Ammeter, Can one be added easily?

[Rsponsford]

I have a 1990 Country Coach Concept. I am trying to be careful not to overload the 160 amp alternator but there is no ammeter installed for monitoring. Do newer CC models have an ammeter to show alternator output? Would be difficult to add an ammeter? Would I have to run wiring all the way from the alternator or can I tap into existing wiring up front?

I've gone through three alternators in the past couple years and I think the probable cause is too much load demand on the alternator. For example, starting the coach when the house batteries are very low, etc. Since I've become more aware of this and avoid high demand loads from the alternator I haven't burned up any additional alternators. When the house batteries are low I'll run the generator to charge the batteries before starting the coach, etc.

At any rate, I would like to add an ammeter so I can know how hard the alternator is working rather than guess. Any help or advice would be appreciated.

Thanks!

[Sweetbriar]

To measure DC amps you'll need to add a shunt as close to the power source as practical and before any distribution points such as fuse boxes or tie points. Your objective is to measure total current from the source. Add the shunt after any distribution points and the measurement will not reflect total power demanded. If you're lucky the power from the alternator has a direct line to the battery and then splits out from there so you can add the shunt at that point.

The shunt needs to be size to match the power source capabilities or your highest demand device. With a 160 amp alternator a 200 amp shunt should work. You will also need to add a metering wire from the shunt to the meter location. Anything 18 gage or larger should be OK and not effect accuracy of the measurement excessively. The hard part is where to install a meter and making it look good. Not a hard project. Something to do on a Saturday if you're not on the road.

[Rsponsford]

Originally Posted by Sweetbriar

To measure DC amps you'll need to add a shunt as close to the power source as practical and before any distribution points such as fuse boxes or tie points. Your objective is to measure total current from the source. Add the shunt after any distribution points and the measurement will not reflect total power demanded...

Thank you for the info. I wonder if I could add the ammeter near the rear run box directly off the alternator and then have a remote readout display up front. I doubt there is a wireless solution for a remote display so I would still have to run wires the full length of the coach, but then the information could be taken directly off the alternator.

[twinboat]

That vintage MH should have a Diode isolator to handle the house charging. The alternators regulator should be controlled by the chassis battery voltage. If that's working as designed, you shouldn't have a high output issue.

I'll bet the sense wire from the chassis battery to the alternators regulator is not connected or connected poorly.

It's also possible that your replacement alternators are not the Duvac style, that was used with diode isolators.

In any case, you should be able to cut the alternators output wire near either end and wire in a shunt. Then you use small, light gauge wires to a gauge. EBay sells a kinds of them.

[Rsponsford]

Originally Posted by twinboat

That vintage MH should have a Diode isolator to handle the house charging. The alternators regulator should be controlled by the chassis battery voltage. If that's working as designed, you shouldn't have a high output issue.

I'll bet the sense wire from the chassis battery to the alternators regulator is not connected or connected poorly.

It's also possible that your replacement alternators are not the Duvac style, that was used with diode isolators.

In any case, you should be able to cut the alternators output wire near either end and wire in a shunt. Then you use small, light gauge wires to a gauge. EBay sells a kinds of them.

I believe you are exactly correct about all of the above and I fairly certain the sense wire with the diode isolator is not connected properly. I have not been able to find a shop in my area that understands the system or application to this MH. I only understand it in theory but not enough to be confident or comfortable messing with it. The replacement alternator is the DUVAC style. While on the road some time back I had a RV shop in Reno look at it and they said there was a wire with a diode that was broken. Unfortunately they couldn't remember which wire belonged where when they put it back together. Exasperating, to say the least. Seems ridiculous to have to drive all the way up to Junction City, OR to know that it's wired correctly.

[cntrylife]

Call Kevin, his Brother is the one who designed the wiring on these and will have the answer

[nothermark]

FWIW You do not need 18 ga wire from the shunt to the meter. 24 or 28 ga comm wire in a bundle will work fine. Shunts are very low value resistors that typically drop 0.05 VDC full scale. The meter is a high resistance voltmeter usually on the 10,000,000 ohm range. The current through the sensing wire will be 0.0000000005 amps. The shunt resistance will be 0.00025 ohms if you are wondering.

I would probably buy something like this:

https://www.ebay.com/i/171927516815?chn=ps&dispItem=1

Run a 3 or 4 pair communications cable like an ethernet cable and split out two color coded pairs to make the connections. Your biggest problem is what they call a dry circuit. Currents are too low to keep oxides off the connections. You might need to clean them with something like this:

https://www.walmart.com/ip/CAIG-DeOx...&wl13=&veh=sem

They also make a smaller can if you can find one. It does not take much to do the job. I have a product kit of the small cans that I have had for years. The idea is to just open up the connections and spray a little into the connection if things get intermittent. Then tighten the connections again. Good for another year or whatever.

[ccfulp]

Originally Posted by Rsponsford

I have a 1990 Country Coach Concept. I am trying to be careful not to overload the 160 amp alternator but there is no ammeter installed for monitoring. Do newer CC models have an ammeter to show alternator output? Would be difficult to add an ammeter? Would I have to run wiring all the way from the alternator or can I tap into existing wiring up front?

I've gone through three alternators in the past couple years and I think the probable cause is too much load demand on the alternator. For example, starting the coach when the house batteries are very low, etc. Since I've become more aware of this and avoid high demand loads from the alternator I haven't burned up any additional alternators. When the house batteries are low I'll run the generator to charge the batteries before starting the coach, etc.

At any rate, I would like to add an ammeter so I can know how hard the alternator is working rather than guess. Any help or advice would be appreciated.

Thanks!

Russ I feely your pain. I also have had to replace 3 alternators in 6 years. Finally enough, so I thought I would make a few changes picked up a 190 amp alternator from ebay without a voltage regulator and after looking I found a Leece Neville dual rectifier 48XX-49XX series which has 12 diodes instead of 6 This was the same type mount but it was larger in diameter than my old 160 amp. I had to get the bracket modified slightly and get a longer fan belt then had to get a voltage regulator the old type where you set the voltage. This allowed the regulator to be moved away from the engine (cooler). In addition I found my solid state battery isolator was bad which might have been part of the problem. The isolator might of had an additional problem since it takes about 1 volt out of the charge. With the old type of regulator I adjusted for this by pushing the charge up to 14.9 at the alternator which gives 14.0 after the isolator. While I have not put on an amp meter no doubt this would be the best way to monitor what's going on with the alternator. On my to do list. Also found that my echo charger had given up the echo which is one of the main reasons for my working the alternator so hard IMHO. I replaced with an amp l start much cheaper and has light to monitor what going on with the charge. Other than that I got a soft wire brush for my drill to polished all connections and added a negative disconnect for the house battery's to eliminate those pesky parasitic drains nobody tells you about that the master switch does not kill. Since you are asking about an amp meter I assume you already know that voltage is a poor way to monitor an alternator since you can have 14.5 volts and almost no charging going on. You have probably already fixed your problem, good luck.

[Rsponsford]

Originally Posted by ccfulp

You have probably already fixed your problem, good luck.

I have not yet added the ammeter, but I do now have the parts I plan to use. When I get around to installing everything I will report back here with the results. Thank you for the additional input!