New LiFePO4 installation charge parameters

[boB]

Muskoka,  I only wanted you to reduce the Absorb voltage momentarily to see if the cycling went away or if the current stayed higher.

I would like to verify my assumption that the BMS is turning ON and OFF where you have it set now.

It looks to me from your video as though a load ( the battery BMS ?) is turning OFF and ON and ON.

boB

[Muskoka]

Ya ok, your meaning with the new firmware I take it.

Thats why I had added that info, "something "wasn't happy until I lowered Absorb to 28.0v, when I had end amps on, but yes not new firmware testing.

Firmware updated for Classic and MNGP, programming done, ready for tomorrow.

[Muskoka]

Bob, if you want me to test a higher Absorb, give me a number. I left things on the default for Lithium, 28.2v when I did the mind meld. I'm ok testing there for the initial run, but would like to try higher at some point, provided the first run at 28.2v is a success. Guess I'll leave End Amps off.

[boB]

No, I wanted you to test with a temporary lower Absorb voltage with the present firmware in the Classic you have.  Before trying the newer software that is

After you have put the newer firmware into your Classic, then you can try it AS IS and higher voltage.

I have a feeling that the same thing is going to happen with the newer firmware after seeing your video though.

boB

[Muskoka]

Ah ok, by 3 in the afternoon the suns too far gone to do anything, this time of year.

And, like I said, I've already tested various lower Absorb voltages, but, End amps was on. So I'm not sure what lowering it today would have shown, proved, I've already tested that, and it didn't go so well.

[ClassicCrazy]

If it was me, I would open that battery and put in a proper active bms that can be programmed and monitored.
Larry

Larry, I'd love to, but I still have a 1.5 week window in which to return the battery for a full refund. I can't be messing it up.

Send it back for the refund  and get a battery with internals you can monitor. It would avoid this guessing game now and in the future.
Larry

[boB]

Ah ok, by 3 in the afternoon the suns too far gone to do anything, this time of year.

And, like I said, I've already tested various lower Absorb voltages, but, End amps was on. So I'm not sure what lowering it today would have shown, proved, I've already tested that, and it didn't go so well.

OK, so when you went to lower Absorb voltages, did it do the same thing as it did in your video ?

Your video really does indicate a load turning on and off to me...  However, a load that your PV array is capable of supporting to a voltage close to the Absorb voltage.   Either that, or that battery plus its BMS is very strange.

I checked out the link for the battery and I like it !  (I think)

boB

[Muskoka]

Yes, it did the same, but was more erratic. The voltage pikes were greater, enough to trip the inverter. And it cycled through the modes quicker I'd say.

Again, todays absorb voltage of 28.6v was the highest I've tried so far, and it didn't trip the inverter, was less erratic with the cycling, but End Amps was off. That is the only difference. There is no loads, nothing. This is basically a bare charge controller, and a battery, that's it. I've said all this before, as detailed as I can, sorry but I'm getting pretty frustrated repeating myself. I'm definitely leaning towards Larry's suggestion, and just sending the battery back. But, I will really be upset if I buy another, and end up right back were I am now.

Larry, where am I going to get a off the shelf battery that has a accessible BMS, one that I can program. I need a battery now, not some diy that I have to build. Maybe at some point, but not now, this is my main system, I can't do without it. Maybe there's a off the shelf battery that has BT capability, I haven't come across one, and likely not one I could afford.

I'm not looking forward to doing this cause I have to tear my systems apart, but I think it's time to remove the Classic, put the Tristar in its place, and see what happens. Then we'll know if it's the Classic, or the batteries BMS.

[boB]

I think trying the other controller is a great idea.

But first,  I don't suppose you happen to have a DC clamp on ammeter do you ?

A Whizbang Junior should also work.

What I would like to know is the current going into and out of the battery itself when the Classic shows Absorb current and BULK MPPT current are changing..  Would be nice to know how much current for sure is going to who.  When the voltage and current is moving.  It stays constant long enough to measure I'm sure.

boB

[Muskoka]

Yes, I do have a clamp on meter.

[boB]

Yes, I do have a clamp on meter.

YAY !!   Can you put it around the battery positive or negative on the battery terminals at least on the battery side of the cable ?

Second question would be, can you read the camp meter and the Classic screen at the same time ?

That would work.  It will also show if it is charging or discharging.

It will also help verify what is being displayed on the MNGP  is at least in the ball park.

[Muskoka]

I just finished removing the Classic, and installing the Tristar. See how that goes first. If the Tristar has problems, the battery goes back.

[boB]

Great !  Can't wait to hear what happens.

I was going to say, next time (if there is a next time) you re-connect the Classic, try changing the MPPT MODE from  SOLAR  to Legacy P&O  mode.  It tracks the maximum power point slower and may tend to produce way less spikes ?  Maybe  ?

boB

[ClassicCrazy]

Some models to consider  Signature Solar,  Orient Power, or SOK - I think they have them in stock in usa but you would have to check . The models I am thinking of have bms that either has display and also software or connect to app that shows discharge mosfet, charge mosfet, and each individual cell voltage.

https://signaturesolar.com/eg4-ll-lithium-battery-v2-24v-200ah-server-rack-battery/
https://www.us.sokbattery.com/product-page/sokess-24v-100ah-lifepo4-battery
https://www.opsolarbattery.com/product-page/100AhServerRackBattery

Larry

[Muskoka]

Update: Full sun day, same issues with the Tristar, battery is being returned. Was nearing the Absorb voltage, I set 28.8v, low end of recommendation from supplier. The Tristar, like the Classic, went to Absorb a few 1/10's at least early, battery voltage was around 28.5v-28.6v, suddenly the inverter tripped, voltage bouncing around, so I shut it all down. I had seen what I needed to see.