Battery EQ and BMS discussion.

[offgridQLD]

This overhead pic gives some better Idea of how the PV is facing and distance. (southern hemisphere to ) Guessing it was taken about 1:00pm or so by the shadows but just a guess.



Kurt

[offgridQLD]

Hmm.... I'm kind of over worrying about what others want to do with there own lithium cells. Mine power my house 24/7 and are fine. I treat them as  I have many other smaller lifpo4 cells from EV projects that are going on 8 years old and are still all considered healthy  So I'm happy with how I am managing them.

I don't fully charge my cells I have a conservation upper limit. As mentioned absorb voltage set points and a CC with tapering current I'm lucky to have 1 or 2 amps going into my bank for a cell level board to deal with. Again I don't use the boards to balance.

You don't need to be balancing all the time a little bit if trimming by hand one or two times a year works. Not worth getting carried away over.

You always have to use some electronics to call the shots. Inverter LVD, charge controller set points, External contractors LVD, HVD. you name it there isn't a situation where a cell can be connected to a charger or a load without having some kind of electronics to keep things under control. Electronics are way more reliable than trusting a human to to it all the time.

Yes I intervene on my automated system to make it work more in the scope I like to work my bank (I could have the set points adjusted down a little on the cell boards to meet my liking)  but even as is if I got run over by a bus then the electronics have my back.

As it is its kind of like having a overload breaker on a electric chop saw if you stall the motor it will cut the power befror it burns out. Though how I am operating now it taking my finger off the trigger when I first hear the motor load up to much. So solving issues befor they come up by human intervention. But if I got lazy or was distracted the overload breaker has by back.


How often do you run your bank all the way down to the bottom knee to check its still in balance at the bottom? and when you do do you have to shut your house system (inverter) down while doing so? I would say you have to be down a lot more that 80 discharged to bottom balance. At 20% SOC your voltage is still in the stiff flat section of the voltage curve.

Kurt

[australsolarier]

i just added voltmeters to each individual cell in the 12V system
intend to add it to the 48v system too

[offgridQLD]

For some reason the 4 red meters reminds me of the dash of the car in back to the future




Kurt

[zoneblue]

Theres electronics and then theres electronics.  Do i trust chinese made inverters, no i dont. Do i trust unbranded dinky, unprotected, balance boards that defy all the conventional wisdome about cable protection and fusing, not even close. Do i trust quality top of the line gear with a long industry track record, and independent third party certification testing, of course i do. Of the 10s of thousands of Midnite charge controllers ever produced, theres only been a single instance to my knowledge of one failing short circuit. So until a BMS is made by someone of midnites calibre, count me out.

[offgridQLD]

My cells boards are from a local Australian company and have been in operation for years in many aplications. Not a chinese rubbish ebay thing.

that said yes there are some things that are not ideal that given the chance I would change about them.

Two friends of mine have designed and built there own BMS and cell boards that use fiber optic cable for the interconnects between boards. So no issue with high shorts or the like.

They used fiber optics as they were building the BMS and cells boards for a  720v DC home built electric car with over 218 cells to balance and monitor. They are now marketing it for stationary storage applications. If I hadn't already purchased my unit I would have gone with it.  It ticks all the boxes that I dot like about my unit.



Kurt

[Westbranch]

Kurt, I just get a time out error from GitHub.io   

[BobWhite]

My cells boards are from a local Australian company and have been in operation for years in many aplications. Not a chinese rubbish ebay thing.

that said yes there are some things that are not ideal that given the chance I would change about them.

Two friends of mine have designed and built there own BMS and cell boards that use fiber optic cable for the interconnects between boards. So no issue with high shorts or the like.

They used fiber optics as they were building the BMS and cells boards for a  720v DC home built electric car with over 218 cells to balance and monitor. They are now marketing it for stationary storage applications. If I hadn't already purchased my unit I would have gone with it.  It ticks all the boxes that I dot like about my unit.

http://dkeenan7.github.io/LyteFyba/

Kurt

Kurt, I just get a time out error from GitHub.io   

me also?

[BobWhite]

Try this link then its there forum thread on the BMS http://forums.aeva.asn.au/weber-coulombs-lytefyba-bms_topic4302.html

Kurt

nada, hmm not getting threw. 

walt

[BobWhite]

Not sure whats going on I cant seem to link to it. I can see the page but if I link to it on this forum it wont work.

Kurt

At least you tried.   
Walt

[offgridQLD]

Try typing in LyteFyba bms into google

Kurt

[BobWhite]

Try typing in LyteFyba bms into google

Kurt

score!  thank you Kurt, ill read into it!   
Walt

[offgridQLD]

Ok I think this thread has drifted way off topic and is being moderated.

Kurt

[Westbranch]

the second link wanted a username and P/W..

third one is all up to date..

tks

[Resthome]

Try this link then its there forum thread on the BMS http://forums.aeva.asn.au/weber-coulombs-lytefyba-bms_topic4302.html

Kurt

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