LifePo battery bank monitor

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I have my two new Chins LifePo 24v, 100 Ah batteries installed and ready to make the final switch over from the AGM lead acid as soon as I have a sunny day to be able to top off the LifePo's.
I didn't spend the extra $$ for the smart batteries, so I have no blue tooth or any other way to access the BMS without tearing the case apart.
The only monitoring I have now is the Context SW SCP display panel, the Classic 150 display and a simple generic digital volt meter wired into the battery bus bars.

Looking for recommendations for a battery monitor. I watched Will Prowse's video review of an affordable monitor:

But it leaves a several questions:
1. with a multiple battery bank should I install the shunt on the main battery cable leading from the bus bar to the e-panel?
2. are there any potential long term issues monitoring the bank as a whole rather than the individual batteries?

Currently considering this unit: https://www.amazon.com/Renogy-Monit...B210TJRZK3EJXHF3JT&qid=1673974254&sr=8-3&th=1

manufactured in China by a US based company.

Thanks

 

[Steve_S]

With a Classic, you can use their SmartShunt "WizBangJr" which is not bad once setup properly, sadly it is only 1 Decimal Point Accurate whereas 2 decimal is better when dealing with any Lithium Based chemistry.

Product - MidNite Solar

MidNite Solar Product Page.

www.midnitesolar.com

RENOGY is a Chinese Rebadging Component Company with a huge marketing dept. They have offices in USA as they sell a LOT to Gullibles and their support/tech depts are a nightmare which is well documented by hoards of folks...

 

[Skip]

With a Classic, you can use their SmartShunt "WizBangJr" which is not bad once setup properly, sadly it is only 1 Decimal Point Accurate whereas 2 decimal is better when dealing with any Lithium Based chemistry.

Product - MidNite Solar

MidNite Solar Product Page.

www.midnitesolar.com

RENOGY is a Chinese Rebadging Component Company with a huge marketing dept. They have offices in USA as they sell a LOT to Gullibles and their support/tech depts are a nightmare which is well documented by hoards of folks...

Looks like the Whiz Bang Jr is the best overall solution. I like my Classic 150. The WBJ will eliminate all the guess work in trying to understand the state of my battery bank. I had seen this product in the past, but never understood what it was for. Wish I had known earlier as it would have saved me a lot of grief. I like that I can simply "plug it in" on my e-panel and don't have to worry about cutting in another device on a battery cable and running more wires.
Thanks

 

[Steve_S]

It is quite a simple thing and works well PLUS you can use EndAmps (brought to you by the wizbang) for your charging profile.
Have a look at how mine is setup/

Link in case you cannot see signatures.

My DIY off-grid Cabin setup in Ontario Canada (24vdc-120vac)

NOTICE: UPDATING November 2022 WIP Good Day everyone, Overview: There is no grid here, no phone lines, cell is so-so (to be polite) so satellite internet is here (not bad actually). I do not have 240VAC, this is a 120V system only. My Solar Panels are mounted separately from my Powerhouse...

diysolarforum.com

 

[Skip]

It is quite a simple thing and works well PLUS you can use EndAmps (brought to you by the wizbang) for your charging profile.
Have a look at how mine is setup/

Link in case you cannot see signatures.

My DIY off-grid Cabin setup in Ontario Canada (24vdc-120vac)

NOTICE: UPDATING November 2022 WIP Good Day everyone, Overview: There is no grid here, no phone lines, cell is so-so (to be polite) so satellite internet is here (not bad actually). I do not have 240VAC, this is a 120V system only. My Solar Panels are mounted separately from my Powerhouse...

diysolarforum.com

Wow. You have a LOT of Ah's. My lead acid (which are going away) only has 360 Ah (rated) times 50% at best - which I never really got since they were damaged by overcharging until the fourth tech support was able to find the problem with the inverter/charger temperature correction setting. I'm installing 200 Ah of LifePo with a view to doubling that as finances allow. I had considered increasing my AGM battery capacity, but glad I didn't since I don't have the charging capacity as it is with the high resistance of Lead Acid.
My home is really stingy on electricity. All my heating is carbon fuels (wood and propane). All lights are LED. The big loads are refer, freezer and well pump. After discovering the Peukert's Law Battery Life Calculator, I was finally able to understand what I can reasonably expect from a bank of batteries. Looking forward to the increased performance and lower charging requirements in the LifePo. They go live tomorrow on a full sun day.
I finally got the Midnite Classic PC software working and am ordering the Whiz Bang Jr. now.
Thanks for the help and feedback.

 

[Steve_S]

Wow. You have a LOT of Ah's. My lead acid (which are going away) only has 360 Ah (rated) times 50% at best - which I never really got since they were damaged by overcharging until the fourth tech support was able to find the problem with the inverter/charger temperature correction setting. I'm installing 200 Ah of LifePo with a view to doubling that as finances allow. I had considered increasing my AGM battery capacity, but glad I didn't since I don't have the charging capacity as it is with the high resistance of Lead Acid.
My home is really stingy on electricity. All my heating is carbon fuels (wood and propane). All lights are LED. The big loads are refer, freezer and well pump. After discovering the Peukert's Law Battery Life Calculator, I was finally able to understand what I can reasonably expect from a bank of batteries. Looking forward to the increased performance and lower charging requirements in the LifePo. They go live tomorrow on a full sun day.
I finally got the Midnite Classic PC software working and am ordering the Whiz Bang Jr. now.
Thanks for the help and feedback.

