Charging an AGM while still being used

[bobfather]

There are a lot of Google answers saying that you can't charge an AMG whilst also applying load. That said, solar panel charging systems do this, they charge batteries that are being used to power household items. Caravan/motorhome AMG leisure batteries are charged while under load. Cars do too however this is a poor example because the car draws from an alternator, not from a battery. In a perfect world, disconnecting the AGM during charge cycle is ideal, but is it truly required. Drawing power during charging will certainly increase charge cycle time but is it harmful in some way to the battery or charger.

I'm trying to set up an uninterrupted 12v supply. I could achieve this with two AMG's connected with a 'close before open' switch allowing uninterrupted output and still allowing charging of the unloaded battery.

Any thoughts?

[bobfather]

buggalugs said:

Almost every car driving down the road is charging an AGM battery while it’s being used

I get that but in the case of cars, the alternator produces so much power that, whilst being driven, all power usage is drawn from the alternator so the battery isn't being loaded. I'm trying to design a system that doesn't have an external 12v supply supporting the battery. Electricity cannot flow in two directions at the same time. When I load the battery I assume that stalls the charging cycle. I'm concerned that the CTek charger will become damaged due to the load trying to draw from the charger