Ammeter for Generator Output

wagwar · February 06, 2013, 01:05:10 PM

I have a battery monitor and a shore power conditioner. Both give me the amp loads on my house battery side and shore power side respectively. I'd like to have an ammeter that tells me how many amps I'm drawing on the generator side. What do I need and where would I buy it. I was thinking a small digital readout or just a simple dial type guage would be sufficient. I could mount it on the wall above the frig with my other guages and monitors.

Any ideas?
Thanks.

bobofthenorth · February 06, 2013, 02:29:55 PM

Something like this will do what you want for a nominal cost:
http://www.ebay.com/itm/Digital-AC-300V-50A-Blue-LCD-Amp-Volt-Ammeter-voltage-Panel-Meter-110v-220v-/180920422127?pt=LH_DefaultDomain_0&hash=item2a1fb28eef

luvrbus · February 06, 2013, 02:33:09 PM

Panetronic sells one that will read the AMP load from the generator

Emcemv · February 06, 2013, 03:10:40 PM

Bobofthenorth

That one on EBay seems incredibly inexpensive....would love to know how it is, do you have one?

Keep in mind that if your generator has any 240v loads along with the normal 120v loads, you would need 2 current transformers and a switch. I think most busses have 120v loads on the generator so the current transformer would be placed around the black "hot" lead coming from the generator and the voltage leads would go to the black and white wires on the generator output. Actually, thinking about this, I will bet that they balance the 120v loads on both legs of the generator so the only place that the current transformer would read total load current would be the white "neutral" lead from the generator to the main panel box.

bobofthenorth · February 06, 2013, 05:46:37 PM

I don't have that one but I have a simple analog meter on my boat. I don't find the price unbelievable.

belfert · February 06, 2013, 05:55:13 PM

The Ebay item is shipped direct from China so that help explains the inexpensive price.

TedCalvert · February 07, 2013, 05:44:57 AM

The current through the Neutral conductor will only be the difference, or imbalance, of the currents in the "Hots".

Ted

Sent from my iPhone using Tapatalk

wagwar · February 07, 2013, 09:47:46 AM

I have a single 120vac output conductor from my generator (with Neutral and ground of course). So, 240Vac is not an issue. I think I need one with a higher amp rating as I could possibly (although unlikely) exceed 49.9A. I see one there rated at 100A.

Just for clarification, the current transformer would go around the hot lead coming from the generator? Should that be in front of the sub-panel or after going through the breaker, but before going into the transfer switch? Or, maybe it doesn't really matter?

I see a couple of problems due to the wiring diagram:

I feed my inverter with AC from the generator and I would want that 'included' in the amp measurements, so the current transformer would have to be 'in front' of that connection down in my inverter bay? I'd have to run additional cable to the display panel up in the house (about 12 feet)?

My monitor panel is inside the house about 12 feet away from the generator sub panel. What size cable would I have to run? If it has to support 50 - 100 Amp, that would be a heavy conductor?

Acausey · February 07, 2013, 01:01:52 PM

There won't be any high current running to the read-out. The transducer senses the current in your generator wiring and sends a low voltage signal up to the read-out panel. It might matter how far the current sensor is from the panel though. I could not find a spec or manual to make sure. It should work in any case, your reading just might be a little low.

As far as wiring, #16 or #14 should be fine. I would hope it comes with instructions to tell you for sure.

~ Andy

Emcemv · February 07, 2013, 03:44:58 PM

Ted

Looks like this is a 120v application so no problem with the neutral. You are very correct, neutral current will just be the unbalance current. I engaged my typing fingers before the brain, thanks for catching that error. It does point out the difficult in monitoring the generator current when you have both 240v and 120v loads. My bus has a meter with a switch to measure both hot leads.

bobofthenorth · February 07, 2013, 07:27:04 PM

Quote from: wagwar on February 07, 2013, 09:47:46 AM

I feed my inverter with AC from the generator and I would want that 'included' in the amp measurements, so the current transformer would have to be 'in front' of that connection down in my inverter bay? I'd have to run additional cable to the display panel up in the house (about 12 feet)?

If by this you mean that your inverter is wired as a pass through ahead of the panel then you would certainly want the ammeter coil ahead of the inverter.