Inverter and batteries

Dairyfarmer

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I think the very top one is what I have.

We use this style of fuses on our pivots. I've also seen them used on inverters. They work as a disconnector too. You would need to use a straight end terminal to get the cable in.
G-211.PNG
 

InternetLuddite

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@Dairyfarmer:- been following this thread with interest. While I have a single phase , want to do something similar to what you have done and need a sparky to at least build another DB to move over all inverter fed stuff. Can you share the costs your sparky charged to do so?

So far how much has this project this cost you?

I got a general quote for a solar panel with 5kw inverter , 15x 295w panels, 4 batteries and all electrics and cost was R155k - if I am going to pay 155k , I expect my house to run as it does normally on Eskom power, but even with this I can't run geysers, kettles.etc according to the quote which sorta defeats the point at that price IMHO

My house draws normally around 400w during the day , 8kw if both geysers are on, 4kw if geysers are off but dishwasher and washing machine are going. At night , when we sleep,.the house draws about 550w (due to external lights).

I think if I can get a 6kw inverter, thanks to the routines I have and everything being on smart iOT timers, I can phase things turning on/off so that the total draw of the house is never more than 5.5kw - I could phase it so that geysers turn on/off sequentially.

So if I think about it , if I do exclude the geysers, pool pump, washing machine and dishwasher, oven from the equation , i need a 4kw system that can run for 8 hours. I want to run the kettle every now and then.. would appreciate any clues on where to start if begin with inverter fed by Eskom and batteries and then later to support solar panels as a power source.
 

Dairyfarmer

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@InternetLuddite

The best place to start is to get a watt meter like a Kill-A-Watt. Test everything and you will get an idea of what the maximum draw (watts) is and the normal consumption (watt hours). Maximum draw is critical as this dictates how many Kw your inverter must be. The consumption will dictate how must stored power you have and what charging capacity you need.
 

Sinbad

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Guys don't forget that your voltage will differ depending on what is happening. If you measure voltage while the charger is supplying charge you will read the chargers voltage. If you measure while you're drawing load, the voltage will be slightly lower than if the batteries were idle.
 

TheChamp

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Of all the multitudes of threads on back up power sources this has been one of the most informative thread and a good example of how threads should be managed, Dairyfarmer created the thread and kept it alive by posting on it every time instead of creating multiple threads on the same topic, well done OP and this thread should be a sticky for future reference.
 

Pineapple Smurf

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totally agree @thechamp , well done @Dairyfarmer
I know this has been covered and well explained but i am going to drop this in again as Dairyfarmer knows very well that multiple batteries in parallel need same length cable (see Method 3 here - http://www.smartgauge.co.uk/batt_con.html ).
I battled for years with 10 new batteries in parallel until i found this method and it works rock solid, i will never in my life wire batteries in any other way. Except for Method 4 but it confuses the crap out of how to wire in 10 batteries like that :ROFL::laugh:
I still use Method 3 and trust me, it works !!!
 

Jaws677

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Great, thanks! Really good info.
I'm looking at getting either of these:
View attachment 627366
or
View attachment 627370 View attachment 627368

May also get some 175A-rated Anderson plugs for the battery disconnect if I can't find a suitable size isolator switch - will go to the local hardware or electrical shop and have a look at the actual sizing of the isolator switches and the max diameter cable they can take. Ideally I want to create a sub-DB off the main DB with everything inverter-connected in one place, so looking at the DIN sizing/boxes.
.
The danger of giving advice on the internet is that you don`t know what you don`t know.
Your intentions are pure and you trying to assist other people but therein lies the danger if you are not a professional or have adequate experience.

So please don`t see my post as an attach, Im just trying to highlight the hidden or unknown danger. This is not wiring up a new amp to your 6x9 in the back of a City Golf, we are working with lethal voltages, and batteries that can easily burn your house down.

These fuses are an example of just this just. Lets look at a draft copy of the new SANS 10142-1-2

https://arepenergy.co.za/wp-content/uploads/2018/11/SANS-10142-1-2-Rev-R-01102018.pdf

1551776676561.png

An inexperienced person with only basic knowledge will only consider the voltage rating and current rating of the fuse when making a selection.

They don`t even know what Short-circuit current Isc is and why is so import to consider when selecting protective devices or equipment. And people don`t understand why equipment with high Isc rating are much more expensive and rather go for the cheaper option.

With parallel batteries the Isc can be potentially very high, and when a fault occurs and the protective device fails to operate then only does it become apparent.
 

