Whew! We’ve been working overtime here at Truck Camper Adventure lately. As part of our recent Expion360 Viper lithium battery upgrade, we just installed a Go Power GP-SW1500TS Pure Sine Wave Inverter. Having a powerful, 240 amp hour lithium battery bank makes having this big inverter practical. Not only that, the smaller, Group 24 lithiums freed-up just enough space in our battery compartment to install it. If you recall, we were using a Go Power 600 watt modified sine wave inverter in the camper before. Unlike that old inverter, however, this new Go Power 1,500 watt inverter has a 20 amp transfer relay that automatically switches its output to the camper’s AC outlets whether we’re on 30 amp shore power or running the inverter off-grid using our batteries.
Finding the right inverter was a bit of a challenge. We looked at several 2,000 watt inverters with built-in transfer relays, but all of them were too large for our camper. On the other hand, the GP-SW1500TS Inverter was the perfect size for our battery compartment. But size wasn’t the only consideration, the unit’s features were just as important. We already mentioned the transfer relay, which is the most important feature, but this inverter also generates a clean waveform with a 60 hz frequency deviation of plus or minus .1 percent with a maximum efficiency of 88 percent. The inverter also provides reverse polarity (fuse), under voltage, over voltage, and AC over current protection as well as short circuit, overload, over temperature, and over voltage protection. The unit also has seven power saving modes of 2 to 8 percent, which are controlled by DIP switches located on the front of the unit.
With an inverter like the Go Power SW1500TS a remote is needed unless you want to manually activate it each and every time you want to use it. The SW1500TS can be controlled using either the Go Power GP-SWR-A or GP-SWR-B remote. Unfortunately, Go Power’s smaller, new Industrial (ISW) remotes will NOT work with this inverter. Don’t ask me how I know, I just do.
After looking at several locations inside the camper, we decided to install the inverter underneath the dinette seat where the batteries are located. How did we get the inverter to fit in the same compartment as the batteries? It wasn’t easy. Like I said earlier, having smaller, sealed batteries made it possible, but with only 6.5 inches of clearance on top of the batteries, we didn’t have much room for the inverter. After looking at several options that involved everything from building a simple wood platform to an insulated wood box cover for the batteries, we opted to go with a simple L-shape plywood platform for the inverter instead. The 14×13-inch platform is supported by a simple 1×2-inch piece of wood screwed into the wall on one side and a plank of wood on the other measuring 8.5 inches high and 10 inches wide. The plywood used in the platform is only 1/2-inch thick. With the inverter mounted, the clearance on the top is only 1 inch with the dinette seat installed. To provide the needed ventilation for the inverter, I mounted a standard RV vent on the side of the compartment.
How did I wire everything up? It was pretty simple, especially on the DC side, though the instructions didn’t explain things very well on the AC side. No diagrams or suggestions on how to wire up the AC side were provided in the inverter’s instructions, which is the most important part of the installation. Fortunately, Go Power has an excellent support staff that is willing and able to answer any and all questions thrown at them. Bob Lane, in particular, was especially helpful. What size wire did I use for the installation? I used oversize 12/2 yellow Romex on the AC input and AC output wires, while 4 AWG cables (with a 175 amp fuse) were used on the DC side. Sources vary on what’s proper when it comes to inverter cable sizes and fuse ratings, but Purkeys inverter cable size chart has proven to be an excellent resource (when calculating the total wire length, both the positive and negative cables lengths are added together). When it comes to an inverter, you can never go wrong by oversizing your wires or by going with the cable size recommended in the inverter’s installation instructions.
The simplest and easiest way to wire any inverter with a transfer relay is to wire it directly to the 30 amp shore power input, but I couldn’t do that because the Go Power SW1500TS is rated for only 20 amps. So I wired the inverter’s input to the main breaker panel using a 15 amp breaker instead. On the inverter’s output, I disconnected the single 14/2 white Romex wire supplying the power to all of the camper’s 15 amp AC outlets from the main breaker panel and connected it directly to the inverter’s output wire using a simple AC junction box (this junction box was mounted underneath the kitchen sink, next to the WFCO 8945 Power Center. A thin wall separates the two. Fortunately, I had just enough wire length-wise to make this location work). See the diagram below on how I wired everything up on the AC side.
Like I said earlier, wiring the inverter was pretty easy. The hardest part with a project like this is running the wires and deciding where to mount everything. I did, however, encounter one “problem” worth mentioning. While testing the AC output, the plug-in circuit tester indicated that we had a bad ground, but this was a false reading. The AC circuit tested fine when connected to shore power, but not when running off the inverter. This erroneous reading is common for inverters in boats and RVs with floating grounds. Indeed, Bob Lane at Go Power says he gets this question all of the time and has to explain that this reading is nothing to worry about. Other than this anomaly, the installation went well and is considered done, though at some point I may upgrade the size of the DC cables and replace the AC outlet junction box with a small circuit breaker box.
It feels good to finally have this project done. We’ve been wanting to do this mod for over a year. We’ve hated having to plug directly into that old, manual inverter. It’s so much easier having an integrated inverter that ties in directly with all of the AC outlets in the camper instead. This translates into less clutter and trip hazards as the new inverter eliminates the need for running extension cords all over the camper. Having a bigger, more powerful inverter also means we can use it to run our new 1,500 watt induction cooktop and the wife’s 1,500 watt hair dryer using any outlet that we want. Of course, having a beefy, lithium battery bank made this mod possible. The entire electrical upgrade was made possible by the lithiums that essentially has given our camper four vice two batteries.
Stay tuned for an in-depth review of the Go Power GP-SW1500TS Inverter after we have time to evaluate it further. Follow Truck Camper Adventure on Instagram to stay up to date on the latest news and developments.