new batteries causing electronics problems??

[Brian W.]

we recently had new batteries and battery cables put in our CD33. we went from a pair of Exide Nautilus group 27's to a pair of Rae NC 31T 1090MCA 's. Well these larger batteries make quite the difference. Every light on the boat is brighter, from cabin lights down to the red pilot light for the sump pump on the electric panel. HOWEVER, we're suddenly experiencing problems with almost all of our instruments. The knotmeter works fine, but our loran (pretty much a backup these days) just reads zeros, our Ratheon Autopilot reads STLK FAIL and doesn't function, the Datamarine Depthsounder is largely stuck on 2.4ft, and the APELCO VHF has no power, as the inline fuse appears to blow everytime it's replaced.

These batteries were installed by a marine mechanic, so I would figure if there were any precautions or problems, he would have forseen them. But it seems a bit odd that we're suddenly having all these problems, all at once.

There's also a new alternator, so I suppose there's the possiblity of faulty regulator, but the lights are so bright with the motor off, and the instruments have the same problems under sail, we figured maybe it was possible these batteries were throwing too much juice at the system. does anyone know if this is possible??

Thanks,

Brian W.

[Bob Loewenstein]

the Datamarine Depthsounder is largely stuck on 2.4ft

Interesting. This happened to my Datamarine last year. It works fine for depths less than about 50', but above about 50 it's always 2.3 or 2.4.

No change in my electrical system, and nothing else (Loran, autohelm, vhf, etc) was affected. I figure it's just a bad solder joint in the receiver unit, but haven't tried to fix it yet.

For your problem, since you mentioned you also got a new alternator, I wonder if there is a regulator failure and things went bad after the engine was run...the batteries just being a red herring.



rfl@yerkes.uchicago.edu

[Anthony P. Jeske-]

Brian:
I would suggest that you purchase a digital multimeter from someplace like Radio Shack and check your voltage.
If the lights are clearly brighter, it would seem to me that you are noticing higher voltage. Could the "expert" mechanic have installed your batteries in series rather than in parallel? Then you'd have 24 volts flowing, which would brighten your lamps for sure, while seriously scrambling your electronics.
Good Luck,
Tony Jeske



ajeske@ixpres.com

[Don Carr]

From what you have said,I concur with Tony. The fact that you went with a larger battery only should indicate that you have more amp/hrs capacity. Assuming your old batteries where fully charged 12-13.5 volts the noticably 'brighter' lights indicates that the battries may be wired in series rather than parallel. After all,12 volts is 12 volts. Would not continue to run the electronics until you get it checked out as you may fry them.



carrd48@netzero.net

[Bob Loewenstein]

Wouldn't some of the lights blow at 24 volts?

[Brian W.]

that's what I figured: 12 volts is 12 volts, and presumably these batteries were designed for this purpose. I'd figure an experienced mechanic who deals heavily in batteries wouldn't wire them in series. is it an easy enough thing to do, "accidently?" how would you look for it? just getting 24 volts from on a test meter?

-Brian

From what you have said,I concur with Tony. The fact that you went with a larger battery only should indicate that you have more amp/hrs capacity. Assuming your old batteries where fully charged 12-13.5 volts the noticably 'brighter' lights indicates that the battries may be wired in series rather than parallel. After all,12 volts is 12 volts. Would not continue to run the electronics until you get it checked out as you may fry them.

[Murray Glue]

I own a marine electronics and electrical business. I would urge you to follow the good advice hereon and get the batteries disconnected
with all haste, then have a marine electrician inspect the new installation. It is not too hard for a do-it-yourselfer to get confused in a confined space and wire things wrongly. It is however inexcusable for an expert. Please let this bulletin board know what your problem turns out to be...

Murray



Murra



gluebatts@yahoo.co.uk

[Mark Yashinsky]

If the batteries are wired in series (24v) then every light "should" have burned out and the electronics "should" have fried themselves. Most 12v stuff is not made to work over 15-18 volts. Like was said, get a voltmeter (do you have a voltmeter on the 12v breaker panel?) and get the volts at the main battery switch. Also, trace the battery cables to the battery switch. If each batteries' + goes to the main switch, your ok, if one battery - goes to the next's +, your not, take pictures for evidence and go back to the "electrician". I would be more inclined to believe the alternator regulator has problmes. If you let teh batteries sit for a day (no engine running, no shore power charging) are the lights about the "correct" brightness (compare to other boats w/ the same type of lights)??? or check w/ a store display. Its possible the alternator is always @ full output and charging the batteries to 15-16v (killing the batteries too), and thats why the lights are brighter (while or right after you run the engine). Again, a voltmeter will tell. Or, previously, your batteries were always in need of charging. Voltmeter, voltmeter, voltmeter and trace the rewiring. Its not rocket science!!!