Moving my family- I need some thoughts on solar to keep food when grid goes down

inthejungle

I need some thoughts on what I should do. I have been asked to move to a new location in W. Africa with my family. The country has power, but has been recently having 8-9 hour outages. With little ones I don't want food to spoil and the Mrs. doesn't want to have to go shopping each day. Thanks for your thoughts

 

We need to accomplish two things

 

 

1-      We have a house with 220 power from the grid, it goes off from what we hear about 6-9 hours at a time in the peak dry season.

2-      We also have the issue of very high or very low power and constant fluctuations

 

I am thinking about using an inverter/charger with a small set of batteries. The batteries would get charged from the grid, when power goes off we would switch to battery knowing we have x amount of time to get power back.

I am thinking that I would have three panels, the main 220 from City power, a breaker box for inverted 220v, and another breaker box for straight 12v. I would have just the fridge on the inverter, then I would use some type of 12v LED light on the 12v panel.

All 220 from city would need a voltage monitor of sorts to shut if it was too high, too low or too much off and on.

If we go from the voltage monitoring to an inverter/charger, then to the circuits then we are running those off the batteries all the time. I would think that we would want to run the fridge off AC power 24/7, then charge batteries from the grid, if grid power fails then we would go to inverter power and run it until the grid was back up.

Is there such an inverter that would do something like this or how do we accomplish this? What are y'alls thoughts?

Thanks for your help

 

 

westbranch

Most GOOD Inverter chargers have some latitude as  to the acceptable power incoming, best start with what you can suss out about the power quality first ... your basic concept to be battery backup is workable but you need some hard facts... good luck

Photowhit

You might consider minimal frozen food and a couple gallon jugs of water (or freezer paks) in freezer, when electric goes out transfer the frozen water to the fridge. Should be good for 8 hours or so...

inthejungle

Thank you for your thoughts- WESTBRANCH the facts I am working on getting are the watts of the fridge, and then time I want back up. I have worked there for the past year helping with power and a hospital. I did a power study and the power was just awful, always 190 or 280ish and up and down most days. We are going to be in the city so the short 10 -20 second outages I saw will probably we hours. The fridge we are thinking of buying has a voltage regulator built into it, and is made by LG.

What do you think about the placement of the inverter and so on? How do I achieve the backup I want. I would assume a simple switch to go from grid AC to Inverter AC would suffice. 
How do I size the inverter for the fridge?

PHOTOWHIT- I hadn't thought about something like that, but the only problem I see is that the Fridge is European and doesn't have much freezer to begin with. 

westbranch

A small chest freezer is best for PW's suggestion rather than the combo types we are accustomed to...
You will need a n Inverter charger that switches automatically to the batteries when the power turns off.

Here is a link to a SAfrica dealer an GT type inverter...  the brochure indicates it is a good fit for your situation of on/off ....
http://www.rectifier.co.za/outback/NEW SPECSHEETS/GTFX2012E-SEALED.pdf

Marc Kurth

I have a customer here in Texas who does a large amount of battery backup business in parts of Ghana. He describes their power situation as "variable at best" but typically on for 24 hours and off for 12 hours. They seem to have rolling blackouts as a load shedding plan.I have not seen his install work, but he describes it as minimalist. Now he is working toward incrementally adding PV as budgets permit.

His first step is to install an inverter charger kit (typically 2000 watts) powered by the mains, with battery bank sized to sustain the minimum critical loads. His typical battery bank seems to be 7.2 KWH to cover a 12 hour load of about 2-3 KWH.

He selected AGM batteries because he did not trust that flooded batteries would get maintained. He expects to get around 5-6 years of battery life knowing that he is cycling about 200 times per year and always getting a fast and full charge - plus float time after every discharge cycle. The first system is about 3 years old and running well.

