- Joined
- Dec 29, 2012
- Messages
- 394
From that:
To that:
HERE IS HOW
Dealing with portable computers I found myself possesing alot of LI-ON batteries.
I like them batteries as they have high capacity (they store alot of energy), they have a nominal voltage of 3.7 volts per cell and they have a very slow rate of self-discharge, so they can be used in numerous applications in the shop.
They have 2 major drawbacks though: They are tricky to charge:
The Li‑ion charger is a voltage-limiting device that is similar to the lead acid system. The difference lies in a higher voltage per cell, tighter voltage tolerance and the absence of trickle or float charge at full charge.
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
They also need trickle charge (i.e very low amperage about 1/10 C) if the cell voltage drops below 3.0 volts.
To charge them properly you cannot use any DC power supply plug it in the mains and forget about it.
I was in search of a charger to be a) cheap, b) DIY and c) easy to make.
Mr Google drove me to the following webpage:
http://www.shdesigns.org/lionchg.html
The circuit presented there, although old, is very well documented and can be build from parts I already have in shop.
After some modifications to the PCB board (we always do! Don't we?) I printed the copper side of the circuit on paper.
As you can see I have cut a piece of copper board, I secured the paper on the copper side using masking tape, drilled all holes and using nail varnish I paint all parts needed to be copper.
Some 10 minutes in a Ferric Chloride bath revealed the copper side of the PCB
I know it is not pretty but it does the job!
After soldering the components I made some charging tests and it worked like a charm!
Now I needed a box to put it in.
An old 500V 16A switch inspired me
After removing all the guts I ended up with a very nice aluminium box.
A cleaning process using the fly-cutter revealed its beauty.
It only needed a lid.
A scrap aluminium offered it.
The lid needed some ventilation grilles that my mill managed to make using a small circular saw.
Some polishing and the necessary labeling and job done! The box is ready to accept the electronics.
Started by making a cut for the voltage meter and a hole for the charging LED
Then the PCB secured in place, the connectors drilled and placed and the wiring between all them parts finished.
Final test! It works as designed! I secured the Lid and I stood proud of my new tool.
I know... I have to replace those ugly bolts on the lid. But on the other hand it shows primitive and "hand made"
I cannot decide on that... its a hard issue..
Thanks for reading this.
Petros
To that:
HERE IS HOW
Dealing with portable computers I found myself possesing alot of LI-ON batteries.
I like them batteries as they have high capacity (they store alot of energy), they have a nominal voltage of 3.7 volts per cell and they have a very slow rate of self-discharge, so they can be used in numerous applications in the shop.
They have 2 major drawbacks though: They are tricky to charge:
The Li‑ion charger is a voltage-limiting device that is similar to the lead acid system. The difference lies in a higher voltage per cell, tighter voltage tolerance and the absence of trickle or float charge at full charge.
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
They also need trickle charge (i.e very low amperage about 1/10 C) if the cell voltage drops below 3.0 volts.
To charge them properly you cannot use any DC power supply plug it in the mains and forget about it.
I was in search of a charger to be a) cheap, b) DIY and c) easy to make.
Mr Google drove me to the following webpage:
http://www.shdesigns.org/lionchg.html
The circuit presented there, although old, is very well documented and can be build from parts I already have in shop.
After some modifications to the PCB board (we always do! Don't we?) I printed the copper side of the circuit on paper.
As you can see I have cut a piece of copper board, I secured the paper on the copper side using masking tape, drilled all holes and using nail varnish I paint all parts needed to be copper.
Some 10 minutes in a Ferric Chloride bath revealed the copper side of the PCB
I know it is not pretty but it does the job!
After soldering the components I made some charging tests and it worked like a charm!
Now I needed a box to put it in.
An old 500V 16A switch inspired me
After removing all the guts I ended up with a very nice aluminium box.
A cleaning process using the fly-cutter revealed its beauty.
It only needed a lid.
A scrap aluminium offered it.
The lid needed some ventilation grilles that my mill managed to make using a small circular saw.
Some polishing and the necessary labeling and job done! The box is ready to accept the electronics.
Started by making a cut for the voltage meter and a hole for the charging LED
Then the PCB secured in place, the connectors drilled and placed and the wiring between all them parts finished.
Final test! It works as designed! I secured the Lid and I stood proud of my new tool.
I know... I have to replace those ugly bolts on the lid. But on the other hand it shows primitive and "hand made"
I cannot decide on that... its a hard issue..
Thanks for reading this.
Petros
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