Bush Man

Thanks, Chris! I have a Meanwell 3 Stage Switching Mode charger http://www.bushpower.co.za/products.asp?pid=256 Will that do the job?

Thanks, Chris How do I email you to arrange details?

Hi Chris! Chris Hobson suggested I contact you re battery balancers - see the Charging Matters thread. From the thread: My off-grid system on a farm in Limpopo as commissioned in September 2016 is as follows: 1. 6 x Enersol 255W panels in two strings of 3 each, installed at a 10% north facing angle. 2. Microcare 3 String combiner box (currently using only 2 strings) 3. Axpert 5KVA inverter - Float at 54V, Bulk at 56.4V, cut-out at 48V, Max charging current 40Amps (being 13% of 300Ah). 4. 8 x Omnipower 180 Batteries, which are actually 150Ah at C/10, giving me a 48V 300Ah system. And also: The Axpert reading was back at 54.0V when I got there mid-morning, but then the place has been standing idle for the past week with only the fridge-freezer running. With the multimeter I measured the top 4 batteries which are easily accessible. Nr 1 and 3 were around 12.5V and 2 and 4 were around 14.5V. Could you give me an indication of cost and other requirements? I'm based in Pretoria.

OK, guys, was up at the farm today, I rigged a temporary gravity supply from up the hill, and it worked like a charm - all the gas geysers igniting etc. So it looks like I'll be able to do away with the pressure pump altogether. The Axpert reading was back at 54.0V when I got there mid-morning, but then the place has been standing idle for the past week with only the fridge-freezer running. With the multimeter I measured the top 4 batteries which are easily accessible. Nr 1 and 3 were around 12.5V and 2 and 4 were around 14.5V. I gather that's not ideal. What should I do?

Thanks, Paul! I keep on being amazed at the range of solutions cropping up from the discussion. I've had a look at your pump - looks nice. My current 800W pump automatically kicks in when the pressure from the normal supply drops below 1 Bar (adjustable). Does your pump have the same functionality?

1. The Omnipower specs I have are as follows: Cycle Service: 2.35+/-1%V per cell at 20/25C If I multiply 2.35 by 24 cells, I get 56.4 rather than 57.6? 2. check them with a voltmeter to see that they are still performing well I have a digital voltmeter. How to I check the batteries' performance?

Thanks, guys, much appreciated - there's a lot to chew on!

Would it then make sense to add additional panels if the batteries can only use 900W of the existing 1500W panels?

Thanks, will switch off the alarm for a week or two in any event and see if it makes a difference. My last question for now. On a typical sunny day last year while charging the batteries mid morning I almost never saw the Axpert PV Input reading exceed 900 Watts, despite the 1500 odd watt panel array. As per Don's input, the current Axpert settings allow up to approx 40 Amps/2000 Watts into the batteries. Why then only 900 Watts on the reading? I have since seen it peak at 1400W once when I switched on the microwave as well, so all the panels are connected and available.

Before I forget, the batteries are indoors in a well ventilated cupboard. Also during December I fitted a contact switch 12V alarm to the cupboard door. Apart from the contact switch it consists of a 12V siren and a small electronic timer for the siren (see attached). I connected it directly onto one of the batteries. Could this have any significant impact on the batteries or recharging? Alarm Timer Instructions.pdf

Thanks, guys - a wealth of information as always! Another string of 3 panels is definitely an option, and not that expensive. Before I go there, however, I would like to see if I can't remove the potential culprit from the equation, i.e the pressure pump. The normal water gravity supply system is also solar dependant (not my solar). The result is that it often runs dry on overcast days, at which point I need to fall back on my backup storage and the pressure pump. Being overcast, this puts strain on the batteries, causing a deeper discharge than originally intended, with the batteries then struggling to recover. I'll see if I can move my backup storage up the slope to create my own gravity feed, and do away with the pressure pump. A point of interest, during overcast weather the six panels still generate 200-300W worth of PV input for most of the day according to the Axpert reading. Taken over 6 hours, this equates to 1200 - 1800Wh, which should be more than sufficient to run at least the fridge freezer and some LED lights indefinitely if I'm not mistaken? Don mentioned in his first post that in order to get to 40 Amps charging current I would need to get to around 2000 Watt of panel input. How is this calculated?

Thanks, Don, much appreciated! My thinking in setting up the system was as follows: The Fridge-Freezer (A++ Rating) draws 600 Watts over a 24 hour period (226kWh/year), and the two bar fridges together do the same. 1200 Watt-hours are thus withdrawn over a 24 hour period. The panels can put back say 1300 watts for 6 hours, i.e. 7800 Watt-hours. My reasoning was that 1200 Watt-hours daily draw as opposed to 7800 Watt-hours daily supply should leave more than sufficient spare capacity for the other occasional uses, particularly as the Axpert allows the dishwasher (used on sunny mornings only) to be supplied directly from the panels. Where lies the error in my reasoning?

Good evening to all! I hope that in time I'll learn enough so that I can contribute as well. With lots of input from the forum, my off-grid system on a farm in Limpopo as commissioned in September 2016 is as follows: 1. 6 x Enersol 255W panels in two strings of 3 each, installed at a 10% north facing angle. 2. Microcare 3 String combiner box (currently using only 2 strings) 3. Axpert 5KVA inverter - Float at 54V, Bulk at 56.4V, cut-out at 48V, Max charging current 40Amps (being 13% of 300Ah). 4. 8 x Omnipower 180 Batteries, which are actually 150Ah at C/10, giving me a 48V 300Ah system. Load is as follows: 1. Fridge freezer - 600W per 24h (as tested over 3 days in December) 2. Two bar fridges on occasion - jointly 600W per 24h (as tested over 3 days in December) 3. Microwave 1500 Watts - only occasionally for a short period 4. Dishwasher 1100 Wh per cycle - only on sunny mornings to draw directly off the panels. 5. A couple of LED globes for lighting 5 800W pressure pump occasionally when the gravity feed water system isn't operational. The place is mostly used on weekends only, with only the fridge-freezer running permanently. I have 2 questions to start off with: 1. The maximum charging current is set at 40 Amps as per above. How many watts would that be? 2. For the first couple of months the system was working as expected. It charged at around 56.4V, and stabilised at 54V before mid day. It was very rare to see it below 50V. In December it was necessary once to allow the system to go down to 46V with the pressure pump working overtime during an extended overcast spell. Since then I have rarely seen a charging voltage above 54V, it typically stabilises at around 52V and it is often below 50V. The Axpert settings are still as before. Could such a single deep discharge damage the batteries, or should I look for something else? Will appreciate your comments!