Battery Monitor

[fudge_brownie]

Eric T recently posted a message containing a link to a battery monitor that plugs into a 12 volt outlet and gives measurements of what charge is left in your battery. I found the unit is only available from Amazon, and will run about $18 US with shipping. Here is the link and description:


http://www.amazon.com/Equus-3721-Bat...8&sr=8-1-spell

I took some time on a recent week long trip to compare the Equus battery monitor that Eric recommended with hydrometer readings. Supposedly hydrometer readings are the most accurate method of measurement short of having expensive test equipment.

I would have to say that hydrometer readings are difficult, touchy and the instruments suffer from poor quality. It took me two purchases to find a working model and the second model is going back as it has filled itself with battery acid and it cannot be easily drained. It is also made of glass. The inexpensive hydrometers give readings on a scale with tick marks between numbers, the glass insert must be balanced so it is floating in the acid you have drawn from the battery. In addition, you must add or subtract depending on what the thermometer tells you. In all, I felt a cumbersome process that is easily skewed. There may be better models available but after visiting four stores I felt I selected the best available, it was less than $6.

Below is a table of what I found with readings from the Equus battery monitor and a hydrometer test. As you can see there is a pretty good correlation of results. I really distrust the hydrometer readings because there is so much chance for error and obtaining a precise reading.

Day Hydrometer Battery Monitor
1 1.281 13.14
2 n/a 12.59
3 1.277 12.57
4 n/a 12.47
5 1.252 12.45
6 n/a 12.30
7 1.221 12.32




From this table you can see my usage over the 7 days, we are running all led lighting but soft white, which is not as energy efficent. My son uses a CPAP at night, in researching his model it draws very little when in the 12 volt mode. The water pump and Max fan would be the only other draw. There seems to be a pretty strong correlation between both instruments and the results.

It is recommended that you not draw a battery below 12.00 on a regular basis as that will shorten the battery life. Assuming that the battery declined the second two weeks at the same rate we could get two weeks out of this new pair of 6 volt batteries.

In conclusion, if you boondock and want to monitor your battery this definitely beats the four colored led’s on the Escape monitor panel. You have a precise number and can even tell what power a particular device is drawing by running it and seeing the monitor change. I recommend a hydrometer for occasional (seasonal) testing on all the cells on your battery but if you want to easily watch your battery the Equus batttery monitor does the trick.

Thank you Eric for the recommendation.

Note: I have no connection with Equus or Amazon.

[bvansnell]

Eric:

I bought the same monitor from Walmart in the US for about $15. You can find it in the automotive section near the batteries in most Walmart stores.

Brian

[fudge_brownie]

Brian

I had heard they were available at Walmart but since I do not shop Walmart I could not check. I did check with their online store and they do not show them available.

[escape artist]

Hi: fudge_brownie...Thanks for the product endorsement and review. "I'm going to the country...sun shine bright on me".
Even tho I don't like Wallo Mar t we will probably be in one...or two so I'll take a look for an Equus there. Alf p.s. we have a plug in monitor but it is for the 110V.
escape artist N.S. of Lake Erie

[thoer]

fudge_brownie - wow - thanks for the great testing!

[Texscapees]

Fortunately, our solar setup includes a solar charge regulator that provides digital display readings of not only the solar charging current but also the battery voltage (to one decimal place) and the battery state of charge (as a numerical %). However, I can't say that I've tested its accuracy as compared to a device like a hydrometer or the Equus monitor.

If this info wasn't currently available via our solar regulator, I'd be looking at getting a battery monitor such as the Equus. It's definitely useful to have more granular data than the stock Escape monitor panel provides. That said, the stock monitor panel is still better than nothing & I'm glad that it came with the trailer - particularly for tracking the holding tank levels.

I sure wish there was an equivalent inexpensive monitor available that could give more granular & accurate/reliable data regarding the tank levels. I've read some good reviews about the "See Level II" monitors but they cost from $200 - $500 depending on the model. [http://www.rvgauge.com/rv.htm]

[cheryls]

Thanks for the info, fudge_brownie! Seems like a handy little meter, especially for someone like me who tends to worry about the battery.

[Bruce Wray]

Take a look at the monitors, AC and DC, that I found at Camping world: http://www.campingworld.com/search/i...d&Nty=1&Ntpc=1

Anyone have any familiarity with either of these products? An old-timer told me that an AC meter was a good idea for full hook-up sites to make sure that you don't unknowingly trash your trailer's electricals.

Bruce

[thoer]

Bruce,

In my opinion a good surge protector with built in testing like this one http://www.campingworld.com/shopping...analyzer/35145 is a better bet then an AC voltmeter. I always plug ours in first, before hooking up the trailer's power cord. By the time you see it on a voltmeter any over voltage (or other problems) have already zipped through all your trailer's electric circuits. But, on the downside, surge protection is much more expensive.

Eric

Originally Posted by Bruce Wray

Take a look at the monitors, AC and DC, that I found at Camping world: http://www.campingworld.com/search/i...d&Nty=1&Ntpc=1

Anyone have any familiarity with either of these products? An old-timer told me that an AC meter was a good idea for full hook-up sites to make sure that you don't unknowingly trash your trailer's electricals.

Bruce

[fudge_brownie]

Eric and Bruce

What Eric states about the surge protector makes sense. The monitors will probably tell you too late that you have a problem. I thought I read that the way the Escape is wired there will be breakers thrown or fuses blown before damage can be done to the power converter. For that reason I have taken to carrying the correct 15 AMP fuses for the converter. However, my recollection of what I read "somewhere" may not be the safest approach to a potential problem.

[Bruce Wray]

I was advised regarding the AC meter that it's most useful for for full hookup places that might have "dirty" power (frequent swings in voltage) and especially "weak" power -- significantly under 110v. But as a relative newbie who dry camps mostly, I haven't bought anything yet.

Bruce

[thoer]

It would definitely give you some feedback about the AC voltage. More knowledge is always good in my opinion. But without some sort of protection then your only choice would be to disconnect from the AC.

Eric

Originally Posted by Bruce Wray

I was advised regarding the AC meter that it's most useful for for full hookup places that might have "dirty" power (frequent swings in voltage) and especially "weak" power -- significantly under 110v. But as a relative newbie who dry camps mostly, I haven't bought anything yet.

Bruce

[Hokie Escape]

Originally Posted by Eric T

Bruce,

In my opinion a good surge protector with built in testing like this one http://www.campingworld.com/shopping...analyzer/35145 is a better bet then an AC voltmeter. I always plug ours in first, before hooking up the trailer's power cord. By the time you see it on a voltmeter any over voltage (or other problems) have already zipped through all your trailer's electric circuits. But, on the downside, surge protection is much more expensive.

Eric

Great tool to protect your "innards"! I'm gonna get one for sure!