I will ask him which inverters and/or inverter-chargers he is using, because I know that he was not happy with some that he tried.

mike95490

I can see as more and more banks of UPS's are installed, that the surge demand on the Grid, when it's eventually restored, will blow it as all the battery chargers kick in and try to bulk up the batteries.

inthejungle

Marc- what you described is exactly what I want to do. We had been pulled out of our last location due to Ebola and because of this I don't want to dump a lot of money in the beginning. You said
"His first step is to install an inverter charger kit (typically 2000 watts) powered by the mains, with battery bank sized to sustain the minimum critical loads. His typical battery bank seems to be 7.2 KWH to cover a 12 hour load of about 2-3 KWH. " That is what I am thinking can you please talk to him and see what he has done and used. That would be really helpful. Thanks

inthejungle

I have a buddy who is going to buy the fridge ahead of time for us, I asked him to look at the spec sheet inside the fridge and send it to me, he is going to get an LG. Here is the info on the inside can anyone help me sort out how to size my inverter for it?

Defrosting Input:  150w

Rated Input of Heater cord:  115 w

Thanks

inthejungle

My numbers I think look like this- is this right

I would assume that we would add these two together so 150+115=265

265/240=1.10 amps

Does that sounds right?

I would assume that 265w with 15% startup power needed would be 265*.15=304.75 or 305

It would seem that a 500w inverter would be fine, I am thinking about using something like this

https://www.victronenergy.com/inverters-chargers/multi-500-va

Do you agree?

Marc Kurth

inthejungle said:

Marc- what you described is exactly what I want to do. We had been pulled out of our last location due to Ebola and because of this I don't want to dump a lot of money in the beginning. You said
"His first step is to install an inverter charger kit (typically 2000 watts) powered by the mains, with battery bank sized to sustain the minimum critical loads. His typical battery bank seems to be 7.2 KWH to cover a 12 hour load of about 2-3 KWH. " That is what I am thinking can you please talk to him and see what he has done and used. That would be really helpful. Thanks

He responded with:
"Ignoring your advice, I am using 24v, 2000 watt AIMS inverter-chargers because of their low cost. So far, no failures."  (Keep in mind that it's only been about a year I think.)

Photowhit

inthejungle said:

My numbers I think look like this- is this right

I would assume that we would add these two together so 150+115=265

265/240=1.10 amps

Does that sounds right?

I would assume that 265w with 15% startup power needed would be 265*.15=304.75 or 305

It would seem that a 500w inverter would be fine, I am thinking about using something like this

https://www.victronenergy.com/inverters-chargers/multi-500-va

Do you agree?

Jungle, others will be along to give a 'more correct' answer, but the math is basically wrong.

The heater is a pure resistance load, so it's 150 watts with no startup needed. The compressor, if that is what the 115 watts represents, is a motor, so the startup my be 10X the wattage. If there is a "lock up rotor" number that would be the peak, but I would use 10x the wattage to be safe! or 1150 watts. These will not run concurrent, so max would be 1150 watts.

This can be low! Modern fridges tend to have softer starting, but I'd hate to have you under size and have to try to return an inverter.

jonr

If possible, buy a refrigerator that has an internal inverter driven compressor.  Then you won't have the startup load problem.

All unused space in the refrigerator should be kept filled with jugs of water.  The same for the freezer, but maybe with a little non-toxic antifreeze to shift the phase change temperature.  20% propylene glycol?

inthejungle

Photo wit- thank you for correcting me- well that changes the picture I knew it sounded strange.  How do you size up an inverter for this?

Jonr- how do you tell if the fridges have an internal inverter driven compressor?

westbranch

Inverter fridges   have  INVERTER boldly displayed in their advertisements and tech information.... at least north of the US /Mexico border and the only models available are >$3000.....in Mexico the lower priced models are available as well as other places in the world..
LG and Samsung are the major brands in N.A..

BB.

Some have used the term "Linear Compressor" (different style of compressor)--But also (should be) an "inverter" type unit (low starting surge).

-Bill

vtmaps

inthejungle said:

Jonr- how do you tell if the fridges have an internal inverter driven compressor?

