Wow! 180 amps is a HUGE draw. A battery
bank of your size could not begin to handle that much draw for more than a short time. in any case it will draw down the voltage immediately and then go down the tubes in a short while. It would take longer with a much larger bank but in the end that is a big draw and the bank would have to be multiple times larger than what you have.
Deep cycle batteries (wet, gel, or AGM) have thick plates which hold the energy inside. They are designed to release that energy in a controlled fashion at a reasonably gradual rate. They have a substantial amount available on outside surfaces and just below but after that is mostly used, the energy has to be extracted from deeper in the plates. It takes some time for the chemistry to happen.
When a big load is on it is handled quickly (like running a microwave for a few minutes) with some immediate voltage drop. If you turned off the load after a few minutes, the voltage will pop back up, the speed depending on the size of the bank relative to the temporary load. When I needed to verify that an alternator
or other charger
was putting out, I would put a cup of water in the microwave (mostly powerboats of course) to take the surface charge off the batteries, otherwise the alternators would not put out to what looked to them as full batteries. I would then run the alternator
and see how many amps it could put out. I had to do the test right away though as the voltage would come right back up if the batteries were left sitting.
Running a long, big load, like a washing
machine or extensive microwaving, would take a battery to its knees and the voltage would dramatically drop. Too much for too long would overheat the batteries (and the wiring
if not sized to handle it) and potentially cook them or even start a fire. Not recommended.
If you want to run your washing
machine you need to run a genset or get a much, much larger battery bank with 4/0 short wire runs and then recharge them for a long time. Ditto for any type of big load, such as a windlass
hauling up 1000' of chain. BTW - it can take an hour(s) for batteries to get close to "equalizing", i.e. the same voltage potential throughout the plates. Equalizing batteries via charging
occassionally is the opposite of that in that you force a high voltage on the outside of the plates in to the innards otherwise the innards don't get fully converted chemically. Wet cells take longer than AGMs. Start batteries plates are designed to release their energy quickly but they can't last as long (and they will drop voltage depending on the load).