230vac transformer Output to pcb.

[betwixt]

They should be OK then, usually when they go faulty they do so completely and it is very obvious.
If the fuse goes again I would be inclined to change it for a 2A or 2.5A one so it has a little more safety margin.

The charge probably continues even when the battery is full, provided it isn't done for too long it doesn't do any harm. If you have an LED to tell you the battery is charged up, it is almost certainly operated by a simple voltage monitor that senses when the pack has reached 12V or so.

Brian.

 

[hobby12]

hi, thanks for reply. I understand now and have ALOT to learn, Im going to get some 2 to 2.5amp fuses and will give it a try, again thanks for the help.....

 

[hobby12]

hi all, well still waiting for the new fuses, anyway my mate wonts to do away with the fuse and replace with this part. I have told him to hold on so i can check with you people first, will it be ok or not?...Anyway this is the part----)

 

[betwixt]

That is very similar to the one mounted inside the transformer. It will burn out under two conditions, more than 3 Amps flow through it or it is exposed to temperatures above 127 degrees. Normal fuses are designed to burn out only when too much current flows through them, the type in the picture does that as well but is also designed to be mounted near to components that might overheat.

Brian.

 

[hobby12]

hi, thanks for the reply. well my mate does not agree and said thats what he took off the transformers coil, where he linked it with a peace of wire. anyway told him to leave it as it is, with the fuse still left in place... I dont think i will be getting anymore help from him, still cant please everyone, safty is more important to me if i carnt make it safe to use then it will go in the bin, but i hate giving up and have to try. anyway thanks for the GOOD ADVICE cheers......

 

[hobby12]

hi all, Well new fuses arrived today. first thing i did was discharge my old battery with a 24v light bulb, i then replaced the fuses with a 2amp anti surge and replaced the charger cover, swithched it on and inserted the battery. I now have a red charging led light and the fuse is holding, keept checking the charger every 5 min or so and after about 1hour 15 min the green led came on and said it was charged. I checked the battery with a dmm and all is GOOD, well i think im going to leave the 2 amp fuse in and (not increase) to 2.5amps as this will give me a much better safty margin.....

 

[betwixt]

Well done!

What I said about the fuse tripping when the temperature was too high does make sense. The reason it is used in the transformer is that under some circumstances, for example if you blocked the ventilation holes, the transformer would overheat even though the current being drawn from it was still within safe limits.

Brian.

 

[hobby12]

hi all, Well charger is working great NO PROBLEMS, I have been looking around on the net how to put together a 12v battery useing 1.2v cells as one off the battery of mine is dead, and i dont wont to be doing this thing that is all over the net, where they hit the battery with a high current to bring it back to life, looks dangerous to me.. anyway I already have the cells, 10 of them but some say its ok to solder them together and some say not to. WHO IS RIGHT?

 

[betwixt]

You must understand that NiCad cells are full of toxic chemicals and if mistreated they can explode and cause serious injury.

If you are happy with the risks, look at: ATV-Projects NiCd Zapper which explains what goes wrong inside the cell when it goes faulty. Not all cells can be recovered but sometimes it's worth trying. The high current method *might* work but can also be very dangerous, the idea is to force a current many times higher (maybe 1000 x higher or more) through the cell to make the internal short circuit burn out like a fuse. The drawback is you don't know if and when it has been successful and the high current will cause a very rapid increase in cell temperature which can cause an explosion within seconds. This is further complicated by the strong chance that the wires providing the current and any switches in line with them will weld together and make it impossible to kill the current quickly. To give you an idea of what can go wrong, I've seen an AAA size cell (the small one) explode and fly 2 metres across the room and embed itself in a wall. Bigger cells will go off with a bigger bang! you were warned!


Also be very careful if you solder directly to the cell, the soldering iron heat can make them explode too. If the cell has metal tags welded to it you can solder to those but I would be very hesitant to solder directly to the cell body itself.

Brian.

 

[hobby12]

hi, wow all that energy from AAA batterys, I would love to be able to build that circuit but dont have the brains. I would (not) even consider doing that to a battery, for the reason it not only puts me at risk but would also put others around me in danger if something whent wrong, I always try to be safe. well it looks to me that circuit does the same thing that i mentioned befor with the high current method, but that circuit is controlled and monitered with safty in mind. I think i will get some new batterys as mine dont have all the tags

---------- Post added at 22:58 ---------- Previous post was at 21:19 ----------

hi, question, can i go from 1.2v 1500mah to 1.2v 1700mah batterys? from what i have read it will give me a bigger capacity and the battery will last abit longer, but also take longer to charge, is that right.....

 

[hobby12]

hi all, well batterys came yesterday, i got the 1700mah as i got no reply for the last question and was told by the people i bought them from that it was fine to go with a slightly higher battery. i have decided not to solder the tags myself as i dont wont to damage the cells my mate has a heavy duty soldering iron, so he said he would do it for me, safer that way as i dont have the experience and he has done it befor. after this battery is done i thinck i will be staying away from electronics to many risk and i need to try and understand OHMS law befor touching thing that i dont understand, SAFER that way...

---------- Post added at 16:19 ---------- Previous post was at 15:52 ----------

hi, does anyone have any good web sights that will be good for me to get started off building small projects, so i can start to learn how to put components together and how it all works....