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Michelle Konzack avatar image
Michelle Konzack asked

Which batteries?

Good morning,


one of my customers has a small 16sqm house called Trian-S with ab

Kostal PIKO MP plus 3.6-1 and 12 solarpanels 275Wp installed.


Unfortunately they have in Poltsaama several times per year an electricity problem for 6-24 hours.


Since the Kostal is connected directly to the Main in the Fusebox, my idea is to open the main cable from Elektrilevi and put a MultiPlus-II in the line. The AC2 will get a Schuko socket for a small 48l MiniOven with two cooking plates.


AC1 has to keep the house alive including an Grundfoss UP15-14B for the underfloor heating system.


However, in my installation this very silent humming of the MultiPlus-II does not matter, but if you have to sleep 2-3m aside it is annoying.


The house is placed on 9 FIBO blocks and it is possible to access the space between the ground and the bottom of the house, hence my idea is to put the Inverter in a Rain/Snow proove box under the house directly on the gravel and go with the 3 power cables and the VE.Bus cable from the bottom into the house.


The question is now, about the batteries, because my customer is a woman, absolutely not technical even if she has some fundamental understanding.


I assume, that I can not place the batteries in the same box like the MultiPlus-II, because they would not survive the direct cold of an Estonian winter of up to -40°C.


Hence I have to place them into the house.


The power consumption over 24 hours is approximately 3-4kWh and I like to know which Batteries (Type ayound size) can recommend for this use.


Note: the MultiPlus-II has to be configured as Sell-Back Inverter AND UPS


Thanks for your help

Michelle

battery charging
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Michelle Konzack avatar image Michelle Konzack commented ·
Should I get rid of the KOSTAL and put a SmartSolar MPPT 250/70 there?


When I had to repair the roof, I have reconnected the solarpanels in a way, that I can easily make two parallel strings of 6 modules without climbing on the roof.


I know, with 6 modules in series I will get a lower power output, but in case the battery goes down and my customer does not want to charge from the GRID, the SmartSolar works always.


Note: the house is only occupied occasionally, he CE if recharging take 2-3 weeks then it is even OK.


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jkmann avatar image
jkmann answered ·

I would hesitate to mount the Multiplus under the house exposed to extreme cold. Condensation on the electronics can destroy the unit, and it's really designed to be kept above freezing. That location would also make any maintenance challenging. However, if you have experience with this working OK in that climate, then go with experience.

Personally, for this application, where usage is occasional and the outages are no more than a day, I would consider a generator as part of your solution to cut down on battery requirements.

If you have space for sealed AGM batteries that will be the most cost-effective solution, and they will be less sensitive to cold than lithium batteries. Deep cycle AGM batteries can usually be drawn down to around 50% of their rated capacity without problems.

Just a reminder that many men are absolutely not technical as well. Designing a system to be "idiot proof" is just good design.

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Michelle Konzack avatar image Michelle Konzack commented ·
Thankyou for your answer.


Many people love my system with 141kWh of SOPzS batteries, but when they here about problems in the Winter, they get cold feeds.


I have installed an Water based Underfloor Heating System using a DieselHeater Eberspächer D5WSC 24V and a custom made HeatingBuffer which includes 4 Heating Elements 2000W and one with 2x 750W (all 48V) which are the break resistors for my 6 Windmills. Yeah I do not want to wast energy, even if the Break Heating is only seldom.


The Battery house has on the front the 4 doors with the 8 Battery sets and on the back the electric room for the distribution panels chargers and Inverters. The whole wooden building is 200mm EPS insulated.


In some meter distance I have a seperate building housing 3 Bottles Propane of each 33kg for my Generator which is currently a cheap China one from a building shop and was just 3 weeks ago falling apart after 1200 operating hours in less then 2 years.


Now I head for a KOHLER-SDMO HXC6000 because it use a Honda GX390 engine for which I have a Tri-Fuel Careburetor which let me use Propane.


If I tell people, that the Generator cost 1990€ and has not even an electro starter hence no remote control, they become already sceptic. And if I tell them, that the manual say clearly, if the generator is not used for a long period (precisely in the summer) it requires a maintenance run for one hour every month... Cost 2,5l Benzin or equivalent Propane.


It is VERY hard to design an Idiot-Proof Off-the-Grid or even Semi-Off-Grid system if the customers are Noobs and live more then 100km away from me.


I have currently for comming year 21 potential customers where only 3 living in a radius of 50km. All others are 100-250km distance. Not a distance where you can just drive there if an error happen.


My Victron Off-the-Grid setup is rock solid and has never let me down in the past 5 years.


Victron is definitively the way to go, but you must know, what you are doing.


I would like to make the Victron certification, but because I can not travel abroad there is no way to participate in any Victron Seminars in France or Germany (the Baltic states are excluded by Victron). I do not know about Finnland or Sweden which would be an option for me, but I do not speak those two languages.


Have a nice XMas

Michelle


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jkmann avatar image
jkmann answered ·

It sounds like you have extensive experience already, so probably little that I can add to your knowledge. Just a couple of thoughts on making a system let's say "idiot resistant."

1) Although it's simpler to make a single, monolithic system sometimes it's better to make separate duplicated systems that normally work together, but also have independence, so that if one piece of equipment fails (which is inevitable), the system can still operate at reduced capacity until repaired. This design technique is used for space vehicles where repair is often impossible. This is a separate point from a "backup system" such as a generator.

2) Although it ADDS complexity, indicator lights (sometimes called idiot lights) and meters collected all in one place make a system problem easier to diagnose for a non-technical person. This is how nuclear power plants used to be designed (I'm not sure how they work now).

When I travelled to Finland and Sweden for business, the people that I interacted with were all very fluent in English. You might try contacting the Victron people there to see if there is a training that will work for you. Also, if your Internet connection is adequate, due to your travel challenge, Victron may make an accomodation for distance learning if you request it.

I admire your ingenuity. All the best!

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Michelle Konzack avatar image Michelle Konzack commented ·
Thankyou for your comments.


But as I sayed already, my farm "Miila Mahe Aed OÜ" is an experimental farm, my tech sandbox and a reference project how on 59° Latitude someone can have an enterprise and being Off-the-Grid.


However, yes it works, but need very much effort to keep it running. Today we got very nice sunshine and I wish, I would have already the new Solarpanels installed, because from my current 1860Wp I got today approximately 900Wh after clean g the Panels. It use only a SmartSolar MPPT 150/70-Tr VE.Can because the 250V version was not availlable at this time.


The 6 new panels have 2460Wp and get a SmartSolar MPPT 250/100-Tr VE.Can which should deliver nearly twice the energy from the first one.


In the summer I have to think about what to do with the Energy, because it will be hard to use up 40kWh. Maybe I will install a circulation pump an some heating elements to heat up a 50m³ heating buffer in my new (I start building in spring) Greenhouse (12m long, 7m deep and 4m high) which fully I slated and should work also in the Winter.


Have a nice Xmas time


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