DSD Charger brain transplant

I didn't like the way my DSD charger terminated the charge cycle so I gave it a little surgery.

I used the LTC4054 chip from Linear Tech (same chip that is in AWR's Nano charger). Since the DSD will accept different cell sizes, I wanted to be able to vary the charge rate. I etched a board to allow 4 different charge currents, although, with the switches I had on hand, I only implemented it with 3 charge rates (approx 100, 300 and 500mA). This allows for charging cells down to the 10280 size.

The LTC4054 is a CC/CV charger and terminates the charge when the charge current drops to c/10. The switch in the pic has 3 positions to select the charge rate. The LED flashes when power is applied with no cell, is on steady during the charge cycle and goes out when the charge is complete.



Before pic


After Pics



Thanks for lookin'

Paul

Hello Paul,

Nice...

Tom

Thanks Tom, it was a fun evening project. (Even after forgetting to print the mirror image of the resist patch and having to re-etch another board ).

I used the toner transfer system - great for making protos.

Paul

I read the other thread about all the problems with the DSD and PS, and would love to do this with the three I have, but am not sure of your details to be able to do it myself. Any chance of noobifying what you did?

just a quick comment, slightley off the subject.

I got one of those cheap Chinese RC123 charger, it would only charge to 3.97volts.

I opened it up to find a trimmer, so I adjusted it.

It now charges to 4.22volts every time.

It`s amazing how much extra power is between 3.97-4.22volts.

regards.

TinderBox (UK) said:

just a quick comment, slightley off the subject.

I got one of those cheap Chinese RC123 charger, it would only charge to 3.97volts.
I opened it up to find a trimmer, so I adjusted it.
It now charges to 4.22volts every time..

Click to expand...

There is no trimmer in DSD charger...

TinderBox (UK) said:

...It`s amazing how much extra power is between 3.97-4.22volts..

Click to expand...

0,1V equals 10% capacity

the charger is not a DSD, the model number is YL-112

http://tjtech.org/~CPF/CY/defective charger.JPG

regards.

LuxLuthor said:

I read the other thread about all the problems with the DSD and PS, and would love to do this with the three I have, but am not sure of your details to be able to do it myself. Any chance of noobifying what you did?

Click to expand...

The thing to remember is that this chip is running in linear mode. That means that the power that doesn't go into charging the battery gets dissipated as heat in the switcher chip. So it is important to match the power supply to the charge circuit. I used one of a couple of surplus 5V regulated power supplies that I picked up surplus for a couple of bucks each. I added a dropping diode to bring the voltage down another few tenths of a volt before it hit the charger chip.

I pretty well used the circuit from the data sheet and added a few resistors in parallel to the current set resistor so I could change charging currents. I etched the board myself, but you could purchase a nano board from Andrewwynn. They are much smaller to work with.

Sorry, I guess this doesn't noobify it too much.

Paul

Could one put the electronics from an HDS charger inside the DSD Charging cradle, "robbing the cradle", as it were? (I know, I know, I couldn't help it ). I use one charger to charge the battery for my EDC B42 XR GT, and the other to charge the 17670 for my SF 6P with 3W Led module. I am also building an ROP/LE and I would like to just use one charger setup for the different batteries. Just a question.

Nice project

Will

Yeah, it didn't noobify it at all! LOL!! I just ordered two Pila chargers from Burlys.

TinderBox (UK) said:

the charger is not a DSD, the model number is YL-112

http://tjtech.org/~CPF/CY/defective charger.JPG

regards.

Click to expand...

The trimmer sounded extremely familiar. I recommend you exercise extreme caution with that charger - one of those blew up on me before. Yes, I did tweak the trimpot.

LuxLuthor said:

Yeah, it didn't noobify it at all! LOL!! I just ordered two Pila chargers from Burlys.

Click to expand...

These new Pila Intelligent chargers are very very nice. Glad I got them vs. the DSD's.

This brings up a blast from the past for me. Here's my home brew two position charger using the same LT4054 chip that I built three years ago and it's still serving me very well.



Didn't have a suitable holder for the cells so I used a Pila charger to test it:



The LTC4054 is a great "economy" charger.

Can the LTC4054 charge protected cells?

vacuum3d said:

Can the LTC4054 charge protected cells?

Click to expand...

Yes, I've used it to charge Pila's.

TinderBox (UK) said:

SNIP...

It`s amazing how much extra power is between 3.97-4.22volts.

regards.

Click to expand...

Gain 25% in capacity, but loose ~50% in cycle life and cell cycle lifetime.

Nice work Chimo and Tinderbox both. FWIW, I like ~4.22V charge cutoff myself. My DSD is seems to be drifting downwards in cutoff voltage over time. As HiltiHome noted, there is no adjustment in the stock DSD.

And even further OT, my older cells are exhibiting some voltage depression; After 24 hours rest, they are ~4.05V, after charger cutoff at 4.17V.

Better smarter chargers get my vote, but a Li-Ion charger is a bit scary for my modding tasts. Making a mistake can be very dangerous.

CM... thanks.

Hi Paul,


Sorry. Borrow your idea for PCB layout. I didn't do the layout job or etch a PCB before.

My soldering work is poor, here it goes.



The 3 resistors on the up right corner were used by slide switch at first, but not used now. If I need more charging current, I need more resisters and more wires. The selector switch is too big to fit in DSD case.

I use a DIP switch to do the job.


Sw 1 OFF would make the Iprog open to ground and cut of the charging. The resistors in series are 1.5k, 1.5k and 3.9k. 1&2 ON would get 1.5k, 1&3 ON 3K and 1&4 ON 6.9k. The charging current are about 660, 330 and 145mA.

Thanks for viewing.

NetKidz. :goodjob: