Yes battery could still be low. Windows and radio don’t take much power, while starting the engine requires a huge amount of amp draw. I’ve found the only reliable way to test without a multimeter is to turn on the headlights for about 5 mins because they have high draw too. Of course you may not be able to tell during the day, but at night they’ll be noticeably dim.
Like Lolaeliz said, it’s not uncommon to get a van with low battery. They sit on the lot longer than most vehicles, and a short test drive here and there isn’t enough to recharge the battery.
You need to go on a long drive for an hour+ to get a decent recharge if the battery is low. If you haven’t done any long drives yet, playing with the remote start probably drained the battery. Each start attempt uses a substantial amount of juice when the battery is low, and requires a bit of rest time between attempts.
Have you tried manually cranking the engine with a key? (I have no idea if the factory remote start completely replaces the key or not). It’s easier to troubleshoot that way because remote start will also fail to work if you have hazard lights turned on, or coolant temp is too high.
By using a key you’ll be able to tell if the battery is too low to start the engine. It will either crank slow (very low), fast click (almost dead), single click or do nothing (totally dead), all the while some accessories will still work.
