Battery Monitor

[Jim86301]

If you don't want to spend $100 plus on a Victron battery monitor try the Elite DCM120100C Multi-function Panel Meter. This inexpensive Coulometer measures both forward (Positive) and reverse (Negative) current flows as well as voltage, amp-hours and percent of charge. I bought one but unfortunately couldn't find a good place to install it in my van. Consequently it is for sale and includes 15 feet of 4-conductor wire. For details see Multi-function Panel Meter Model Elite DCM120100C. I'm asking $30 for the meter and wire (free shipping to contiguous U.S.). New, open-box.
Jim

[55 Nomad]

Hi Jim
I recently bought a 2006 Roadtrek. I am looking for a voltmeter and saw yours. Is it still for sale? Thanks
George

[rowiebowie]

Jim's monitor would be a good price. I prefer the Renogy model I have. The main reason is no buttons to push. It's display continually shows battery charge %, remaining amps, voltage, watts in/out, and amps in/out. If the backlight is constant on, you know current is flowing out. If the backlight is slowly pulsing, you know the battery is charging.

No cycling through buttons, it's all there all the time.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[booster]

Renogy doesn't explain how their monitor works in the manual, don't know if there is more info elsewhere.

Can you set things like charge efficiency, tail amps and volts, reset manually to 100%? if not, what does it use for settings? A big deal is how they determine full charge and reset to 100% automatically, if they do it that way.


If a lot of this stuff can't be set, it may be applicable more to lithium only, where the charge efficiency is near 100% and no overcharge of amps above 100% needed to show full. In that case it would be a simple coulomb counter that compares that count to the setting for battery bank capacity and not good for lead acid batteries.

[rowiebowie]

Originally Posted by booster

Renogy doesn't explain how their monitor works in the manual, don't know if there is more info elsewhere.

Can you set things like charge efficiency (No), tail amps (No) and volts (Yes), reset manually to 100% (Yes)? if not, what does it use for settings? A big deal is how they determine full charge and reset to 100% automatically, if they do it that way. (You can manually reset to 100% as stated above, but it automatically resets based on programmable voltage setting.)


If a lot of this stuff can't be set, it may be applicable more to lithium only, where the charge efficiency is near 100% and no overcharge of amps above 100% needed to show full (I set it to show 100% at 13.8 volts but charging profile drives volts to 14.6 before cutoff). In that case it would be a simple coulomb counter that compares that count to the setting for battery bank capacity and not good for lead acid batteries. (Doesn't it boil down to trusting your charger to bring the battery to 100% or as near as possible? If that is the case, all you can do is set the monitor to at or near the top of the charging profile voltage.)

See above.

The monitor will allow me to visually verify the charging profile (in my case lithium) and monitor drains. Relying on the charger setting to do it's job, wouldn't it tell you the status of lead acid as well, or at least as close a possible and allow much better status checks than no monitor at all?

Like I said in an earlier post, at some point you have to install components, program them correctly, and then rely on them to do their job. This monitor allows me to verify my components are doing just that.

Perfection is great, but I'll take great if I can't have perfection.

[booster]

Originally Posted by rowiebowie

See above.

The monitor will allow me to visually verify the charging profile (in my case lithium) and monitor drains. Relying on the charger setting to do it's job, wouldn't it tell you the status of lead acid as well, or at least as close a possible and allow much better status checks than no monitor at all?

Like I said in an earlier post, at some point you have to install components, program them correctly, and then rely on them to do their job. This monitor allows me to verify my components are doing just that.

Perfection is great, but I'll take great if I can't have perfection.

That was exactly my point in regards to lead acid batteries. Some even applies to lithium if you cut off and reset at 100% and the charger goes longer and higher voltage as you will add a bit of unaccounted for amp hours.


You can't determine full on a lead acid battery by charging or even rested voltage, or by returned amp hours, anywhere near accurately because of the charge efficiency being involved. Add to that there are very, very, few lead acid battery chargers that will charge a lead acid battery consistently full and not overcharge. That is why other monitors check voltage and charge current to determine full charge and reset.


You could do the same on the Renology, but you would have to watch the voltage and current and reset manually to keep accuracy, or it would get worse and worse on every cycle.


Personally, I would spend a little more and get a more lead acid battery friendly monitor if that was the kind of battery I was going to keep track of.

[Jim86301]

Hi George:
The Multi-function Panel Meter is still available. I sent you a PM regarding mailing it to you. The manual is at: http://bjimages.net/Elite/Elite_DCM120100C.pdf.
Thanks,
Jim

[JohnnyFry]

I have this meter and find it works very well. There is a caviat, however, in that you must be able to calibrate it yourself. Basically you need a knowledge of calibration of electrical instruments, an accurate DC ammeter an accurate DC voltmeter and a known resistive load. The instructions provided are sketchy, probably translated from Chinese. I don't want to discourage anyone but you should know the limititations going in.

[Jim86301]

You are correct! Calibrating these types of meters is somewhat of a pain and the instructions a bit convoluted, but this is true of all of them that I have looked at. I suppose the problem is that there is such a huge variety of battery types and capacities which the meters need to be able to deal with.
Jim