BATTERY Monitor App

I have one seems to work ok

Another one on Amazon for US$24
http://www.amazon.com/dp/B00X1MMNIG/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687742&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B0184XHL1K&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1H5TBV17F44VVRSXHWC6

I don't have one. I looked at it and thought what a great idea. After looking at the detail more, I came to the conclusion that while it looks sexy, it is probably another toy that I wouldn't really use.

The concept of measuring the camper battery remotely is really appealing but using a phone app to measure it over bluetooth isn't perfect.

The reviews on google play pretty much all say it is flaky and unreliable. And the specs say the range is up to 6m in open air.

play store site inc reviews

"** Subject to environmental conditions , obstructions such as bonnets , car panels , solid objects will reduce the transmitters range." And that is reduced from 6m.

After considering it more, I think you need a dedicated 'always on display', not something the you check from time to time when you remember by opening an app.

Unfortunately Bluetooth isn't really the right radio technology to go through several sheets of steel panels, and about 8 - 10m distance. Think of how dodgy and choppy it is with music when you are playing it even less than 5m from a stereo in free air!

I'm still looking for something to do that job at a reasonable price

There are a number of models available. At a range of prices.
Some have alarms, some measure current as well as volts. Even temperature.

I would not want one. I go bush to get away from the b.. phone!