Crank Battery Drained

[Triton Dave]

2000 Evinrude Ficht 200HP Model #E200FPLSSC, serial #G04778459. Bought 3 new Platinum AGM Diehard Marine batteries and new 15amp, Tri-Bank Dual Pro on-board charger March 2015. I typically fish once per week and keep charger plugged in when not fishing. No problems until last 2 times out this year my crank battery will not turn the motor over at the end of 4.5 hours fishing. Had livewell recirculating pumps, Humminbird 900 series graphs running. Sears says battery does not have bad cell- charger is working and keeping batteries trickle charged to 12.8-13 amps. Checked alternator with volt meter and seemed to be working as amps climbed gradually as motor idled. I am no mechanic but something is not right- any ideas?

[Joe Reeves]

Sounds like you have a new but faulty battery..................

Check the battery with a hydrometer, actually testing the fluid in the cells themselves.

I have found quite often that a failing cell will only register using the hydrometer as a testing unit.

The "state of the art" battery testing equipment you'll encounter at Pep Boys or any other store of that type is worthless in my humble opinion as it will not show up a failing cell that easily registers via a hydrometer.

If you take a battery in for testing, check it with a hydrometer first, and if a cell shows up bad with the hydrometer.... then take it in for testing, and take a hydrometer with you. When they tell you the battery is okay and try to send you out the door with a faulty battery... whip out the hydrometer to show them otherwise.

[Triton Dave]

Crank Battery Drained

Joe- the Platinum Diehards are sealed AGM batteries. How do I check these with a hydrometer? And what type of hydrometer do you recommend I purchase? I thought there was a good chance that when I took this into Sears to check they did not test fully.

[Triton Dave]

Joe- I do have a digital voltmeter - Will this work?

[Joe Reeves]

Originally posted by Triton Dave View Post

Joe- the Platinum Diehards are sealed AGM batteries. How do I check these with a hydrometer? And what type of hydrometer do you recommend I purchase? I thought there was a good chance that when I took this into Sears to check they did not test fully.

Yes, Sears has one of those "State Of The Art" testers. I really upset one of their technicians there when I proved that "good" battery had a bad cell. However my battery was one whereas one could add sulfuric acid if need be and therefore using a hydrometer was no problem.

The sealed batteries never entered my mind when I was typing my previous reply and I don't know what to tell you. I feel sure that in observing the top of that battery, there is a way to unseal it BUT I'm also sure it would void all warranty if you go into it.

Hydrometers are all alike... a little gizmo inside that pivots on a pin that shows a cell as poor, good, best, or some such thing. Costs a couple bucks or so, really a cheap tool and indispensable in my opinion.

[Triton Dave]

OK. Only thing I can think of is buying a new battery or swap one of my trolling motor batteries for the crank. May suffer trolling motor performance, then. Could the 16 year old alternator be the cause?

[Joe Reeves]

I feel sure that you have a tachometer, and if so, be advised that the tachometer operates off of the alternator pulses.

Bottom line, if that tachometer is functioning perfectly, you can pretty well count on the alternator being trouble free.

[Triton Dave]

I do have a tachometer & it seems to be working fine. I did not know that the alternator works off of its pulses. How would I know if it was not working properly?

[Triton Dave]

Joe- Thanks for all of your ***istance.

[Joe Reeves]

Originally posted by Triton Dave View Post

I do have a tachometer & it seems to be working fine. I did not know that the alternator works off of its pulses. How would I know if it was not working properly?

Dave... The tachometer, if not being fed the proper pulses, would simply act weird, not show the proper rpms, have the needle drop to nothing perhaps... it just wouldn't give you a normal reading, nor stay in one particular false rpm setting.

Let us know what the final word is with the battery. (Joe)

[Triton Dave]

Last night, after 4.5 hours of fishing, I left motor idling during weigh-in. Have a 15 minute idle home & dumped caught fish (motor idling). When I got the boat on the lift and plugged in on-board charger, the crank battery had less reserve (1 red light) vs. trolling motor batteries (2 red lights). With all of that idling, I would have expected to see the opposite?

[Triton Dave]

BTW- tach is operating normally.

[Triton Dave]

Not sure if my "quick reply" was posted. I fished 4.5 hours Weds night. I left the motor idling during weigh-in and idled back to my boat house (30 minutes total). When I plugged my on-board charger in, the trolling motor batteries had more reserve power (2 red lights) than my crank battery (1 red light). With all the idling, I would have thought my crank battery would be closer to fully charged?!

[Joe Reeves]

Yes, it was posted. I've been thinking about it. Frankly I don't know what to make of it.

I haven't went back over all the posts yet... BUT... I'm a$$uming that you do not have a voltmeter installed? I'm wondering at what rpm would the voltmeter start showing a increase in voltage.

[Triton Dave]

Actually, I do have a volt meter installed on the dash. I would need to see what the reading would be at an increased speed. If I remember correctly at idle, the RPM reading is between 1100-1200 RPMs. I do not remember what the volt meter readings are at idle or increased RPM's. I can check tomorrow and report back.