Monitoring your battery voltage

chuckshaver

What do you use to monitor your battery voltage.

ericnliz

chackshaver, Please see the note left on your battery switch question. We'll try to help, just need more info. Thanks!

ScottG

I use the INNOVA 3721 Battery and Charging System Monitor plugged into the 12 volt port above the sink. There are lots of other similar brands and models.

Keep in mind that these are designed for checking automotive systems. When used to monitor your camper's deep-cycle battery, the little lights will change colors like a discotheque as you add and remove loads. This is normal. As long as you pay attention to the actual voltage reading, these cheap units work fine for basic monitoring.

chuckshaver

Thanks, looks great.

ericnliz

Again, thanks for helping Scott!

jcfaber1

I use Bogart Engineering Trimetric meter 2025-RV.  You wire it in through a shunt and program in the amp capacity of your batteries.  It gives you much more information on the state of charge.  A very solid investment.  $200.
John 

JustJohn

I use the same one Scott uses.

Photomom

The voltage will also vary. A fully charged battery will be something like 12.6v with no load, but will likely read lower if it is supplying power to something - we've seen as low as 11.5 if the fridge is running on 12v.

And if the battery is being charged by the converter or your car's alternator, it should read over 13 volts (unless there is a load.) Don't expect it to always read 12.6 like the nice picture.

jkjenn

I installed a Victron BMV-700. IF you just need a rough idea, the 12v receptacle style are fine. If you like to be precise and have a penchant for number crunching, you might want something more sophisticated like the Victron or Bogart Engineering models.

Tabaz

I installed the same unit as Jenn. VERY impressed with the accuracy and amount of info it provides. Get the Bluetooth dongle to send info to your smartphone/tablet.

jkjenn

OutbackAZ said:

I installed the same unit as Jenn. VERY impressed with the accuracy and amount of info it provides. Get the Bluetooth dongle to send info to your smartphone/tablet.

I used the app with the Bluetooth dongle, all summer. It was awesome!

Nomad

I'm in the ScottG camp - don't need precise and no longer deal with spreadsheets - There's a word for needing to be precise isn't there? ;-)

jkjenn

PXLated said:

I'm in the ScottG camp - don't need precise and no longer deal with spreadsheets - There's a word for needing to be precise isn't there? ;-)

Employed?

Nomad

Naw, not even close :-)

jcfaber1

Wise would be the word.

ScottG

Hmmm, but I can infer the health and charge of my battery simply by observing fluctuations in voltage under different conditions. Arguably, that requires a certain degree of wisdom. Therefore, am I not also wise? Perhaps even wiser than those who require a constant stream of expensive detailed data to accomplish the same end?

Or...am I just a wise-###?  ;-)

chuckshaver

Pandora's box.

jkjenn

ScottG said:

Hmmm, but I can infer the health and charge of my battery simply by observing fluctuations in voltage under different conditions. Arguably, that requires a certain degree of wisdom. Therefore, am I not also wise? Perhaps even wiser than those who require a constant stream of expensive detailed data to accomplish the same end?

Or...am I just a wise-###?  ;-)

That plug in voltmeter isn't nearly as accurate... so your premise is shot.

Nomad

The first was too far up the alphabet, the second, off the scale ;-)

ericnliz

ScottG, Or maybe just too much time on your hands. PXL, totally agree. Jkjenn, A little overboard, maybe. Not building a piano, just campin'! I can think of a whole lot more to do when I'm camping than make spread sheets on anything. Let's see, fishing, hiking, swimming, relaxing, chopping wood for a nice fire........HMMMMMMMMMMM.

Nomad

ericnliz - Been joking with Jenn about spreadsheets and details for almost ever. It really comes down to what makes you comfortable so you can get out and enjoy the other things. If details set you free, cool :-)

jcfaber1

Some of us like to actively manage our batteries.  I prefer to not carry a generater.

ScottG

According to my trusted Fluke multimeter, my $15 plug in voltmeter is plenty accurate, thank you very much! 

Actually, I like gizmos as much as anyone (although I draw the line at them calling me on the phone...ha ha). Some of the "wisdom" I claim comes from understanding the power draw of various devices--thanks in part to Jenn's spreadsheets. I've also been smitten with her Victron since she posted about its install almost a year ago, though its cost/benefit ratio makes it a low priority for my purposes.

