Ultimate Checklist Before Buying a Van
Part II - Power Needs
The importance of enough power is a common topic. How much battery power do I need? How many solar panels? What type of inverter? The questions go on and on. I have addressed a few of these areas for your consideration when looking at a campervan.
Appliances and How Much Power Will You Use
First off appliances…different appliances can run off different types of power. The common sources are 120 volt AC, 12 volt DC and gas.
Refrigerators
For refrigerators, we like 12 volt over all other options. For most (if not all) manufacturers, running on 12 volts DC for the fridge is more energy efficient vs 120 volt AC. Many can run off gas, but they need to be relatively level to continue to operate and then you have to figure out what to do with the gas. While having a gas canister inside is done quite often, it is not recommended for safety reasons. You also have to continue to be able to fill up or replace the canisters.
Cooking surface
This is commonly either gas or 120 volts AC. Gas has its concerns (see the Refrigerator discussion) and 120 volt AC cooktops are a hog of energy. You will need to weigh the safety and refill concerns of gas vs the battery power needed for 120 AC. See the Battery and Solar sections for more insight into the generation and storage of energy. For me, I went with 120 AC and a portable Coleman propane stove. Best of both worlds. Built in gas burners would be the most convenient but then you lose countertop space. And the more countertop space you have the better! Carefully look at the available countertop space. Nice additions are flip top extensions and slide out cutting boards.
Water heaters
There are several options out there for water heaters. Many think just getting an on demand unit will be the easiest. Be aware they are huge consumers of energy. I use a 5 gallon water Bosch heater that is powered by 120 volts AC. It heats up water quickly and holds it for the day so I only need to run it 10-20 minutes for all of my needs. I have it on a timer so that I can ensure it does not run all the time.
Think also of what you will be using hot water for. Will it be a shower (indoor or outdoor), sink, or all of the above. Many people swear by showers…both in a good way and bad way. I have the ability to take an outdoor shower in the back of my van, but also rigged something up that allows me to take a shower inside my van without the need of a permanent shower taking up space. I will post about that separately. When evaluating the hot water heater, whatever type it is, also look to see how easy it is to adjust or drain and service if needed. As a side note, hot water heaters have a relief valve. Make sure it is pointing to the area it will cause the least damage if it does trigger. As an extra safety measure, I have my water pump on a switch so if there is a leak I just turn off the pump and I do not have to worry about continued damage.
Microwave
I have a 700 watt Magic Chef microwave and it serves me well. They are a big consumer of electricity, so the lower the wattage the better. That said I have not done a study to see if I want to cook a potato, how long it would take in a 700 watt microwave and then do the same in a 1400 watt microwave and see how much energy each uses, but the 700 watt works for me and it takes up very little space as compared to the higher powered ones. They are also cheap.
Outlets
Make sure there are outlets in places you will use them. Look also for a mixture of 120 volt and 12 volt ones. It is okay to plug in an adapter to get 12 volts from a 120 volt outlet (just like you do at your home), but it is better if the 12 volt outlets are running on their own circuit so there is minimal energy loss due to the use of the inverter. And….a very nice addition to look for is if the outlets have usb ports. I find it invaluable!!
Batteries
Lithium is the way to go. Acid batteries are heavier and they decrease in performance as they drain. Lithium runs at 100% until it just cuts off. They are expensive (we called them our ‘golden batteries’ because they were so dang expensive), but they are well worth it. Make sure you have the right charger for the batteries though…not all solar chargers for example are compatible with lithium batteries.
Speaking of batteries, having a DC to DC charger is a must. It is a device that allows you to charge your house battery while driving and when you stop it isolates the house battery so it does not drain the van battery.
Also a HUGE recommendation is to have a battery monitor. We did not start with one (well we had several monitors, but not specific to the battery) and we put a Victron one in. It’s the best. It tells you how full your battery is and how much is being charged into or drawn out of the battery.
