Wheel Battery Charger

Wheel Battery Charger
Can a 6w cordless phone power pack run 24 hours on a 70w hand held inverter?

This will be hooked up to my solar panel batteries in the basement. The battery output is continuously 12v. I’m planning on connecting all my phones to my batteries in time. I also have a trickle charger active on standby if the voltage gets too low to keep the batteries at 12v when I have no sun. My solar panels are about 105 watts in total and they also have a charge controller. I have 5 large wheel chair batteries for power.

It might work.
Snags might be the threshold for turning on. Most inverters have to have a certain level of current flow or they turn off. 6 watts may not be enough to keep it on.
Second problem may be that the inverter is not intended for continuous use. Make sure that it can have good airflow to keep it from heating up.

From an engineering aspect there may be a better solution.
The flow you are suggesting is to go from the batteries @ 12 v DC > Inverter @ 120v AC > wall wart @ DC to power the phone. Each of those transitions has a significant power loss.
A more efficient method would be to use a DC/DC power supply. Depending on the voltage and connector size of your phone, you may be able to get an off the shelf unit originally designed for automotive accessories. Old cell phone car chargers may work.

On a few DC systems I have installed a 12v outlet (cigarette plug) so that cell phones and laptops could be easily charged when the commercial power was out.

Schumacher SE4020 Wheel-Style Charger/Starter