Battery draining

Ronniewhite

Petty Officer 2nd Class
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May 26, 2022
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I have a 2000 Johnson 25hp 3cylinder. I got a used Napa battery, it's not even 2yrs old. It had to be charged when I got it , it was at 25 percent. I checked it after fishing 2 nights ago and it was at a 100percent. I just checked it now and it was almost dead. The key wasn't turned all the way off. Would that drain the battery? There's nothing on the battery that could be draining it. It's just for starting the motor.
 

mike_i

Ensign
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Jun 28, 2017
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918
What is the capacity of the battery? Did you buy a used battery? What kind is it? Starting or deep cycle? Get it load tested. What are you useing to test? Do you have a bilge pump? Check the battery voltage with the motor running. First get it load tested.
 

Ronniewhite

Petty Officer 2nd Class
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May 26, 2022
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It's a Napa matenice free battery. Just motor on it for starting. Yes it was used .
 

saltchuckmatt

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Jul 19, 2019
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I have a 2000 Johnson 25hp 3cylinder. I got a used Napa battery, it's not even 2yrs old. It had to be charged when I got it , it was at 25 percent. I checked it after fishing 2 nights ago and it was at a 100percent. I just checked it now and it was almost dead. The key wasn't turned all the way off. Would that drain the battery? There's nothing on the battery that could be draining it. It's just for starting the motor.
Charge it up and take to any auto parts store and have them load test it. I'm pretty sure that the key being on can produce that situation. Pretty easy to diagnose though, charge it, and leave the key off, then test.
 

Ronniewhite

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Ya im doing that right now. I was just wondering if anyone new if the key being on could cause this.
 

F_R

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Jul 7, 2006
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I don't think leaving the key on will cause that, IF it is only used for starting, as you said.
Are you fishing at night? Lights?
Easy to check for drainage with an ammeter. Many multimeters have an up to 10 Amps DC scale.
 

saltchuckmatt

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I don't think leaving the key on will cause that, IF it is only used for starting, as you said.
Are you fishing at night? Lights?
Easy to check for drainage with an ammeter. Many multimeters have an up to 10 Amps DC scale.
Again, and I think F_R could be right, but leaving the key on with certain ignition systems can cause a drain. You state that after fishing the battery was at 100% and then when you came back to it it was empty. What you didn't say is how long was that? Was that a day was that a week? Also, I was always told leaving the key on an engine is not running is also hard on the system so don't do that again which I'm sure you probably already know. F_R again is correct, you can check for a drain by doing a periodic draw test. You do use an amp gauge but it does take some knowhow. Also a lot of the YouTube videos on it are incorrect. Again, and I repeat, it's easy to take the battery somewhere to have a load test. Try and eliminate one problem at a time. Hope that helps.
 

kbait

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Nov 13, 2007
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Leaving the key in ‘on’ position will not draw on battery, as battery has nothing to do with spark. But if you have something connected to the “I” (ignition) post on the ignition switch, that will be energized and can draw current. Like a gps puck for gps unit. (Even if gps is switched off). That post is energized when key is on, motor running or not.
 

F_R

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Leaving the key in ‘on’ position will not draw on battery, as battery has nothing to do with spark. But if you have something connected to the “I” (ignition) post on the ignition switch, that will be energized and can draw current. Like a gps puck for gps unit. (Even if gps is switched off). That post is energized when key is on, motor running or not.
x2. Battery has nothing to do with the ignition system. But some accessory such as a tach connected to "I" might.
 

airshot

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Jul 22, 2008
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When you say battery is 100% ....what does that mean ? 12.6 volts and above is a full charge....below 12 volts is pretty much dead. 12.3 volts is approx 60% full..etc. Check with a volt meter to be sure. If the battery has dropped below 11.8 volts then it needs replaced as most wont recover from that low of a charge
 

Ronniewhite

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May 26, 2022
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Again, and I think F_R could be right, but leaving the key on with certain ignition systems can cause a drain. You state that after fishing the battery was at 100% and then when you came back to it it was empty. What you didn't say is how long was that? Was that a day was that a week? Also, I was always told leaving the key on an engine is not running is also hard on the system so don't do that again which I'm sure you probably already know. F_R again is correct, you can check for a drain by doing a periodic draw test. You do use an amp gauge but it does take some knowhow. Also a lot of the YouTube videos on it are incorrect. Again, and I repeat, it's easy to take the battery somewhere to have a load test. Try and eliminate one problem at a time. Hope that helps.
It was 2 or 3 days of sitting with the key on. I charged it yesterday and went fishing last night got 3 walleye too👍. I checked it this morning it was still charged. The key is off so I will see what happens over the next couple days.
 

Faztbullet

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Leaving the key on will drain the battery as it turns the rect/reg on thru the purple wire.
 

Ronniewhite

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That makes sense because I just went out and checked the battery with my charger and it's still charged
 

oldboat1

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I would opt for a couple of those NAPA batteries, fully checked out. Charge them overnight with your A/C charger when the boat is in the yard. Use one for starting only.
 

Ronniewhite

Petty Officer 2nd Class
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May 26, 2022
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199
I would opt for a couple of those NAPA batteries, fully checked out. Charge them overnight with your A/C charger when the boat is in the yard. Use one for starting only.
That's all it's used for is starting
 

Crosbyman

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as per post 7 (FR)..... measure drain current with key ON only.....

in any event the solution is simple...
 
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