Battery drain on F150. Serial #1B944986

[shuddyssoup]

On memorial day the wife and I were going to take the boat out. I went out and was going to turn the motor over and the battery was dead. Grabbing a voltmeter I found the battery to be at 5 vdc. Assuming my yellow top had gone bad I went and purchased a new battery and installed it. Motor Serial #1B944986 It was connected to my Stealth One DC and AC chargers, a #2 wire to a battery cut out switch and the big motor. When installing the wires back on the post (all wires were connected with a screw on lug and then attached to the battery with a standard post. I noticed arcing when reattaching and thought perhaps it was related the to the charger and it's lights. 2 days later, the battery was back at 5 vdc. I disconnected everything except for the AC charger to bring it back to full charge. I disconnected the charger and the only wire attached was the big motor lead. When attaching it I noticed arcing. Within 48 hours the battery was down almost 3 volts to approximately 10.5 vdc. Oh, prior to that a friend suggested unplugging the wire harness from the controls up front which I did. What could be causing this drain ? I looked for trim relays but couldn't find them under the cowling. Any help would be greatly appreciated.

Very Respectfully,
Mike

[idratherbeefishin]

Battery drain can be difficult to find . You need to have the volt meter hooked up and start pulling fuses one at a time and watch for voltage jump . When it jumps back up u found the circuit that is actually pulling the draw could be on the motor side could be on the boat side.I have also heard of the charger actually having internal problems pulling the draw itself need to disconnect your charger system and use a known good charger and see if that fixes the problem before you start checking all the fuses.

[shuddyssoup]

Oh it's definitely the outboard. The battery sat last night @ 12.9 vdc. Only think hooked up was the AC charger which was unplugged. Hooked the motor lead back up this morning and within 2 hours the battery was already losing volts. I guess, like you said I can pull fuses in the fuse block on the motor since there's only 3 or 4 and go from there.

[shuddyssoup]

So I pulled all the fuses in the fuse block on the outboard. I still had the arc at the battery when touching the positive lead to the post. At 1330 on Sunday I connected the outboard to the battery. Three connections total. 2 from the AC charger and the motor lead. With nothing connected to the battery, it sat @ 12.9 VDC. As soon as the motor was attached the voltage dropped to 12.7 I kept track of the voltage every few hours and it would drop approximately .10 every 2 hours. On Monday when I got home from work at 1930 the battery was down to 10.88 vdc. I removed the motor lead and within an hour (no battery charger hooked up) the battery rose to 11.2. The multi pin cable to the helm is disconnected. I checked my grounds on the motor and they look good. Any ideas guys and gals ?

[idratherbeefishin]

So I pulled all the fuses in the fuse block on the outboard. I still had the arc at the battery when touching the positive lead to the post. At 1330 on Sunday I connected the outboard to the battery. Three connections total. 2 from the AC charger and the motor lead. With nothing connected to the battery, it sat @ 12.9 VDC. As soon as the motor was attached the voltage dropped to 12.7 I kept track of the voltage every few hours and it would drop approximately .10 every 2 hours. On Monday when I got home from work at 1930 the battery was down to 10.88 vdc. I removed the motor lead and within an hour (no battery charger hooked up) the battery rose to 11.2. The multi pin cable to the helm is disconnected. I checked my grounds on the motor and they look good. Any ideas guys and gals ?

Try doing what u just did but this time unplug the pcm and charge up your battery and see if it holds the correct voltage . The draw could be in the pcm. If not there then u might have to pull 1 reley at a time to see , might have a stuck relay

[OldTimer57]

It can ALSO be the charger. You should fully charge, then unhook everything and let it sit for 24 hours. Then hook up just the charger, unplugged and check after 24 hours. I once had a dual-pro that did exactly that. If it is the motor, start by checking the main power relay on the powerhead. Ought to have no connectivity when ignition is off.

[CatFan]

Arcing when connecting to the battery is normal in most cases. You obviously have something wrong, but don’t use that to help troubleshoot the problem.

[shuddyssoup]

OldTimer57, I don't think it's the charger because it was hooked up for several days, unplugged the volts never changed. It's definitely on the motor side because when I have my meter hooked up to the terminals, as soon as I connect the motor, the voltage stops dwindling. When I get home from work tonight, the battery should be fully charged again and then I'm going to unhook the PCM and let her sit overnight. See if that's the issue ... And CatFan, thanks. I'll just keep using the dvm and watching my numbers. With that said, now that I think about it, I might pull the fuses again and see what happens. Considering I was expecting no arc if one of the fuses circuits was the issue. Thanks y'all for the input.

[MichaelJ3]

I think you should unhook the charger too...even if the charger charges the battery, it could also drain it when unplugged, if there was an issue with it.

[shuddyssoup]

MichaelJ3 ... when I first started troubleshooting I thought you were correct on that. I was sure it was one of my chargers. I did unhook the DC charger ( I have a Stealth One Charger ) but left the AC charger hooked up. With just the AC charger hooked up (unplugged), it remained at full charge for several days so I'm assuming that it's good. I just know that with just the Motor wire attached, the voltmeter starts dropping as soon as it's hooked up.

