Cheap solar for the Upgrade


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Bryan1

Guru

Joined: 22/02/2006
Location: Australia
Posts: 1225
Posted: 03:37am 09 Jun 2024      

GRRRRRRR connected up the 1.5Kw this morning and after getting this second MPPT going found it went into fault mode as the input voltage was 110 volts   So it does look like I'm going to have to rewire all the panels in parallel and wouldn't it just figure got 5 M4 connectors left and I need 6 of them.

So Murphy has been laughing at me all morning like at every turn a curve ball was thrown in.

So a trip into MM next week to get more parts and another day on the roof to get the work done.

Regards Bryan

Godoh
Guru

Joined: 26/09/2020
Location: Australia
Posts: 418
Posted: 08:26am 09 Jun 2024      

Hi Bryan, I connect my panels as 2 in series then parallel the banks up. That way I keep under the maximum ( low voltage) level for non licenced wiring. I use two or 3 way parallel connectors to parallel the banks. They are pretty fast and easy to use.
Sounds like you are having fun,
Pete

Bryan1

Guru

Joined: 22/02/2006
Location: Australia
Posts: 1225
Posted: 05:33am 15 Jun 2024      

Well wouldn't it go figure told my wife NOT to use the genset until I got a new extension lead as the last one shorted out and what did she do blow up the charger with that shorted cable.  

So now got my shed charger which only for a 260AH battery and outputs around 35 amps, now what surprised me that 4Kw genset lasted around 9 hours of running the charger. So with not too much loading it's just purring along.

I decided to get a quote on a 48 volt 1000AH forklift battery and it was around that 10K figure I thought it may be. Today I sent an email for a new charger to suit that 600AH battery thats been powering the home for over a decade.

When it's day after day of pea soup for weather no amount of solar will help so that 4Kw motor conversion project may just need to get finished and up in the air. But with a good 100 metre wire run finding the right cable will be the first job and for digging the trench that new tractor is looking better by the day.

Regards Bryan

Godoh
Guru

Joined: 26/09/2020
Location: Australia
Posts: 418
Posted: 07:35am 15 Jun 2024      

Hi Bryan, what sort of current does the underground cable have to carry.
100 metres is a fairly long run.
I am guessing that you are going to run 240 from the generator to the battery charger that is 100 metres away. If you are pulling 15 amps through you underground cable you would need to use 6mm cable at least. That would allow you to pull around 20 amps at 230 volts max.
Sounds like you have your work cut out.
Maybe it is also worth pricing VRLA batteries as well as Fork Lift batteries.
It sounds like your power needs are fairly high
Cheers
Pete

Bryan1

Guru

Joined: 22/02/2006
Location: Australia
Posts: 1225
Posted: 02:41pm 17 Jun 2024      

Hi Pete, When I load tested this conversion in my lathe all those years ago when it got to cut in my VFD complained of over current and my lathe was in 5:1 back gear. I saw a glimpse of 89 amps on the clamp meter. I setup 2 truck batteries for 24 volts as the load and used a 100 amp bridge rectifier.

Did 3 off load tests and the 100 amp bridge rectifier let out the magic smoke on the 3rd test and every reading on the cutin was around 90 amps.

Now with these motor conversions one can only get what on the name plate and with mine being 4Kw I do think 2-3 Kw would be the working range.

I do intend to bring down the current with wild AC and rectify at the shearing shed where the new power base is going to be setup.

I do need to get some hot water heaters to use as as a dumpload as when the batteries are fully charged the current has to go somewhere.

There is a few scrap yards in town so I do need to get down there and have a look and see what they have and I'm thinking 400 amp arc welding cable as the minimum so with a 3 runs yes it is a bit of cable.

Regards Bryan

Godoh
Guru

Joined: 26/09/2020
Location: Australia
Posts: 418
Posted: 12:49am 18 Jun 2024      

Hi Bryan, I don't get why you want to use welding cable. That seems very excessive for what you are doing.
From what I read in your posts you are sending AC from the generator shed to the other shed. Then charging batteries with that.
So there must be an inverter at the shed where the batteries are.
My thoughts are that you would be better off adding a capacitor bank in parallel with the shed batteries to help with starting current.
Maybe I am not understanding your setup.
The price of welding cable, even if you could get it in 100 metre lengths would be astronomical.
Also why three cables. is your converted motor 3 phase?

Pete

Bryan1

Guru

Joined: 22/02/2006
Location: Australia
Posts: 1225
Posted: 09:15am 22 Jun 2024      

Pete the output of the motor conversion is 3 phase AC and after winding I wired it up in double delta as it is the max current we want isn't it.

Now when it is pumping 3Kw out small diameter cable will just heatup thats why heavier cable is used for long runs.

So my plan is the output from the 4Kw goes to my shearing shed then Wiseguy's inverter will send down the 240 volts to the main electric box for the house.

Godoh
Guru

Joined: 26/09/2020
Location: Australia
Posts: 418
Posted: 10:14pm 22 Jun 2024      

I get what you are trying to do, but it seems to me that you will be spending a lot of money that you don't need to.
In the days when I was an electrical contractor, I installed quite a few underground cable runs.
The longest I can remember was 150 metres, it was a 100 amp supply for a house. I used 50 mm building wire for that job.
You need to work out the maximum current you are going to draw from the cable, then calculate the voltage drop over the length at that current.
The standards say you have to keep it under 5%. That would be fine in your case.
There should be online cable voltage drop calculators that make the job easy.
Pete

Bryan1

Guru

Joined: 22/02/2006
Location: Australia
Posts: 1225
Posted: 04:30am 23 Jun 2024      

Well got a reply back on Feildlines and 2awg or 35sqmm will be enough as the wid AC will be at a lower current than the DC. So when I'm down town this week I will go have a look at the scrap yards also go see my mate in the Bridge as those old dry cells can go which can offset the cost.

Once I get my sectional roller project finished I'll start on this 4Kw project as still got a heap to make like slip rings, the main steel frame, source and mount the disk brake etc. Also got to workout a solution where a solenoid can force the oil to brake the blades in high winds.

As this genny is going to be a down wind one with no tail that disk brake will be the key to the blades lasting the test of time.

Regards Bryan