With regard to the battery size, I use 2 170 amp hour Renogy lithium batteries for a total of 340 amp hours of storage. When I have been boondocking and doing no driving, I have at times needed every amp hour that could be stored. The number and capacity of batteries that you will need is directly dependent on how much driving (or not) you will be doing every day, your energy consumption and the power of your solar panels. See the Solar section for more info.
Solar
If you are going to be driving each day then you can probably get away with 200 watts of solar panels. The better recommendation though is to have 400 watts, and this is very common. Your house batteries will charge faster with more solar panel wattage. As stated in the Battery section, I have 400 watts of solar panels and two lithium batteries with a total capacity of 340 amp hours. When boondocking for weeks at a time (no driving), the amount of sunlight becomes a key factor with regard to whether your batteries will be topped off each day. In Arizona in the winter there are just 7 hours of daylight. And with panels flat on the roof, peak charge is for only a couple of hours. I watch my energy usage so I do not run out of power because there is not enough daylight to fully charge the batteries each day. I would not be happy at all with only 200 watts of solar power.
Now that said here are my typical energy uses each day:
120 volt items:
Microwave: 10 minutes each day,
Laptop charger: Plugged in most of the day.
Water heater: 15 minutes every other day
Hot plate: I use it sparingly when boondocking…perhaps 15 minutes every day or so
Tea warmer: 5 minutes each day
Hair dryer: 5 minutes every other day
12 volt items
LED lights: several hours each day (more in the winter than summer)
Phone charger: Nightly
Refrigerator: runs 24/7
All of this adds up to about 1250 watts of use, which if you think in amps, that is about 120 amps given loss over lines, etc. So that means if I make no adjustments, I need to collect at least that much daily from my solar panels, or I have to start the van to charge the house batteries. The battery bank I have will store over 4000 watts of energy or 340 amps. So if I did not charge the batteries at all (solar or via the van) I could run for 3-4 days before the batteries were drained. This has happened to me. This was because the batteries did not get totally charged from the solar panels. While in Arizona in winter, I did a study and found I put in about 60 amps of energy from the solar panels each day. When I was driving each day I had no worries at all about energy usage and did not regulate myself at all. Since I am not driving and the sun is limited, I cut down my consumption so that I use 60 amp or less each day.
So you can see if I only had 200 watts of solar panels, I could only use about 30 amps each day. That would be doable, but not what I would want to do.
On the topic of solar panels, they can be wired in series or parallel. There are lots of write ups out there about each, but the deciding factor for me was if they are in series and a panel is in the shade, none of them will charge. If in parallel and one panel is in the shade, it only impacts that one panel. Because of this we also mounted the panels on top of roof racks instead of inside of them (with rails above them on the edges). We did not want the shadow of a rail to shut down a panel. We also did not put a Maxxair vent near them for the same reason…did not want a shadow to shut down a panel.
Bottomline, do your math and figure out what you will use and what the appliances consume. Then look at the energy sources coming in and decide how much is enough for solar and batteries. Of course you can also use ‘shore power’ (plug your van into an outlet). That works when you are in a location where that is available. I wanted to be able to survive without that option as it gives me more freedom and does not cost as much. I can park overnight anywhere for any length of time and know my power will be okay.
Inverters
You need to have a good inverter. The size is based on your intended use. We installed a 3,000 watt pure sine wave inverter. Pure sine wave energy gives you cleaner electricity. You will need one that you can hard wire into and if desired one that has outlets that you can plug into. Ours has both and has served us well. We in fact used this as our main power source for all power tools, etc. during the build once the solar and batteries were installed. When looking at a van, just make sure it is a good quality inverter. Renogy is the most popular. It is what I have. It can be replaced so this will not be a deciding factor to buy or not buy the van, but it can help you determine if you need to get it a bit cheaper to cover the cost of replacement. Good inverters range from $500 to $1500.
Click here to get to a tool that you can use to calculate projected power usage.