The DC ammeter in my electrical panel was acting strange for a while now, registering unusually high and erratic readings. Last month on our week long cruise, the meter pegged at the high end (50amp) and stayed there. After checking for a dead short some where, I concluded the meter had died somehow and just bypassed it for the remainder of the cruise. I ordered a replacement meter through Tidewater marina, and installed in last Friday. When I reconnected the meter and turned on the breakers, the new meter also hit the maximum peg (new meter is 80amp). I have a Link 2000 monitor on the house bank that gives me a completely redundant amp measurement, and it is acting fine. It tracks the amp draw in a manner that appears to be exactly in line with what is running at the time. There surely isn't an 80 amp DC draw in the boat that I don't know about, or the batteries would be dead of the boat would be on fire. I even tried shorting the two leads from the ammeter by touching them. If there was a high draw on those leads, would have been some sparks, but nothing. The ammeter is mounted in the panel, just "downstream" of the main breaker, with the output going to the DC bus on the breakers. Other than the remote possibility that the new meter is also bad, I'm stumped. Any ideas. Oh, and these meters have an internal shunt.
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Rex
I would start by putting an inductive probe on the supply line to the main breaker. This will tell you if in fact you have that kind of drain. The odds are that you don't have two meters with exactly the same problem. You can test any ammeter remotely with a battery and a small load (like a light bulb) to see if it is working correctly.
I would start by putting an inductive probe on the supply line to the main breaker. This will tell you if in fact you have that kind of drain. The odds are that you don't have two meters with exactly the same problem. You can test any ammeter remotely with a battery and a small load (like a light bulb) to see if it is working correctly.
it's not the meter....
Turn off all your DC power switches, Then turn on the DC main and turn on the DC switches one at a time, to tell what circuit the problem is in. Good Luck
Turn off all your DC power switches, Then turn on the DC main and turn on the DC switches one at a time, to tell what circuit the problem is in. Good Luck
did you check the meter shunt?
It's not likely it was the original meter or any single circuit. My guess is the shunt is bad and should be replaced. Don
It's not likely it was the original meter or any single circuit. My guess is the shunt is bad and should be replaced. Don
Rex...
Would agree with Don that it is probably the shunt. I just installed a new ammeter in my H34, using a shunt-less one due to lower DC current usage than probably on your 43.
Would agree with Don that it is probably the shunt. I just installed a new ammeter in my H34, using a shunt-less one due to lower DC current usage than probably on your 43.
No shunt
No separate shunt to be bad... it is internal on both the old meter and the new one. The new meter assembly would have to be bad out of the box to show the same behavior as the old meter that I replaced. The meter pegs with the the main breaker on and all loads turned off at the breakers. This does not look like an actual problem with a load. I checked the leads at the meter when disconnected, and there is definitely not a high amp draw that would peg the meter. Any other ideas?
No separate shunt to be bad... it is internal on both the old meter and the new one. The new meter assembly would have to be bad out of the box to show the same behavior as the old meter that I replaced. The meter pegs with the the main breaker on and all loads turned off at the breakers. This does not look like an actual problem with a load. I checked the leads at the meter when disconnected, and there is definitely not a high amp draw that would peg the meter. Any other ideas?
Rex, same thing happened to my meter
I'll try to link the discussion, though your internal shunt is a different situation, which surprises we, given the size of the extenal shunts I have seen.
I'll try to link the discussion, though your internal shunt is a different situation, which surprises we, given the size of the extenal shunts I have seen.
Looks like I need a shunt for the new meter
Thanks everyone, including Scott for your thread. I talked to the meter manufacturer on Friday. I appears that I need a shunt for the new meter. I should have guessed, but the hunter dealer never mentioned the need when the supplied the replacement. I'm working on getting a shunt from a distributor who serves the manufacturer. At this point, it looks like the original 50amp meter had an internal shunt. The replacement I ordered is 75 amps, 50mv, which does imply need for a shunt. Apparently the original failed internally. The replacement appeared to have the same issue only because I don't have the external shunt. Only hope I didn't trash the new meter during the brief time I had it connected and turned on.
Thanks everyone, including Scott for your thread. I talked to the meter manufacturer on Friday. I appears that I need a shunt for the new meter. I should have guessed, but the hunter dealer never mentioned the need when the supplied the replacement. I'm working on getting a shunt from a distributor who serves the manufacturer. At this point, it looks like the original 50amp meter had an internal shunt. The replacement I ordered is 75 amps, 50mv, which does imply need for a shunt. Apparently the original failed internally. The replacement appeared to have the same issue only because I don't have the external shunt. Only hope I didn't trash the new meter during the brief time I had it connected and turned on.
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