A point on Peukerts laws on Lithium, it is quite IRRELEVANT as it does not apply... That is a terribly dead horse topic, beaten, killed, buried, dug up & beaten more, reburied and dug up again for another go, several times.

FYI, Midnite uses a Deltec 500A/50mv shunt which are very high quality.
BTW: Your EndAmps is 5A. (100AH X 0.05=5A) It is not additive either.

Again, not knowing if you can see signatures, here's another link that will help you along....
Steve_S-Tech: My Final Config for Midnite Classic SCC & JKBMS' w/ Large Bank (works amazingly well) Includes Charge Profile & BMS Config

 

[Skip]

A point on Peukerts laws on Lithium, it is quite IRRELEVANT as it does not apply... That is a terribly dead horse topic, beaten, killed, buried, dug up & beaten more, reburied and dug up again for another go, several times.

FYI, Midnite uses a Deltec 500A/50mv shunt which are very high quality.
BTW: Your EndAmps is 5A. (100AH X 0.05=5A) It is not additive either.

Again, not knowing if you can see signatures, here's another link that will help you along....
Steve_S-Tech: My Final Config for Midnite Classic SCC & JKBMS' w/ Large Bank (works amazingly well) Includes Charge Profile & BMS Config

I was using Peukert's law to evaluate my Lead Acid. That's what pushed me over the edge to dump them for LifePo.

 

[Steve_S]

I was using Peukert's law to evaluate my Lead Acid. That's what pushed me over the edge to dump them for LifePo.

I started with Heavy Lead (Rolls Surette S550's) and when they got tired I started my journey to LFP. When I first setup my offgrid system anything Lithium Based was still in "Ludicrous Cost" mode and many of the current products were not available (Not even Victron products).

 

[Skip]

I was using Peukert's law to evaluate my Lead Acid. That's what pushed me over the edge to dump them for LifePo.

By the way, my Midnite Solar e-panel which mates with my Conext SW came with the Midnite Solar 500A shunt installed for the battery negative cable. It even has a negative battery bus bar mounted on it too. https://www.midnitesolar.com/productPhoto.php?product_ID=569&productCat_ID=45&sortOrder=4&act=p
Very cool.
I'll just have to shut the entire system down and pull the shunt out of the cabinet to access the mounting screws since I don't have a right angle screwdriver. That cabinet is getting crowded.

 

[Delphinus]

I was using Peukert's law to evaluate my Lead Acid. That's what pushed me over the edge to dump them for LifePo.

If you are short in energy you can use both lead a LifePo4, I'm doing it for the last month without problems, after deplete LiFe, BMS shut down discharge and AGM keep the system running, even today I shutdown my LiFe to install number 3 and, AGM kept the system.
I run my Life at 90% so never overcharge AGM.

 

[Skip]

If you are short in energy you can use both lead a LifePo4, I'm doing it for the last month without problems, after deplete LiFe, BMS shut down discharge and AGM keep the system running, even today I shutdown my LiFe to install number 3 and, AGM kept the system.
I run my Life at 90% so never overcharge AGM.

do you have a second charge controller or a switch to go between the two different batteries?

 

[Delphinus]

do you have a second charge controller or a switch to go between the two different batteries?

I only have a charger, in my case is an Deye Hybrid Interver, having been using lead and life for the past month, I know that AGM never get fully charged because I do a cycle per day but it works.

My, concerne is summer when I will have over production and LiFe got full charged, then inverter will put more than 0.1C charging but since I won't need extra energy in summer I will disconnect the fuses of AGM.

P.S. I balance at 3.4V but since I install a new battery I'm doing tests.

This my config:

 

[Steve_S]

View attachment 130280

Change your Power Off Voltage from 3.450 to 2.600.
If it powers off @ 2.450 you won't be able to restart the BMS to charge it, you never want any cell to go below 2.5 and you certainly want a bit left to restart the BMS and not have it shutoff immediately for recharging.

I'd also suggest you don't short change yourself. Set the UVP(V) to 2.900 and UVPR(V) to 2.950 or 3.000

 

[Delphinus]

Change your Power Off Voltage from 3.450 to 2.600.
If it powers off @ 2.450 you won't be able to restart the BMS to charge it, you never want any cell to go below 2.5 and you certainly want a bit left to restart the BMS and not have it shutoff immediately for recharging.

I'd also suggest you don't short change yourself. Set the UVP(V) to 2.900 and UVPR(V) to 2.950 or 3.000

I assume from 3.450 to 2.600 mean 2.45 to 2.600, thanks I didn't know that, will change all BMS to 2.6V

I had the UVP at 3.0 and UVPR at 3.05 and don't want to go down than that, because now I have more energy I increase the lower values for testing to 3.080 and 3.13V.

Haven't analyse LF280K values but with LF105 going from 3.65 to 2.5 to a more conservative value the difference was 7Ah, my plan in summer is to cycle at 85% capacity.

With 90% capacity LF105 will do 2000 cycles, and at 95% only 750 cycles, I know this EVE graph is at 1C and we won't use it but I don't trust hypothetical values without historically proven data so my reference will be that the cells will do 80% of the advertised cycles and I want to use them for 5 years.


Thanks for you post I'm new to this and your posts help me a lot, by my experience probably in some months I will agree with you