Extended boondocking
We just got back from three weeks on the road. Almost all of it was boondocking without electrical hookups. Without an external electricity source the battery in our trailer can probably supply electricity for about 4-5 days before needing to be recharged. We were able to go ten days easily by keeping the trailer plugged into the 7-way connector on the Model X almost all the time.
We only needed to plug the trailer into an electrical outlet once during the trip in order to recharge our lead acid trailer battery. We did that during a planned overnight stay when we moving from one location the next. Overall we were really happy with our ability to stay off grid with this combo.
Some observations.
Over one ten day stretch our trailer battery went from 100% to 52% (120aH from trailer battery)
Over another eight day stretch our trailer battery went from 100% to 70% (~72AH from trailer battery)
The MX on average was supplying ~2-3amp/hour to the trailer (depending on SOC of the trailer battery).
The 7-pin output turns off after ~6-8 hours of non-use of the MX. Occasionally I would wake the car (if needed) with the key fob.
The MX main battery pack dropped no more than I would expect from phantom loss during that same period of time.
Other notes
Based on the OBDII the DC/DC runs at 14.5V most of the time when the car is not "sleeping". This is whether the 7-pin is hooked up or not.
There is a voltage drop from the 14.5 connector to the the trailer battery end is ~13V. This is a result of the long run combined with a small gauge wire in the extension. The battery is at the back of the 24' trailer plus the 10' extension cord I use from the MX.
One other thing. Due to the voltage drop of the long wire run it's not possible to charge the trailer battery to full from the MX. I'm thinking of adding as buck/boost converter at the trailer battery end in order to bring up the voltage and allow full recharging from the MX.
There is a voltage drop from the 14.5 connector to the the trailer battery end is ~13V. This is a result of the long run combined with a small gauge wire in the extension. The battery is at the back of the 24' trailer plus the 10' extension cord I use from the MX.
One other thing. Due to the voltage drop of the long wire run it's not possible to charge the trailer battery to full from the MX. I'm thinking of adding as buck/boost converter at the trailer battery end in order to bring up the voltage and allow full recharging from the MX.
I may try using the solar plug input (built into the trailer). This way I could use larger gauge wire which would result in less of a voltage drop (and possibly eliminate the need for the buck booster).
Love your blog. Please post an update for 2021 when you get a moment. Hope all is well! -Bryan
ReplyDeleteThanks. Will do.
ReplyDeleteHi there!
ReplyDeleteWe are one labrador retriever, two people, one Terra Firma Road Chief (arriving this weekend), and we too drive a Tesla (an S) but won't be towing with it. We live in Canada and because of the border closure were unable to drive down to pick up our trailer hence it is being delivered here. We have been enjoying your blog and are wondering if there is a way to privately exchange email addresses. We have never actually seen a Bowlus other than the Facetime tour with Helena nor have we spoken to another Bowlus owner and think it would be a good idea to have some contact with fellow owners as opposed to just the good people at Bowlus!
Sincerely,
Judy and Gary
Gary,
ReplyDeleteHappy to get in touch. Email me at i.doco@yahoo.com
Barry
I'm starting to look at the Bowlus and Airstream trailers now. One thing that concerns me about the Bowlus is the small size of the tanks (water, grey, black). I'm fine with a cassette toilet but the 19 gallon capacity of the fresh water tank is a major issue when boondocking. How do you manage?
ReplyDeleteDepends on where and how long we are boondocking. If we are judicious with showers we can go 4-5 days without topping off.
DeleteOtherwise we carry folding water cubes. So we'll either use them to transfer water from a nearby source to fill the tanks. Or we will fill them up ahead of time if we know that there is no source nearby.
On our most recent trip we stayed in the National Forest outside of the Grand Canyon for a week. We carried 19 gallons in the main tank and an additional 15 gallons in the cubes. Only used about 25 gallons, including multiple showers over the course of the week.
Since the showers were outside our grey water tank had plenty of capacity. OTOH we diid have to dump the portable cassette twice. Not a big deal since there were vault toilets and a dump station in/near the GC NP.