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wizpic
Joined: 23 May 2004
Posts: 324
Helped: 22
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 23 Dec 2007 2:08 Intelligent battery charger circuit |
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I've looked at that charger it looks good and converted the code over to Proton but never really tried it in real life only on dev board.
But i have menu system working in something else the data that i upload into excel is on something else but all these can be added together.
The trouble with that oshonsoft is that the computer exe will only do i battery if i understand it correctly but i have not really looked into it.
My view if your spending so much time on development time in desgining somethig then I like to leave space for add on or modifactions and go for the best to start with because there is always room for improvements well that's the way I look a it
wizpic
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 23 Dec 2007 8:02 Re: Intelligent battery charger circuit |
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"I asked that som time bacj and many posts after you say that, I've already seen that article, I use Proton and was wondering what Dexter wrtoe his in, Has I want to build a bigger vesrion of it of it, And I asked dexter if he would not mind sharing code but he never answered the question, like I said I would understadn if he did not want to, a yes or no woudl be fined instead of been ignored Very Happy"
Sorry about that .I thought that by not giving an answer you will understand that the answer is NO. Or at least not at this time . I did not meant to ignore anyone .
"I just wnated to know how to control the HPWM in realation to the charging voltage by using the A/D routine and then sending it out to control the LM317 and the mosfet."
There is no need for a HPWM.I just used an plain-simple ON-OFF to obtain the desired PWM signal .The frequency of PWM is approx 1HZ , with duty cycle changing from 6% (trickle charge ) 50%(slow charge ) and 99%(Fast Charge) .After this time a discharge pulse (aprox 2.5X Icharge) of 5ms is applied ,pause for 20msec and then measure voltage .
"1- If battery is near 1 volt the charger not start, display show E A (no bat inserted), in this case I need to charge a little bit in another charger and then put back to start the charger. "
RE:Battery discharged to much(not by this charger I believe) . Some Intelligent commercial chargers do that too.Try to adjust the the POT accordingly
"2- The charger only charge for about one and half hour and then the display show P (peack failed). "
Re: Battery needs reformatting or battery is dying (old age) .A couple of charge -discharge cycles might fix that . If your battery feels warm (> 37C ) that means battery is old and charger safe timer mechanism (10min with no voltage increase) prevented further heating of cell(s) ; otherwise reformatting will help .Either way I found discharging (prior of charging )beneficial for capacity retention , or at least not causing damage to the battery.If you use battery packs discharging and trickle charging helps balancing the cells .
I already used Excell to verify and plot data (thats why I choose REALTERM) .Charger is performing fine.As all of you noticed , the prices on NIMH batteries are quite affordable so why spend a lot of money for a fancy charger .I am using 5 year old NiCd/NiMh batteries and they are performing fine (only 10-20% capacity loss )
I wanted a simple charger without rings and bells , but still with good performance and plotting data capability . I prefer no switches ( idiot free design) .
The ideas behind this charger are : cheap , simple , robust , efficient , NICD/NIMH compatible.
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wizpic
Joined: 23 May 2004
Posts: 324
Helped: 22
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| 23 Dec 2007 9:52 Re: Intelligent battery charger circuit |
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| Quote: |
| Sorry about that .I thought that by not giving an answer you will understand that the answer is NO. Or at least not at this time . I did not meant to ignore anyone |
Well I was thinking that but if it was me I still would have replied to it answering the question,
would you ignore your kids if they asked you a question ? and think becasue you did not answer them they woudl think the answer would be no.
I can understand why you want a simple idiot prove charger, But I was thinking more along the lines of a lead acid battery charger for a caravan which may only get used 3/4 times a year (if I'm luvky may be 10 times a year).
My idea was to charge the battery then discharge the battery to see how good it is becuase there is nothing worse than going away for a short break and finding out the battery is faulty and because it can be parked up for 6 months or more then you could set timers to discharge the battery by 20-40% then charge it up agan this would stop the batteries sulphating up if there kept on charge or left in a discharge state for long periods of time.
well that's enough of what I will be doing, has this is about ni-cad charger but that's where I got my idea from and thought i could use this has a base biulding block
keep up the good work
wizpic
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 23 Dec 2007 10:17 Re: Intelligent battery charger circuit |
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"My idea was to charge the battery then discharge the battery to see how good it is becuase there is nothing worse than going away for a short break and finding out the battery is faulty and because it can be parked up for 6 months or more then you could set timers to discharge the battery by 20-40% then charge it up agan this would stop the batteries sulphating up if there kept on charge or left in a discharge state for long periods of time. "
About that , take a look here :
http://p198.ezboard.com/bleadacidbatterydesulfation
I'v build a simple desulfator device (P-Mosfet version) and found it quite useful for lead acid battery preservation / storage / regain_capacity.