Just because we all pull the same camper doesn't mean we all have the same interests, take the same approach to things, or would even like each other if we sat around the campfire (though I find that hard to believe...). Keep the info and opinions coming--it's all good! 

ericnliz

PXL, I agree, different strokes 'ya know. jcfaber1, I don't carry a generator either. Like a lot of us here, prefer solar. I manage my battery, but also manage my usage of it as well. ScottG, Totally agree with your last statement about not having same interests. I like gadgets, and gizmos too, just not when I'm camping. Jen, wasn't trying to pick on you, just like Scott said, different interests. As long as you are enjoying yourself, that's all that matters, right? Did you ever find out what was causing the bubbles on your trailer by the way? Hope you get that one sorted out. Just remember, keep the shiny side up, and between the ditches!  

Nomad

I carry a gen but it comes out only when necessary - realized last week I had started it for almost two months so took it out but solar is my go to. Don't really find hauling it around much hassel. Sure comes in handy when you do need it.
As far as monitors, 22 months and the little cig plug monitor has served my needs just fine. All I need is a reading of 12.4, don't need 12.4013578 :-)

Verna

@jkjenn, I proud that you keep up with your spreadsheets. That truly is a great thing. I had to do a lot of paper recording and later on there was the computer input recording of data at the phone company for almost 40 years. My life is simpler now. I do have an app to record my expenses and income, cash or direct deposit. But no more spreadsheets. 

I told a former co-worker that all of the information we took so much time and effort to learn didn't matter after retirement, unless he continued in the telephany field. I told him I have so much room freed up in my brain that I feel free. It's simpler to add camper and camping info and retain it now, rather than being frazzled while working trying to remember specific little bits of knowledge. You'll understand in a few years. 

Instead of my old plug-in voltage meter, I bought one that is under my reading lamp above my head in bed. I can see it without my glasses (yes, that's good!).  I do have the SeeLevel gauge, but I have to push a button to see it. I'll keep both. 

ericnliz

PXL, I only have the monitor inside, by the pump switch. Like you, don't need a whole bunch of #'s to tell me when it's low. The seven pin on my TV serves me well for those rainy, cloudy days. Just try to limit my usage as much as possible. That being said, I'm not working out of my trailer either, so my usage is lot less than others may be. About the only time you actually find me, or my wife in the trailer is sleeping, or showering. We have an outdoor kitchen we use, so pretty much everything is out of doors for us. 

Nomad

I have used the seven pin for a quick jolt when I didn't need much and it wasn't worth pulling out the gen.

DurangoTaB

I don't know how many other TV's have a 400W, 110V outlet like my 2012 Tacoma...but I'm wondering about using it with a 2/4/6amp charger in a quick charge pinch.  Kind of an expensive "generator", but for us 2-3 day campers, it might be a backup cheaper than a 1-2K Honda generator. We have an 80W Zamp, but we also like to camp in the shade...we have a 25ft. (14ga.?) Zamp extension cord, but I'm also wondering how much that slows down charging (E=IR?).

I'm "wondering" a lot this morning...it's 49degrees...yay Fall!

jkjenn

DurangoTaB said:

I don't know how many other TV's have a 400W, 110V outlet like my 2012 Tacoma...but I'm wondering about using it with a 2/4/6amp charger in a quick charge pinch.  Kind of an expensive "generator", but for us 2-3 day campers, it might be a backup cheaper than a 1-2K Honda generator. We have an 80W Zamp, but we also like to camp in the shade...we have a 25ft. (14ga.?) Zamp extension cord, but I'm also wondering how much that slows down charging (E=IR?).

I have a 110 outlet, although I am not sure of the wattage. This is a good question.

  I'm "wondering" a lot this morning...it's 49degrees...yay Fall!

Insanely jealous. Returned home Saturday to a broken air conditioner, 90+ degree weather with brutal humidity. Still living in the T@b, for the most part. A/C repair guy comes this AM.

jcfaber1

Durango tab, your 14 guage cable is yielding a 3.5% voltage loss.  What this means is you start out at 17.5 volts and by the time it gets to the battery it is 16.95 volts.  If a fully charged battery is 14.5 volts then you have 17.5-14.5=3 charging volts.  With the voltage drop, 16.95-14.4= 2.45 charging volts.  This represents an 18% reduction 2.45/3.0 in charging ability over the 25 ft cable.  You would be much better with a 8 guage cable.
John