Limiting AC charging draw?

[CaliforniaCurmudgeon]

I started researching Solar to give my mother options for her off grid RV living. (started another thread about that)

However, I have been struck with an idea for camping because I use a CPAP. I tested it over 48 hours (2 nights) it drew 597 watt hours. 1 night with the humidifier with a peak of 90.1 watts and 399 watt hours. One night without the humidifier it peaked at 42 watts and 198watt hours.

My truck came with an AC inverter installed. It lists it as 110v AC 400watt max, but the manual specifies 400 watt is in park, 300watts while in drive with lots of warnings if you exceed that.

Something like the 640wh milk crate system that is on the William's channel. In addition to the CPAP probably look at charging 3-8 phones, smart watch, or tablets. 3 if just my wife and I, and 1-2 devices for each of 3 children (teens to mid-twenties) who might accompany. Powertac rechargeable flashlights as well.

With 1-4 100watt solar panels to charge it during the day when camping. Not really looking to mount them on the truck because it is my daily driver. Plugging it into the truck to recharge on longer journeys. For example I am considering a 2-3 week road trip, which will have several days of 8+ hours driving during daylight hours. However, I am not sure what options are available for AC charging and limiting it to keep within the trucks specifications. Any thoughts or recommendations?

 

[sunshine_eggo]

Are you proposing to charge your backup system with the AC inverter in your truck?

If so, assuming you want to charge a 12V battery:

300W/12V = 25A, so any 12V charger < 20A should be more than safe to charge via the truck's AC inverter.

200W solar would be sufficient to charge 200-400Wh in mediocre solar conditions.

 

[CaliforniaCurmudgeon]

Are you proposing to charge your backup system with the AC inverter in your truck?

If so, assuming you want to charge a 12V battery:

300W/12V = 25A, so any 12V charger < 20A should be more than safe to charge via the truck's AC inverter.

200W solar would be sufficient to charge 200-400Wh in mediocre solar conditions.

So for space of storing them, so multiple 100watt panels could be used. Seems like 400 watt panels seem to be about 6'x4' roughly, which is harder to store in a pickup bed that is only 6'6" long and also storing camping gear, ice chest, etc.

 

[DThames]

Not sure this is what you are looking for but.....
When camping and needing more than the 150w from my van's built in inverter, I have a 750w that I can clip onto the battery by just opening the hood. I even have a place where I can secure it (under the hood) if I want to break camp and drive to the store. I need to be careful to not run down my main battery, so like when making coffee, I idle the engine.

For CPAP support, a milk crate built would be great. I would consider some small, easy to handle solar charging but supplement that with charging off of the engine alternator. You would really want a small charger that the amp load on the alternator would not be a lot, maybe limit to what a 12v socket could handle.