Very Hot Charge Controller

[Easyyokefilms]

I have a 40A MPPT HQST charge controller. Got it during raining season so it wasnt really getting full power from my Panels. Was pushing out about 15A to my 12v 200ah battery. Now raining season is off and it has started outputting about 38, 39A. Meaning it is working at full power. I noticed it was quite warm to the touch from the front, then I touched it from the back and this guy burnt my hand. It was extremely hot. Is this how SCC works when they work at maximum power? Is it supposed to be that hot? I was even planning to over panel for when rain starts again but with the way the controller is currently very hot, now that there is full sunlight, I am afraid to do it. Is this the normal way SCC get very hot when they are outputting peak power? And can I still overpanel the Charge controller. Was planning to add one more panel to it for days there isnt enough sun when I usually get 15A which is too small for my battery.

 

[Mattb4]

Yes it can get hot while outputting max current. If your SCC is passive cooling (no fan) than it needs to be mounted in a open shaded location with good air flow. If your ambient temperatures are hot and humid this is going to be more of a problem.

 

[AshleyL]

........check your BMS if there is any OVP triggered.
Many years ago, when I was still a newbie in lifepo4, I set the charging voltage at 14V for my 4 cells.
The BMS was so hot and even melted a bit.
It turned out that the cell was unbalanced/runner and it triggered BMS OVP. So..........where the rest of the power go? Into the solar charge controller itself......

EDIT:
Plugged in an active balancer with auto trigger at 13.6v via a relay and start charging at 13.4v and slowly increase it 0.1V up to 13.8v for the balancer to work its magic. Problem solved and there is no longer any serious heating on my charge controller.

 

[Easyyokefilms]

Yes it can get hot while outputting max current. If your SCC is passive cooling (no fan) than it needs to be mounted in a open shaded location with good air flow. If your ambient temperatures are hot and humid this is going to be more of a problem.

Can I work a fan for it or something. It doesnt have a fan and my ambient temperature at the moment is around 32degree Celcius(89F).

 

[Easyyokefilms]

There is no

........check your BMS if there is any OVP triggered.
Many years ago, when I was still a newbie in lifepo4, I set the charging voltage at 14V for my 4 cells.
The BMS was so hot and even melted a bit.
It turned out that the cell was unbalanced/runner and it triggered BMS OVP. So..........where the rest of the power go? Into the solar charge controller itself......

EDIT:
Plugged in an active balancer with auto trigger at 13.6v via a relay and start charging at 13.4v and slowly increase it 0.1V up to 13.8v for the balancer to work its magic. Problem solved and there is no longer any serious heating on my charge controlle

There is no OVP triggered. My cells are balanced

 

[AshleyL]

There is no

There is no OVP triggered. My cells are balanced

Good to hear that. Guess it is just the charge controller mosfet normal heat.

 

[Q-Dog]

Does your MPPT have over temperature protection?

 

[Mattb4]

Can I work a fan for it or something. It doesnt have a fan and my ambient temperature at the moment is around 32degree Celcius(89F).

Might be able to rig up a 12vDC computer fan to help cool it with ducting to the back side. Not sure if your SCC has load terminals which might help with control.

 

[Easyyokefilms]

Might be able to rig up a 12vDC computer fan to help cool it with ducting to the back side. Not sure if your SCC has load terminals which might help with control.

Yes, it has a load terminal. So I can rig up the fan to the load terminal, right?

 

[Easyyokefilms]

Does your MPPT have over temperature protection?

I dont know what that is. But I know it comes with a temperature probe for preventing low temperature charging

 

[AT1(AW)]

I had the same problem. My SCC is mounted on a piece of plywood right above my batts. I cut out a 3" hole and mounted a 3" 12v PC cooling fan behind the SCC, and hooked it up to my batts. The positive goes thru a 40°C temperature switch so it only comes on when the SCC gets hot, and shuts of when it cools down. Or as Mattb4 suggested the load out from your SCC, I personally am not a fan of that output, and have mine shut off.

 

[Rednecktek]

Yes, it has a load terminal. So I can rig up the fan to the load terminal, right?

Yes, you can just wire it right to the load terminals. For a more advanced project, you can wire a simple thermostat into it so it's not running all winter long.

 

[wme]

Flat mount or vertical mount. Air flow ya know.