I'm in need of a constant current supply of 34 Amps to charge the solar batteries in the workshop. I've discovered that the type of battery that I am using which is a lead crystal unit requires an occasional charge current 20% of capacity (170Ah) during the bulk phase keep them in good condition. There are a couple of simple circuits out there and the pass transistors are the ubiquitous 2N3055/TIP3055 types, TIP3055 is my preference as I have some large heatsinks ready for use.
I'm going to need rather a lot of these for the required current and genuine ones are a must. Can anyone recommend a reputable source? I did try Langrex first but they only have listed lower rated TIP3055T in stock, Cricklewood Electronics price seem reasonable if they are the real McCoy. Are there any recommendations for other pass transistors, I've looked at TIP35C but these also look a bit dubious to me as so many sources are Chinese.
If anyone has any other suggestions for circuits to build I would be interested to see them.
John.
I'm going to need rather a lot of these
Define a lot?
I can certainly help as I've more than I need in stock, but I'd like a few left just in case. As I've often said John, my stock is your stock considering all the help and time you given me over the years.
![20230208 115253[1]](https://www.radios-tv.co.uk/wp-content/uploads/wpforo/attachments/884/13697-202302081152531.jpg "20230208 115253[1]")
These are all genuine stock no Chinese tat
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Thanks very much Chris, I think at least ten for it to be reliable. I can see you are blessed with a good amount 2N3055 but unfortunately I would need to source heatsinks where I have a number of ex plasma TV boards with suitable chunky heatsinks ideal for TO-3P packages, but I will have a look to see if I have anything suitable for for drilling for TO-3.
Posted by: @Crustytv
can certainly help as I've more than I need in stock, but I'd like a few left just in case. As I've often said John, my stock is your stock considering all the help and time you given me over the years.
I know, but as you have helped me out with parts so many times I don't want to appear as a scrounger, I'd be more than willing to pay the going rate for genuine as there is so much dubious stock out there.
John.
I know, but as you have helped me out with parts so many times I don't want to appear as a scrounger
That you will never be! Besides, you've seen my work shop stores, I've more than enough parts to last both you and me, more years than we have left on this earth combined.
I'd be more than willing to pay the going rate for genuine, as there is so much dubious stock out there.
I wouldn't hear of it.
We can always trade, some of your expertise/time, helping to get a couple of my Fergy VCR's working (3V29/3V30/3V44 etc)
Thanks very much Chris, I think at least ten for it to be reliable.
No problem, I can supply 10, I can also test on the DCA55, picking the best. 👍
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Very much appreciated, thank you.
John.
@jayceebee 10 x 2N3055 ready.
![20230209 112606[1]](https://www.radios-tv.co.uk/wp-content/uploads/wpforo/attachments/884/13723-202302091126061.jpg "20230209 112606[1]")
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Thanks for that Chris, I've also managed to find some plates drilled for 2 x TO3 transistors. They are a bit thin so some force air cooling will be needed, I'm sure I did have a bag of CPU fans somewhere but I haven't located them yet.
John.
John, I've had a hunt in my stores and found a number of heat-sinks, a few of these. They currently have a BU208 installed, but I reckon if you drill as I indicate on picture two, you could accommodate 5 x 2N3055 on each. The heat-sink is a two part affair, a 2mm large steel plate, and riveted to that is a 5mm ally plate, they're quite weighty. Between those two plates, you will also find a large fixed insulation layer.
Yours if you think they'll be suitable, no problem if not, I'll harvest the BU208's though. 😉 I believe these heat-sinks came out of a few ITT CVC20 TVs. There might be more, but I'd have to go digging.
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Excellent, much more meaty than what I dug out. I might be wrong but I think they might be G11?
John.
Yes, definitely G11! There used to be isolated cases of the insulation breaking down (arcing) but I don't think that will be a problem for 2N3055 since they won't be running anywhere near the voltage or frequency of a line output stage!
