Programming a Tracer charge controller for LiFePo batteries

[wrybread]

I'm helping a friend wire up some LFP batteries, I"m really loving these 280ah cells.



(Coming soon: lots of tidying of the wires, ha. And he insisted on mounting the batteries there above the water tank, I hope it's ok longterm. He says he's never had any moisture there.)

I donated my old Tracer 40 amp charge controller to the cause, and programming it was a bit more involved than I expected. I was expecting to select battery type "LFP", but it looks like I have to choose "user" and put in the parameters manually.

I found Battle Borne's instructions and used those as a starting point:

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battlebornbatteries.com

They recommend:

Over Voltage Disconnect 14.7 V
Charging Limit Voltage 14.6 V
Over Voltage Reconnect 14.6 V
Equalize Charging Voltage shut off or 14.4 V
Boost Charging Voltage 14.6 V
Float Charging Voltage 13.6 V
Boost Reconnect 13.3 V
Low Voltage Reconnect 10
Under Voltage Warning Reconnect Voltage 11.5
Under Voltage Warning 11.5
Low Voltage Disconnect 11.0
Discharging Limit Voltage 10.5
Equalize Duration 0 or set as low as possible
Boost Duration 180 minutes

I had to set low voltage reconnect to 11.1 (instead of 10). Anything lower got an error. And equal charge = 14.6 (14.4 got an error)

Thoughts on these parameters?

Using a JBD 4s BMS if that's a factor, and we have three 260-watt 72-cell panels.

Programming it through the MT50 box since we don't have a cable, though I could make one if we need one.

 

[sunshine_eggo]

boost to 14.4V. 14.6V requires absolutely perfect balance.
float to 13.5V
Boost duration 30 minutes

 

[Tim Tim]

If you buy the bluetooth dongle you can download the app for your phone and it has a dedicated LiFePO4 profile.

 

[mikefitz]

Lower the boost voltage to 14.2, may need lower if cells are not well balanced. Set equalisation volts same as boost and equalisation time to 10 minutes, ( equalisation is not needed for lithium but values need to be set as it cannot be disabled).
Low and high disconnect/connect, warnings, discharge limit, only control the load outputs of the controller, ( that you are not using). These have no effect on battery charging.
The peramerers that control charging are: boost voltage and duration, float voltage, boost reconnect.
I use 14.0 boost, 13.4 float, boost duration 15 minutes, where the charge current is 0.2C or lower.

Hope there is a suitable 'master' fuse at the battery positive.

Mike

 

[Northernchateau]

I have a suggestion based on what I see in the pic. It looks like you have a black 12ga or 10 ga wire to your BMS.
That's fine but make sure you have a fuse or breaker in the system that goes along with the wire size.
It's a lot easier to change a fuse or re-set a break vs something melting or catching fire.

 

[wrybread]

Thank you! And @Northernchateau, that 8ga wire and is temporary, we ran out of wire lugs so couldn't trim that or make another. There will be two 8ga wires in final form that are a bit shorter than that. I hope 8ga is beefy enough.

As far as fuses, he made that box (the 2x4's) without leaving enough room for the fuse on the positive terminal so I had to put it on the fusebox input, for now at least. If you look at the bottom of the blade fusebox under the charge controller you can barely see this guy:



I much prefer to put that on the battery positive of course and hopefully he makes a bit of a change to his battery box, but I don't see a huge disadvantage to putting it there.