Big Red

Holding off on a MPPT controller

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I’ve decided to hold off on getting an MPPT solar controller for my truck for now – even when the benefits are obvious like on a partly cloudy day like this morning when I shut off the inverter, changing the resistance and actually boosting the output of the panel.

For the most part I have sufficient power with the two accessory batteries and don’t need the benefit compared to the PWM charger I currently have. The system preformed well enough on my October road trip even if I know on many days I’m not necessarily getting the best possible performance out of the solar panel. I say replace it when the PWM charger dies but the truth is without capacitors or non solid state components that’s unlikely to happen any time soon.

Plus if I were to get the larger Renology Rover MPPT charger I’d have to relocate the inverter and several other components which would require lengthening and cutting several wires to make things fit which is quite a bit of work. I do like all the diagnostic features of that charger though. One of the off gridders I follow online is a big fan of the Victron MPPT controllers which are pretty much the size of the PWM controller currently have.

Honestly the system works fairly good. Why put more money into something that works fine now?

Solar panel installed to top off battery when camping multiple days

Brakes Again

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Looking at the rotators and brake pads on my truck, I believe the reason the passenger side pads failed prematurely was that there was a stone trapped between the rotator and brake pad. The stone became embedded in the pad, and lead the pad to wear unevenly, so that one of the pads on the passenger side front wheel was so worn down on one corner it was virtually metal on metal. There was a deep — 2+ mm deep groove in the rotator and a matching deep pock mark in the inside corner of the pad where the rock was embeded. Little piece of gravel from a dirt road. Who knows how long that rock was in there — I noticed the groove several years back but didn”t think much about it — but it continued to grind it way away.

Sucks. But at least it wasn’t that expensive to fix, the truck is quiet, and the brakes work well.

Curve in River

MPPT controller

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Still chewing over upgrading to an MPPT solar controller for my truck. With winter coming and the solar angle declining, an MPPT controller might charge my batteries much quicker than a PWM controller, especially with the sub ideal conditions in the woods.

Low Voltage Disconnect Relay - Solar Controller

MPPT is great as it can buck or boost voltage from the solar panel appropriately to maximize charging speed. In contrast, the Renology PWM controller like I have now works but it’s often either using PWM to reduce voltage (wasting the excess power from the panel) or the panel isn’t producing enough voltage to properly charge the battery in less than ideal conditions. Bucking or boosting the voltage one can trade amperage for voltage and vice versa for the ideal charging voltage and best ratio of resistance for maximum panel efficiency.

100 Watt Panel

I am looking primarily at the Renology 20 Amp MPPT controller, which I’ve seen online for under $100. I would have to rewire a few things to make it work, including mounting it where the large inverter is now and moving that back to the shelf in the cap. No decisions have been made but I’m continuing to think about my options.

The 750 watt hour plus weekend

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Over a three day period, I generated and consumed over 750 watt hours of power using the solar panel on my truck. It’s been a hot and buggy weekend so many nights I was up late burning the lights into the wee hours of the day and running the fan to keep cool. But during that 72 hour period at camp I was able to keep my truck turned off and everything fully charged without problems entirely on solar. While my system is too small for powering a house or cabin it works great for camp power, and had no problems when it was relatively cloudy on Saturday.

100 Watt Panel