The "inverter" fridges have variable speed compressors.   It is more efficient to run a compressor at half speed all the time than to run it at full speed half the time.   Whatever its called, the key is that the compressor runs at variable speed.  The low startup surge is a bonus.

DC powered fridges with the Danfoss compressor all have variable speed compressors.

--vtMaps

inthejungle

I just found out that a buddy bought one these- probably will get one that is just a bit bigger, but should have the same type of compressor.

LG FRIDGE It has the inverter compressor- with that in mind how should I size up the inverter?

westbranch

the tech section has NO tech specifications, just physical size...  you will probably have to contact them directly...  please let us know what you are able to garner ...
TW My standard 2014 18 cu ft GE fridge runs easily on a Cotek 1500W inverter... the newer the better, power use drops a bit each year

inthejungle

THANK YOU for all of your thoughts. I have had a very frustrating morning trying to get info from LG.

 I have contacted LG about that fridge and LG US and LG France say that they can not give me any more specifications on the compressor. What should I do? How do I size the inverter? How do I size the batteries?

westbranch

try LG Hong Kong....??   http://www.lg.com/hk_en

inthejungle

nothing, I tried calling and e-mailing a few days ago

inthejungle

LG is basically saying unless I am a tech they won't speak to me

Dave Angelini

Try looking at stores that sell LG in your market. The inverter based or linear compressors are fairly new technology and my experience with your part of the world is often not where a manufacturer wants to place new technology.
Look for inverters that are supported there also. Outback and Schneider for instance have fairly good support in the big cities there. I would think a 24V inverter/charger and about 400 AH of battery would back your refrigeration/basic house loads up and cost around $3K US. You also want to find as local as you can of a supplier of the battery for warranty, if possible.
Good Luck

inthejungle

I received a picture of the compressor, then searched and found a PDF from LG that gave me this info. Can someone help me size things up? The numbers from the PDF are:

220-240 AC
Max input Power 260w
Max input current 3a

I am thinking of using this inverter, because it is setup for multiple inputs from grid and genset if I want it in the future

https://www.victronenergy.com/inverters-chargers/multiplus-12v-24v-48v-800va-3kva

westbranch

240V - 60-225 HZ -LRA2.2  3PH....  that is 3 Phase  the I believe., don't know the influence that has.  That may be the reason for the warning about using the Controller,  seen at the top of the label

Dave Angelini

Isobutane refrigerant was in a clients fridge that leaked here in California last year.
 The warranty repair from a leak went on for months. The manufacture gave my friend back their money. At the time they did not have anyone licensed to fix and refill the refrigerant here.

Victron is a good company also.

It would be very hard to get accurate data on the specs you have because they are not taking the variable speed into consideration,  the size of box, and ambient air temp./defrost.

inthejungle

Thanks for your thoughts, any suggestion how I might be able to plan well with all those in mind? Do I size off the highest number?
We leave in a few weeks and I need to order this week. Thanks

Dave Angelini

You can't design until know what your loads are?
If I were you I would just plan on a typical refrigerator you can buy in your country.
What do you have now? 
If Victron makes a 2KW or more inverter/charger you should be fine.
Depending on what batteries you can buy would be how I chose 24 or 48V.
Usually you can find a 400 or so AH battery @20Hr rate. If I could get one like that I would choose a  24V inverter.
It will be cheaper to replace batteries when they fail.
Good Luck!

inthejungle

I think that I am going to go with this LG refrigerator, after looking at things these are my numbers

260W AC = 300W DC /12V = 25A @ 10hr = 250AH. If I assume that to be the absolute worst case and discharge 50%, that would be 500AH batteries,

I am thinking 1600w inverter and 500ah batteries

westbranch

and add another fudge factor for the battery inefficiency of recharging a min 10% and max 30% for the amount of watts needed to replace what you draw out (250 Ah), just to be safe so 550 to 650Ahr battery...  yes I know you did bump up the 260W but you can also have hotter ambient temps than expected and that also adversely affects batteries, lower output capacity (2 day) and (daily) recharge efficiency...