My grid tied system was installed in August 2017 consisting of 2 x 5kW (48V) Mercer inverters with 18 x 310W (3 strings of 3 per inverter) solar panels and 4 x Shoto 12V, 200Ah batteries in series.

I want to go totally off-grid and are considering replacing the battery set with 24 x 2V, 585Ah mining locomotive batteries (FNB MTL19XF) which I can purchase for a very good price. My energy consumption is on average 1300kWh per month. Stove and geyser already on gas. 

Would this be wise to do? Your expert advice will be appreciated.

 

41 minutes ago, Rudolph said:

24 x 2V, 585Ah mining locomotive batteries (FNB MTL19XF)

My opinion, it boils down to costs.

What do the 585Ah batteries cost?
Age?
Life expectancy?

Because the alternative is Pylontech batteries ... and you can get a few rand back on the lead in the end. 🙂 

Edited May 23, 20197 yr by Guest

Second hand lead-acid batteries are always a big risk. But if you know they've had an easy life and were looked after, they could be good value. Bear in mind that assuming that these are the flooded type, they will likely require some maintenance, and many Axperts don't have the 64 V option, which is really needed for periodic (monthly to three-monthly) equalisation charge.

If you can get the batteries at scrap prices (or close enough to it), the risk is on the low side. All depends on the price.

I can get a set of 24 x 2V cells for R53,000 (New) which includes all the connectors and a watering system. The cells are First National MTL19XF 585A/h. In underground conditions these batteries last for 5 years plus in very harsh conditions. I know of someone with a similar set on his farm that have been running now for 25 years powering ,fridges, lights and security systems.

Will Pylontech work with my Mercer inverters? I doubt that Pylontech will be cheaper for the same A/h.  

10 minutes ago, Rudolph said:

Will Pylontech work with my Mercer inverters?

Yes, though you'll probably need ICC on a Pi to have proper SOC control.