Sunday, November 3, 2019

Day 79 - Tucson, AZ

High clouds this morning
The owner of a 5th wheel a couple of spaces down gave me a tour of his electric system. He has had this system installed for around 4 years and he lives full-time in the rig for about nine months of the year. He spends the winter in England.

The nine 200 watt panels on the roof are tiltable but he never bothered. Three strings of three panels go to a combiner box on the roof and come down to 45 amp breaker before going into a Victron MPPT charge controller. The voltage from the panels is around 60vdc and 10amps per string or about 30 amps total. The output from the charge controller is nominally 24 volts so the output current would max out at around 75 amps.

N.B. 24vdc. He has four 50AH LiFePO4 24 volt  batteries. He used 24 volt batteries so the wire size could be reduced as the current would be halved. For the AC side, he installed two Victron 3000watt hybrid inverters so he could power both sides of the AC breaker panel. For DC power, there is a 75 amp 24vdc to 12vdc box also sold by Victron. It doesn’t provide enough current for the hydraulic pump for the jacks and the slides so there is a 12vdc AGM battery just for the hydraulic pump. The 12vdc battery is charged either through the connector to the truck or the Progressive Dynamic three stage converter. He has the same battery monitor and adds the Victron Color Control monitor screen which shows graphically the status of all the components. Using the touch screen, you can dig into configuration, stats, and history For each component. When plugged into shore power, one of the inverters can charge the house lithium batteries. If plugged into lower capacity shore power, the inverters will pull battery power to make up the difference between what is available and what is needed. Pretty cool setup.

This is kind of what I was looking at but if this RV is too fragile for boondocking, then maybe not. I may scale back everything and continue using the flooded batteries. Maybe four 200 watt panels of solar wired in two strings of two. Still use a Victron MPPT controller and a single Victron hybrid inverter to replace the existing Magnum inverter.

On another note, we stopped at the Saguaro National Park visitor’s center which was right up the road from Ace Hardware. The park is 80% wilderness even though it is really close to Tucson. It was originally a National Monument but became a National Park in the mid-90s. There is an 8 mile driving loop but decided to return for that and some hikes. It was feeling pretty warm by noon even with the high clouds.

I am getting close to the magic 89 days so I will be flying to Fairbanks in a couple of days. Some appointments, some things to do at the university, and probably go to coffee on Thursday. You know, the important things.


  1. Yeah, impressive and lots of $$$$$. That would be cool to set up and operate. Next to gen enough electric to hybrid the diesel. See you Thursday.

    1. Not having to “manage” power is pretty nice. The hybrid feature is pretty nice. I.e. using battery power to provide additional current for smaller shore power connections. Such as running A/C when plugged into 15amp.