Batteries For My Water Pump Tent System

Buying some batteries this week to power the small 200-watt inverters. I will use them in my washing tent for the 20x24 and 35x35 inch ambrotype plates. The idea is to have 2 or 3 wash stations in the tent set up on tables. Instead of running power cords from the trailer batteries I am hoping I can power the tent agitation pumps independently. 

I came with the idea of using off-market inverters made for Dewalt tools and batteries. This plan will also give me extra battery power which I am sure I will need in the years ahead. I added a second lead acid battery to my power set up in the trailer (running in parallel with the earlier battery) but I do not think that will be enough. Several times last year I drained the single trailer water pump-power battery. I will need solutions like these little portable Dewalt units when I am working in far off Canadian locations. When you're in Northern Yukon making pics at this extreme level, you will need many portable power sources for your gear.

200watt inverter, battery to 110v

The problem I am facing is getting the batteries and the chargers I need to run the inverters. The batteries will need to run the agitation pumps for long periods of time. I usually wash plates for several hours with multiple water changes. Real Dewalt lithium battery's cost a fortune, around $100-$200 CAD each. I am experimenting with after brand copycat batteries. Those are much cheaper, but of course quality might be an issue. I bought my first two copy batteries for $79.99 and my second two for $72.99. I just bought 2 more after brand batteries from a different company that included a battery charger for $89.99. 

Copy cat Dewalt batteries and 2nd charger

For the washing tent I now have 6 batteries, 2 inverters, 2 pumps and 2 chargers. The pumps work off the inverter/battery set up; I tested it today. I am not sure for how long the battery will run the pumps for, 1 hour? 2 hours? Also, how long will these batteries recharge and keep their load? I am hoping at least 3 years but that might be asking too much. 

Agitation water pump, have 4 now, 2 for the tent, 2 in the trailer.

I HOPE THIS IDEA WORKS!!!

Note* I also have two agitation pumps in the trailer. I can do a 20x24 wash tray with one plate in there as well. 35x35 plates will be too big for the trailer. All the washing of the super large 35x35 inch plates will have to take place in the tent, or tents.

Note** Having a second battery charger is important, as it halves the time, I will need to recharge the batteries when they are all drained. I will buy another battery-charger combo if the first one works well for me. Three chargers and 8 batteries should be enough for now!