Digital Battery Monitor?

[BERT]

Hi everyone, I have been lurking here for a while getting ideas for my new "to me" cargo trailer. I saw a post somewhere, and despite searches and no results, about a digital battery monitor. I think it was actually for RC cars. Does anyone have a link to this post or know what the product name was? Thanks!

[dreadcptflint]

There are a ton out there. I have a meter on my solar regulator. Is this what you are looking for: http://www.amazon.com/Vector-VEC008-Digital-Voltmeter-Battery/dp/B003AFTXKK

[eamarquardt]

Any volt meter will be able to tell you the state of charge of your battery, within limits, based upon its voltage.

http://www.otherpower.com/otherpower_ba ... ering.html

There are also devices that will measure the amount of power you've drawn from your battery:

http://www.powerwerx.com/tools-meters/w ... nline.html

Depends upon how much energy you want to spend keeping track of energy.

Cheers,

Gus

[Shadow Catcher]

There is a temperature compensated battery state of charge table Excel spread sheet.
http://jgdarden.com/batteryfaq/SoC.xls

Another source for an in line meter (about $60) http://www.rc-electronics-usa.com/buy-products.html

If you are serious about monitoring your battery something such as a TriMetric http://www.bogartengineering.com/products/TriMetric is a good choice particularly if you are going to be adding solar, and the RV meter is about $150

I have bought things from Powerwerks suggested by Gus as a source and had good service.

[planovet]

I used a volt meter that I found on eBay. It works fine for me.

http://cgi.ebay.com/Red-DC-7V-30V-Volt-Panel-Meter-Doesnt-Require-Power-/110661356331?pt=LH_DefaultDomain_0&hash=item19c3ee4b2b

[pete42]

The one you are seeking is a "Turnigy 130A precision watt meter & power analyzer".
it is the one I have and I think I bought it here http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10080

great little meter and does more than tell you the volts.
pete

[GPW]

Pete , you sound like an old RC'r ??? We get a lot of things like that from Hobby King ... third the price of the wattameter... does the same thing ... that's a home run !!!

[pete42]

While I have built airplanes no RC models all full adult size.
I have never done any RC anything but it looks like a lot of fun
I just found the meter and thought it would be a good way to keep track of my battery, I sold the trailer but the meter is still in bag unused.

pete

[BERT]

Thanks Pete, thats the one I remember seeing.

And thanks to all of you with those useful links. I will explore them further as my project moves along.

[droid_ca]

sorry to veer off a bit but is there an electrical timer basically a device that gives an approximation of how long you can run on the current load that is being used?

[GPW]

D, you can easily make a rough guess by dividing the battery capacity , by the current draw... C (battery capacity -amps )/ A ( average current draw - amps ) = Time
That's where a good inline meter comes in to monitor your amp draw... Measuring only the battery Voltage alone can be misleading as most batteries have an operating range Far from O Volts ...

[pete42]

GPW said something that made me remember if you do use the Turnigy it can be powered by the battery it is moitoring
But if the battery runs down then the power to the meter would also be lost

to allow the meter to be used to measure down to zero (0) volts
you need to power the meter with another battery through it's aux. three pin power port.
a nine volt battery can be used since it only powers the meter

using a nine volt battery also allows the meter to hold the stored info until reset.

pete

[fromeo]

Anybody know if that turnigy works bi-directionally? Meaning, will it track power into the battery as well as out? Or is it a charge the battery and reset the meter type deal?

I run a Victron BMV-600 (http://www.victronenergy.com/battery-monitors/bmv-600s%20and%20bmv-602s/) in my big trailer, monitors in/out, peurkert factor compensation, shows SOC, guesstimates time left, does the dishes, etc.. love it, but it was a bit spendy. It would be great to find a lesser expensive alternative to install in the build project.

Here's the display from the Victron:



- Frank

[parnold]

The turnigy looks to be an exact clone of the Doc Wattson that I use. The Doc Wattson does not track both ways.

[parnold]

In reading the directions for the Doc Wattson, it can track from charger to Battery, but the wires would all have to be reversed. Not worth it for me.