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Pawel_K
Joined: 28 Dec 2007
Posts: 2
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| 28 Dec 2007 11:44 Re: Intelligent battery charger circuit |
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How many of batteries can I load using this charger ??
Here is also interesting circuit but now it can charge only two batteries.
(Sorry for my english)
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 28 Dec 2007 13:25 Re: Intelligent battery charger circuit |
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| This charger is suitable for 1-4 batteries .
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Pawel_K
Joined: 28 Dec 2007
Posts: 2
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| 28 Dec 2007 18:09 Re: Intelligent battery charger circuit |
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| How make to load 8 batteries with this charger ??
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 28 Dec 2007 20:03 Re: Intelligent battery charger circuit |
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Simple .Divide 8 batts. into 4+4 batts..This way you can charge 4 batts. at a time.
or
Increase Vin from 12VDC to 20VDC , adjust the switch to "skip discharge " position and that is it. But you need a bigger heatsink for LM317 also.Fail to adjust the switch to "skip discharge " position and MOSFET and/or Power discharge resistor will burn.
First method is better (better control over individual elements).
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TCPIPV6
Joined: 01 Jan 2008
Posts: 6
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| 01 Jan 2008 21:27 Re: Intelligent battery charger circuit |
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Hi Dexter Dude,
This chager is exactly what I was looking for! Great work, thanks. I needed a charger with a serial output. I've build the charger and for some reason Í'm only able to burn the PIC (with bumblebee) with the "snapshot" file you created. Is it possible that you take another "snapshot" (with read all option) from the latest version (incl. the discharge disable option) and post it here?
Another problem I'm having is that if I connect the common of the display to +5V, I don't recieve serial data anymore. The display works after doing this.
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 02 Jan 2008 12:51 Re: Intelligent battery charger circuit |
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Did you used 330ohm resistors on PORTB or forgot about that ?
The latest version was already posted (using the switch to inhibit discharge mode ) .
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TCPIPV6
Joined: 01 Jan 2008
Posts: 6
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| 02 Jan 2008 13:21 Re: Intelligent battery charger circuit |
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I didn't forgot the resistors on portB to the display.
The latest version you've posted, was it a "snapshot" or a compiled hex-file?
Only the snapshot is working for some reason.
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 02 Jan 2008 13:55 Re: Intelligent battery charger circuit |
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The "reason" is that only the "snapshot" contains the configuration bits that must be set when programing PIC. This Bits are recognized if present in hex file.
You must set manualy:
"For burning must use this settings :
IntOsc/ IO WDT=off PWRT=off MCLR=OFF BODEN=ON CPD=Off CP=off "
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TCPIPV6
Joined: 01 Jan 2008
Posts: 6
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| 02 Jan 2008 15:16 Re: Intelligent battery charger circuit |
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| I cannot find the configuration bits in my programmer software (bumblebee and galvawisp). I therefore opened the hex in ic-prog, set the configuration bits and saved it. Let's hope this works.
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RenatoBR
Joined: 25 Feb 2007
Posts: 24
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| 02 Jan 2008 19:46 Re: Intelligent battery charger circuit |
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Hi Dude,
Again here, no succces until now.
Bought two new NIMH 2500 mA to make tests.
The charge fail the peak two/three times and then finalize the charge.
One single cel, impossible to charge, fail the peak several times.
Four cells, fail the peak and after power off/power on, finalize the charge.
I don't know why, but if I insert batts +- charged the charger finalize without problem, with empty batts I need to power off/power on two to three times when fail the peak.
For the tests above I'm using the hex_switch and NIMH 2500 mA and 1600 mA.
Are you sure this charger is good for NIMH?
Discharge: I didn't comment before, but I have problem here, because it discharge only 170 mA max with two or four cells.
Have used 0.8R, 0,47R and 0.1R, the max discharge stay at 170 mA.
I have built this one from the link below and is working for two or four batts, no succces with one single cell.
http://myweb.absa.co.za/eric.brouwer/electronics.htm
It was very difficult to make calibration, I don't konw if I did the correct procedure.
