Good Day ,

 

I have a Mecer sol-i-ax-5p inverter ,12 X 360W solar panels and 2 X LITHUIM LFP BATTERY 5.5 KwH/7KWp 42-69Vp SCh BMS & RCOM.

 

I mainly use the solar system for a 1.2kw bore pump and Tesk PMC5-40 1.1kw VSD 230V pressure pump.

 

The pressure pump is working well with the system ,however the borehole pump seems to be draining batteries a lot even during the day when there is good sunlight 

 

Are there settings l can use on the inverter to use mainly power from the panels when using the Borehole pump as l use it to pump water to a 5000litre water tank during the day .

 

My borehole is 30meters deep and the tank is 200m away from the borehole on a slight uphill.

 

I am completely off grid and don’t  have any other source of power .

 

I would appreciate any suggestions .

 

Thanks,

 

Victor 

 

 

 

 

 

2 hours ago, GarethA said:

I mainly use the solar system for a 1.2kw bore pump and...

The problem is that the load is relentless, and solar power is intermittent.

You might be better off with a solar motor/pump inverter on separate panels, or perhaps split the panels between the 230 V inverter for general power and the bore pump. The bore pump will then operate at variable speed, running faster (more load) as there is more solar power available. The pump inverter will optimise the motor speed to get the most from the available solar power. You might want some sort of changeover so you can occasionally use the battery if needed, but most of the time just pump when the sunshine is good. If you don't get enough water moved that way, you just need more panels. If your tank gets full, switch off the bore pump (preferably via some automatic method).

It might be difficult to find a solar pump inverter that operates with a single phase motor, I don't know how that works.

What Coulomb says.  AllPower in PE have a fantastic borehole pump which costs around R20K.  The place I used to stay has one.  2 x 120W panels, no batteries, comes with a mppt controller.  We fed 3 x 10KLt tanks also about 200m away, up a hill with no problem, kept them full and every few days we had to switch the pump off or the tanks overflowed.  If you need more volume you just parallel more panels. 

What head and flow rate can the current 1.2kW borehole pump achieve? Model code available to check spec sheet? I tried looking up similar pumps, and found a 1.1kW borehole pump with a 38m head, and a 1.5kW with a 45m head. Considering you're going 30m deep, then uphill at a slight incline over 200m, I'm just wondering how much scope you've got to reduce the power to the pump until the flow rate drops away. Might be a non-issue in this case, just wondering.

The 1st thing I would check is what level in kW are you getting from the panels during the day. If PV is mostly used for the pump then one would expect the 4.3kW of panels should be able to power the pump most of the time without dipping into the battery accept when there is clouds. 

1 hour ago, Scorp007 said:

The 1st thing I would check is what level in kW are you getting from the panels during the day. If PV is mostly used for the pump then one would expect the 4.3kW of panels should be able to power the pump most of the time without dipping into the battery accept when there is clouds. 

Agreed, if you're pumping in full sun at midday the power should be covered from solar. Part of the reason I was wondering what the head and flow rate are. And in the end the runtime to fill the tank versus time pumping against gravity.

1 hour ago, GreenFields said:

Agreed, if you're pumping in full sun at midday the power should be covered from solar. Part of the reason I was wondering what the head and flow rate are. And in the end the runtime to fill the tank versus time pumping against gravity.

That was another good point. My line of thinking was if the thermal protection is adjusted at the correct amps the pump would trip if it is labouring to overcome the total head even when running from batteries. Also one needs to check on the inverter what the total load is when borehole and the pressure pump is running. Could be that the pressure pump is the culprit although it only works for short periods. 

This morning at 09h55 just before LS I found 2 of my strings were producing at 42% and the 3rd one at 50%. All 3 facing north but the 2 at 42% are flat on a car port and the 50% one at a 26deg tilt. 

This gives an idea of PV available for about 4hrs in the day to power the pump from PV.