Off grid system needs beefing up.

[Raul]

Some of you may remember about 3 months ago I built a system for a holiday home. I had it running here in London for a while as a bench test then installed it on my holiday home in the Carpathian Mountains.
I would like to say a BIG THANK YOU DERECK and all you guys that have contributed directly or indirectly for the info and knowledge I needed and found on this site.
So my system consists off: 6x240w trina poly, 150vdc 35a victron mppt charger, 1200w 48v victron inverter, bmv 700 victron battery monitor with a 500a shunt microprocessor controlled and a Bluetooth dongle connected to the charger. The batteries are used agm yuasa 100ax8= 2 parallel banks of 48v.They are coming up to 5 years bought them for scrap value and intend to upgrade them when they show any weakness.

Here is my problem;
our consumption was 95kw for the 46 days we stayed there =average of 2kw a day of AC power used. this is all good with one situation where we had no sun for 3 days and the 4th day we had to conserve power to get the batteries finish the absorb and go into float before sunset.
The array is on the roof facing south east so after 5pm or so we loose quite a bit of useable power. During sunny august by 10am it was on float compared to the September early October I barely reach absorb by 3-4pm. To improve on this I was proposing to add 600w+ of panels on the west side on a separate mppt .

My other problem is a unexpected added consumption that was not on the plans before. We used to have a gravity feed water from a land 400m up a hill. Unfortunately I used to share the use of those wells with my neighbours . We bought the land dug six wells interconnect them and draw from 1 with a 60mm pipe 400m down hill. One uses more than the other and leads to re prime the pipe every few days , had enough and dug my own in the garden but I have to use a 1kw pump to feed the house. It works fine to a extent This pump usage was not anticipated therefore puts a strain on batteries and inverter specially when somebody is having a shower and the fridge wants to start. I was proposing to get another identical inverter and parallel stack them if its possible.

I know I can add panels on the west side and a additional mppt charger linked to the existing charger . What I'm not sure if I can parallel the inverter or to go for a bigger one.

[Naptown]

I did not see a generator listed.
You need to have one even if it is a small honda EU
adding panels may mean upgrading or adding another charge controller.
Some inverters can be stacked check with victron to see if possible with yours. Should be in the documentation that came eith the inverter.

[inetdog]

Stacking another inverter may not be enough by itself, depending on whether your battery bank can handle the extra current without excessive voltage drop.

[Raul]

I have a genny but I would rather not use it . The panel option means longer harvest time also extra available power to be used if needed while the sun is still up. It will need to work on another mppt so adding a controller is not a issue. The inverter upgrade is to cover the surge while the pump is on and the fridge needs to start. In all other situations works fine , 200a @48v batteries are holding good with a 3 day reserve is more than we need,.
We use this place 2 times a year 6 weeks at a time and 12 weeks in total. In between it gets shut down . I got somebody to turn it on every month for few days to cover the self discharge .

[Mike90250]

I guess you already have the pump installed in the well. Try to find out what the "LOCKED ROTOR AMPS" spec is, that is what the inverter, batteries and cables have to supply to start the motor. If the batteries and interconnecting cables are too small, the inverter will be starved for power and not able to start the pump.

I'd consider using a 2nd inverter of enough size to power the pump only, and select an inverter with a "sleep" or "standby" feature, so that when the pump is not running (95% of the time) the inverter is sleeping and not consuming a lot of idle power.

Adding more PV and another controller sounds like a good idea, and gives you redundancy if one fails.

But this will stress your current battery bank, and so, use it till it fails, and then plan on installing a larger one for the new loads. Don't bother installing more cells now, wait till this bank fails.

The specs for the larger inverters read thus: (I chose the XW like I have/use)

Electrical Specifications
Table A-1
Xantrex XW Power System Electrical Specifications
Xantrex XW6048 120/240 60
Continuous Output Power 6,000 W
Surge Rating (10 seconds) 12,000 W (15 s) (stand-alone invert mode)

Xantrex XW4024 120/240 60
Continuous Output Power 4,000 W
Surge Rating (10 seconds) 8,000 W (20 s) (stand-alone invert mode)

Dig for your inverter specs, and match the surge to the pump starting demand

[Raul]

Thank you Mike.
I gues another pump only dedicated inverter is one solution or a larger one all together. The existing one is a 1200w- 2400w surge . Pump surge is 2400w I measured it . It uses up all the surge leaves the fridge to struggle . Amazingly it worked but the inverter was screaming like a welder so we had to unplug the fridge when using the shower.
I got plans to build a garage so I may go for a large enough inverter to service the pump and the garage . The battery bank it will be upgraded but so far this agm behaves well and the interconnects are large enough for 80a I believe 25mm2 stranded copper thinned with crimped ends .

