Average voltage when boat is running?

[ryangtn]

I have a 2011 21v. My voltage gauge always shows 12, never higher, never lower. Every vehicle I've ever had has some fluctuation in the voltage. In fact, most of my cars run around 14v when the engine is running. Do all Supra's just show 12 all the time or is there something strange with my boat?

Thanks in advance for any feedback!

[tg0824SSVGG]

My 2008 generally shows close to 14 ... but you have a LOT more "electronics and computers" in between the batteries and the display than i do.

[jeffreyk573]

My 2005 shows around 13.5! I've been worried that it was too high. Guess its about right. But I am pretty much stock.

[OneCent]

My 21v 2008 - 13.9 to 14.2

[tg0824SSVGG]

There was just another thread on here in the last few days about voltage - and how to measure it looking for drops.
I would suggest you measure at the points they suggest (at least the ones you have, such as across the battery) and see
that you do have the voltage that all are suggesting, and you are used to.

Perhaps some boob programming the computers decided that 12v means 12 and that people have a hard time realizing that
when it's at 12 you're already in trouble - but fixed the display at 12? Who knows, you know how the computer programmers are ... (guess what "I" do
for a living).

Todd

[92SupraComp]

people, NEVER TRUST THE GAUGE! always measure with a volt meter at the battery. If you rewire your boat(s) as I have, then you will get 14 volts at the gauge...

[Wylietunes]

Analog gauges are fine for normal monitoring, but for diagnosing a potential problem, a digital volt meter is the only way to go.

1st thing I would do is take a volt meter to the back of the gauge both with and without the engine running and get a reading and compare is to what is read at the battery. If there is a huge voltage drop, you may be looking at a poor connection or failing cable. You may also discover that nothing is wrong, its just the nature of the beast with an analog gauge.

[tg0824SSVGG]

Michael,

I am guessing that a 2011 has no ANALOG gauges, and that even the ones that might "look" analog are likely fed
by the computer. Just guessing, since all I have is an ANCIENT 2008, where there are a LOT of things that look analog but
are not.

But - using the DVM is the only sure way to go, that is certain.

Todd

[Wylietunes]

Todd,

I do not know what every year model of ever model of every boat manufacturer has. If it has a needle, its analog, regardless of where its signal comes from. So my comments where meant as a generalization. If the gauge is digital and has a readout that shows 2 places to the left of the decimal and 2 places to the right and shows no higher then 12.00V, then the above advice is still relevant. Start at the gauge's input and work back to the source until the voltage is found.

[92SupraComp]

wylie. No, my 2007 Suburban has 6 gauges, they are digital. The have a needle that moves, but, they are digital. They are stepping motors that the computer can trace the location of. Pure digital control, nothing analogue. So, just because there is a needle, doesn't mean analogue.

[Wylietunes]

92Supra,

Your 07 tow truck gauges are not stepping motor, its called PWM. If the needle is mechanical, as opposed to an LCD, dot-matrices or other digital readout, then the gauge is analog. There is a huge difference between a mechanical needle moving across hash marks and a digital readout.

But to get back on topic, we are discussing the gauge in ryangtn's boat, not your truck.

[Blackntan90]

I need to check this also, I noticed Saturday at the lake that the gauge shows 12 volts all the time- I do believe it should read 14 when the engine is running, at least running should be higher than 12 volts. I am going to check like everyone stated on here with my DVOM in case the gauge is just ' like that' and does not reflect the alternator charging the battery. My alternator looks suspect to me, as we bought the boat used with 300 hours and it was on it then...not sure if it is even a marine alt. And Michael is correct- if it has a needle it is an analog gauge, decimals and it is a digital gauge.

[92SupraComp]

If your boat has always shown 12 volts when running its fine. Our Supra and CC both showed 10volts not running 12 volts running. Our CC has 810 hours, and our comp, has at least 1700+ hours. Both original motors, alts, everything. Except the comp, it no longer has GT40P heads, other than that original. The alt might look suspect, but, they work fine. I rewired both boats last year, and now they show 14 volts running, 12 volts not...

[ryangtn]

I appreciate all of the great feedback on this. I will definitely be looking into the wiring and running some additional tests. Thanks again!

[rideevol]

Do your initial measurement at the battery. 12.7 volts is desirable for a fully charged battery with engine off.
Engine idling should increase voltage above 12.7 volts which indicates charging, still at the battery posts. Now you have a baseline. Any measurements at gauges, choke heater wires, alternator output wire etc. will now add to your understanding of wire and connection condition. RPM does have some effect even on an alternator so voltage up to 14 is also normal for healthy charging, especially after an engine start-up.

[Torque]

13066

If you zoom in on the first gauge on the left, this is my boat running. Stuck on 12v.

[DAFF]

On my 03 Launch the voltage gauge is 12 on start up and will hold there until the RPM exceeds 1500... The needle shoots up just under the 14 volts mark. Many gauges have read incorrectly over time. The best way to test voltage is with a independent voltage tester period.

[92SupraComp]

DAFF, i think you alt needs looking at, sounds like its having trouble exciting. My CC excites the alt even at 250 rpm. I have a very low idle tuned in on that puppy...

[blackout_58]

Here is what mine looks like if it helps
13141

[Moor]

Do your initial measurement at the battery. 12.7 volts is desirable for a fully charged battery with engine off.
Engine idling should increase voltage above 12.7 volts which indicates charging, still at the battery posts. Now you have a baseline. Any measurements at gauges, choke heater wires, alternator output wire etc. will now add to your understanding of wire and connection condition. RPM does have some effect even on an alternator so voltage up to 14 is also normal for healthy charging, especially after an engine start-up.

This is good advise, id start here. for what its worth, my relic 88 sunsport idles at 600rpms, alternator puts of 13.7v at that rpm. my gauge shows 14v at idle. earlier this year my gauge was stuck on 12 just like yours, alll the time. my charge wire from the alternator to the battery was bad, i had to run a new wire.

Check output at the back of the alternator while running, and check the batterys also. if you have over 12.5 at the alternator, but less at the batteries, check the charging wire from the back of the alternator to your batteries. If they are both above 12.5, then id suspect a faulty gauge or a voltage drop somewhere in the instrument cluster. This shouldnt matter if its a digital or anolog gauge, The voltage running through the wires should be the same