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z-zk-z avatar image
z-zk-z asked

MPPT 100/20 very HOT, case @ 150 degree Fahrenheit (65 Celsius)

20230215-150452.jpg20230215-150414.jpgMy SmartSolar charger MPPT 100/20 48V manual says to install it on a wall (vertical) and I have it on a flat surface (horizontal). It has been working fine but it is running very HOT (case @ 150-degree Fahrenheit (65 Celsius)). I added a steel plate under it (where its heatsink is located) to help spread the heat and I am worry that it will fail in future because of too much heat. 1st question: should I move it and relocate it on a wall (vertical position)? Would that really help? It is running at its full rating of 20 amps to charge 48-volt batteries and feed a load but the duration at 20 Amps is probably around two hours each day. 2nd question: Should I purchase a larger MPPT (size???)? Please see photos for my setup

MPPT SmartSolar
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4 Answers
wkirby avatar image
wkirby answered ·

Vertical mounting will help a lot. Natural convection currents will be encouraged to flow past the vertical fins of the heatsink which will greatly improve the cooling performance. If vertical mounting will be difficult, then you'd have to resort to forced cooling with a fan.
Running it at full chat for a couple of hours will get some heat into it, not really a problem if the cooling is sufficient.
Whether or not you need a larger MPPT depends upon how much PV power is at the input. It's difficult to provide an answer without knowing that.

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snoobler avatar image
snoobler answered ·

That's a crapton of battery for a 20A MPPT.

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Michelle Konzack avatar image Michelle Konzack commented ·

There is no problem with it.


I have also 2940Ah and only a SmartSolar MPPT 150/70-Tr VE.Can because I need Autonomie over longer period, but the 1860Wp Solarpanels delivered more then twice the energy I needed.


Hence I had energy for 14 days total darkness.


Now, when mostly all is installed and running (energy consumption is nearly the Harvesting) I add an additional SmartSolar MPPT 250/100-Tr VE.Can (2460Wp) to it and produce up to 45kWh per day which is roughly 3 times more then the Consumption.


For next year I schedule to double the Batteries. But for this I have to get first my BMS running (yes, I will monitor and balance the 2V Lead Acid cells and have to get my Cortex M0 running with the ColorControl GX and Cerbo GX).


If it works, maybe Victron is interested in taking over the product.


Have a nice day

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z-zk-z avatar image
z-zk-z answered ·

I have two 445 watt solar panels in series (and added two additional panels in series and connected them in parallel with the first set in order provide the maximum current to the mppt charger) feeding the 100/20. The solar panels voltage is about 80 volts and the three EG4-LL batteries discharge to about 93% overnight. It takes the 100/20 mppt less than one hour to charge the three batteries back to 100% by providing 20Amps to the batteries and feeding the load. It gets very hot because it is running at 20 Amps. I am thinking to purchase a Victron 150/45 smartsolar mppt but that will probably get hot for providing 45 amps to the batteries.

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nickdb avatar image nickdb ♦♦ commented ·

Using a shunt as a busbar. Completely inconsistent use of cable colouring to differentiate between - and +. Exposed cable at lugs.

I would clean all that up and get some proper busbars, or for the batteries just use the spare terminals for stacking as intended.

Your’re likely to introduce heat and loss with less than optimal connections.

Any mppt run at max for sustained periods is going to get properly hot.

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Alexandra avatar image
Alexandra answered ·

@z_zk_z

Vertical mounting yes. It is clearly stated in the manual.

You are within opertaing tempertaures, see the tech specs. You will be seriously derating at 65°C though

You will also read in the tech specs it has over temperature shutdown for its own protection. But obviously you dont want repeats of this. Electronics really don't like heat so do what is humanly possible to reduce it.

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