MPPT 75/10 replacement options

JB30

Active member
Simple question, from someone with very basic understanding of solar / electrical.

Have a single 100w panel trickle feeding main battery to support fridge etc. My controller has had a hardware failure and need to replace. However might repurpose in a future build with more panels / batteries. Any danger in replacing with a a more robust controller to future proof?
 

NatersXJ6

Explorer
I’m pretty happy with my Victron 75/15 MPPT, but I thought that it wouldn’t charge a 12V battery without at least 2 panels in series to get over the starting voltage. What is your panel voltage?
 

JB30

Active member
Ah interesting. Product spec says “Open Circuit Voltage (Voc) 22.5V”. I remember researching appropriate setup When I installed this all a year or two ago and ended up with the 75/10. Perhaps wise to just replace with the same and not mess with what worked!
 

jonyjoe101

Adventurer
IF your going to upgrade later with a bigger panel, I recommend the makeskyblue 60a mppt (cost me 130 including shipping) . I recommend it because it has an LCD screen where you can program it (no bluetooth needed). It has a fan to keep it cool. But a feature I like is that it has voltage calibration, you can calibrate the controller to the batteries terminal voltage. Every controller I owned had voltage drop problems, being able to calibrate it is a very good feature. The 50a/60a version has a feature that prevents voltage surges when used with lithium, thats a feature not found even on the more expensive namebrand controllers.
I had the controller for 2 years and used it on a 240 watt panel (produced about 12 amps) and on my 365 watt panel (produces up to 27 amps) , it will easily work on your 100 watt panel and leave you with room to upgrade. Also I use it to charge my 220ah lifepo4 (14.6 volts) and also my 312ah li-ion (12.6 volt) battery banks and also works with lead acid, it handles all the batteries you might use it on.
On your 100 watt panel and a lead acid system any controller will work with it even a cheap 20 dollar pwm controller. Being a low voltage panel the most amps you will get out of it with pwm or mppt is about 5 amps.
1 makeskyblue 60a.jpg
 

JB30

Active member
THanks @jonyjoe101. Good info. Although for my application the little victron fits snuggly under the hood. Space is at a premium in the ol’ Jeep :)
 

NatersXJ6

Explorer
You might be cooking your Victron under the hood. I ended up putting mine in the passenger footwell in an attempt to find a slightly cooler living space for it. So far it has worked well, but I haven’t really checked on it often.
 

NatersXJ6

Explorer
Agreed. In a world of compromises, I chose to give up potential battery longevity in favor of electronics life. It does occasionally charge when too hot, but I keep adding water as needed.
 

jonyjoe101

Adventurer
I was reading up on the victrons and some of the controllers shutdown power production when the controller temp reaches 40c (104f) , the temperature when the engine is running is about 150f under the hood, also sitting in the sun the temperature can reach those temps also. If you put the controller inside the car, it can easily reach 150f with all the windows closed.
But one good thing is the 100 watt panel wont put too much stress on the controller. Maybe put a fan blowing on it when you got it producing power.
 

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