I'll give you a tip: That flag is from some European country that has just approved same-sex couple marriage and adoption.
EVA --
You've made my day -- I have a sulfated battery for a 126-Class Mercedes -- when I choose to run my 560 or 420 I have to swap out the battery! Your circuit is going to be put into action. A new battery is a small fortune for these 18 year old cars.
You've made my day -- I have a sulfated battery for a 126-Class Mercedes -- when I choose to run my 560 or 420 I have to swap out the battery! Your circuit is going to be put into action. A new battery is a small fortune for these 18 year old cars.
OT: Aha Spain!
Your battery charger/desulphater implementation looks like good and evolved design to me.. I hope you have marked it copyrighted - it would be a pity if someone profitted from your labors. Don't ask me how I know 😡
Kevin
Your battery charger/desulphater implementation looks like good and evolved design to me.. I hope you have marked it copyrighted - it would be a pity if someone profitted from your labors. Don't ask me how I know 😡
Kevin
Eva, thanks for your contribution to this thread!
my parts are in the mail, and jackinnj's post reminded me that my moped battery needs to have a go as well.
thanks
Marius
my parts are in the mail, and jackinnj's post reminded me that my moped battery needs to have a go as well.
thanks
Marius
Note that my circuit is only experimental and I'm mkaing changes from time to time.
For example, I've replaced the 0,1 ohm 4W wirewound resistor for two non inductive 0,25ohm 1/2W resistors in paralell. This reduced dramatically the inductive spikes seen at the beginning and the end of the current sense pulse, so I also had to change the 1k/1nf spike-filter to 2k2/100pf. That fixed a potential instability issue.
I've also changed the gate resistor to 47 ohms in order to speed up switching and reduce losses.
I'm also experimenting with lower frequencies (1Khz, 3Khz,10Khz, 20Khz, 40Khz, etc...) and discontinuous mode by increasing the values of the 22k timing resistor and/or the 1nf timing capacitor. Nor I'm sure about the optimum frequency, neither I know if some dead time is usefui.
I recommend experimenting, altough that requires plenty of parts to play with and an oscilloscope.
For example, I've replaced the 0,1 ohm 4W wirewound resistor for two non inductive 0,25ohm 1/2W resistors in paralell. This reduced dramatically the inductive spikes seen at the beginning and the end of the current sense pulse, so I also had to change the 1k/1nf spike-filter to 2k2/100pf. That fixed a potential instability issue.
I've also changed the gate resistor to 47 ohms in order to speed up switching and reduce losses.
I'm also experimenting with lower frequencies (1Khz, 3Khz,10Khz, 20Khz, 40Khz, etc...) and discontinuous mode by increasing the values of the 22k timing resistor and/or the 1nf timing capacitor. Nor I'm sure about the optimum frequency, neither I know if some dead time is usefui.
I recommend experimenting, altough that requires plenty of parts to play with and an oscilloscope.
good thing i went with mark's (mwmkravchenko) suggestion.
I'm not on a level that alows me to experiment to seriously, i do get a genereal understanding of how stuff works, but not enough to be able to improve them--yet.
right now though, i'v got some soldering to do.😀
-marius
I'm not on a level that alows me to experiment to seriously, i do get a genereal understanding of how stuff works, but not enough to be able to improve them--yet.
right now though, i'v got some soldering to do.😀
-marius
You have just built a SMPS controller such as 3842. You could also buy one.
3842 starts to run until its supply voltage reaches nearly/more than 10 volts, so you need a auxilary supply to power the IC.
3842 starts to run until its supply voltage reaches nearly/more than 10 volts, so you need a auxilary supply to power the IC.
Eva said:
You are right and I had the same idea but I didn't have UC3842 ICs in my spare parts collection when I decided to build that circuit. I store only generic low-cost things like: resistors, capacitors, ferrite and iron-powder cores, magnet wire, MOS/bip/IGBT transistors, thyristors, triacs, diodes, op-amps, comparators, CMOS 4000 ICs, optocouplers and some PICs. You can build almost anything with these (much more than I actually do 
) . I store only a few specific ICs, like TL431, SG3525A, TL494, L4981A and IR2112.
) . I store only a few specific ICs, like TL431, SG3525A, TL494, L4981A and IR2112.
Eva,
This design is simple and elegant, uses no expensive parts that aren't available on 3/4 of the planet.. Easier to deal with from the usual hobbyist standpoint.. There aren't any weird or unobtainable parts in your design, and in the future you can always substitute the available equivalent gate, flip-flop or discrete as parts are obsoleted. (I.E. I like it.)
