Battery stays at 12.5v, but tach works correctly(?)

[jacksonjrs]

I just started my 1984 force 85hp for the first time this year. I had the water muffs on and it was running at about 1000 rpms. The voltage gauge says 12.5 with the engine running or not running. I tested the green/yellow wires (2) and that circuit is not open. I checked the red wire from the regulator to the battery and that tests good with both an ohm meter or test light. The ground wires all tested good. I had switched from the rectifier to a voltage regulator using the instructions posted on this forum and it worked perfect last year. Today I switched back to the original factory rectifier and had the same results (tach works, volts stay at 12.5 with engine running)

So what am I missing?? The only thing I can think is that I have a bad rectifier AND voltage regulator.

 

[my1stboat1]

Re: Battery stays at 12.5v, but tach works correctly(?)

WAS that at idle... raise the engine rpm up and hold it at 2500 rpms and see what the your gauge starts reading ... or put an ohm meter on the battery and check ur voltage with the engine running and off and compare it to your gauge...

 

[fucawi]

Re: Battery stays at 12.5v, but tach works correctly(?)

if its been standing then charge the battery .then your boat system will quickly bring it up to 14.4v........I always charge the battery before a trip

 

[Frank Acampora]

Re: Battery stays at 12.5v, but tach works correctly(?)

Is this something that just started happening or did you just not notice it before? Does the battery take enough charge to crank the engine? If it does, then as above, disconnect it and check voltage at the battery itself. If it now reads correctly, the volt meter is incorrect. These gauges are not terribly expensive and not necessarily all that accurate.

 

[jacksonjrs]

Re: Battery stays at 12.5v, but tach works correctly(?)

Battery is brand new. I verified the 12.5 volts by the gauge on the boat dash, and a multimeter at the battery terminals. Last year it was reading at 14.5 with the engine running, even at idle. Since last year the only I've changed has been the battery. I was running a yellow top optima, now I'm running a marine battery rated at 825 cca.

 

[TMALEGA]

Re: Battery stays at 12.5v, but tach works correctly(?)

Not sure if it helps or not but when i run the marine battery on my engine it only shows charging to 14.0 on my volt gauge. Then if i put the cheap auto battery i had laying around and use as my trolling battery. Then the gauge reads around 16.5 so i think the style of battery may make a difference. I am not sure if this is helpful or not but i do notice a difference in readings between different batteries i even tried it with a 3rd battery and got a different reading then also.

 

[jacksonjrs]

Re: Battery stays at 12.5v, but tach works correctly(?)

I was wondering about that also. I guess I should try another battery than and see what happens. Before I was just using a regular auto battery, and that is the only thing I have changed.

 

[fucawi]

Re: Battery stays at 12.5v, but tach works correctly(?)

THE only reason you are getting different readings is the state of the battery ...sulphated ..high reading scrap ....50% charged showing 12.5 ..your outboard will take a long long time to charge it ....there is no difference between..auto maring sealed leisure etc only advertising bullcrap and warrantee ....still lead and acid