Cause of Battery Drain?

I am looking for the cause of a battery drain that seems to be happening when boat is not in use. ( Starting battery ) Last year I upgraded to a Huminbird Sonar/GPS unit with a GPS puck mounted in back of the boat. Also have a lowrance unit with built in GPS mounted in the front. Power switch is off and the key is in the off position. If I have not recharged wiht the onboard charger for a couple of days the starting battery has lost voltage. I really didn’t want to disconnect everything. Is that the only way to stop the drain on the battery or do I need to keeep the charger plugged in all the time? thanks Dave

You could put everything on your power switch. I had to do that because the samething was happening to me.

Your GPS pucks are probably the culprit. They will draw votlage even if the unit is off.

-J.

With my HDS locators and sonic hub the Boat dealer put a shut off switch at the battery. You mentioned starting battery. Is your starting battery a true deep cycle? I am betting it is not meant to be used as a deep cycle. Your electronics use a lot of juice along with live well, radio etc. Remember if your outboard is a modern one with an ecm module it is continuously drawing power. What amp alternator is your main engine putting out? If you do not do long runs it may not be able to keep the battery adequatly charged during a fishing trip. You may want to use a dedicated deep cycle battery for all of your accesories. That way you always can start the main motor.

Mwal

i put a switch on both my GPS and sonar. stopped my problem.

Need a master switch between the battery and the electonics to stop the GPS from drawing current.

I used to kill batteries all the time.

Far less than advertised lifespan regardless of brand.

I finally tracked my problem to that

small but obviously problematic

drain was coming from the radio.

It was the hot line that keeps the unit powered up enough to remember the presets and such.

I finally added a switch to cut that and have not been killing batteries ever since.

The easy solution is to put an on-board charger to the battery and keep it plugged in all the time when not in use.

-J.

Maybe not a problem in this case, but Minnkota sez to unplug the power from the i-Pilot as it also drains batterys- – jerr

Quote:

---

Need a master switch between the battery and the electonics to stop the GPS from drawing current.

---

Would this not be needed if you disconnect the unit when the boat is not in use, correct?

Thanks!

I got sick of chasing it on the Pontoon. I just unhook one of the terminals when not in use for more than a few days.
Another thing to consider is whether or not your outboard is charging. I’ve had that problem with two outboards recently and initially I thought it was a idle drain. Not so. Make sure your outboard is putting out voltage when its running. I was able to troubleshoot this both times by using volt meter function on the graph.

If you take the head off, the current drain by the GPS will stop. Still could be a drain from the radio or other devices as pointed out by others.

JT

Does your onboard charger charge your starting battery? If not then that is where your issue is coming from like stated earlier unless you make long runs the starting battery is not getting fully charged between uses.

Edited to add only the Lowrance GPS draws juice the Hbirds shut off with the unit.

Thanks for everyone’s input.
Couple of additional thoughts.
1. I do have an on-board 3 bank charger, that charges the starrting battery when plugged in. I saw a comment to leave it plugged in when not in use. Does this reduce the life of the battery?
2. Saw another comment to install an on/off switch. This seems to possibly be the best solution. How would I do this this, what type of switch? where? Is this easy to do?
thank you

Yes with the on board chargers you can leave it plugged in all the time.. As for the second question some type of master power switch would work.. A lot like the ones you see for nav lights and live wells..

on mine, i left the on-board charger connected, but went up the power line and put a fuse box there. Put a cut off switch to it. Now the OnBoard will charge, but nothing can draw while the boat is ‘off’.

Quote:

---

2. Saw another comment to install an on/off switch. This seems to possibly be the best solution. How would I do this this, what type of switch? where? Is this easy to do?
thank you

---

You can buy a simple master battery disconnect switch at Fleet Farm. The ones I’ve seen go on the + terminal and then there’s a big blade switch that you can open to disconnect the battery. Simple and effective.

Or you can go with the marine version that looks better and is more corrosion resistant. My big boat has this master switch, which controls the two starting batteries: http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=112462&catalogId=10001&langId=-1&storeId=11151&storeNum=50523&subdeptNum=50543&classNum=50547

You may need to install multiple switches if you’re running a 24 volt setup plus your starting battery.

Grouse

Grouse