Battery Power Fluctuation and Power Issue Marble Falls

[ScottyE]

New to the group but I love how helpful everyone is in here and wanted to join!

I can't tell if I have an alternator problem or something else. and I think it's multiple issues.

I have one of those battery switches. Battery "one" has always been worthless. It never can keep a charge , I am wondering if something is draining it. even after I replaced it , I could never use it to start the boat.

I just put two new batteries and added a Noco charger to see if that may help. The problem seems to have gotten worse.

I charged the batteries all night then took the boat out yesterday , I turned the engine and master power off and sat for about 20 minutes. when I tried to start it back up, there was just a clicking noise.

I had to use a noco booster to get it to turn over. Once I got it started the batteries were fluctuating between 9 and 11 volts on my gauge.

then after I was moving in the water , suddenly the boat starting losing power. I reduced the throttle, slowed to a stop , put it in reverse for a few seconds thinking I may have gotten something tangled up in the prop

then put back in drive and started going again. it kept losing power even though I wasn't moving the throttle.

I have a mechanic coming later in july but I thought if it's an alternator or regulator or maybe a switch or fuse that's causing it to drain I may be able to fix it myself with some guidance and be able to use it for this long weekend.

(I have a third battery that i'm guessing is for the refrigerator onboard that I don't use).

looking for any help you guys can offer. I am in marble falls , tx by the way. on LBJ if anyone knows a mobile mechanic that wants to make some money this weekend!

 

[Vikingstaff]

If losing power when underway, my immediate thought is alternator. The fact it drains when everything is also shut off with battery switch on off makes me think there is a parasitic draw somewhere. So both could be happening.

Also, how old are the batteries? On top of the above, or due to it, are the batteries shot, so they wont hold a charge anymore, regardless of other issue(s)? I am sure others with better knowledge and insight will chime in. Given what you have done, and what you are experiencing, I’d take it in as I am thinking multiple problems might be happening. I would have batteries tested. If they fail, new batteries. I would also probably get that alternator checked. After that, I would real world test how its operating and holding its charge.

 

[Seadoorxpguy]

If you can duplicate the issue with a voltmeter hooked up it would help isolate the issue. What do you have for a engine? What are the batteries charging at with the motor running in neutral? Theres a lot going on with that switch and all the wires coming off it. Whats all the extra stuff connected to the stud next to the safety hub? It drives me crazy when people land stuff like that when you have a empty fuse block right next to it.

 

[PRaudio]

I can see the Noco charger leads to the batteries, but what are the second small battery wires connected to? Sounds to me like parasitic draw before the battery switch given new batteries are rapidly draining with the switch off. I believe all electrical loads but the motor tilt are after the switch... which makes those extra wires suspect to me.

If you don't have an ammeter/voltmeter, you could disable the battery switch and remove positive battery connections and check for arcing; you could possibly see a spark if the draw was large enough and the battery is charged. Might also try removing the positive main terminal [and the unknown-to-me wire], then fully charge the battery. Remove the charger and see if the battery then holds a charge. Reattach the main or "unknown" wire one at a time to see if either causes the drain.

My dealer told me not to run my switch in A+B mode as it could strain the alternator if both batteries were low, so possibly your alternator might be compromised if that were the case. Does your Noco charger ever indicate full charge? Seems like it wouldn't if there were a large parasitic draw.

 

[LaurencetheAdventurer]

Great advice from prior posts, possibly a few helpful nuggets:

1) Invest in a multimeter and spend a couple of hours to learn how to use (youtube, multimeter for dummies, google), and test your batteries and draw when everything is off. This will probably require the battery to be disconnected. Google 12V battery health to locate a diagram of volts needed for a healthy battery. Then test the draw between each battery and the main hookup before reconnecting (not running - 1 with everything off (1-2 on), 1 with accessory on. Document results - will be good data and might point to the issue. Being new, the batteries should be good, but as noted this will help let you id a parasitic draw.
2) IF the battery / parasitic draw are not the issue2, then it MOST LIKELY IT IS the alternator since you are loosing power while underway (unless it is a short - possibly from a wire loosing it's protective covering from abrasion over years or a poor wiring job). You should be able to find a way to test this with the multimeter via google (testing my outboard alternator with a multimeter).
3) NOTE - The power steering (if you have) is hooked up to only 1 battery and can draw down a battery in a few hours. My Service tech said this is the instruction from Bennington, and stated in writing "Bennington suggests a 2 battery system be run in 1+2 mode" while underway (implying that when stopped, turn to 1 or 2). However, from your description this does not seem to be the issue.
4) Off Topic but - I Run my Noco maintenance cycle after each season - it requires a manual selection - be sure everything is off including the 1-2 switch and helm. I understand this will help the batteries last longer.

Keep us posted!