[MichaelJ3]

Then, yea, you probably have an issue.

I'd consider disconnecting the alternator first...but Don may have better advice.

[shuddyssoup]

You might very well be right ... this new motor is so different than my Promax because it's so neat and tidy under the cowling and there's hardly anything under it. That's not a complaint.

[idratherbeefishin]

U find the battery draw yet ?

[OldTimer57]

My suggestion for this is as follows:

(1) you need a good DVOM that reads current as well.

(2) use the 10a setting and with every wire unhooked from one post of the battery, take the wires one at a time and connect to one of the DVOM probes (other probe should be attached to the empty battery post.)

(3) record the amp reading for each wire.

There will always be some parasitic losses as even when turned off, things still use some power to maintain some settings, etc.

A good battery (cranking) will have something around 100 amp-hours of storage ability. That means a current draw of 4 amps will flatten that battery in 24 hours. And actually 12 hours of that will leave the battery in a dangerously low condition that can result in damage. Here's some guidelines:

1 amp of draw will flatten the battery in 2+ days (amps x hours = drain, so 1a x 48 hours = 48 ah of drain, about ½ the total battery capacity). One 100ma (.1a) drain will take 500 hours to burn through ½ of the full charge, which is about 3 weeks. Obviously you have a much higher drain than 100ma. So step one is to record each drain separately and see where the big drain is. If it is the motor, then you zero in on that, starting at the main relay as the PCM and such will definitely burn some power if they are on all the time. Once you know which wire is producing the excessive drain, you have reduced the problem search space significantly since all the other parts don't have to be examined...

Notice that measuring voltage is not very helpful, you need to know what is drawing the current. Voltage is pretty static until the charged state degrades. Measuring amp draw will specifically lead you in the right direction. ANYTHING that connects to both + and - battery posts (motor, dash, sonar units, charger(s), stealth chargers, audio systems, compartment lights, the list goes on and on. And any of those things can discharge a battery far faster than you might expect. Sounds like your drain is going to be north of 1.0 amps, so it should be pretty obvious with the ammeter results.

Also, the arc is not very revealing. My motor will produce a noticeable arc when reconnecting, yet my cranking battery shows no issues after sitting for several days disconnected. So the ammeter is the way to find this.

[EuropeanAM]

Then, yea, you probably have an issue.

I'd consider disconnecting the alternator first...but Don may have better advice.

Alternator is a possibility, as is the MPR (Main Power Relay).

[shuddyssoup]

Sorry guys, because of rain and continuing issues with my right knee replacement I haven't been able to get out and check things out. Today should be the day I can look at it. OldTimer57, I do have a good DVOM which also measures frequency but the amp portion is only 2. I tried doing that the other day ( I didn't have numbers like you gave me as far as impact by amp) but I received no numbers. I believe that's because I may have blown a fuse on the amp side of the meter. Don't it before. Because of work schedule and commute I haven't been able to devote the time needed but now that I'm off for a week, I'll be able to spend more time on this. Don, where is the main power relay on this motor ? I appreciate all that you're helping me with guys ...

[shuddyssoup]

So the fuse was blown on my DVOM and because it's still good although ancient, I went and picked up a newer model clamp on style that will range to 10 amps DC/AC. Have pulled the leads on the Alternator and will check in the morning. Thanks again, y'all.

[OldTimer57]

Clamp-ons are problematic. Work well with A/C (none on a boat). Work fairly well with pulsing D/C (as in the trolling motor). They depend on the expanding/contracting magnetic field to make the measurement. With a pure D/C device connected, there is no pulsing within the power circuit, and the clamp-on won't sense anything and be misleading. Much better to measure with an in-line, which most clamp-ons will do if you have the correct probes. If you blew the 2a fuse, you already have a clue that the drain is too high as that should NOT happen with everything turned off and the ammeter inline. Mine has a 2a setting and a separate jack for 10a testing. If you blow the 10a fuse, that would really be an issue. :)

[lpugh]

To make a clamp on very accurate, take length of wire and coil it into 10 loops. Connect this in series with the circuit being tested and place the clamp over the 10 loops. This will make a 100 amp scale 10 amps or a ten amp scale one amp.
Though I have found my fluke low current probe when zeroed every time it is relocated to be quite accurate on DC, less than 50 ma error
This is how I used to measure very low current flows with analog equipment such as Sun VAT 40's

[lpugh]

Clamp-ons are problematic. Work well with A/C (none on a boat). Work fairly well with pulsing D/C (as in the trolling motor). They depend on the expanding/contracting magnetic field to make the measurement. With a pure D/C device connected, there is no pulsing within the power circuit, and the clamp-on won't sense anything and be misleading. Much better to measure with an in-line, which most clamp-ons will do if you have the correct probes. If you blew the 2a fuse, you already have a clue that the drain is too high as that should NOT happen with everything turned off and the ammeter inline. Mine has a 2a setting and a separate jack for 10a testing. If you blow the 10a fuse, that would really be an issue. :)

Magnetic field only does not need to be changing states.