March 29, 201610 yr Hi there I am busy buying the hardware for a grid tied solar system. I already have 2 off 5kva Axpert inverters. Looking to supply on average 30 - 40kwh per day. I do have 3 phase electricity but don't have 3 phase appliances etc. Just try to balance the loads. In fact have an emergency inverter and battery on one phase which keeps lights and some plugs on. The other 2 phases supply everything else with ease. Questions 1) how many ah can the 2 inverters in parallel take. I am looking to get about 200ah 12v batteries. 3 or 4 parallel strings. 600 or 800ah 2) Should I rather do a bank per inverter although this will be expensive. Notes: A) I do have a large flat roof that can handle even 30 pv panels at least 1 phase will be connected to eskom for ovens, pool with heat pump and underfloor heating if used. Looking at gas oven options. Unlikely that they used at the same time so single phase will be ok. C) I may look at a 3rd inverter later
March 29, 201610 yr 47 minutes ago, FRZ0n said: 2) Should I rather do a bank per inverter although this will be expensive. Axperts can't do that. They will shut down if the two units detect different voltages. Not an expert on this, that's what I heard. Only thing that limits battery Ah is if you can charge them using the chosen inverters. Rule says charge current of 13%-15% of Ah capacity, so in theory take the combined charge capability of the two Axpert MPPTs, and you can add 5-6 times that amount of battery. :-)
March 29, 201610 yr I've seen 2 Axpert 5kva inverters with a battery bank of 16x 260Ah batteries, basically 1040Ah @ 48V. Just remember, if you are going solar, you'll need enough panels to charge the bank
March 29, 201610 yr The 5Kva model is limited to 60A for Solar charging. 900ah x 13% gives you 117A. I think this is a little too high for two inverters. I would not go this high as this does not leave much room to play with. Depending on the size of the panels but I think for 30 you are going to be better of with 3 inverters
March 29, 201610 yr Author I've seen 2 Axpert 5kva inverters with a battery bank of 16x 260Ah batteries, basically 1040Ah @ 48V. Just remember, if you are going solar, you'll need enough panels to charge the bank I know. 10 or 12 panels per inverter. 250 or 300w
March 29, 201610 yr Author The 5Kva model is limited to 60A for Solar charging. 900ah x 13% gives you 117A. I think this is a little too high for two inverters. I would not go this high as this does not leave much room to play with. Depending on the size of the panels but I think for 30 you are going to be better of with 3 inverters I have 2 inverters now. And may upgrade to a 3rd later. Currently preparing my battery purchase. But want to buy the max allowable for the inverters. Would be great if I can use 16 batteries as mentioned earlier. (Sorry for not crediting poster. On phone)
March 30, 201610 yr 15 hours ago, FRZ0n said: Would be great if I can use 16 batteries as mentioned earlier. (Sorry for not crediting poster. On phone) Larger batteries... less strings :-)
March 30, 201610 yr Author Larger batteries... less strings :-) Now to find reasonably priced 200ah or more batteries
March 30, 201610 yr 18 minutes ago, FRZ0n said: Now to find reasonably priced 200ah or more batteries Trojan T105RE. 6V, 225Ah. 1600 cycles to 50% DoD. Around R2600 a battery or thereabouts iirc.
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