But they seem to be rated just for battery maintenance, not running acessories. I would mount an inverter as well to power my laptop for remote recording. This coleman, which is the same as Sunsei with a different mounting system, both made by ICP, is 9 amp, compared to 1.8 on the less expensive one.
I hope it is a viable alternative to dual batteries and aftermarket alternator.
You still need the storage capacity for dealing with cloudy days as well as other obstructions like trees, canyons, etc.. Also the sun is only up during the day and lights are needed at night.
I've done allot of solar assisted camping and every so often you get stuck and have to charge via the engine or some other outside source. We setup our system with solar being icing on the cake. We sized our battery bank for 2 days between charges. 3x would have been better, but it was a common battery size. We sized the solar to 2x daily use figuring we had the engine and 120VAC chargers as potential backups. That happened to be common large panel output and we figured on two panels at some point in the future for expansion of electrical use. Last time I went camping I brought the microwave. I was going into very dry country with an all fires burning ban. Not having to mess with a comp stove was nice.
Something to think about: If your battery bank is made of 3 smaller 12VDC lead-acid batteries in parallel. You can then re-hook them up in series and use them for welding.
I've also thought about bypassing the truck all together, and just hooking the solar to battery bank, and inverter from there.
I only want to run a laptop, for recording tree frogs, and spring birds, whooping cranes. Lights and cooking are taken care of already. We also camp via bicycle only and pack like this (very light) even with a vehicle.
We cook via propane bottle and quick light handle, propped on rocks. Our meals are all dehydrated types, so all we do is bring water to a boil.
Best to look at the demands of the device. 9W at 12V is only .75A. That isn't much. I've been looking for a panel to suppliment my battery when I'm camping, but not driving that day. My little battery runs my Engle fridge with 2A demands just fine for a day or two, depending on how hot it is outside. I've been looking for a 1A (12W) panel I can use to supply some of the fridge's demands so I don't need to run the truck and recharge.