Thornwave Powermon-5s

[Horsefly]

I'd forgotten that I had written stuff here about the Thornwave Labs Powermon-5s long ago. I've had it for quite a while now, so I have more experience with it. Unfortunately it is mostly not good.

At it's basics, I would expect the powermon-5s to do a good job coulomb counting, and giving an accurate representation of the SoC (State of Charge) of the battery pack. At this it seems to fail. It looks as though the algorithm it uses is for lead acid batteries, as it assumes there is some sort of self-discharge. I had a BMS, a Victron Smart Shunt, and the Powermon-5s connected to my test LFP pack for several weeks, with no loads. The initial state was about 82%, and that was reflected on all three units. After about three weeks the Victron and the BMS still showed about 82% (I think one of the two may have dropped to 81%), but the powermon-5s showed 71%.

The data logging does not work in any useful way. You can set the sample period to anything from one sample per second to one per minute. Unfortunately the labeling of the data only works for one sample per second, and even then the data appears to not be logged correctly. There is no way to export the log data anyway, as you can only look at it on the App.

The one very handy feature of the Powermon-5s is the relay control. It has a relay that can be programmed for a number of conditions, including a high voltage disconnect, low voltage disconnect, high current disconnect, or timers. I will be using the powermon-5s in my system, but only for this relay control.

 

[GVSolar]

I'd forgotten that I had written stuff here about the Thornwave Labs Powermon-5s long ago. I've had it for quite a while now, so I have more experience with it. Unfortunately it is mostly not good.

At it's basics, I would expect the powermon-5s to do a good job coulomb counting, and giving an accurate representation of the SoC (State of Charge) of the battery pack. At this it seems to fail. It looks as though the algorithm it uses is for lead acid batteries, as it assumes there is some sort of self-discharge. I had a BMS, a Victron Smart Shunt, and the Powermon-5s connected to my test LFP pack for several weeks, with no loads. The initial state was about 82%, and that was reflected on all three units. After about three weeks the Victron and the BMS still showed about 82% (I think one of the two may have dropped to 81%), but the powermon-5s showed 71%.

The data logging does not work in any useful way. You can set the sample period to anything from one sample per second to one per minute. Unfortunately the labeling of the data only works for one sample per second, and even then the data appears to not be logged correctly. There is no way to export the log data anyway, as you can only look at it on the App.

The one very handy feature of the Powermon-5s is the relay control. It has a relay that can be programmed for a number of conditions, including a high voltage disconnect, low voltage disconnect, high current disconnect, or timers. I will be using the powermon-5s in my system, but only for this relay control.

As I recall, there is a Peukert setting for LifePo4 in the configuration menu. I didn't notice it at first and reset mine. The default was LA, I believe.

 

[GVSolar]

This is not really on topic but seems there is some collective wisdom here on schnieder sw 4024 here .
I have recently purchased one for my auxiliary off grid system.
My issue is although now the unit defaults regarding battery chemistry suits my AGM bank it seems to me that when i come to replace with lifepo4 in the future i need a SCP to configure to custom battery configuration for lithium ?
At 20% of the initial purchase price of the sw 4024 its a bit annoying and concerning that when i do come to replace batteries in the future SCP may not be available as per the com box.
My dilema is Should i bite the bullet and get one now or not worry as generator / charging is basically opportunistic and algorithm not really necessary ?
regards confused

Absolutely. SCP is essential to getting the most out of your SW4024. And yes, it is a pain that it is an expensive add-on.
I have a Combox as well, which allows for remote monitoring and adjustment.

 

[Horsefly]

As I recall, there is a Peukert setting for LifePo4 in the configuration menu. I didn't notice it at first and reset mine. The default was LA, I believe.

Yes, when I was always using the LiFePO4 setting for the Peukert setting. It's disconnected now so I can't double check. When I contacted Thornwave Labs I told them I suspected that setting was being ignored somehow, as the self discharge seemed like that of a lead acid battery. He / they never replied to me.

 

[GVSolar]

You might try again. I've always had good luck with replies from Raz. Good thoughts.

 

[corporate.joe]

After using my powermon-5s for 90+ days I have noticed that it is quite off on the SOC. Kilowatt hours used is in the positive as much as 2kwh. Obviously this number shouldn't be positive. AH remaining seems more correct when compared to the present cell voltages. Is this normal with smart shunts? Should I do a reset the next time my batteries are completely topped off? I've got the Peukert setting correct.

Anything else I can check to eliminate user error on my part?

 

[Horsefly]

After using my powermon-5s for 90+ days I have noticed that it is quite off on the SOC. Kilowatt hours used is in the positive as much as 2kwh. Obviously this number shouldn't be positive. AH remaining seems more correct when compared to the present cell voltages. Is this normal with smart shunts? Should I do a reset the next time my batteries are completely topped off? I've got the Peukert setting correct.

Anything else I can check to eliminate user error on my part?

Yeah, see my earlier post (two prior to yours). I've got both the Powermon-5s and the Victron SmartShunt in my system, as well as the JBD BMS. The Pmon-5s has never seemed to get the SoC right. The data logging has also been broken, in that it works for the highest frequency of sampling, but seemed wrong otherwise. Right now I'm using it only for the relay control, depending on the SmartShunt for the SoC.

I did notice a couple of days ago that there was a new firmware available for the Powermon-5s, but I haven't tried it yet. You might try it to see if it improves.

 

[corporate.joe]

Yeah, see my earlier post (two prior to yours). I've got both the Powermon-5s and the Victron SmartShunt in my system, as well as the JBD BMS. The Pmon-5s has never seemed to get the SoC right. The data logging has also been broken, in that it works for the highest frequency of sampling, but seemed wrong otherwise. Right now I'm using it only for the relay control, depending on the SmartShunt for the SoC.

I did notice a couple of days ago that there was a new firmware available for the Powermon-5s, but I haven't tried it yet. You might try it to see if it improves.

I don't use the app interface at all since I got my Pi pulling the data into a database, so I'm unsure what the "fuel gauge" reads for percent remaining. What I noticed is that the kwh remaining figure is way off. The AH remaining looks to be pretty spot on. So, I use a little math in my Prometheus query for grafana to display the kwh remaining using the battery voltage and the AH reading from the shunt.

I'll try and check out the new firmware when I get a chance. Probably when I do a full top-off of the packs to add a third. I have to reset the AH pack size at that time anyways.

 

[neilticktin]

On the PowerMon-5s, I use it all the time and am pleased, save one issue … Bluetooth range. I have to stand outside the battery compartment or just above the battery compartment inside the rig to get signal. I fully understand the installation instructions to place the unit somewhere that interference will be minimized but reality is that’s not always realistic given the nature of what the device does. It *has* to be near the batteries.

Anyone find a way to extend or repeat the range?

 

[Campin]

redirected my post - Troubleshoot PowerMon