I am constantly having to deal professionally with obsoleted parts so the fact that this design has nothing subject to obsolescense is a huge benefit.
Kevin
This design is simple and elegant, uses no expensive parts that aren't available on 3/4 of the planet.. Easier to deal with from the usual hobbyist standpoint.. There aren't any weird or unobtainable parts in your design, and in the future you can always substitute the available equivalent gate, flip-flop or discrete as parts are obsoleted. (I.E. I like it.)
I am constantly having to deal professionally with obsoleted parts so the fact that this design has nothing subject to obsolescense is a huge benefit.
Kevin
Is it better to use a small, low gate charge FET such as IRF510? It simplifies the drive circuit and increase the turn-off speed.
Big FET with low Ron seems unnecessary, since the average current is low, there's no heating problems.
Big FET with low Ron seems unnecessary, since the average current is low, there's no heating problems.
I used IRF540 because it was what I had at hand and it's very easy to find. Feel free to try other devices, but note that even a IRF540 with its low Rds-on requires heatsinking.
kevinkr said:
I've had a device like that in may car for a few years. The second battery it was on lasted I think twice as long as the previous battery. I'me not really sure whether it was the battery brand or the device that made the difference. I guess I'll know with this third battery.
Note that such a device draws a small amount of energy from the battery so it will end up discharging it after several days (thus sulphating more than it desulphates). It's not a good idea to leave the desulphator permanently connected, except in case the car is used very frequently.
Eva said:
I often wondered about that when I got it. It just seemed the little thing was designed just to be bolted to the battery terminals. The first battery actually did have a little shorter life than I expected, only about a year totalling a daily drive for about 30 minutes in the city. The second battery was a different brand and lasted real long, two years at least. If these things really do extend battery life, it should be promoted to save the environment.
soongsc said:
1 year? That Really sucks. 10 years is more likely battery life in here, 6 years at least. Maybe cold climate in here prolongs battery life 😀 (they are also oversized(1.5-2X) compared to warmer countries to ensure enough cold cranking amperes)
mzzj said:
Maybe the temperature also has to do with chemical reaction. I certainly would love to have batteries that last 10 years! They only lasted about 2 years while I was in southern part of the US. Cowboy country.
I would expect a car battery to last at least 5 years before trying to recycle it, some may happily last 10 years. Something has to go terribly wrong in order for a battery to last only one year, namely a faulty charging circuit or unexpected discharge currents.
Also, there is a funny issue with sealed and gel batteries in hot climates: As the battery is discharged, the electrolyte is dissociated into H2O and sulphur, and then, excess heat causes pressure buildup inside the case and forces the battery to vent, thus allowing some H2O to evaporate.
Since these batteries are sealed, there is no easy way to restore lost H2O, so while charging the electrolyte is not able to fully recombine back and capacity is progressively lost. The excess sulphur binds to lead plates causing unrecoverable sulphation, since it has nothing else to bind to. Even if you dare to open a hole on the case and refill, you'll never know how much distilled water is required (too much also causes capacity loss).
Also, there is a funny issue with sealed and gel batteries in hot climates: As the battery is discharged, the electrolyte is dissociated into H2O and sulphur, and then, excess heat causes pressure buildup inside the case and forces the battery to vent, thus allowing some H2O to evaporate.
Since these batteries are sealed, there is no easy way to restore lost H2O, so while charging the electrolyte is not able to fully recombine back and capacity is progressively lost. The excess sulphur binds to lead plates causing unrecoverable sulphation, since it has nothing else to bind to. Even if you dare to open a hole on the case and refill, you'll never know how much distilled water is required (too much also causes capacity loss).
Eva said:
Mostly when my batteries die, they just act funny for about a week or so and then goes. Not chargeable any more. I remember the mechanic mentioning the battery being shorted internally.
i m working on a constant voltage current limited kind of a pulse lead acid battery charger , running at 27khz , and if i m not wrong , which by nature a kind of a desulfator as well , few things i need to know about..
1 . do i need to add L/C filter after rectifier diodes
2 . is direct dc with ripples harmful for battery,
this is a 3 yrs old and only thread discuses about desulfator , i hope every one on this thread still doing diy. thanks to all
1 . do i need to add L/C filter after rectifier diodes
2 . is direct dc with ripples harmful for battery,
this is a 3 yrs old and only thread discuses about desulfator , i hope every one on this thread still doing diy. thanks to all
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