question

shivadas avatar image
shivadas asked

MPPT 100/20 vs 150/45 functionality: temperature sensor, relay?

Hi, I'm new to all this and am trying to set up my system.

Most likely I will be installing 2 sets of 3x18V 5.5A panels in parallel, each to a MPPT 100/20 charge controller.
It looks like the 150/45 has more functionality, like being able to attach a battery temperature sensor, and having a relay. Aside for the fact that I could then connect all these into 1 MPPT, is it the case that it has more functionality? (It will be a LiFePo4 battery)

MPPT ControllersTemperature SensorRelay
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1 Answer
wkirby avatar image
wkirby answered ·

I usually advise to get the highest capacity charge controller that fits your budget.
The 150/45 will serve you better in the long run as it will allow your system to expand if it is not initially used to full capacity.
Relay output and remote on / off are useful features. There is no external temperature sensor on the 150/45, the temperature sensor is internal.
Did you read somewhere that it's possible to attach an external sensor?

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shivadas avatar image shivadas commented ·

I guess I must've read wrong. This is all new to me.

From what model onwards is there the capability to add the external sensor? Or can I do this through a bluetooth battery sensor (does that exist?)?

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shivadas avatar image shivadas shivadas commented ·

@WKirby: Specifically, since it is a bluetooth mppt, can I use a Smart Battery Sense?

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wkirby avatar image wkirby ♦♦ shivadas commented ·

Yes, the Smart Battery Sense will provide battery terminal Voltage and and actual battery temperature over a Bluetooth connection to the Smart MPPT or multiple Smart MPPT's connected to that same battery.

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shivadas avatar image shivadas wkirby ♦♦ commented ·

Thank you @WKirby

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