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Time to upgrade


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It is time to upgrade the system... 

The old system: Installed by others

16 mm cable fed from the meter box to Sub DB (80 amp mcb in the meter box...it should be a 25 mm cable from the meter box)

The sub DB made up of :

3 circuit breakers each feeding 1 x 5 kva inverter (each supplied by a 10mm twin+e)

3 circuit breakers each through a timer feeding 3 geysers

1 circuit breaker feeding a manual changeover switch and from there to a Sub DB which splits to various sub DBs on the property. 

3 x 10 mm twin + E cables from each of the 3 inverters into the manual changeover...connected together at the changeover switch.


3 x 5 kva (48 VDC) connected in parallel. 

3 x 48 VDC battery banks (each made up of 4 x 105 amp/hr lead acid batteries) 

each bank has  a 100 amp fuse connected directly to the positive terminal.

Cabling used to link the batteries 35 mm flexible cable.

Cabling from the battery bank to the copper bussbars mounted below the inverters ...35 mm flexible cable ...all the same length.

Will add the setup parameters of the RCT inverters once i download the pics.


The system was installed inside a cupboard in the middle of the house ...with poor ventilation.

The system lasted around 3-4 years ...then started showing signs of reduced battery capacity... just under 5 years in ...there was a horrific smell and I was asked to check the system... i disconnect the batteries and removed the entire system... and suggested the system is relocated in an outside room with good ventilation.

The one unit which was removed and used as a temp. solution for the home office ...worked for one night ...was then switched off...went back the next day to disconnect the batteries because they were gettinging hot ...switched on the unit it made a funny buzzing sound and wouldnt switch on ...took it back to my workshop and reconnected the system to test ...when i switched it on ...it made the same buzzing sound then bang and that was it ...the screen went dim and the fault light came on ...disconnected it.

Phoned around and tried to find someone with experience in inverter repairs... a very helpful guy at mustek gave me a number for a person in Durban who has some voltronic inverter experience.

I removed the top off the entertec battery and found the water level low... flushed it out and now going to fill half distilled water and half battery acid ...then going to charge it using a 10 amp auto pro 10 ...and see how it responds... if it works i will take the other 11 batteries back to the battery shop and do the tests again ...if any fail the tests ...they will be engraved with a cross... the rest will be stripped and cleaned and filled till they reach 23.7 kg (as per spec sheet) then i just need to figue out how to glue the top back on...so it is easy to remove when required... something to note when purchasing lead acid batteries ...how easy it is to remove the plug to refill the batteries ...i will definitely be paying attention to that if i decide to use lead acid deep cycle batteries in the future... in some cases it is as easy as removing the label... in my case the entertec premium power plus required a hammer and a big screwdriver to break whole top off. 

The old system is going to be scrapped or sold. 

If anyone wants to make and offer for the old batteries and 5 kva units ...please pm 


Then it is time to start designing and building the new system...to be discussed in the next post. 

Please feel free to comment or offer advice ...as i am new to this whole solar /inverter thing and dont have enough experience to make wise decisions at this point. 

Edited by isetech
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The new system ...to plan as we learn...and hopefully by the time the building is ready (in 2 months time) we have a much better understanding about solar... inverters and batteries ...no solar at this point in time...but it might be an optional extra.

The supply cable from the meter box to the new Main DB  will have to be upgraded to a 25 mm x 2 core ecc cable.

From the main DB: 

non essential items to fed from this DB.

60 amp feed to the change over switch (16 mm) 

3 x 25 amp feed to the inverters (4 mm )

From the inverters to the changeover switch (3 x 4mm)

From the changeover switch to  Sub DB 1 (16 mm)

From Sub DB 1 to :

Sub DB 1 A (10 mm) 

Sub DB 1 B (10mm)

Sub DB 1  C (10mm)

Sub DB 1 D (6 mm) 

Gate (2.5mm)

alarm (2.5mm) 

CCTV (2.5mm)


All stoves to be replaced with gas.

All lighting to be replaced with LED.

Gas geysers to be considered...**** low voltage shutdown system will isolate geysers during load shedding or power failures.

Pool pump ... ****as above

The reason for the *** low voltage cutout... geysers...pool pump and other services are fed via Sub dbs in outbuildings...this is the best option to date ...if a better solution is found it will be changed.

once i have drawn a site plan with all the power points ...i will complete the list.

The inverter will need to be sized to carry 60 amp total ...3 x 5 kva or another option if we can find one...make to be determined. 

The batteries will need to be sized to carry a load of around 20-30 amps (if possible...still need to figue all this out) during load shedding for at least 2 hours...the load can be reduced to essential services to increase backup time...batteries to be determined.

The system will require battery monitoring...voltage ...SOC and temperature at the battery banks.

The room is being built with adequate ventilation..humidity (rust and corrosion) and consideration for bugs and reptiles to be taken into consideration as these critters certainly know how to short out PCBs.














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