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Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1206

Posted: 03:48am 24 Feb 2024

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Well checked today and still no change it's still in fault mode so I thought better to check the current draw on the battery and 4.4 amps was the reading, but when i zero'd the clamp meter it was showing less than a amp draw. So it does look like the toroid will be OK to use again.

Pic's will come when I start stripping this Kipoint inverter as it was custom made for me back in '05 which did get this type of inverter on the market. Many years ago I contacted Kipoint asking for info on this inverter and told the story. This enginear designed that inverter and went out on his own and made his fortune then retired to a good life.

So it will be a good insight to what he did back in the day and this is way before the Oz inverter came about off memory.

Cheers Bryan

Edit: while I was writing this post I was thinking the best guy to decipher this circuit is by far is Rodger so sent a PM to him.
Edited 2024-02-24 14:02 by Bryan1

Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 378

Posted: 04:41am 24 Feb 2024

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Hi Bryan have you checked the Kipoint inverter over. As it was built so long ago , some of the electrolytic capacitors may have just dried up. If so they can be replaced fairly easily.
I did some hunting this week and got some wire for my transformer.
I am hoping to be able to pull around 3kw when the sun shines so put together a core from two torroids, 180mm od 90mm id and 100mm high.
I found that the 90mm id is pretty tight for a 14 volt inverter.
I wound the secondary ( 230 volt winding) with 2.8mm wire and then got hold of some flat bar for the primary. It is fibreglass insulated bar that is 12mm wide and 3.5mm thick. So that works out to be 42mm squared.
I only just had enough room in the core to fit it.
If I were to make any more 24 volt transformers I would increase the ID of the core to at min 110mm. More if I was going to use battery lead for primary cable.
The 2.8mm wire works out to be 6.158 square mm so going by the 4 amps per square mm rule it should be fine for 24.6 amps, So should handle my car charger fine.
The primary is close to the mark at 42 mm squared so should handle 168 amps.
This transformer works out to be good for around 3.5kw at best.
So make sure that your transformers are big enough.
I made mine oversized as I want to be able to pull 3kw when the sun is out and we are charging the car.
Have fun and hopefully you can get the home made inverters going fine and maybe even repair the kipoint.
Pete

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1206

Posted: 07:48am 24 Feb 2024

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Pete when I did the test run with this cheap inverter I built doing the load test with 2 vacuums drawing 3.5Kw ran fine and I did try my air compressor and mig welder which all ran fine.I
I reckon I killed the surge on this kipoint years ago when I welded up the 2 ovens on this 1850's stove I got here for a total rebuild. Went from a 24 volt 735AH fully charged battery to one flat battery when I finished and that inverter took it all in it's stride.

The next weekend it wouldn't run my 8" bench grinder or even a 6" one so I did know it was on it's last legs, that was a few years ago too and upto this weekend powered my shed fridge fine.

I did find I had 2 connectors left off the ching board I got so it will be a case of powering my soldering iron off the inverter outlet to connect the shed grid power. May get to it tomorrow but it does look like next weeks job and I have taken the solar input off the battery as it is fully charged.

Many years ago I sent 25 off 50x15mm round neo's to Oztules and he made an electric car out of old car batteries and just used that dual axial flux wind genny he made using those magnets to charge it. So more then likely I will go that way with my 4Kw motor conversion and with plenty of hills on my place it will be a test for it

Cheers Bryan
Edited 2024-02-24 17:49 by Bryan1

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1206

Posted: 04:23am 25 Feb 2024

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G'Day Guy's,
So I took the inverter over to see Rodger and after we hooked it up still had the same fault, so had a good look and Rodger sprayed some gunk onto some of the connectors to ensure they made contact etc.

Anyway I did suspect the green power pot was suspect and when I turned the pot the second led went green so the fault was gone. We decided to take that led board out where we found yes that pot was worn out, now the original pot was 5K and as only a 10K was available that was put in as a replacement.

Hooked the board back up and sure enough 2 green leds so I used the heat gun on full setting and it ran fine.

Next was to test a big load so we tired the air compressor and honestly the inverter nearly had it going before going into fault mode.

So we tried the pool pumps, with both running about 2Kw's found at first turning both pumps at the same time didn't work but turning one on then the other after did work so we had 2Kw load and left it running until the fan came on the inverter.

So for an inverter close to 20 years old is back to run for a few more years as a 2Kw inverter at best. Now I'm going to setup my other inverter so when I do need that extra power it's there but for low power stuff like my machineshop this old inverter just worked before so it will be good to see if it still does.

Cheers Bryan

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