Logo
FULL SITE MENU

1980 454 voltmeter question?

P

Pal

Contributing Member
Hi guys, I have a 1980 searay sedan with a 454, with two batteries and a red Perko of the 1-2-all-off variety.
I have noticed that the voltage gauge on the dash always runs low on both the flybridge and the inside helm. They both seem to set themselves with the needle in the discharge area. But, the PO said that it has always been that way (for six years) and the batteries have always been fine. Starts great. He thought it was "just hooked up wrong but never changed it".
The gauge also doesn't work the way you expect, with it raising up with revving or whatever. Just kind of stays wobbling around the discharge area. Any ideas? Thanks, Pal
 
Re: voltmeter question?

I'd start by inspecting the wires leading to the gauge, especially the gound wire.
 
hi, thanks I'll do that (somehow)..yeah I'm tryng desperately to learn how to use a multimeter so I have some confidence in my findings. I KNOW the end at the voltmeter itself is a nice clean tight ground. But how to check the other end, wherever it is..
I bought a cheapy (8$) voltmeter at my local Harbor Freight just to see if it reads "differently" than the one I have in there. I'll check it out next weekend. I was out there and froze butt last weekend. Forty eight degrees with no shore power. :)
 
Most boats have ground wires attached to a bolt somewhere near or on the bellhousing, The negative from the battery will usually be bolted to the same spot. Check this to see if it might be loose, and check to see if the wires have a good connection to the fitting attached on the bellhousing. Look under the dashboard to see if you have a buss bar that a negative cable from the bellhousing might bolt to, and if you have a fuse panel under the dash, check to make sure the bolt is tight there as well. Prior to getting any tools around the fuse panel or bus bar/bars it would be wise to disconnect the positive waire from the battery, or if you have one switch off the battery at the Perko on / off switch. Also check the starter solenoid for good tight connections on all wires attached.

Good luck, and I hope you find the solution.

Mikes402jetboat
 
Thanks Mikes, I will check all those places. It's good to know where they are to just know it.
But listen to this: I went out to the boat last weekend and brought my new cheapy replacement voltmeter that I bought with me. I turned on the ignition, I touched the leads i'd put on it to the places the existing voltmeter is wired. It jumped right up to 12 volts.
So now I'm guessing the existing voltmeter, which looks original and so is about thirty years old either needs adjustment, or replacement. Or lubrication?
The only funny thing is that the top flybridge voltmeter reads the same way as the one below, the one that I checked. That's why I thought it wasn't an individual gauge problem, but a "system" problem....
 
Try putting the hand held voltmeter tester (preferably a digital) across the battery that is on charge with engine running at least 1500 rpm. If the voltage is not between 13.8 and 14.5 VDC, then there is a charging system problem, alternator / regulator / wiring. The PO may have not been 100% upfront with you with the "it's been like that for 6 years and has worked fine". After all, he's selling the boat and probably doesn't want to create a situation where the price will go down, but I may be wrong..... If the voltage is OK, then it's you built in meters. Just seems odd they would both read the same eronious reading. What are the chances ??????

PS: If engine is running and you only get 12 VDC, that signifies a bad charging system. Should be at least 13.8 VDC at 1500 RPM. Engine off and 12 VDC is even just normal to low for static batteries that have been charged.
 
Hi 04fx, Just seems odd they would both read the same eronious reading. What are the chances ??????
That''s exactly what I thought.
Try putting the hand held voltmeter tester (preferably a digital) across the battery that is on charge with engine running at least 1500 rpm. If the voltage is not between 13.8 and 14.5 VDC, then there is a charging system problem, alternator / regulator / wiring.
I'll try that. Had hand surgery, ugh. Out of business for a while.
If engine is running and you only get 12 VDC, that signifies a bad charging system. Should be at least 13.8 VDC at 1500 RPM. Engine off and 12 VDC is even just normal to low for static batteries that have been charged.
Thanks for the numbers, I'll check it.... Pal

PS: Can you clean or lubricate gauges like that?
 
Guages are sealed and, generally, can't be fixed. They are reletively cheap, so I would just replace w/ 2 of the same thing, if found bad.
Put meter across gauge terminals and see if hand held reads same thing as gauge. If it reads the same, it's wiring. If different, it's gauge(s)
 
04fxdwgi said:
Guages are sealed and, generally, can't be fixed. They are reletively cheap, so I would just replace w/ 2 of the same thing, if found bad.
Put meter across gauge terminals and see if hand held reads same thing as gauge. If it reads the same, it's wiring. If different, it's gauge(s)
Click to expand...

