Author Topic: Lithium battery charge profiles  (Read 22356 times)

mahendra

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Re: Lithium battery charge profiles
« Reply #135 on: January 04, 2016, 04:56:43 PM »

 can you elaborate a bit more boB?
1.5kw on Midnite classic 150(whizbang jr.) networked 0.660kw on classic lite 200 ,245ah 48v battery bank, Outback vfx3648

ClassicCrazy

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Re: Lithium battery charge profiles
« Reply #136 on: January 04, 2016, 05:51:58 PM »
From the Classic Manual

AUX 1 - Control Settings (12V @ 200Ma or Dry 1A Contact)
SOC % Low
This mode will set AUX1 to 0.0V according to the LOW % and HIGH % settings. HOLD (LOW) and
DELAY (HIGH) activation TIMES can be set in seconds. SOC %=HIGH=0V SOC %=LOW=12V
SOC % High
This Mode will set AUX1 to +12V according to the LOW % and HIGH % settings. HOLD (LOW) and
DELAY (HIGH) activation TIMES can be set in seconds. SOC %=HIGH=12V SOC %=LOW=0.0V
If the classic is set to do an auto-restart at 23:59 (midnight), the state of the AUX1 will be remembered
so it will return to the last state (+12V or OFF) after it resets and comes alive again.

So you can hook up a relay to AUX 1 to control whatever according to what the SOC is .
system one
Classic 150 , 20 Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

Cniemand

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    • My You tube Video about "Bottom Balancing" LIFEPO4 cells.
Re: Lithium battery charge profiles
« Reply #137 on: January 07, 2016, 03:30:31 PM »
I'm not sure it is inherently bad that Lithiums are at 100%SOC. Rather I feel it is more of a condition where you are dealing with the sharp jump in voltages due to the steep charge curve on the top and lower ends. Plus, not all cells will be the same capacity regardless of manufacturing dates/batches. Thus you find yourself dealing with over-charging some cells in the hopes of getting the others to 100%SOC.

LFP cells work quite well simply using the ENDAMP function. It brings them to what they consider to be fully charged without getting into dangerous sections of the charge curve.  LFP cells use 0.05C for their ENDAMPS. 100aH = 5a or 180aH = 9a (180*0.05=9)

For FLOAT (With the idea of having a full battery when the sun goes down) you need to use a voltage slightly above their resting voltage. In LFP cells that works out to 3.34v (resting). I chose to use 3.375v as it keeps them full while not being enough to slowly overcharge a cell throughout the day.

Whatever you do, stay away from EQUALIZE. No need to cook your cells.
OFF-GRID @ 8500FT : 2000 Watt Array : 8 - CS6P-250P ; VFX 3648 ; WBjr ; MN CL200 #6738 ; Firmware #2079  
48v LiFePo4 : 16 - CALB CA 100 aH in Series - 5 kWh ; No Active BMS - Bottom Balanced
Charging Parameters : Bulk - 55v, Absorb - 5 EndAmps @ 55v, Float - 54v or 3.375v per Cell : ZERO EQUALIZE

Cniemand

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Re: Lithium battery charge profiles
« Reply #138 on: January 07, 2016, 03:35:24 PM »
Added: I wouldn't trust the ENDAMP function (at face value) unless you are using a WBjr. The WBjr sees exactly what goes into the bank (Already calculating for background loads) so you get an accurate ENDAMP. Without it, as I had lived for a couple years without one, you have to add a few amps to the ENDAMP number to get a rough estimate. I figure that when everything is idle in the house it still consumes 2-3a, so I setup the ENDAMPS to be 8 rather than 5. Since purchasing the WBjr it is safe to bring it back to 5.

I also like having the WBjr because it allows you to fully use your system as soon as you wake up because you do not need to compensate for heavy background loads (possibly over-charging your LFP pack) as it knows what is going in/out of the bank.

In other words.... ME = Happy camper!
OFF-GRID @ 8500FT : 2000 Watt Array : 8 - CS6P-250P ; VFX 3648 ; WBjr ; MN CL200 #6738 ; Firmware #2079  
48v LiFePo4 : 16 - CALB CA 100 aH in Series - 5 kWh ; No Active BMS - Bottom Balanced
Charging Parameters : Bulk - 55v, Absorb - 5 EndAmps @ 55v, Float - 54v or 3.375v per Cell : ZERO EQUALIZE

aussiejohnny

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Re: Lithium battery charge profiles
« Reply #139 on: January 11, 2017, 11:06:36 AM »
Hello, sorry to kick this one off again. 
But are there any specific charge profiles to set the classic 200 for a 400ah lifepo4 battery bank?   Has anything changed in the past year in regards to how someone using lifep04 batteries has set their classic?
I nearly have my wiring all done, bar picking up my 16x100ah cells in the city next week (swapping them with 4 x 400ah cells i haven't used yet) and wiring them in. 

Thanks.

ClassicCrazy

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Re: Lithium battery charge profiles
« Reply #140 on: January 11, 2017, 01:25:13 PM »
Hello, sorry to kick this one off again. 
But are there any specific charge profiles to set the classic 200 for a 400ah lifepo4 battery bank?   Has anything changed in the past year in regards to how someone using lifep04 batteries has set their classic?
I nearly have my wiring all done, bar picking up my 16x100ah cells in the city next week (swapping them with 4 x 400ah cells i haven't used yet) and wiring them in. 

Thanks.

Are you planning on using bottom balancing ?
Are you going to have any kind of BMS protection ?
I would make sure you have something independent of the Classic to disconnect if voltage goes too low.

Larry
system one
Classic 150 , 20 Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie