Normal Battery Voltage upon ignition - Maxum Boat Owners Club

clint · 08-10-2009, 02:50 PM

Hi There,

2400SCR. Does anybody know why the voltmetre indiciates 10-12V when boat is running? Shouldnt it be readin 14V?

Probs with the alternator?

Thanks

Clint

seapuppy · 08-10-2009, 03:50 PM

yes it should read 14.5 volts dc.....problems with the alt. or the gauge...

SP

irate:

clint · 08-10-2009, 09:58 PM

the gauge is faulty. i connected batteries to an analogue voltmeter. When engine is off both batteries read 12V. When i start the engine they remain 12V however when i rev the engine they read 15V. is this normal or should they read 15V on normal idling as well? with regards to the gauge shall i replace it or can i fix it?

seapuppy · 08-10-2009, 11:04 PM

gotta remember...when the engine is at idle...the voltage is reduced cuz it's not spinning as fast...faster it spins...the more voltage is produced....but I'd get another gauge just to make sure...

SP :hello:

Gazjen · 08-10-2009, 11:34 PM

It should still be charging at idle not as much but it should still charge, the best way to tell is with a ammeter in line that will give you a good idea but also if your not getting any flat batteries that's a good indication too

A free test you can do is to run the engine at idle turn everything on you can think of (your after a substantial current draw)and listen for the engine note to change if it does you know its working if you cant hear anything check the voltage again with everything still switched on if its reading 12V plus you should be fine

clint · 08-11-2009, 08:29 AM

thanks guys very helpful

Stressleave · 01-08-2010, 12:20 AM

Sounds like the voltage regulater is getting bad in the alternater, 15volts is getting alittle on the high side.

Paul

ss3964spd · 01-08-2010, 01:27 PM

Agree with Paul, 15V is too high.

If you suspect a problem forget about the gauge for now (they can, and do, go bad or offer approximate readings) and take all your measurements at the battery. Just a bit over 12V is normal with engine off and no other loads. With engine idling and no other loads 13.7 to 14.5 is typical. Outputs above the norm indicate a bad regulator, outputs below indicate a bad regulator, alt, or wiring. Once you're certain everything is working then address the gauge.

Dan

seapuppy · 01-08-2010, 04:17 PM

actually a batt. runs at about 12vdc...the charging circuit has to run at about 14.5 vdc to charge the deep cycle type batt's......so..if your gauge is registering anything above 12vdc..that should mean it's charging the batt....
now if your idling at say 600rpm...and the volt meter is reading 12vdc...then your ok...if your registering less than 12vdc..your alt. is not putting out enough pwr to run the engine and anything else...if your registering over 15 vdc..then (to be sure use a digital vo meter)..then the regulator is failing ....
a few things can affect the the output of the alt...fan belt loose...brushes in the alt. are worn out....rectifier circuit is faulty..which are the diodes....ie regulater....

SP