Unhappy with off-grid 48 volt system

[russ]

Sorry, this is one area we never go to. Buy yourself a Victron Phoenix 48V1200W inverter and your problems will be over. Get MicroCare to refund you and you will have a system that will work for the next 25 years and the money back from MicroCare will pay for the Victron and you will have some money surplus. the Victron can overload 100%. this inverter will drive a kettle or microwave with you fridge, TV and lights. The price is +/-R7000 excl. Vat

Never again do you try to sell here - OK. I thought you were trying to help the guy so I left it in but you turned out to be nothing.

[mapmaker]

Sorry, this is one area we never go to. Buy yourself a Victron Phoenix 48V1200W inverter and your problems will be over. Get MicroCare to refund you and you will have a system that will work for the next 25 years and the money back from MicroCare will pay for the Victron and you will have some money surplus. the Victron can overload 100%. this inverter will drive a kettle or microwave with you fridge, TV and lights. The price is +/-R7000 excl. Vat

His problems can not be over until he has a properly sized, single string, battery bank. That is necessary, but may not be sufficient... There's a lot more to the system (controller, wiring, connectors, inverter, etc) that need to be checked out.

--mapmaker

[Victron]

Good inverter

Sorry, this is one area we never go to. Buy yourself a Victron Phoenix 48V1200W inverter and your problems will be over. Get MicroCare to refund you and you will have a system that will work for the next 25 years and the money back from MicroCare will pay for the Victron and you will have some money surplus. the Victron can overload 100%. this inverter will drive a kettle or microwave with you fridge, TV and lights. The price is +/-R7000 excl. Vat

[Mike90250]

repeating Sunkings test method:

You need three tools to determine battery condition: Hydrometer, Digital Volt Meter, and Thermometer. A good hydrometer will have thermometer built into it. Click here for Method of Procedure. Read it several times until you are confident you grasp the procedure then report back. Be patient it will take a while to go through all your batteries. Consider yourself lucky if you can find just 4 good ones.

Stick with a 48V system, more efficient, less loss than trying to backtrack to 24V.

If you cannot find enough good batteries, there is always the Golf Course. A common golf cart battery is 6V, 200ah or more. 8 of those, wired in series, would be about as cheap as you can get, to keep the system going while you debug what's wrong. 48V 200ah : 9600watt hours, 4800 useable. And 2 banks can be paralleled easily, if you connect to the terminals properly: (on the "diagonal")

http://www.smartgauge.co.uk/batt_con.html

And it could be that the fridge is the culprit. If it's not an energy efficient model, it can really chew through the batteries.

[Bastian Bakkes]

I am a supplier and lost seriously with MicroCare inverters where the customers didn't want to pay me and I had to upgrade them to a good make.
Now, six months later, MicroCare come with an invoice(R35K) for the faulty inverters we send back to them.
I think you have a serious system and just need a good inverter. Where is your place? I can stop there sometime. We work al over SA.

In the Alexandria-area , 90 km's from PE , towards East London .

[Victron]

MicroCare

I am a supplier and lost seriously with MicroCare inverters where the customers didn't want to pay me and I had to upgrade them to a good make.
Now, six months later, MicroCare come with an invoice(R35K) for the faulty inverters we send back to them.
I think you have a serious system and just need a good inverter. Where is your place? I can stop there sometime. We work al over SA.

[Bastian Bakkes]

Is your system still going? We had similar problems, it was the inverter. Get yourself a good inverter. Also look at "Hello Peter'

Let me answer it this way , system is still installed but not going . For me to manage this unreliable system , over a distance of 140 miles , is sooooo difficult . Therefore I leave it switched off , least frustration . Glad you found a solution .

[Victron]

Low quality inverter

Is your system still going? We had similar problems, it was the inverter. Get yourself a good inverter. Also look at "Hello Peter'

[Sunking]

Unfortunately your " Method of procedure " can't be clicked on .

Try again, my bad forgot to put the link in.

OK got your location. Go edit your location as it is too precise to have the public see it. I got what I need to know. Lets just say Port Elizabeth South Africa and call it good.

[Bastian Bakkes]

Unfortunately your " Method of procedure " can't be clicked on .
My wife and I go to this farm every second weekend , it is 140 miles away from where we live . I will make certain when visiting again , about the watts drawn . At this stage I can tell you , when we are not at this house , it is only a small bar fridge running as well as an alarm system switched on . That's all . When we are visiting , we've got a computer running during daytime and switched off at night , a .37 kw pressure pump supplying fresh water for dishwashing of the minimum utensils after meals . We kind of live like campers during our visits , having for instance a barbeque at evenings . We will each take a shower ( gas ) before bed time ( again the .37 kw pump will supply water to the shower ) and maybe in the morning . Total showering time will not be more than 12 minutes for the combined 2 sessions . For that 12 minutes , the 2 LED lights will be switched on , add another 12 minutes for general "getting ready for the day " . During our evening meal you can add an hour where the double tube fluorescent light , 46 " long , will be switched on . After that hour , the fluorescent light gets switched off , where upon we will switch on the 4 LED downlighters in the living room . Roughly after an hour , we will go to sleep , using only a torch in the room .
The situation will differ somewhat once again I employ someone on the farm . The main difference will be that this person will be using a washing machine , only during daytime , and the addition of a TV with decoder .
Hope this will help in meantime .

[Sunking]

SK summed it up . I am going to select 8 batteries . What will the correct way be to test them ? I’ve got a 10 Amp Ctek battery charger and a hydrometer , have no load tester . Will these tools be sufficient in order to select the best batteries ?.

