Old Silicon Chip Magazine project. Solar/Wind controller

[AprilSteel]

I have a few of these kits , that mostly run OK however I have one with a problem which I can't find yet.

It blows the chips .

If I put new chips in it and connect the battery first then the panel everything seems fine.

If I take the battery leads off and put them on another 12 Volt battery there is a spark and it takes the chips with it . I should say chip as its the 4011 chip that goes mostly.

Its called K008E Solar Charger/regulator put out by Oatley Electronics

I've put a circuit below and would appreciate your thoughts on what might be happening.

 

[duke37]

I would look at C7/R16. C7 should be discharged in 10 or 20 seconds. If this is not done, then switching on for the second time will put too much voltage on the 4011 input. A high value resistor on the 4011 input would protect it without affecting the operation.

Check that the supply voltages are correct.

 

[AprilSteel]

Thanks . Supply voltages are OK I checked C7 and R16 both OK . While there I added another 1 meg on the input to 4011 . You were right , that had no effect on the 4011operation.

While messing I discovered the 4011 was OK in fact and what had gone was the 5 volt regulator IC2 which is an L4949


Your tractor looks like a massey harris but can't really tell ,the pic is too small . Seems to be alongside and old grey ferggy . I've got two MF 175's and an old petrol/ kero david brown 25C.
Im a bit into old gear myself.

 

[shrtrnd]

Those CD4011's are early CMOS (Complementary Metal-Oxide Semiconductor) IC's that are very sensitive to static.
If you're continuing to experiment with this circuit, I think Duke37's advice to wait a while for the caps in the circuit
to discharge is a good idea. It doesn't take much to blow the CMOS IC's if they're temporarily over-voltage.

 

[(*steve*)]

You could also write to Silicon Chip and ask them. They get enquiries like this and publish them along with their suggestions.

I subscribe to silicon chip, so if you do this and don't have access to the magazine (and they don't reply directly to you) I could pass along their answer.

 

[debe]

That kit is an Oatley Electronics kit & is still available from there as KIT K009D, same circuit. It was designed by Oatle y electronics, so I would direct any questions to there not Silicon Chip. If you go to there site & go to that kit, there is a PDF file on how it works. This is a picture of the Kit I built some years ago & still works fine. There is a chance they are not desined to be connected & disconected to a battery with a load creating a spike.

 

[AprilSteel]

Incorporating Duke37's suggestion to increase the input impedance and let the caps sit between connection swaps I put one back into service and it worked fine . Changed batteries with a wait time and it all seemed to go pretty well . Thanks

On the one above its quite a bit different to mine .Whats under the big heatsinks ? I'll have to go read the pdf just to find out now . Thats one thing I don't like about this design - The ins and outs are not marked clearly on the board. When Silicon Chip magazine produced a circuit quite a few followers would produce a kit . It was quite popular then

 

[debe]

The circuit is exacly the same as you posted for the K008E kit. The switching MOSFET & the dual Shotkey diode are surface mounted on the back of the PCB. I fited the heat sink as it quite often has to pass 10Amps & gets quite warm

 

[AprilSteel]

Can anyone tell me how I can add protection to the L4949 chip please? Thats the one that seems to be blowing.

 

[debe]

the max recommended voltage on pin 1 is 28V, so if the battery is disconnected & then reconnected there may be a high voltage spike taking out the IC. There is a 15 to 20V Zenner ZD1. But you could try a 15V Zenner across pin 1 & ground as some extra protection.