PL11 Fan slow speed question

[sjoram]

Not an issue but perhaps somebody can help. I have the PL11 version modded to 14.4V and worked great for programming my BMW and maps on my Ducato!
I wanted to use it to charge my van LifePos and while it ramps up to 70Amps and 14.3V it shuts down after 10-15 seconds. Also, the fan does not ramp up to screehing or run at all really as I would expect. I assume the thing is shutting down thermally but my question is if the modifications are affecting the fan control in anyway? I may just leave it and buy another unit to fast charge the batteries but if it is a simple thing I'll happily change something in the HP.

Any insight welcome....

[reymond555]

I also have a modified PL11 running at 14.25V; I even use it to power vehicles. You should check the thermistor(s). These are located near the MOSFET heatsink. You can check them with a soldering iron at a high temperature; the fan should spin extremely fast. Another thing to note is that the fan has four lines: GND, VCC, TACH, and PWM. If one of these fails, the power supply will shut down a few seconds after being turned on. Now, if your power supply works fine without a load and stays on for a while, then it would be worth checking thoroughly. If I remember correctly, removing a thermistor will cause it to shut down because it won't detect it. You could try restoring the firmware and returning the system to its original state. Also, if you've moved or the power supply has SMD potentiometers on the control board, return them to their original settings. As I said, I have this power supply modified in both voltage and firmware, and it works perfectly. When the temperature starts to rise, the fan speeds up, and vice versa. Therefore, my recommendation is to thoroughly check these components and, if possible, try another fan. They often have some issues like these. Greetings to everyone from Costa Rica.

[sjoram]

Many thanks Reymond! My fan does not ramp up. I did nothing other than solder resistors in to change the OP voltage protection. I didn't do any firmware changes or anything else. I'll open it up over the weekend and have a proper look now I think I know what to look for!!!! I might be back to you :)

[sjoram]

OK so I have just opened it up. I can see nothing wrong. The fan is spinning fine. However, when I load up the thing at all like with a car bulb drawing 5Amps the fan ramps down and not up! It doesn't stop but just slows down. Very odd :(