Geoff.D

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The advice given in post number 207 is excellent!
You are playing with very large currents, way beyond what is found in any other system anyone normally gets to do with. If you are prepared to spend R155 000 o a system, then ensure that you are knowledgeable. Investing in a full sett of the regulations is peanuts compared to even the cost of a battery.
So my advice is:
1. Register on the Power forum. And see what others have done and experienced. https://powerforum.co.za/
2. Spend the money and get a copy of the regulations, the full set or at least those that are applicable to alternative power sources. Even if you only use the regulations to verify and check on quotes you get. We all seem to believe that the marketplace is full of people and companies that know what they are doing. The truth is completely different from that belief!
3. At least you will know what products to buy. It is an expensive exercise and you don't want to buy twice, ever! The maintenance replacement costs are already something you will have to take into account.
4. Make sure what you build and instal WILL meet the regulations. If you have a fire in your house and you have not complied with the regulations your insurance WILL NOT PAY.
5. Do your sums properly! Take into account all the costs! Everything including added insurance burden, replacements etc.


A. On a more practical side, simply forget ALL components and bits and pieces installed in vehicles, caravans and the like. They are not suitable for large installations of over 2 kW.
B. Make sure you have the right tools to do the job. A "piece of bloudraad en n tang" is NOT good enough!
C. Make sure your RTFM! There are no shortcuts when installing large systems. One mistake and you WILL be in big trouble. See the power forum for examples of what has happened to some installations over a simple thing like using the wrong Circuit Breaker on a Battery.
D. By all means, if you are inclined to do the work yourself, do so BUT always do it with safety in mind.
E. make sure you get the system signed off by a suitably qualified person. (and BTW, the local electrician in a small town, even if he does local CoCs is almost certainly NOT a suitably qualified person).
F. Document your installation! With decent drawings!
G. Put your maintenance plans in place! And stick to them.

This is by no means a complete list, but a start. And I am not trying to put off DIYers.
I am a committed DIYer, and firmly believe that work done for yourself, provided you take it seriously is better than on H of a lot of so-called professional work done out there in the real World.
I am just stressing the fact that this is beyond the normal day to day garage project.
 

howardb

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The danger of giving advice on the internet is that you don`t know what you don`t know.
Your intentions are pure and you trying to assist other people but therein lies the danger if you are not a professional or have adequate experience.

So please don`t see my post as an attach, Im just trying to highlight the hidden or unknown danger. This is not wiring up a new amp to your 6x9 in the back of a City Golf, we are working with lethal voltages, and batteries that can easily burn your house down.

These fuses are an example of just this just. Lets look at a draft copy of the new SANS 10142-1-2

https://arepenergy.co.za/wp-content/uploads/2018/11/SANS-10142-1-2-Rev-R-01102018.pdf

View attachment 627722

An inexperienced person with only basic knowledge will only consider the voltage rating and current rating of the fuse when making a selection.

They don`t even know what Short-circuit current Isc is and why is so import to consider when selecting protective devices or equipment. And people don`t understand why equipment with high Isc rating are much more expensive and rather go for the cheaper option.

With parallel batteries the Isc can be potentially very high, and when a fault occurs and the protective device fails to operate then only does it become apparent.

Thanks for this good info - although I have a fair layman's knowledge of electricity/electrical circuits/AC vs DC/etc, I will not be doing the work myself - I always try to find out and understand what the requirements are beforehand so I don't get ripped off by someone claiming to be a qualified electrician; it's unfortunate, but I've been taken for a ride too many times before, so would rather find out what actually needs to be done so I can watch out for the chancers/errors made.

Although I've bought most of the main parts/equipment needed, I would still have a certified (and reliable/knowledgeable) sparky do the final install, connection, checking and CoC, as well as give advice on the breakers, fuses, circuits, etc - with the equipment cost outlay so far, I certainly don't want to take a chance on a sparky that says they know what they're doing and then takes shortcuts - way to costly in all manners.

I think I've posted pictures a fair while back showing my main DB spaghetti mess - essentially done by a reliable and qualified sparky (company), provided a CoC, but I also re-checked by another different sparky a few years later who also gave a clearance and CoC after some building work was done - the DB mess speaks for itself:
DB Board 2.jpg
Still not happy with it and would rather toss the whole lot and get it done properly - now is an ideal time while I'm introducing the backup/solar and also having the phases/balancing reviewed. Any info or advice from these threads is a bonus in understanding what and what not to avoid.
:)
 

Geoff.D

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Thanks for this good info - although I have a fair layman's knowledge of electricity/electrical circuits/AC vs DC/etc, I will not be doing the work myself - I always try to find out and understand what the requirements are beforehand so I don't get ripped off by someone claiming to be a qualified electrician; it's unfortunate, but I've been taken for a ride too many times before, so would rather find out what actually needs to be done so I can watch out for the chancers/errors made.

Although I've bought most of the main parts/equipment needed, I would still have a certified (and reliable/knowledgeable) sparky do the final install, connection, checking and CoC, as well as give advice on the breakers, fuses, circuits, etc - with the equipment cost outlay so far, I certainly don't want to take a chance on a sparky that says they know what they're doing and then takes shortcuts - way to costly in all manners.

