Programmable Battery Monitor Choice?

[Johncfii]

Is anyone using a programmable battery monitor that they can recommend for reliability and accuracy?
By programmable, I mean:
1. AH indication is scalable to the Outback Power shunt that I already have in place. (50mv = 500 amps)
2. “Charged” and “Discharged” alarm relay trip points are programmable.

 

[snoobler]

Victron BMV-7XX, but you're also paying for the shunt.

 

[Johncfii]

Thanks for the recommendation, snoobler.

I considered a whole bunch of different battery monitors. None will do everything I was hoping for, but partially on your recommendation, I ordered a Victron BMV-712. It comes pretty close, and I’m hoping that the somewhat premium price will reflect in quality and accuracy. The shunt that comes with the unit is the same value as the one I already have, so at least I compare them for accuracy.

 

[snoobler]

I'm 99% sure it can do #1 and #2; however, what other features are you looking for?

You can download the victronconnect app and go into the demo library. It will show you all settings and features.

 

[Johncfii]

I was hoping to find a battery monitor that has two programmable “alarm“ relay outputs. The Victron units only have one programmable relay output, at least as I can tell after reading the user manual.

I‘m still trying to settle on the best way to manage the charging of my large bank of home LiFePO4 cells, with the intent to usually operate them between about 20% and 80% SOC. I need a way that my wife can operate the system, with no intervention, while I’m away from home for a week or two at a time. I was thinking that one relay output could trip at an upper SOC (to idle the SCC), and another relay output could trip at a low SOC to take inverters and DC loads off line. I understand that SOC needs to be recalibrated regularly, but hopefully it will remain reasonably accurate for a couple of weeks at a time,

I think that I’ve figured a way to accomplish what I want to without either relay output, but I’m still experimenting to find the way to manage SOC that I like best. Or I might decide to use the one Victron relay output, set to trip at a low SOC, to take the inverters and my direct DC loads off line.

Anyway, I’ve decided that I still want a decent stand-alone AH meter and SOC monitor that is more flexible than the one built into my Outback Power system. The Outback AH meter resets to zero every night at midnight, and I don’t like that. The Victron units look like a good value. There is quite a bit of grumbling on line about the Victron BT app, but I don’t plan on using that anyway.

The JLD404 battery monitor has two programmable relay outputs, and it is cheap, but it has no provision to program a battery charge efficiency factor, and it gets a lot of poor reviews on reliability.

 

[Johncfii]

I installed the Victron BMV-712 several days ago. It’s a nice unit piece of kit. The Bluetooth app works great. Maybe the BT problems that other reviewers complain about were fixed with some version update. In fact, the BT app works so well that I never look at the actual meter display.

I especially like that the SOC can be set//reset at any SOC level, and not just at full charge, as with many other monitors. AMPs and AH in/out agree very well with my Outback Solar metering, but SOC has some significant deviation. I cant tell which is correct. I need to do a bunch more tests to find the correct Charge Efficiency and Peukert Exponent settings,

 

[GVSolar]

I can heartily recommend the Thornwave PowerMon - Bluetooth Battery Monitor - very versatile - can measure up to 60A with integrated shunt - and 500a with external shunt - logging capabilities - nice android/iphone app - coulomb counting - can monitor SOC in % and by remaining time at current discharge rates - can fire SSRs to disconnect/connect according to set parameters - using programmable LFP charge manager - remote on/off with phone app. I've been using it for 6 months - excellent. Customer support is very responsive and helpful.

PowerMon - Bluetooth LE Advanced Battery Monitor / DC Power Meter with data logging

We developed the PowerMon device to provide an affordable, high-tech solution for monitoring electrical systems. Whether you're in an RV, camper, or boat, utilizing solar systems, or managing off-grid setups, PowerMon is designed to meet your battery monitoring needs. Remotely monitoring DC...

www.thornwave.com

 

[Johncfii]

I can heartily recommend the Thornwave PowerMon - Bluetooth Battery Monitor - very versatile - can measure up to 60A with integrated shunt - and 500a with external shunt - logging capabilities - nice android/iphone app - coulomb counting - can monitor SOC in % and by remaining time at current discharge rates - can fire SSRs to disconnect/connect according to set parameters - using programmable LFP charge manager - remote on/off with phone app. I've been using it for 6 months - excellent. Customer support is very responsive and helpful.