What a great idea, why disn't I think of that! :)
 
Pal said:
Hi 04fx, Just seems odd they would both read the same eronious reading. What are the chances ??????
That''s exactly what I thought.
Try putting the hand held voltmeter tester (preferably a digital) across the battery that is on charge with engine running at least 1500 rpm. If the voltage is not between 13.8 and 14.5 VDC, then there is a charging system problem, alternator / regulator / wiring.
I'll try that. Had hand surgery, ugh. Out of business for a while.
If engine is running and you only get 12 VDC, that signifies a bad charging system. Should be at least 13.8 VDC at 1500 RPM. Engine off and 12 VDC is even just normal to low for static batteries that have been charged.
Thanks for the numbers, I'll check it.... Pal



Hey, PAL,

Thought I would add a little chart showing battery charge state:
State of Charge12 Volt batteryVolts per Cell100%12.72.1290%12.52.0880%12.422.0770%12.322.0560%12.202.0350%12.062.0140%11.91.9830%11.751.9620%11.581.9310%11.311.89010.51.75

As you can see, 12 VDC output of a "fully charged battery" is low, actually less than 50% charged.......
Click to expand...
 
Hey, PAL,

Thought I would add a little chart showing battery charge state.

Documents and Settings\Any\Desktop\untiltled.jpg


As you can see, 12 VDC output of a "fully charged battery" is low, actually less than 50% charged.......
 
Hey, PAL,

Thought I would add a little chart showing battery charge state.

State of Charge12 Volt batteryVolts per Cell100%12.72.1290%12.52.0880%12.422.0770%12.322.0560%12.22.0350%12.062.0140%11.91.9830%11.751.9620%11.581.9310%11.311.89010.51.75

As you can see, 12 VDC output of a "fully charged battery" is low, actually less than 50% charged.......
 
Hey, PAL,

Thought I would add a little chart showing battery charge state.

State of Charge12 Volt batteryVolts per Cell
%chg Voltage on battery Voltage per cell
% chg_____Battery VDC__Cell VDC
100%_____12.7_________2.12
90% _____12.5_________ 2.08
80% _____12.42________ 2.07
70%_____ 12.32________ 2.05
60% _____12.2_________ 2.03
50% _____12.06________ 2.01
40% _____11.9_________ 1.98
30% _____11.75________ 1.96
20% _____11.58________ 1.93
10%_____11.31________ 1.89
00%_____10.5_________ 1.75

As you can see, 12 VDC output of a "fully charged battery" is low, actually less than 50% charged.......

Sorry for multi posts. Power kicking out here ALOT during this blizzard in NY and I'm stupid....
​
 
Last edited:
04' - there's an "Edit" button you can use to "fix" previous posts. Think there's a time limit but its plenty long enough to fix things like above.

also, what's the rest of the of the details with the chart? Guessing its regular lead-acid chemistry? I'm sure there's a temperature dependancy, too.
 
Yeah, I was using the edit, but power bumps during the blizzard was making everything do dumb things and I was dumb
for trying to send stuff during the strorm.

The chart is just a quick ref for lead acid. There certainly will be variances for temp, but generally speeking I use 70 deg F as a ref
when talking generalizations. One poster said he was told his batteries are good when charged at 12.0 VDC and replied 12.0 VDC isn't a good charge. So if it's around 70 deg F and batteries are lead acid, then the chart could be handy. Suppose I should have stated that in last post.

Thanx for clearing that up
 
The chart is just a quick ref for lead acid. There certainly will be variances for temp, but generally speeking I use 70 deg F as a ref
when talking generalizations. One poster said he was told his batteries are good when charged at 12.0 VDC and replied 12.0 VDC isn't a good charge. So if it's around 70 deg F and batteries are lead acid, then the chart could be handy. Suppose I should have stated that in last post.

Thanks Again! I'll be able to look at it (The chart), keeping in mind the low temps around here now. It's no blizzard like you have, but it's still about fifty degrees. I know, we are wusses out here. My sis lives in Vermont, they were buried I guess.
Pal
 
View attachment 1508

Pal,

Do you have your batteries on charge when not in use? I have these dual circuit chargers at home and use them constantly when equipment is not in use. One in garage for the Harley and an extra battery, one in shed for tractor / yard equipment and am getting one for the boat, to perminently install, to charge both batteries seperately at same time while home on the trailer.