[Mike90250]

...... Pump surge is 2400w I measured it . .....

Not at all likely. A pump that draws 1Kw running, will have a 2 second surge of at LEAST 5 KW. You can only measure that surge with a $400 peak hold meter, or a storage scope with a ballast resistor in series with the pump. A $200 clamp on meter cannot capture the short surge a motor draws when starting, their averaging system prevents that. I guarantee it !

And remember your inverter losses, when just sitting there powering the 5 watt radio in the garage door opener, the inverter burns 30 watts (mine burns even more) just sitting there. That, over 2 cloudy days, along with your other inverter's losses, will really bite your batteries.

I want you to be able to install a decent system that will be able to start your pump at 6 in the morning, after a cloudy day, and the batteries are low, an inverter that is too small, won't give you water.

[Raul]

I measured it with a kill a watt type meter that records the high spikes. In normal operation mode it draws 800-950w . It has a large capacitor and thermal overload and in addition I added am pressure switch that controls the pump by sensing the pressure . This it has a additional large capacitor and a circuit board and allows you to set the on off pressure .
I also have moved the one way valve 8 feet or so up the pipe so the pump does not start under pressure load except of the submerged depth that varies as I use the water.
The pump is a Wasserkonig WKM5600-80

[Mike90250]

I measured it with a kill a watt type meter that records the high spikes

OK, I was totally unaware of any inexpensive peak hold ampmeter . I guess you are all set to enjoy.

[SunEagle]

OK, I was totally unaware of any inexpensive peak hold ampmeter . I guess you are all set to enjoy.

Remember that "kill a watt" meter is only good for 120 volt equipment that are plugged into a receptacle. Having a quality "clamp on" AC/DC meter is well worth the cost in the long run.

[inetdog]

Remember that "kill a watt" meter is only good for 120 volt equipment that are plugged into a receptacle. Having a quality "clamp on" AC/DC meter is well worth the cost in the long run.

But any ammeter, clamp-on or otherwise, will only let you know the VA (volt-amp) consumption at a point in time.
It will not tell what the Watt consumption is if the device has a low power factor. Lightly loaded motors and some electronics can have a power factor as low as .5.
Nor will it easily tell you the consumption per day of a device which cycles on and off automatically.

[SunEagle]

But any ammeter, clamp-on or otherwise, will only let you know the VA (volt-amp) consumption at a point in time.
It will not tell what the Watt consumption is if the device has a low power factor. Lightly loaded motors and some electronics can have a power factor as low as .5.
Nor will it easily tell you the consumption per day of a device which cycles on and off automatically.

I have no issue with someone getting a kill a watt meter along with a quality clamp on AC / DC meter and multimeter. (I have all 4 types).

All of those have "specific" functions that the others may not have and combined will provide the full range of electrical data for most user needs.

There are also high end power quality meters, (which I have some access to) that not only do what all the others above do but will also provide live and historical data (including graphs) to help determine what if any issues are around.

Just like a mechanic, carpenter or any other Trade person. Having the right tool makes your day go easier.

[Raul]

To make it clear a kill a watt meter in Europe doesn't exist is a American thing as well for the 120v thing, only on building sites. We got the efficient 230-240v grid. What we have is a similar device that's why I used the word (type).
It has many functions ; voltage, frequency, timer , cost unit, power and peak power . The peak power is so rapid that you have to scroll thru the menu to se it recorded as it happens so fast . You can zero that value if you want to se the next spike or it will be covered by next bigger one but it will not show a lower value if you haven't deleted the one recorded. I'm not sure if is accurate but it's pretty spot on normal consumptions. I do have 2 multimeters and one measures to 600a ac and the other to 20a DC ; I do use them but prefer my plug meter for certain stuff. Ah almost forgot my ancient true rms is handy to .

[Mike90250]

It has many functions ; voltage, frequency, timer , cost unit, power and peak power . The peak power is so rapid that you have to scroll thru the menu to se it recorded as it happens so fast . You can zero that value if you want to se the next spike or it will be covered by next bigger one but it will not show a lower value if you haven't deleted the one recorded.

That is just awesome. Wish we had those on this side of the 120V pond.

Well, you seem pretty confident in it. Does it measure Power Factor - I didn't see that listed in your specs.

[Raul]

I have measured that as well with a friends fluke345 , he works for the grid. Then I changed the 2.5mm to a 4mm armoured copper cable to the pump due to distance and with the capacitors I still cant get to 1 but no negative. I will have to make sure the inverter I chose will be to service this pump only and if necessary I might use 2 extra conductors to double up on the 4mm as I berried a 5 core. THD it varies up to 5% almost when demand increases.
I'm still learning, but I think I will get there or there abouts.