Trimetric Battery Monitor for $140

[Aquah0lic]

I am considering this monitor. Can anyone reccommend it?

Trimetric TM2020 Battery Monitor System

[solarjames]

It is a great meter!

simple.... easy to use...easy to install..Provides all data

It used to be sold as the Xantrex battery status monitor (Tm-500A)

Made by Bogart Engineering

Bogart Engineering | manufacturer of the TriMetric battery monitor which measures volts, amps and amp-hours for battery systems

[colemj]

I can second a recommendation. We have had ours for 7 years and it is fantastic. Almost everyone I run into with a more expensive Link system complains about how it loses track and needs to be reset/recalibrated regularly, or how it just goes bananas on them randomly. Our Trimetric has never required recalibration and has never wigged out on us. Even though it is not a "marine" device, there has been no corrosion or other salt air problems with it. It is a first class piece of equipment at a great price.

Mark

[solarjames]

The guy that designed the meter is Ralph Hiesey. He is known as one of the more brilliant minds in the solar industry. They also sell the Penta Metric which is a more advanced meter.

[JayH]

Originally Posted by colemj

... Almost everyone I run into with a more expensive Link system complains about how it loses track and needs to be reset/recalibrated regularly, or how it just goes bananas on them randomly. Our Trimetric has never required recalibration and has never wigged out on us. ...

You don't have to recalibrate it because it is recalibrating itself. From their document explaining SOC (here):

1.First the battery must be initially charged fully and synchronized with the Meter. When the
charger is charging the battery, the Meter senses that the battery is charged when two conditions
are met: (1) battery voltage must exceed the “Charged setpoint voltage” (which you have
previously set.) and (2) the charge current (amps) must decline to below the “Charged setpoint
amps” (which you have set).
2. When the above occurs the Meter then declares the battery “charged” by flashing the “charging”
light, and resets the “Days since charged” to 0.

My Victron BMV-602 does this also and I don't like it. I have solar panels and when the panels are exactly supporting the house demand (charge voltage, but low current) the monitor incorrectly decides we're full. Consequently I have turned off the automatic sync and have to deal with it gradually losing capacity until I sync it manually. It looks like the TriMetric will suffer the same problem. Mark, do you have solar?

[goboatingnow]

I notice that in its decription of its amp counting, theres no mention of the Peukerts exponent, amp hour counting to determine the state of charge is no good unless that factored in

Dave

[colemj]

Originally Posted by JayH

You don't have to recalibrate it because it is recalibrating itself. From their document explaining SOC (here):

1.First the battery must be initially charged fully and synchronized with the Meter. When the
charger is charging the battery, the Meter senses that the battery is charged when two conditions
are met: (1) battery voltage must exceed the “Charged setpoint voltage” (which you have
previously set.) and (2) the charge current (amps) must decline to below the “Charged setpoint
amps” (which you have set).
2. When the above occurs the Meter then declares the battery “charged” by flashing the “charging”
light, and resets the “Days since charged” to 0.

My Victron BMV-602 does this also and I don't like it. I have solar panels and when the panels are exactly supporting the house demand (charge voltage, but low current) the monitor incorrectly decides we're full. Consequently I have turned off the automatic sync and have to deal with it gradually losing capacity until I sync it manually. It looks like the TriMetric will suffer the same problem. Mark, do you have solar?

Yes, we have solar and I know about the days since charged calibration. I was trying to describe the amp hour out/in function and how it screws up on Links. I rarely look at the days since charged, but am always interested in how many amp hours have been removed/put in to the batteries.

After a time of taking current out and putting it back in, many monitors lose track of the net value and might, for example, show the batteries as being down 50Ah when they are really down 250Ah (or vice versa). Our Trimetric never does this.

Also, our Trimetric doesn't have a problem with state of charge accuracy. The percentage of charge it shows is accurate. What isn't accurate is the "Days since charged" function, as mentioned above. This is where it is difficult to get the set points correct with multiple charging sources. However, the days since charged function provides entirely useless information to me. I know the batteries are charged when the "amp hours from full" value is close to zero.

I don't know if that answers your question. In summary, the "percent charged" and "amp hours from full" functions (which are the "capacity" information) are always accurate, but the "days since charged" function (which is mostly useless information) can be inaccurate depending on how your charging sources mesh with the set points.

Mark

[JayH]

Originally Posted by colemj

I don't know if that answers your question. In summary, the "percent charged" and "amp hours from full" functions (which are the "capacity" information) are always accurate, but the "days since charged" function (which is mostly useless information) can be inaccurate depending on how your charging sources mesh with the set points.

The document referenced earlier continues:

3.When the charging is finished, and the batteries start to discharge again then the “Amp hours from full” is reset to 0.00, and Battery%Full is reset to 100%. (This assumes that the “auto reset” is on,)

I guess your "auto reset" is off. In that case you must have the "efficiency factor" nailed.

Four months after installing it, I'm still trying to get my BMV dialed in. After a few days it shows the battery as discharged deeper than it really is. I can tell by the acceptance charge rate that the battery is fuller than the SOC indicates. I recharge to 100% most days anyway, so it isn't difficult to resync the monitor manually.

Does your solar take you to 100%? It could be that your monitor really isn't tracking perfectly (showing -5Ah when you're really down -10Ah), but is recalibrating when you hit 0Ah and the batteries keep taking more. Sorry, I'm just trying to comprehend how your TriMetric maintains accuracy.

[colemj]

I think you are right - it does reset itself when charged. In our case, the solar usually brings it back to just below full charge, but never into float (-10Ah or so), so never trips the "charged" criteria. So the Trimetric keeps a running tab all the time without resetting itself. Sometimes when we aren't using much power, the solar takes the batteries all the way into float mode. In those times, or when we use the battery charger, I see the "amp hours from full" go positive (+10Ah or so). Then it resets itself when the charging source is removed. I believe the monitor is accurate to 1-2% during use over time and that those times when the batteries go into float, the monitor resets its accuracy.

Maybe we are lucky, but the Trimetric never seems to be more than +/- 10Ah off on a 675Ah battery bank. I watch it approach "0Ah" at the same rate and time as the batteries are going into float mode.

Mark

[goboatingnow]

Maybe we are lucky, but the Trimetric never seems to be more than +/- 10Ah off on a 675Ah battery bank. I watch it approach "0Ah" at the same rate and time as the batteries are going into float mode.

Thats the easy part of batery monitoring, all you do is monitor charge current. The tricky part is when trying to estimate when your battery is half empty not full.

[prroots]

I'm evaluating battery monitors and would like recommendations for a very simple one bank system consisting of a 440 Ah battery bank and a 200 W Air Breeze wind generator. I just need V, A, and Ah displayed as a numeric value. The Victron BMV 600 seems to do that and the installation seems simple. Cost is $158 and includes the required cabling and shunt. Can anyone tell me why another make/brand might be a better choice based upon functionality, price, or reliability? Thanks
Pete