LifePo4 Charging

Started by steven_ucf, November 03, 2020, 09:28:11 AM

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ClassicCrazy

Quote from: Steve_S on December 20, 2020, 04:04:42 AM


It would be nice if the WizBangJr had voltage profiles for different chemistries.

There are 3rd Party monitors which can provide more accurate SOC.  Several Models below, some with Shunts, others with Pickups.  *Search part number on Amazon/EBay, several vendors carry them.
https://peacefair.en.made-in-china.com/product-group/yeKnbFSoPrWd/DC-Electric-Energy-meter-catalog-1.html

Steve ,
I don't get what you mean by the SOC not working for different battery types ?
The Whizbang is just counting amps in and out and voltage doesn't matter to it right -  so what would be different ?

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

Bob D

Quote from: boB on December 19, 2020, 11:19:19 PM

The Classic charges Li batteries just fine.  You will have to set it properly to work with your batteries.

If your Li battery's BMS has an output to tell the charge controller that it is charged, the Classic's AUX2 has an input that is just for that function.



Gonna use AUX2 this way - does anyone know the impedance?
And is it safe to use 24 volts?
Classic 150, Magnum 4024, 12-215W panels, 12-85-13 forktruck battery

boB

Quote from: Bob D on December 20, 2020, 10:15:29 PM
Quote from: boB on December 19, 2020, 11:19:19 PM

The Classic charges Li batteries just fine.  You will have to set it properly to work with your batteries.

If your Li battery's BMS has an output to tell the charge controller that it is charged, the Classic's AUX2 has an input that is just for that function.



Gonna use AUX2 this way - does anyone know the impedance?
And is it safe to use 24 volts?


Well, Aux 2 input it designed to work up to around 17 or 18V as I remember.   It is 10K Ohms into a 3V Zener inside.

But recalculating, that 10K Ohms hits a 3V Zener so at say, 25V input to Aux 2, that would be  I = (25V-3V) / 10K = 2.2 mA

The resistor is a SMD and would have to dissipate around 2.2mA X 22V = 48 mW.

I would add another 10K Ohms maybe just to play it safe.   The input threshold for a high or a "1"  is around 5V as I remember but might be lower actually.





K7IQ 🌛  He/She/Me

Steve_S

Here is a chart for LiFePO4, other chemistries are different
WizBang is reporting 26.3V at 96% but that is 3.287 per cell.

Bob D


Well, Aux 2 input it designed to work up to around 17 or 18V as I remember.   It is 10K Ohms into a 3V Zener inside.

But recalculating, that 10K Ohms hits a 3V Zener so at say, 25V input to Aux 2, that would be  I = (25V-3V) / 10K = 2.2 mA

The resistor is a SMD and would have to dissipate around 2.2mA X 22V = 48 mW.

I would add another 10K Ohms maybe just to play it safe.   The input threshold for a high or a "1"  is around 5V as I remember but might be lower actually.
[/quote]

Given that the 24 volts is nominal and will be somewhat higher, it is probably best to use a lower voltage.
Picking 12 volts, and using your calc, the input would be 0.9ma. If I put a 10K and 40K resistor in series, and grounded the 40K, there would be 12V at the junction, assuming the 0.9 ma is correct. This setup also has the benefit of pulling AUX to ground when the 24V is removed.
Since the calcs might not be accurate, using a couple of 50K trm pots would allow tuning at setup.
Does this make sense?
Classic 150, Magnum 4024, 12-215W panels, 12-85-13 forktruck battery

australsolarier

steve_s
voltages on a lifepo4 to figure SOC does not mean very much. unless you want to stop drawing power and let the battery settle in for an hour or so.
also 3.65V is rather on the destructive end. 3.5V is now the generally accepted charging V. and keep in mind when charging towards the end some cells might be higher than others.

ClassicCrazy

Quote from: Steve_S on December 21, 2020, 03:28:36 AM
Here is a chart for LiFePO4, other chemistries are different
WizBang is reporting 26.3V at 96% but that is 3.287 per cell.

The Classic with Whizbang does not calculate SOC based on voltage. It does it based on how many amps go in and out of the battery compared to what was programmed in for the batteries total AH capacity .

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

boB


Here is a video with the Classic and Lithium batteries...

https://youtu.be/YsE1JPGg7Co

K7IQ 🌛  He/She/Me

dapdan

Vic,

No lighting strikes recently and you are correct I am in the Caribbean, Barbados to be precise. I have another classic workinig just fine at the same location. The classic shows around 41v when no input breaker is off.

Thanks