I just ran across this battery monitor. Looks interesting, no shunts, it reads battery capacitance and from that can determine battery capacity. Has anyone tried one of these?
Balmar Smartgauge Battery Monitor (http://www.balmar.net/?product=smartgauge-44-sg-1224)
I'm skeptical. This sounds too good to be true. With no shunt, it has no reliable way of knowing load. Without knowledge of load, is that voltage an unloaded voltage that gives a good idea of battery state of charge, or voltage under unknown load.
I imagine this might sort of work by guessing when it is not loaded and not being charged, then taking a snapshot.
But the PDF file uses the word proprietary where I'd like to see facts.
They claim 5% accuracy after it "learns" your battery after a few cycles. West Marine here in Mpls has one, I'm going to try it. I'll run some measured load tests with my inverter, and report results.
Here is a review with some testing:
Smartgauge monitor review (http://www.pbase.com/mainecruising/smart_gauge)
Looking forward to your reports Peter.
Mounted the Smartgauge panel yesterday, today will run the wires. Next post will be report on how it works.
(http://www.foreforums.com/MGalleryItem.php?id=3041)
Anxiously waiting the report. Nice when someone else does the initial testing. ^.^d
Wiring is done. Been through the setup, the initial charge defaults to 75%, but if you know the state of your batteries, you can set the start point. My house batteries have been on float all morning, so I set the initial charge at 100%. From here according to the manual, it will learn over a few cycles. Note the Aims display is not accurate - shows only 75%.
(http://www.foreforums.com/MGalleryItem.php?id=3043)
(http://www.foreforums.com/MGalleryItem.php?id=3042)
Peter, how's the no shunt battery monitor going?
Been wondering about that also.
Roland
The first battery monitor went with the '91 when we sold it. I was very happy with the readings as verified with known discharge testing that I did using a 200 watt light bulb and a 1500 watt electric grill as inverter test loads.
I bought another one and just got it installed into the Roadtrek. I haven't been out camping yet this spring so it hasn't been through the few discharge cycles needed to synchronize with the house batteries.
My solar panel is keeping the house batteries at full charge, the monitor is showing 100% in the photo.