still think my batteries are shot since charging with the batteries isolated hasn't helped. Touch jumper cable ends together and only get the faintest sparks. VERY faint.

More later.

 

[kenn]

What about when the solenoid is NOT activated? I'm seeing an instant and large drop merely by connecting the isolated battery to solenoid--before I even activated the solenoid with the starter button. I assume there shouldn't be any voltage draw unless the solenoid circuit is closed via hitting the starter button. Mine drops from 12.8v to 7v without even hitting the starter.

Wow. If true, there's a really really bad connection in the path somewhere.

I still think my batteries are shot since charging with the batteries isolated hasn't helped. Touch jumper cable ends together and only get the faintest sparks. VERY faint.

Are you saying that if you put jumpers right on on the battery and you touched them together eek: Kids - don't do this) you only get faint sparks?

(Usually you get a loud snap and a 1/4" melted crater on one or both jumpers and drops of molten copper here and there. Kind of why you shouldn't do this)

 

[Sandy Stone]

(Usually you get a loud snap and a 1/4" melted crater on one or both jumpers and drops of molten copper here and there. Kind of why you shouldn't do this)

Or sometimes the jumpers will weld themselves together and you have a REAL problem.

 

[JonnyQuest]

Update:
Yep. Batteries are shot. Alternator and charger putting out properly. Hooking up spare battery and back to normal start with no voltage drain measured so far. When new batteries are in ill do a final check for drainage issues again. Looks like one cell went bad and killed the rest in short order.

With that in mind, question about my Xantrex echo charge controller. Is it possible for the one bad cell to to drag down the other bank of batteries across the echo charge regulator? I thought it was designed to allow one way current flow only, to permit bank 1 to feed current to bank 2 once bank 1 is fully charged? If there is a possibility for depleting the entire bank with an echo charge unit I can start a new thread to explore possible issues.

Thanks, JQ

 

[JonnyQuest]

Partial good news. Two of the four golf cart batteries tested good after separate charging. Charging in series inhibited the good batteries from recharging while coupled with the bad ones. Pairing the good batteries together worked we'll. These batteries retained 11.8 volts after ten seconds of cranking. Yay!

I expect the remaining two to prove bad but I am going to try charging then separately to see if even one can be resurrected. Best I can figure is that on the last trip out, which was fairly rigorous, the batteries got shaken enough to slough off some battery detritus and short out one of two of my 3yr old batteries.

Next step is to separate and attempt to charge the remaining two batteries.