Renato
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 03 Jan 2008 7:46 Re: Intelligent battery charger circuit |
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This is a fast charger => charge current need to be at least 0.5xC where C= battery capacity .So , for 2500mA you must use at least 1250mA charge current in order to work properly .All fast chargers works like that.
I am using this charger with following batts:
- 1-4 NIMH 2700mA ( charging at 1600mA)
- 1-4 NiMh 750mA (charging at 800mA)
- 1-2 NiMh 1600mA (charging at 1600mA or 800mA.Same results)
- 1-4 Nicd 900mA (charging at 800mA)
- 2 NiCd 260mA ( charging at 800mA)
I used a switch and an resistor (0.75ohm) .When the switch is on , the LM317 sees 0.75+0.75 => 1.5ohmi => 0.83A ; switch off => 0.75ohm only => ~1.6A
" the max discharge stay at 170 mA. "
Re: Try a better FET .Those used on PC motherboards are excellent (low Vgs treshhold).Did you measure 170mA with a scope , because a DVM won't give you a correct measure (two slow) .If you want to chose a better FET , remove the PIC , put 5V to the GATE of FET and then take a reading with DVM.This is the correct way to measure " max. discharge pulse ".
Calibration should be quite easy .Maybe you are using a low quality POT .I use something like this one:
Very soon I will release a new version of hex with improved 1 batt voltage detection and discharge ON/OFF switch .
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RenatoBR
Joined: 25 Feb 2007
Posts: 24
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| 03 Jan 2008 18:57 Re: Intelligent battery charger circuit |
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"This is a fast charger => charge current need to be at least 0.5xC where C= battery capacity .So , for 2500mA you must use at least 1250mA charge current in order to work properly .All fast chargers works like that.
I am using this charger with following batts:
- 1-4 NIMH 2700mA ( charging at 1600mA)
- 1-4 NiMh 750mA (charging at 800mA)
- 1-2 NiMh 1600mA (charging at 1600mA or 800mA.Same results)
- 1-4 Nicd 900mA (charging at 800mA)
- 2 NiCd 260mA ( charging at 800mA)"
Very important information Dude,
I thought I could charge with C5/C4 like Triton charge, this was my big mistake.
To use high current I need to change the power supplay.
I have charged 2 NIMH x 2500 mA using 1.106 Amp. and worked very well.
I'm waiting for the new hex.
Thanks for your help.
In the link below there is a insteresting charge:
http://www3.telus.net/public/kimlynne/
Renato
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 04 Jan 2008 7:46 Re: Intelligent battery charger circuit |
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http://www3.telus.net/public/kimlynne/charger.html
I like the PWM approach .
It's interesting but charging NiMH based on Temperature amount does not work.I used that in my previous attempts. A better aproach is to use deltaT but I do not like that because I still have to use an temperature sensor ( two more wires to outside and a little more difficile to calibrate ).
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 05 Jan 2008 7:09 Re: Intelligent battery charger circuit |
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As promised , new hex:
http://depositfiles.com/files/2949642
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wizpic
Joined: 23 May 2004
Posts: 324
Helped: 22
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| 05 Jan 2008 10:50 Intelligent battery charger circuit |
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is the schematic the same has the last versrion ?
wizpic
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 05 Jan 2008 15:38 Re: Intelligent battery charger circuit |
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Schematic is the same as last one (switch included , see below)
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donkey41
Joined: 19 Feb 2002
Posts: 89
Helped: 2
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| 06 Jan 2008 3:09 Re: Intelligent battery charger circuit |
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hi,
I have a litte different problem.
Suppose, I have a charger to charge optimaly according to my need, and suppose
that I have an apropriate source of power, via AC-DC adapter, to drive my
intended load (led, motor, whtever).
I want to have a system which should run normaly from power source (AC-DC adapter)
and want to have the battery backup for the case when mains power is not there
(through which the AC-DC works).
I know, I can use a UPS for this purpose, but I want to build myself a simple
circuit which can switche from power source to battery backup.
I have tried to search the forum and google, but could not get my answer (perhap
because I dont have specific keywords to search this kind of topic).
If it is discussed already somwhere in this forum, kindly forgive me
and let me know the link.
regards.
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RenatoBR
Joined: 25 Feb 2007
Posts: 24
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| 06 Jan 2008 17:00 Re: Intelligent battery charger circuit |
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I have made some tests with the charger_v1.2.hex.