PowerMon - Bluetooth LE Advanced Battery Monitor / DC Power Meter with data logging

We developed the PowerMon device to provide an affordable, high-tech solution for monitoring electrical systems. Whether you're in an RV, camper, or boat, utilizing solar systems, or managing off-grid setups, PowerMon is designed to meet your battery monitoring needs. Remotely monitoring DC...

www.thornwave.com

GVSolar .... thanks. This unit looks VERY similar in capability to the VICTRON unit for only 60% of the cost. If it had TWO relay outputs, it would be even more attractive. My son-in-law is going to need something like this, so we will consider it seriously when he is ready to buy something.

 

[Cdkipp]

GVSolar .... thanks. This unit looks VERY similar in capability to the VICTRON unit for only 60% of the cost. If it had TWO relay outputs, it would be even more attractive. My son-in-law is going to need something like this, so we will consider it seriously when he is ready to buy something.

The unit I would have mentioned if I had seen this earlier is the Bogart Trimetric. This meter was the gold standard for RVers for quite a while but I think Victron now holds that position. Still has the accuracy but none of the flashiness of the Victron. They have added an optional wifi module recently. It can only run one relay. http://www.bogartengineering.com/products/battery-monitor.html

 

[Campin]

I can heartily recommend the Thornwave PowerMon - Bluetooth Battery Monitor - very versatile - can measure up to 60A with integrated shunt - and 500a with external shunt - logging capabilities - nice android/iphone app - coulomb counting - can monitor SOC in % and by remaining time at current discharge rates - can fire SSRs to disconnect/connect according to set parameters - using programmable LFP charge manager - remote on/off with phone app. I've been using it for 6 months - excellent. Customer support is very responsive and helpful.

PowerMon - Bluetooth LE Advanced Battery Monitor / DC Power Meter with data logging

We developed the PowerMon device to provide an affordable, high-tech solution for monitoring electrical systems. Whether you're in an RV, camper, or boat, utilizing solar systems, or managing off-grid setups, PowerMon is designed to meet your battery monitoring needs. Remotely monitoring DC...

www.thornwave.com

Hi GVSolar. I recently purchased the PowerMon and trying to figure out SPST relay options. Have you added a relay to the PowerMon or maybe someone can answer relay questions? I’m in need of help...Thnx.

 

[Johncfii]

Thanks for the recommendations.

I thought I would post a follow up on my experience, so far, with the Victron BMV-712. So far I am VERY pleased with it. After some testing with my large LiFePO4 battery packs, I am seeing very accurate state-of-charge readings, with very little drift over the period of a couple of weeks. I have found that setting the “Battery Charge Efficiency” factor to .98, and setting the Peukert exponent to 1.0 seems to result in the most accurate tracking of SOC, over time. But that is with my charge and discharge rates, which generally are oretty steady at about a C5 to C10 rate.

It turns out that I do like having the conventional round meter that comes with the BMV-712. I don’t often use the blue tooth app, though it is very nice for setup. It is nice to easily see SOC at my control panel without opening my iPhone.

Another thing that I like about this battery monitor is that I can recalibrate the SOC meter at any battery SOC. Many only allow the user to re-calibrate at 100% SOC. I believe that I know exactly what my pack voltage should read at 50% SOC, after resting overnight. I can run the pack down to exactly 50% SOC in the evening (per this unit) and confirm the calibration, or adjust slightly, in the morning. Since I am normally operating my pack approximately between 20% and 80% SOC, this is very useful. Only rarely has any adjustment been needed, though I need more months of operation to know all of this exactly.

The Victron unit was a bit more hassle to install than I hoped. This is because I could not use the 500A/50mv Outback Power shunt that was already installed in my system. The Victron shunt, with the same ratings, is a dedicated and more sophisticated unit. It required some re-routing of my battery leads to make room for it.

 

[GVSolar]

Can't speak to the relay issue - I've never used one. But I can say that Raz (the owner/designer) at Thornwave is very helpful - and does reply to email questions... he walked me through a couple of thing.... a good guy.

Hi GVSolar. I recently purchased the PowerMon and trying to figure out SPST relay options. Have you added a relay to the PowerMon or maybe someone can answer relay questions? I’m in need of help...Thnx

 

[Campin]

Can't speak to the relay issue - I've never used one. But I can say that Raz (the owner/designer) at Thornwave is very helpful - and does reply to email questions... he walked me through a couple of thing.... a good guy.

Thnx GVSolar, yes I’m in touch with Raz too. ...just like to bounce questions off sources to grasp what I‘m working with.... Cheers!