Monitoring Multiple Batteries

[haycord]

Assuming two (2) 12v 100AH LiFePO4 RICH SOLAR batteries wired in Parallel: What is the best way to monitor each battery separately for condition over the long term? I'm concerned that one battery would eventually develop problems and I would only be seeing the 'combined total' with the Victron 500A Smartshunt.

Is it so simple as to have a Smartshunt on each battery? Or - would the 'combined readings' give me enough information to flag a need to go check each battery with a DMM? Thanks

 

[Craig]

If they are parallel there is no way to monitor each cell. However it could be possible to put a shunt between the two cells and see how much energy is going between the 2. I have never heard of this but I can't see why it wouldn't work

 

[E. Cho]

Thoughts.

Does each batteries have it's own BMS?

Are the BMS accessible by a BMS display or via a smartphone app and Bluetooth? If there is a BMS but no app access, you might be able to replace the BMS with one that has Bluetooth connection and a smartphone controlled app?

If no BMS, then add one to each battery, that is s BMS which has Bluetooth and a smartphone app, or if a JK BMS, you could add their smallish display to each battery, which monitors all connected cells per battery BMS without a smartphone or app. The JK BMS display is about $30-50 USD.

You could also add a Heltec or Neey cell balancer to each and run it 1-4 times per year to balance the cells and view the status of each cell before during and after balancing.

 

[mikefitz]

Unless you already have the batteries there are alternatives with Bluetooth BMS that allow access to battery status via an app.

Assuming you have the Rich Solar batteries that do not have Bluetooth, then a low cost shunt monitoring current in each battery negative would be useful, with a single smart shunt monitoring total current and system SOC.

https://www.amazon.com/DROK-Digital-Multimeter-6-5-100V-Amperage/dp/B017BDQHE6/ref=sr_1_6?crid=Q4GQP2V6DEGB&keywords=12v+battery+current+monitor&qid=1690912660&sprefix=12v+batterycurrentmonitor%2Caps%2C236&sr=8-6

You could have a battery monitor for each battery, perhaps a low cost unit.

https://www.amazon.com/QWORK-Battery-Monitor-Voltmeter-Ammeter/dp/B0824X5MKM/ref=sr_1_13_sspa?crid=Q4GQP2V6DEGB&keywords=12v%2Bbattery%2Bcurrent%2Bmonitor&qid=1690912859&sprefix=12v%2Bbatterycurrentmonitor%2Caps%2C236&sr=8-13-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9tdGY&smid=A2M49RHWISCA2E&th=1

Most installations just connect in parallel with a single battery monitor.

A useful test meter that could be used for commissioning, fault finding and ocassional monitoring of the current share of parallel batteries, is a DC clamp meter,

https://www.amazon.com/VENLAB-Multimeter-Auto-ranging-Temperature-Capacitance/dp/B0BVZJ7NCZ/ref=sr_1_1_sspa?crid=2DVSASYTPT7AJ&keywords=dc+clamp+meter&qid=1690913209&sprefix=dc+clampmeter%2Caps%2C277&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Mike

 

[haycord]

I was an Industrial Electrician for most of my life and we had many really large battery banks that required routine monitoring and testing on a per/cell basis. So naturally when I see Solar Battery Banks - my first question is how do users determine when a particular battery starts being a problem. Monitoring the 'bank' with a quality device like the Victron is simple enough - but that is only good so long as all batteries are contributing equally to the group. If the group performance begins to deteriorate - a group monitoring device (a single Victron) provides no indication as to 'who' is dragging down the group. Of course, because of my experience I could easily make that determination by testing but I'm looking for a more 'automated' method commonly used that I can watch from my phone (Lol). As well as - what is the specific Red Flag you look for that tells you to grab your meter and start testing?

I plan to expand my (RV) system significantly and am curious how others do it. I can already see I should have looked at batteries that had Bluetooth BMS on-board. And I will certainly look at that going forward.

I do have the Fluke 87V and 337 Amp-Clamp so I'm in pretty good shape for testing.

Thanks to all who replied.

 

[E. Cho]

You can't monitor per cell if the cells are not connected with a monitoring wire per cell to a BMS with Bluetooth and or active / passive balancing.

Swap out the BMS or add a dedicated active balancer that has a Bluetooth app. These are both wired / connected to monitor each cell ad well as the entire 12v battery, then a shunt monitor to monitor the group. Not sure how else you cam monitor each cell.

Lots of threads here on BMS and cell balancing and battery health to search and read through and videos on YouTube to watch and learn how to best use them?

 

[haycord]

Understood. The Solar power world is new to me so I can see I've got some research to do. Too bad these manufacturers tech support people seem to disappear after the sale. Thanks for everyone's comments.