Amperage draw

capecodcruiser

Active Member
Aug 1, 2008
525
Falmouth, MA
Boat Info
2001 310, 350 HO's/Vdrives.
Engines
Mercruiser MPI 350 HO's
I have finally started my spring commission and I have a potential problem that just started as I put her on the hard last fall. I had left the battery switches on over night(as I always do) and came back the next day to not being able to open engine hatch. So I just winterized and decided to deal with it now. I plugged the Promariner charger in and all 3 batteries are now up and charged. But when it is on float charge I am still seeing 1amp of juice being consumed. I turned the breaker switch for the battery charger off and the amp gauge(on my remote monitor) went to 0. Breaker back on, 1amp again. I am going to put my meter on it and see what is the exact reading, but does this sound normal to you guys? I can't figure out why the charger is consuming 12volt power. Last season I could leave the main battery switches on while we were on the hook, etc. and no problems. Normal consumption, etc. I just may need to dig into this more but wanted to run it by the "experts" first to get some idea's. Thanks
 
~1 amp trickle charge for three batteries sounds OK to me...

Your batteries draining down when assuming nothing is on is your mystery.
 
You need to disconnect the batteries, put your meter in the circuit between the cable and the batteries, you can do this at the batteries or at the battery switch if you have easy access to it. After you have done this then you start disconnecting circuits until you find the one with the high draw. Then work that circuit to find what component is drawing power when it should not. Just had a thought, load test all of the batteries, if you have one bad one it will kill the rest, I will say here that probably your charger would be charging higher amps than it is, but it is still a possibility. Good luck, this could be the proverbial needle in a haystack.
 
Don't the C02 detectors draw some juice? I also heard there may be a slight draw from some stereos, or of course if there are any led monitoring lights on.
 
All good points, thank you. I plan on doing the amperage check to absolutely pinpoint the "leak". I hate mysterious electrical issues! I'll post back once I figure it out.
 
Don't the C02 detectors draw some juice? I also heard there may be a slight draw from some stereos, or of course if there are any led monitoring lights on.

CO2 - Carbon Dioxide
CO - Carbon Monoxide

The CO detectors draw very little and would not drain the batteries overnight. Most FM radios draw a small am out of current to hold the presets, again should not be enough to kill the batteries overnight.
 
CO2 - Carbon Dioxide
CO - Carbon Monoxide

The CO detectors draw very little and would not drain the batteries overnight. Most FM radios draw a small am out of current to hold the presets, again should not be enough to kill the batteries overnight.

Thanks for the correction, Jim - i failed 7th grade chemistry miserably, as you can tell!!!
 
I had a similar issue with my car a short while ago with the battery draining overnight. Much to my surprise it turned out to be a defective alternator. I would imagine a marine alternator would react similarly, but don't know for sure. I'm not suggesting you run out and replace the alternator but if your planning to disconnect each component at a time while monitoring the draw you may want to include the alternator.
 
before you looking for possible draw, disconect batteries and load test them to make sure they are ok. it maybe just a bad battery
 
Great input guys! Thanks. I was actually able to work on the boat yesterday and made some progress on this issue. I will attempt to summarize what I have found. I started at the batteries with my meter. I found that it is the port engine battery that is the issue. This battery is the start for the port engine, power for engine hatch lift motors, and "control panel main". This is the push button breaker system under the helm station. I quickly blew the fuse on my meter which means it is drawing more than 10 amps at rest. I didn't have another fuse but used my test light in series with the battery cable and battery terminal. The light was on nice and bright with everything hooked up. I started removing the fuses for the Garmin GPS/radar that I installed last year. Voila, the light went dim! So, my issue is with the head unit of my chartplotter. This unit has never worked properly as far as turning it on and off. The on/off button on the unit has not worked correctly. But I never have had battery problems before with it in the 3 years I have had it. I will be contacting Jim at BOE to ask his advice, but I am pretty sure he will tell me to call Garmin directly. I had a problem with my Radome last year that they had to send me a new one, so I am a little uneasy with the Garmin brand right now. I do a fair amount of night time boating and the last thing I need is for this unit to go down in the middle of a night time cruise or crossing. I will keep everyone updated as I learn more.
 
Thanks for update, and good luck getting everything rectified. Please keep us posted - I, too had a similar problem with a chartplotter. It was on a new boat, and it would "freeze" - could not turn off at unit. The mfr did replace it, and the problem didn't recur, but it is a huge nuiscance, as you know.
 
Just bought one of these today to monitor future events. In my opinion, these should be included in the gauge package on the boats. If you lose your batteries while on the hook, it can really ruin your day. I am all about having as much information available to me about the systems on the boat. I am interested to see how this goes.
http://www.xantrex.com/power-products/power-accessories/linklite-battery-monitor.aspx

Let me know how you like it. I looked into something similar, but was discouraged by the guy selling it, because of how my battery banks are setup. I've got 4 batteries on 2 banks, and he said the way SR configures it, I wouldn't be able to get a read, for each battery, individually. He said it would measure each bank only.
 

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