Inverter wiring questions

[Offgridsteve]

Still learning but currently msystem is set up like this :

2 - 100 watt panels wired in parallel
1 - 12v 100ah battery
P30L charge controller

I recently found a good deal (brand new on marketplace) on 2 more of the same panels so I purchased another identical battery. So with this I can double my solar array to 400w and increase my battery back storage to 200ah. I’m wiring the panels and batteries in parallel so keeping the system at 12v.

I run a 6 cubic foot Unique DC fridge off the system. Increasing the size of everything so I have less issues during cloudy spells, which happened this fall and winter as I live in Maine.

In addition to the deal on Marketplace the seller sold me a 1500 Vertamax inverter for cheap (again, brand new). I was all set to wire up the inverter to my batteries but didn’t realize that there are four posts on the inverter (two positive posts and two negative posts).

Do I have to use all four? And if so, how? Do I actually run two positive wires to the one Positive post on one of my batteries and then the same with the negative wires? Just seems like a lot of wires and want to make sure I’m not over doing it.

My understanding is that my charge controller will have the + wire connected to battery 1 and the - wire connected to battery 2 and then the complete opposite with the inverter...

I appreciate all the help! I feel like once I have a plan and start to move forward there’s always something that I’m unsure about.

 

[snoobler]

Have you consulted the manual on the Vertamax?

It is advisable to connect chargers/loads across your battery bank as you describe; however, there is no need to use opposite terminals, and it is preferred not to. In many cases, your batteries should be floated and your panels are actually providing the current the inverter is using, so it's beneficial to have them on the same terminals.

You're in the sweet spot on your battery to solar ratio. Batteries typically need to be charged at 10-20% of their capacity. This is subject to your actual battery specification. At 200Ah, 30A of charging would put you at the 15% point. The absolute minimum you should consider it 5-6%, and you never want to exceed the battery's maximum recommended charge current.

Your charge controller can't handle any more panels.

I'm going to guess that your fridge uses about 0.66kWh/day. You have 12 * 200 = 2.4kWh of battery capacity; however, you should not use more than 50% to maximize life. That puts you at 1.2kWh usable, so you have about 2 days of reserve power. Obviously in an emergency, you could use all your battery capacity at the expense of cycle life.

You need at least 660Wh/400W = 1.65 solar hours per day (link #5 in my signature for your location) to ensure you can restore your daily usage. Of course, this does not take into account any system or device inefficiencies.