Unknown Battery Drain

[Musky Plug]

  

Hey everyone,

I’m looking for some insight into a battery drain issue on my boat. I’m experiencing a problem where, about an hour into a day on the water, I get a low battery warning on my Helix 9 unit, but not on my Helix 7. I get the low battery warning only when I start the main motor. Both units, along with my live well pump, bilge pump, and main motor, are powered by the same Group 31 lead-acid battery 225 Res. I've tried turning the brightness down or even putting them on night mode, replacing the battery - which temporarily solved the problem, but it happened again on the second trip with the new battery-, testing the battery with a multi meter - which shows it holds a charge -, a voltage test by keeping the negative end of the multi meter on the negative post and checking each positive lead - all reading were 0 -, checked all fuses which seem to be in order. Not quite sure where to go from here. Any help would be greatly appreciated.

[Terry]

It may be not enough current going to the unit you may need to beef up your wiring 

double check your connections too

[BillM]

Probably your stock wiring.  My Lund did the same thing until I ran dedicated wires to a distribution box for my finders (Two Helix 12s).   Fixed the problem instantly.  

Edited September 5 by BillM

[Musky Plug]

25 minutes ago, Terry said:

It may be not enough current going to the unit you may need to beef up your wiring 

double check your connections too

I had these units first installed when I got the boat, had the exact same battery. I got a new battery at the beginning of last season (replacing old one due to age)and never had an issue until end of last season. Wouldn’t I had the same issue originally? 
 

I check battery connections regularly. 

Edited September 5 by Musky Plug

[Musky Plug]

13 minutes ago, BillM said:

Probably your stock wiring.  My Lund did the same thing until I ran dedicated wires to a distribution box for my finders (Two Helix 12s).   Fixed the problem instantly.  

The units are wired directly to the battery with an inline fuse. 

[Musky Plug]

I forgot to mention in the original post that a few times when I’ve gone for day trips, my main motor won’t start right way when I turn the key over. It takes a few tries to get it going and makes a sound like it’s not running properly? Also had the batteries charged overnight on the minn kota charger. 

[HTHM]

Check your batteries health. May be time for replacement. 

[Musky Plug]

1 hour ago, HTHM said:

Check your batteries health. May be time for replacement. 

The battery is new. Got it in June when I returned the old one as I thought it may be the problem.

[AKRISONER]

to me it sounds like you have some kind of parasitic drain thats pulling down your battery when not in use causing you to subsequently have low voltage. I think the only way to check is start by ensuring you full charge the battery, consider disconnecting everything from the battery and only hooking up the humminbird units directly to the battery with heavy enough guage wire and attempting to start the motor. What guage of wire did you use to wire the units? Typical is 10 guage, and furthermore you want to be running marine tinned copper, any regular copper strand will corrode and cause resistance throughout the line.

if its shutting off your units still after doing all of these things, either your battery is shot, which even with a new battery you can ruin it within a few uses if you discharge it too heavily and dont recharge it properly, or the battery is shot because your charger is overcharging and boiled off the water in it.

one of the mechanics on here could also maybe provide some insight, but im not sure if a bad stator/starter could cause significant battery issues?

Remember Shut offs are your friend, things like livescope, and control panels can be nasty at drawing down batteries. speaking of, that reminds me to go turn my livescope shut off off!

Edited September 6 by AKRISONER

[smitty55]

For a vehicle there is a certain procedure to follow to check for parasitic drain and the same practice should work for your boat. Make sure everything in the boat is hooked up but turned off. Disconnect your main negative battery connection and put multimeter leads set on mA between the battery and the cable. For a vehicle normally what would be normal current draw is in the area of 25 milliamps (.025A) Again, in a vehicle if the draw is much higher than that then what you do is start pulling fuses one by one until hopefully the current draw drops down to normal when you pull a specific one which will isolate the faulty circuit. In your case on a boat I would think that current draw should basically be zero or very close to it and if not it will be much simpler as there are much fewer circuits for you to isolate, so if you read 100mA for example disconnect your different units one at a time until the current draw drops back to zero or close to it and that will tell you which circuit is causing the problem, whether its bad wiring or an internal issue with one unit or even a switch for that matter. Good luck.
 

[RandyLinden]

Hi
When you go to start your engine and the graphs show low voltage it is because the engine is pulling power from the battery not leaving enough for your electronics at the same time. As others have pointed out there are a number of things that need to be checked. You have indicated that the battery is new. Make sure that it is correct for your boat, confirm that it has enough cold cranking amperes for your engine. Larger modern outboards need 1000 CCA and often have starting issues if lower a CCA battery is used. As an example there are some engines like Mercury Verados that specify AGM batteries because the characteristics of an AGM works better when starting a Verado. Next test the new battery to ensure that it is actually good. It is not uncommon for a brand new battery to have a problem like not fully charging or holding a charge or not capable of producing the required amperage. Once you are confident the the battery is correct and good double check all the wiring and pay extra attention to all connections and connectors. A bit of corrosion or a poor connection will cause problems. Wiring your electronics directly with heavier gauge marine wire is a good idea. Depending of the length of the run and the equipment it powers I use 12 awg to 10 awg for most electronics make sure there is a fuse or better a breaker with a shut off near the battery. Confirm that you charger is actually fully charging the battery. As AKRISONER has mentioned it is possible that your on board charger is not shutting off at the correct time and is destroying the battery by over heating and boiling them. After all of this you still have  a problem follow smitty55's advice and trouble shoot for a  parasitic drain. If all checks out and problems persist you could install an additional dedicated battery just for all your electronics. From your description I'm betting that you need a need a new battery... hope this helps.