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If your house bank (“auxilliary battery”) is dead (nothing is working) we have both short-term and long-term problems. Let's start with the short term issues.
In addition to you having no power in the van, sitting at very low states of discharge is damaging to both lead (Pb) and lithium (Li) batteries. It is important to get battery voltage off the floor ASAP.
The fastest form of charging is by alternator; if you have alternator charging start the vehicle and take it for a drive.
Solar, if present, will often be a gentler charging method. MPPT will run normally but PWM charge controllers will be especially weak when battery voltage is lowest.
Shore power chargers are often quite weak (like 10A) but if you can stay on the charger for hours or days the battery will recover charge.
If you have or can borrow jumper cables you may be able to “jump” your house battery from the vehicle with the van running. Relatedly, a lithium jump pack meant to jumpstart the vehicle may bring the bank up high enough where you can charge normally.