You need three tools to determine battery condition: Hydrometer, Digital Volt Meter, and Thermometer. A good hydrometer will have thermometer built into it. Click here for Method of Procedure. Read it several times until you are confident you grasp the procedure then report back. Be patient it will take a while to go through all your batteries. Consider yourself lucky if you can find just 4 good ones.

This will just be for a kick off . Replacing them with 2 volt cells seems to be the way to go . Then I am going to connect 5 solar panels of 245 W each , to the system , using 1 controller.

Slow down Sir getting into a hurry and not planning things out is what got you into trouble the first place. Forget battery replacement right now as you have no idea how much energy you really need. You gotta figure that out first before we tackle batteries.

5 is a Prime number and you cannot configure 5 panels any other way than all in Parallel, or all in Series neither will work in your case. This is a 48 volt system right? I need your panel specs and controller make and model to tell you how to configure the panels. Most likely will use 2 of them in series, maybe 4 of them in a 2 x 2 if you can find 8 batteries, or possible 6 of them in 2 x 3 configuration. 5 is not going to work

Should I replace the inverter and with what ? Can you give me prices of Midnite Solar Classic 150 controller and a reliable inverter ?
I would appreciate it if you esp will patiently guide me through this obstacle , please !

Again you are getting ahead of yourself. Lets get you at least 4 good batteries connected to a charge controller up and working with 2 panels first.

Here is your homework assignment in addition to finding yourself at least 4 good batteries. Write down everything you want to run on a piece of paper. Note how many watts the thing uses and how many hours each day you want to operate it. Then total the watt hours up For example

Clock 10 watts x 24 hours = 240 watt hours
Lights 50 watts x 4 hours = 200 watt hours
Laptop Computer 4 watts x 4 hours = 160 watt hours
TV and Satellite Receiver 60 watts x 4 hours = 160 watt hours
Total Watt Hours in a day = 760 watt hours.

Here is what is shocking us all. What you said you used in your first post was very modest sounding like you have meager needs of 1 to 2 Kwh per day. But have a monster sized system capable of 7 Kwh each day made with poorly matched components especially the batteries. In all honesty it sounds like you only need a fraction of that and is why you have to figure it out. If I am right I can figure out how to use what you already have and will only need to buy some new batteries. Right now I am guessing a 990 or 1470 watt system using just 4 or 6 of your panels, one of your charge controllers, and replacing your batteries with 8 6-volt 225 AH batteries wired in series for 48 volts so you can use your 48 volt inverter. BUT YOU GOT TO FIGURE OUT your daily watt hour useage as we cannot do that for you.

So get to it and then I will help you.

EDIT need to know your location.

[Bastian Bakkes]

Now that I heard what all of you experienced solar people ( esp ) had to say about my kind of system , the question is how am I going to solve this complex mess . There is another problem , a social one I did not mention to you : the supplier / installer of the system is a good friend of mine . I am not prepared to ruin our friendship as he denies any weak link in this system . From his point of view , he blames the batteries which were not brand new when installed . Apart from that , he reckons everything is in balance . We came a long way together and I will rather want to fix this system myself than loosing him as a friend .
I am not into electricity ( I am only a dairy farmer ) , but I can help myself with a lot of things in life . The big question I pose to you esp , is it possible for you people to guide me step by step through my system in order to get it sorted out ?. Someone else asked me whether the panels are wired up properly ? Another one asked whether the wires are thick enough ? I did not realize that it’s possible to wire these panels incorrectly . What then is the correct way ?.
SK summed it up . I am going to select 8 batteries . What will the correct way be to test them ? I’ve got a 10 Amp Ctek battery charger and a hydrometer , have no load tester . Will these tools be sufficient in order to select the best batteries ?. This will just be for a kick off . Replacing them with 2 volt cells seems to be the way to go . Then I am going to connect 5 solar panels of 245 W each , to the system , using 1 controller . Should I replace the inverter and with what ? Can you give me prices of Midnite Solar Classic 150 controller and a reliable inverter ?
I would appreciate it if you esp will patiently guide me through this obstacle , please !

[inetdog]

*****Looking back you may be correct that the OP did wire 7 batteries in parallel and then had 4 of those banks wired in series. Seems back assward and confusing to me.

If that really is a correct description, please do not blame the OP for the design, blame his expert who did the installation.

[Mike90250]

7 parallel batteries - OMG Disaster waiting to happen. OK, it did happen.

Microcare is not in any of my "good" brands.

You will have to do a complete survey of your system and figure what your loads actually are,
re-configure any good batteries, and see if your PV is enough for your loads.

And run the generator some to keep the batteries charged and not destroy them.

[SunEagle]

Mike, the OP clearly stated that he had four sets each consisting of seven batteries in parallel and that those sets were then put in series to make up the battery bank. That is one possible but not recommended way of getting 48 volts from 28 twelve volt batteries.
The more conventional way to do it would be to make up seven strings of four batteries each and put those strings in parallel, which would probably be better than the above but still unworkable in the medium to long run.
Dereck at first misread it the same way you did, but realized his mistake. The system is a 700AH system, not a 400AH system.

No. I agree with Mike the math doesn't work. If you wire 7 12volt batteries in series you get an 84 volt bank not 48 volt.

If the OP has 28 - 12 volt batteries he has the wired in 7 groups of 4. Those 4 are in series which gets you the 48volt 100Ah bank. Then he has 7 of those banks in parallel which will get him his 48 volt 700Ah system.

Still a big bank to maintain and hard to charge.

*****Looking back you may be correct that the OP did wire 7 batteries in parallel and then had 4 of those banks wired in series. Seems back assward and confusing to me.