Steve_S-Tech: My Final Config for Midnite Classic SCC & JKBMS' w/ Large Bank (works amazingly well) Includes Charge Profile & BMS Config

[MrM1]

sure could use some help on my Midnite config. bulk and absorb seem to work fine. when I hit float under load, it fails to actually bring it up to appropriate float voltage. as soon as it hits absorb limit and into float, bank immediately goes to 26.8 and drops as if the Midnite is not even charging. clearly the Midnite is not seeing the load.

what's config'd wrong?

Are you using a Whiz Bang Jr? Seems to work well with a WBJ.

 

[x98myers7]

I'm considering a WBJ.... but not sure it's going to help.

So, Steve... basically what you're saying is what i'm experiencing is expected. I kinda knew that, but didn't want to admit it, lol. That's a bummer. that's an advantage to an aio system. my Growatt scc was able to see the load required and pull more power from solar to compensate. effectively, i'm now not realizing my battery bank capacity. once the midnite hits float mid-day, it's starts discharging and never goes back into bulk. UGH. not sure what to do. this is a huge bummer.

now seeing REBULK. need to dig. okay, so rebulk voltage was 8v. I'm going to set that to 26.4v and then drop absorb duration to 45mins and see what happens today. wondering what would happen if i set rebulk higher, like 26.5v. that should kick back to bulk at 85% capacity, right? then rerun the absorb/float cycle? i'll try and play with rebulk the next few days.

i'm guessing i need to have rebulk at 26.5v and the absorb duration around 30mins. that way it cycles between the charge modes more quickly. thoughts?

my load is two freezers and a refrigerator. so, there's a nearly constant 350-400w load on the system. 2kw array in michigan. CHINS lifepo4 batteries with internal BMS.

 

[Steve_S]

Well, I have a WizBangJr and let that handle the EndAmps, never tried without a WizBang on there... it is what makes the Midnite Smartshunt in combo with their Deltec 5001/40mv shunt.

 

[RayE]

JK BMS - What parameters is the SOC reset based on, is it ovpr/uvpr OR ovpt/uvpt?

 

[aentrop]

JK BMS - What parameters is the SOC reset based on, is it ovpr/uvpr OR ovpt/uvpt?

I am doing some testing right now and it looks like SOC resets as soon as one cell hits the OVP(V) value.

So I have mine set to 3.65v but my pack is well balanced and never went over 3.5v. So once my pack was charged it just hung around 92%-94% SOC.

Someone has said 2 charge cycles to get the SOC in sync, so next step i'm trying is some more charge cycles to see if anything triggers the SOC to bump to 100%. If not the next step I'll try is to run the V on up till I get to 3.65v.

Probably whats going to end up happening is me lowering my BMS OVP down to 3.5v permanently.

 

[Steve_S]

My packs reach 100% SOC and show it as such without hitting Over Volt Protection.

 

[aentrop]

My packs reach 100% SOC and show it as such without hitting Over Volt Protection.

Ok, I'll need to redo my testing. I went out of order last night out of impatience and triggered OVP. So far in my testing 100% of times that I have hit OVP limit my SOC and immediately bumped up to 100%. I am logging and monitoring all of the bms data thru Hoem Assistant so I can track everything and go back and compare notes on charge cycles.

I'll start over with 3.65v OVP setting and reset everything. I will charge the pack to max 13.8v (3.45 at the cells) and let it run thru a few cycles to see if I can get it to trigger 100% OVP without letting any of the cells ever cross over above 3.5v

Edit: Also, I don't quite understand the Total Charging Cycle Capacity entity just yet, that number seems to only increase... Maybe thats what it is supposed to do? I am not sure if this entity is being calculated by Home Assistant, or if this is being provided by the BMS directly.

For the record I am monitoring 4 JK-BMS's right now.
JK-BD4A8S4P (two of these in 4s config)
JK-BD6A20S10P (in 16s config)
JK-B1A20S15P (pending install, will be 16s config)
JK-B2A20S20P (in 16s config)

 

[aentrop]

MEDIA=[/MEDIA

I think most here know how to calculate SOC without a problem. This thread is not about calculating SOC, we already know the SOC based on how many watts we have put into or pulled out of the battery. We are trying to figure out how the BMS calculates what it thinks the SOC is, aka what algorithm it is using. This way we can have a better understanding of why it is not accurate sometimes, and possibly we can find a couple of small adjustments we can do to help it work better.

 

[Capt Bill]

You are Most Welcome my friend... Interesting coincidental timing eh.

I gave up on anything Midnite - quit their forum too..
Entering into EndStage of my Cancer now has redirected me a LOT as the end is visible and it's no joy.

Thanks, ... I just used this post do download a manual for my new JKBMS B2A24S20P ... just getting started on my DIY 48v 305 Ah build. First time on 48 volt and a JK BMS :+) Getting my Reference from you and this forum .... Also.. Recently got interested in how BMSs and possibly and EG4 3000 All In One ... get Remotely view and adjusted over an Internet Connection. I believe some folks are doing that for customers, and maybe there extra home(s)? /// ... While I am PC Computer Savy ... I am a newby in that Arena of my Curiousity; and fishing for clues of what to research for . Tahnks in Advance if anyone has comments o that :+)