Solar Inverter Low-Voltage Warning/Shutdown

[Josh M.]

Here is a link to a handy voltage drop calculator that I use.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

Plugging in your specifications, I see this.....
View attachment 114062

It appears that you are only loosing 1V at that distance, which is probably OK until you get your MPPT controller. Then you can wire more panels in series to reduce voltage drop more.
View attachment 114063

Keep in mind that the better controllers have higher voltage limits, so If you can stomach the extra money, a higher quality controller with a 200V limit (Epever 5420AN) will allow you to run strings of up to 4 grid-tie panels for hundreds of feet. Right now, I'm funneling 8A through 10 gauge wire at 120VDC for 130' without any measureable voltage drop. Then you'll have the liberty to place your arrays just about anywhere you want, which is likely to increase overall production even more.

That's great information! Thank you! So, if I'm reading this correctly, with my current setup, I could extend to 33' without a detrimental loss?

 

[Doggydogworld]

Great to hear you're figuring out ways to stretch your on-battery hours. Off-grid is tough without an unlimited budget. It'd be great if the Flagstaff guy can help. See if he has any extra meters available to sell. Guys like that often have leftovers after upgrading to better equipment. Might save you a few bucks and move the relationship along.

I keep coming across people who say that completely draining lead-acid batteries will kill them in as few as 50-100 cycles. One guy in the UK did a video in which he tested different battery types and graphed it all, so it's not just a myth. You really want to keep them above 50% except for the occasional emergency.

Have you seen any improvement in your daily Ah as measured by your charge controller?

 

[Josh M.]

So, a couple weeks ago, I was finally able to purchase one more battery which now gives me a total 4 105Ah batteries, and I have hooked them up in 24V 2S4P set up. I know it's not the battery solution suggested, of buying the 6V golf cart batteries, but it's again due to budget constraints. Winter is coming and I have to shell out a healthy chunk of money for rock for my driveway and a roof over my awning/screen room. I was also able to purchase the materials for the frame for my PV array. These things have made a huge improvement. As long as we unplug the fridge, as we have been doing, the solar lasts all night long now and is only dropping about 1-1.5 volts depending on how much the furnace runs at night. Which lately has been quite a bit. On weekday mornings when I have to get up at 6am for work, I do need to kick the generator on for a few hours until the sun hits my panels, but on weekends when I don't need to get up early and kick on my laptop and internet, the solar lasts easily until the sun hits my panels and starts charging up by battery bank again.

As time goes on, we will continue to work on improving the system with better batteries and panels, charge controller and inverter. We will just have to make due with what we have going now until other higher priority items are taken care of.

Again, I appreciate all the help you guys handed out and I will continue to look back at this thread as a guide for those improvements. Thanks!!