Accuracy of Link 10 battery monitor questioned

[ShrimpBurrito]

Hi folks,

I just bought a Xantrex Link 10 meter off eBay, and while in transit, I decided to look through the online owner's manual. It comes with a 500A / 50mV shunt -- I didn't give it much thought when I bought it, but a relative with many years as an electrical engineer pointed out that the shunt won't be sending very much voltage when under a typical Trailmanor load.

The TM has a 30A fuse, so certainly the load will never be more than that. But I'm thinking a more typical load is 5-10A. Basically a few lights and intermittent use of the heater. So even during a 10A load, the shunt will only be sending 1mV to the Link 10, and 500uV (0.5mV) when there's a 5A load. That's a very minute amount of energy, easily influenced by interference from nearby sources or even a ground loop.

Granted, the instructions say to use twisted pair wire for the shunt feed, and I also plan on using shielded twisted pair for extra protection. But that doesn't seem to significantly offset the very low voltage for the meter to accurately detect.

I called the manufacturer, Xantrex, and they said it is within the accuracy specs listed in the manual for the specified current range, which in my case, is 0-40A. But they didn't offer any explanation as to why.

Certainly, using a different shunt could remedy this problem, but doing so will offset the meter readings. I could use a 100A / 100mV shunt, and then simply divide the amps displayed by 10, but I'm trying to make simplify my life, not make it more complex. If beer clouds my vision, I may not even see the decimal.

Any thoughts on the subject? Are the Link 10 owners out there finding that their meter is accurate?

For those who are interested, the specs are on page 59 (second to last page) of the Link 10 manual here:

http://www.xantrex.com/web/id/72/docserve.asp

Short of making any changes to the install ahead of time, I'll probably just end up installing and comparing the current reading with a multimeter.

Dave

[cali camping]

I've found the it to to be spot on. I have a 210 AHr Lifeline AGM Battery and the newer 3 stage charger and the Link 10 monitors, displays and keeps track of whats going in and out of the battery. If something happened to this one I would definitely get another.

I'm using the standard 500 shunt.

Have fun with it!

Dave,
I have a Trimetric with a 500 amp shunt. I could have used the 100 amp shunt, but I have a 1800 watt inverter. Amp readout with the 500 is one decimal place, with 100 2 places. I don't feel the need to have accuracy to 2 decimal places. I think you will be very happy with your Link 10 and 500 amp shunt.

Dave

I'm not sure which shunt I have, but it all works fine. The only problem I have is that the water heater resets the Link 10 when I start it. That is due to the small voltages you are talking about and the distance from my meter to the water heater controls. I mounted mine below the sink where the other monitors and switches are. You might choose another location to avoid that interference. But the small voltages seem to be just fine as far as the Link 10 and accuracy are concerned. I like mine a lot other than the reset issue.

[ShrimpBurrito]

I got it hooked up, and although I haven't checked it with a multimeter, it seems to be measuring accurately. Overhead lights are be clocked at ~1.25-1.4 amps, which is consistent with another member's readings. And my 6A 3-stage charger is putting out exactly 6A. So it's certainly accurate to at least within a few tenths of an amp.

Interestingly, the fridge consumes 10 amps. Yikes.

Bob - I too put my Link 10 under the sink with the rest of the gauges, but I took a few steps which I hope will eliminate interference from the water heater controls. First, I used wire that was both twisted and shielded for the shunt feeds, and ran a second wire for the other 3 conductors. Coming from underneath the bathroom floor, I also ran the wire on the floor of the cabinet, just on the inside of the cabinet edge, as opposed to up where the water heater switch is, and then up the right side of the cabinet adjacent to the fridge.

I haven't tested the water heater yet, but the thermometer that I also recently installed (which was having problems) no longer gets reset by the water heater switch after I put in a choke core (thanks to Bill's suggestion) and wrapped the probe in foil.

Dave