One NIMH 2500 mA - current 1.13 A - fail peak many times
One NIMH 2500 mA - current 1.36 A - fail peak many times
With two cells, works very well with 1.13 A.
I have tried simulation with this last hex and Proteus, didn't work.
Error message:
FATAL: [U1] Program or EEPROM data has invalid address [2000] for this device
Real Time Simulation failed to start
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 06 Jan 2008 18:52 Re: Intelligent battery charger circuit |
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Proteus can be quite silly sometimes .Hex file is "snapshot" from my PIC ,and it is working fine in my charger .
I tried to recharge an over discharged element (using previous version ).The charger refused to charge and displayed E+A .The charger started only when I recharged (outside charger) a little this ellement . So , I'v made some modification to software and now the charger works fine with these over-discharged elements <=> charger_v1.2.hex solves this problem.
If you like here is charger_v1.2.hex without config. bits .Proteus will be happy with it but is the same software as before.
http://depositfiles.com/files/2970624
"One NIMH 2500 mA - current 1.13 A - fail peak many times "
RE: Did you format these batteries ? (slow charge at c/10 followed by discharge at c/10 .Repeat procedure at least 3-4 times).
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RenatoBR
Joined: 25 Feb 2007
Posts: 24
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| 07 Jan 2008 16:16 Re: Intelligent battery charger circuit |
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"RE: Did you format these batteries ? (slow charge at c/10 followed by discharge at c/10 .Repeat procedure at least 3-4 times)."
OK, I'm recycling the new one I have bought.
Coming back to charger from Eric Brower, I'd like to know if I'm doing the correct calibration.
The author wrote:
CALIBRATION: Apply voltage to charger output. Adjust R4 so that D4 comes on at 0.5V per cell. i.e. for four cells, calibrate at 2V.
NOTE: Suitable for 2 to 8 cells.
My procedure:
For 2 cells - power up the charger with batt in and calibrate pot (pic pin 1) a little
bit more then 1 volt.
For 4 cells - the same pocedure and calibrate pot (pic pin 1) a little bit less then 2 volts.
If I calibrate exactly at 1V and 2V. the charger does not work properly.
Calibration for 1 batt: I have tried several ways, with and without batt in, but the peak fails several times for each time I try to charge 1 cell.
What you say?
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TCPIPV6
Joined: 01 Jan 2008
Posts: 6
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| 08 Jan 2008 13:42 Re: Intelligent battery charger circuit |
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Dexter,
After the discharge, the status on the serial monitor changes from Dch to Bin.
I assume Bin means batteries in and 35 seconds cooling down. After 35 seconds the charge starts but te status remains on Bin. Is this normal?
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RenatoBR
Joined: 25 Feb 2007
Posts: 24
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| 09 Jan 2008 13:31 Re: Intelligent battery charger circuit |
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TCPIPV6,
Is your charger working?
If no, use this calibration from Dude that is easy and you donīt need pc to check.
"I made some tests .The ratio between (Charger output) / Voltage on Pin 17) should be 2.1:1 . So if you have 0.803V -> adjust Pin 17 to 0.382V ."
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TCPIPV6
Joined: 01 Jan 2008
Posts: 6
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| 18 Jan 2008 15:51 Re: Intelligent battery charger circuit |
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RenatoBR,
So far I can see the charger is working. It discharge, waits 35 seconds and then starts charging. I didn't wait for the whole chargeprocess to complete. Is your charger showing a charging status via the serial port?
I'm not able to test the charger for a couple of weeks from now.
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TCPIPV6
Joined: 01 Jan 2008
Posts: 6
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| 02 Feb 2008 21:27 Re: Intelligent battery charger circuit |
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Dexter,
Is it normal that the charge starts but te status remains on Bin?
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Dexter Dude
Joined: 26 Oct 2007
Posts: 45
Helped: 1
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| 04 Feb 2008 7:14 Re: Intelligent battery charger circuit |
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No .It is not normal . The charger stayes in Bin state only for 35sec. Please read previous discussions .
I have re-uploaded hex file here :
http://depositfiles.com/files/4413624
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tiochico27
Joined: 05 May 2008
Posts: 6
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| 05 May 2008 20:47 Re: Intelligent battery charger circuit |
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Hello 4 all
I need .hex files from this project why the site have been deleted the files upped by Dexter Dude, again...
Dude, can you send files to mais e-mail or up him to a site again?
THX Bro
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