Have had one for bike for a while now. Harley battery is going on 5 years old now and still strong as an ox. 1st battery only lasted 1 1/2 years on a Battery Tender, which went kaput and toasted the battery. They aren't cheap, around 170 ginkos, but neither are batteries.
 
Do you have your batteries on charge when not in use? I have these dual circuit chargers at home and use them constantly when equipment is not in use. One in garage for the Harley and an extra battery, one in shed for tractor / yard equipment and am getting one for the boat, to perminently install, to charge both batteries seperately at same time while home on the trailer.

Have had one for bike for a while now. Harley battery is going on 5 years old now and still strong as an ox. 1st battery only lasted 1 1/2 years on a Battery Tender, which went kaput and toasted the battery. They aren't cheap, around 170 ginkos, but neither are batteries
Hi Well I have been going out to the boat once a week for two days per visit (a hunderd mile trip) :( and I only run the shorepower and turn on the built in converter when I'm there. That's what the PO said he did, and it worked well for him....?
 
Docksidemarineservices said:
Did anyone ask if you have voltage gauges or Amp gauges?
Click to expand...

Hi, It's a voltage guage..

Hmm, dya mean that maybe position in the dash is REALLY is wired for an ammeter? But there's a volmeter in there? As you can tell I know nothing about electricity..

Thanks to everyone, Pal
 
Last edited:
Voltmeter connection

View attachment 1517

Ammeter Connection
View attachment 1516
An ammeter is wired in series with the battery load, both terminals have to them. A voltmeter is wired accross the battery, one terminal to + and other to -. If voltmeter was wired like an ammeter, nothing in the boat would work because everything would need to go thru the voltmenter. NOPE..... Here is a link to a short tutoral on how to connect a meter to test general things. http://www.wisc-online.com/objects/ViewObject.aspx?ID=AMT2304

Pops
 
"Hi Well I have been going out to the boat once a week for two days per visit (a hunderd mile trip) :( and I only run the shorepower and turn on the built in converter when I'm there. That's what the PO said he did, and it worked well for him....?"

OK, you must have a built in charger "converter ???????" if you are doing that..
Pops
 
Could you take a picture of the meter and post it to make sure? A Sea Ray of your year would have an amp gauge. If you have a volt meter now you will need to check some wiring connections. The charging system with an amp gauge feeds the batteries through the amp gauge.
 
Could you take a picture of the meter and post it to make sure? A Sea Ray of your year would have an amp gauge. If you have a volt meter now you will need to check some wiring connections. The charging system with an amp gauge feeds the batteries through the amp gauge

Hi Pops, Thanks for the re[lies. I'll get a picture the next time I'm out there. But yes I have a converter, in the engine compartment. Maybe a Raritan, can't remember. The gauge is a voltmeter. It (and the one on the flybridge) both only move up a little (not up to the "good" chargeing zone) when the engine is started, and then kind of stay there, they don't seem "active" at low/high revs etc.
I haven't been able to do any work on it because of hand surgery recently. But I'll get to it as soon as I can. Thx, Pal
 
If a voltmeter was installed in place of an ammeter, unless it has a remote shunt, nothing connected to it would work, or it would smoke the meter. Too much voltage drop due to high impedance...... If there was a remote shunt, it would read zip due to not high enough voltage to make meter move because of the very low volt output of the shunt to what should be an ammeter. Most ammeter's are in fact a voltmeter, just a very low voltmeter. Most ammeter's (up to 60 amp) have the shunt built into them, providing the low voltage needed to move the meter.
 
If you connect a handheld voltmeter accross the terminals of your dash meter, then the discussion could be probably finalized.
4 possible scenerio's:

1. If the handheld reads battery voltage or close to it, and the voltmeter in the hole is reading different, then panel meter is
probably NG.

2. Lower than battery voltage displayed on hand held, but matching panel meter, then probably a lousy connection somewhere in
voltmeter sense leads / harness.

3. If much lower than battery volts is displayed, and everything electrical still works, except dash meter, then is it may possibly
require an ammeter with a remote shunt.

4. If nothing connected to the meter works, then it's probably supposed to be a ammeter with internal shunt.
 
Boy, you guys are great! I feel like a sluggard but just can't do the diagnostics yet. I went today to get a new cast. This one is supposed to come off Jan 17th. Until then I am just doing little cleanups on the boat.
One problem is if I use the hand/arm then the cast abrades the incisions, so I am in pain for a few days after. So. I will copy all this great stuff, apply it as soon as I can, and get back to you.* Really appreciate the thought you've given this. Pal
 
Back
Top