I think I've posted pictures a fair while back showing my main DB spaghetti mess - essentially done by a reliable and qualified sparky (company), provided a CoC, but I also re-checked by another different sparky a few years later who also gave a clearance and CoC after some building work was done - the DB mess speaks for itself:
View attachment 627790
Still not happy with it and would rather toss the whole lot and get it done properly - now is an ideal time while I'm introducing the backup/solar and also having the phases/balancing reviewed. Any info or advice from these threads is a bonus in understanding what and what not to avoid.
:)

So a three-phase supply, with only one phase covered by E/L all using a common neutral bar?
 

deesef

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I got 100A ANL fuses from a car audio fitter. They were R150 each with the fuses. I can hook both leads for the battery to one terminal. I had to cut the arch out of the cover to get two cables in.
View attachment 627258

I decided not to buy a dc isolator. I can just remove the cable from the battery or remove the fuse.

Cable I went with 25mm2 welding cable. It's about R75/m and can handle 400A. The ring terminals were easy to put on. Strip the cable back and remove a few strands if needed to get the cable into the lug. Heat the lug with a big solder iron. Behind the ring is a hole and you push your solder in there till it's full. Far better than crimping. remember to orientate the ring terminals. They have a raise and a flat side. Cables connecting batteries must have both flat sides on the bottom. The rest just dry fit first to see. Especially where two cables go onto one post.
View attachment 627262
I used 10mm on the batteries, 8mm on the fuses and 6mm on the inverter. Get some red and black tape because the cable either blue, grey or green. Mark positive and negative ends with red and black respectively.

Cables must all be the same length. i.e the cables joining batteries in series must be the same length. Cables from the batteries to fuses must be the same length. Fuses to inverter the same length. Get your batteries as close to the inverter as possible. It is cheaper to raise the battery holder than to buy longer cable.

I'll take some close up pics today.
It is preferable to crimp lugs that carry high current. The problem with solder is that it is not a very good conductor. When a high current passes through the soldered joint (eg when charging the batteries), heat is generated due to the solder's resistance. This caused the solder to melt. Eventually the solder will set in such a way that there is little or no contact between the wire and the lug (ie, a dry joint).

You will not find a soldered lug on a car battery lug, welding cables, etc for this reason.
 

Dairyfarmer

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So a three-phase supply, with only one phase covered by E/L all using a common neutral bar?
That is more common than you would expect.

In all the houses I have stayed in (I have mover over 17 times in my adult life) lights, 3 phase stoves and geysers have anormally been left off the EL.
 
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Pineapple Smurf

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It is preferable to crimp lugs that carry high current. The problem with solder is that it is not a very good conductor. When a high current passes through the soldered joint (eg when charging the batteries), heat is generated due to the solder's resistance. This caused the solder to melt. Eventually the solder will set in such a way that there is little or no contact between the wire and the lug (ie, a dry joint).

You will not find a soldered lug on a car battery lug, welding cables, etc for this reason.
i think you are spot on there. i have always soldered.
But here in my lighting department i see guys only use massive crimpers, some of these are hydraulic crimpers :oops: These cables are for our biggest generators, 200KW 3 phase
 

Dairyfarmer

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@dennis.se.foon
The auto electrician guy who helped me with my lugs explained it to me this way: The battery connections should never get so hot as to compromise the solder. If it does then something is seriously wrong and degrading solder will be a warning for you.
 

Geoff.D

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@dennis.se.foon
The auto electrician guy who helped me with my lugs explained it to me this way: The battery connections should never get so hot as to compromise the solder. If it does then something is seriously wrong and degrading solder will be a warning for you.

Correct, but also a bit of a risk. The cabling, lugs, and terminal connections should all be rated at least 1.25 times the maximum short circuit current expected. If you monitor the voltages across the batteries and you start seeing issues of variations that should not be there, touch the terminals and connections. If any are hotter then the rest, it is starting to fail on you.
I personally prefer crimped connections only.
 

deesef

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@dennis.se.foon
The auto electrician guy who helped me with my lugs explained it to me this way: The battery connections should never get so hot as to compromise the solder. If it does then something is seriously wrong and degrading solder will be a warning for you.
Correct, but also a bit of a risk. The cabling, lugs, and terminal connections should all be rated at least 1.25 times the maximum short circuit current expected. If you monitor the voltages across the batteries and you start seeing issues of variations that should not be there, touch the terminals and connections. If any are hotter then the rest, it is starting to fail on you.
I personally prefer crimped connections only.
It will never fail until it fails . These batteries charge at a fairly high current and the chances are that one or more joints will give intermittent problems some time in the future. It will be great fun, with long and interesting swear-words and bundles of expensive spare parts being replaced until the damned dry-joint is eventually discovered.
 

Jaws677

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In industry we would never allow any soldering of lugs.

The correct lug with the correct crimper.

After a stranded cable has been crimped we will cut one of the lugs open. Inside the crimp the stranded cable must look like a solid copper conductor then you are doing it correctly. No air gaps or spaces.

Unfortunately these crimpers are expensive as they are mostly hydraulically operated to generate the require torque to crimp the lug to specification.

Solder lugs are fine for 6x9 terminals, and even in your case it will work. But it's not something I would ever recommend or do myself.
 
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