Re: Using charger (in my case: iMax B6) as power supply

[Paweł Si]

2015-10-11 18:12 GMT+02:00 Valentin Py <valen...@gmail.com>:

Hi!

Would it be technically feasible to add a function in the firmware to be able to use the charger as a programmable power supply ?

I don't know how does the charger exactly work, but I suppose it's a simple switched-mode power supply with a battery charging algorithm that set voltage or current.

If you think it's not a really big deal to add it, I will try to find a moment to program that.

 

Great! Please see:

https://github.com/stawel/cheali-charger/tree/powerSupply

a lot needs to be done yet, especially a new PID is needed.

Best Regards,

Paweł

[Igon]

This version definitely can work with resistive loads :)

[Igon]

https://groups.google.com/d/msg/cheali-charger/EuhUAoyecso/Doj3F2fBEgAJ

Hardware voltage feedback was done for my new charger - T610

I did not find 240k at the moment, so it works with 180k

1A ~ 2V in calibration

Modification of SMPS_PID_200W.cpp allows me to play with all charger function except calibration

2x AA NiMH at 1/3C

Charger needs some light load for discharging capacitor or an output voltage decreasing will be extremelly slow

btw Program::dischargeOutputCapacitor() knocking off small protected LiPO's at powerfull chargers.. 5A is a bit too much

[Igon]

Load disconnection 1A --> 0A  &  5A --> 0A  at 10V

Top curve - input voltage (noisy - ground not connected)

Bottom curve - output voltage

Load connection 0A --> 1A  &  0A --> 5A  at 10V

Load disconnection and connection at 1A, 2V

Load disconnection and connection at 1A, 20V

[Paweł Si]

2016-03-04 23:57 GMT+01:00 Igon <igg...@gmail.com>:

Load disconnection 1A --> 0A  &  5A --> 0A  at 10V

Top curve - input voltage (noisy - ground not connected)

Bottom curve - output voltage

your mod looks quit simple, I like it.

I wonder, what is considered as a acceptable transient response time and voltage,

for a regular power supply?

 

btw Program::dischargeOutputCapacitor() knocking off small protected LiPO's at powerfull chargers.. 5A is a bit too much

you are right, I changed it to 1A.

[Igon]

charger's transient can be redused to
+1000mV; -1400mV at 10V 5A
+150mV; -210mV at 2V 1A
with 180k resistor connected in series with C11

So, "laptop" power adaptors: 12v, 5a 2.4 Ohm load

with short wire soldered to PCB (~10cm)
+140~170mV
-160~200mV

original 12V power cords, at output connectors
+600~750mV
-600~800mV

50W charger easily jumps to 10V from 2V 1A load
and drops from 10V to the ground at 10 Ohm load connection