9V NiMH battery charging circuit

[iking]

Sir pakipost final diagram. Thanks

madame ito po ung gawa ni neneng nucleus



parts list:
B1 - battery snap
DC socket
R1 - 500 ohms
R2 - 75 ohms
R3 - 4.7k ohms
R4 - 500 ohms
C1 - 10uf 25V
D1 - LED red
D2 - 1N4004
D3 - 1N5242B
D4 - 1N5235B
D5 - LED green
U1 - LM317T
U2 - LM431

eto naman po ung less 20 or 25 petot





parts list:
R1 - 8.2k
R2 - 47
C1 - 0.33uF 50V
D1 - 1N4007
D4 - 1N5242B
IC3 - LM317T
LED
battery snap
dc socket

galing sis! nice! +1

thanks chairman bhadz

[insomartin]

^ disposable nga pala yung battery nang head amp mo noh? i think if you would use a smt na LM317T it would be a LOT smaller and would fit sa ilalim nang battery. imho.

[insomartin]

but for anything else, guaaaapo mo! hehehe nagkaidea ako! +1 infinity points.!

[iking]

^dinadissect ko na headamp ko e hehe.. yup dispose na sya sa 100-1000 charge cycles sabi ni master wiki.. nice sir marting, mas maganda nga kung smt lahat para diretcho saksak nalang sya sa wall charger, portable nga talaga hehe..

salamat sa puntos

[Gbreaker]

ayos ln gpo b n mglagay aq ng capacito & LOAD parallel sa battery? xe gagawa po aq ng RJ45 tester with USB charger

[alchemist1987]

pwde rin poh b ito gmtng charger sa 6v???

[ponkan]

mga ser! bago lang po ako pwede po bang magtanong...meh thesis po kasi ako ngaun (nvm deep details about that) so device po xa, battery operated, so yung battery embedded sa loob ng device what i need is to make a charger 9v NiMh battery charger..may condition nga lang po that yung battery is capable of charging while yung device is nakaopen, parang sa cellphone po, diba pwede xang i-charge while inuse yun lang po  

[renekenshin]

Ilang ampere po yung kailangan para sa charger? Meron ako 9v 250mAH na rechargeable battery ilang oras kaya ito mai-full charge using your charger circuit? thanks

[Ikasamoko]

maki sawsaw na rin...meron ako nabili na 4 pcs ng NiMH na AA @ 2800mA yung isa...

baka may alam kayo na ckt ng charger nito...yung meron cycler...charger/discharger...

meron ako nakita dati using PIC at may LCD pa..di ko lang ma remember saan ko natisod yun...

[OPTIMUS PRIME]

dami naiisip pati sawsawan nadali na hehehehe. May LCD na charger?---
cd-r king cellphone battery charger may LCD na
mura na din ang Ni-MH charger ng CD-R king may battery na kasama pede na sa violebot (violet na mobot)

ito ba?--http://www.oshonsoft.com/picchargerlcd.html baka lalo mahal ang kinalabasan nyan hehehehe

[Ikasamoko]

bruha ka talaga...

may nabili ako Akari charger may kasama na 4pcs na AA @ 2800mA

gusto ko sana kulikutin if they are telling the truth...


ayaw ko nyan...wala ako 876...

[OPTIMUS PRIME]

bruha ka talaga...

may nabili ako Akari charger may kasama na 4pcs na AA @ 2800mA

gusto ko sana kulikutin if they are telling the truth...


ayaw ko nyan...wala ako 876...

Q/10 lang naman ata needed sa safe charging sa Ni-Cd.
Ako minsan pag wala na papel, ballpen at PSU na lang hehehe.wag lang makalimutan baka pumotok.

[Ikasamoko]

it reminds me of one matinik na guy...charged a 3.6volts cp batt sa 12vdc @ 3amps....

ng sumabog sinisi pa yung battery...peke kasi...lol!!

[macky]

^hahaha, natawa naman ako dun sa pagsisi sa 3.6V cp battery = "peke kasi"

[makuy]

sir gandang araw, gumawa din ako nitong charger base sa schem ni sir nucleus. tanong lang po ilang volts po dapat ang ma measure sa battery termimal? yung akin po 6.7v

[bravokilo]

Wow, this is a long running thread  I noticed. Well, sisters, in our RC world, we had to learn a lot about Nicad and NIMH charging. Parejo sila actually, magaan lang and MH for the same capacity. Pero mas malakas and current delivery rate ng Nicad. Anyway, NOT ALL can be fast charged altho it is abused in most cases. The safest charging ratge is called the C10, 10 for 10% of capacity. So, for a 500 mah nicad, 50 ma ang C10 for 15 hours assuming galing sa 1.1V and nicad. The standard charger "for dummies" from Futaba is a 45-50 ma wall charger. The 4 cell pack is charged in series as well as the 8 cell pack in the transmitter.We have duplicated this charger many times when someone needed a charger.

While constant current is suggested in many mags, the tapering current worked well for us for many years which means no voltage regulator is used. Instead it is a simple traffo cum diode charger. If you will put an ammeter in series, you will note that the current tapers as the battery gets charged. That is because as the battery gets charged, its internal resistance drops and it therefore draws less current. The rule of thumb is to put 50% more charge on an exhausted battery. At 10%, it would take 10 hours to put back 100 % of the spent energy. But the rule is to let it charge 50% more, thus 15 hours. Actually, this is not technically accurate since the charging rate actually tapers and is not constant. so the current put back is not really 150%.

For the Futaba charger, it is interesting that the traffo is a plain 200ma traffo with 19V on its secondary with a center tap. Let's call the terminals 1,2, and 3. 1 and 2 is used to charge the 4 cells with a diode, and LED, and resistor in series. A resistor is paralled to the LED so the LED does not burn up. Forget the voltage, calibrate the charger as to the current running to the battery. Adjust the resistor to get the 50 ma. Choose the parallel resistor to an LED to get the right brightness. Do the same for the 8 cells.

If you want to build a charger for higher capacity batteries, get a bigger traffo. The current should remain at C10. But you have to adjust the parallel resistor across the LED. It should drop a voltage of 1.5 only, the usual LED voltage.

THIS CHARGER IS "FOR DUMMIES" CUZ YOU CAN LEAVE IT HOOKED UP FOR WEEKS WITHOUT HARMING YOUR CELLS.

HOW TO DISCHARGE THE BATTERIES

     If you had gone to a race track in the old days, you would see battery packs being discharged with auto light bulbs. The RC car packs had 6 cells so the the max V was 1.4v x 6 or 8.4V. 12V auto bulbs can be used. to increase the discharge rate, just parallel more bulbs. BUT THE VOLTAGE WAS BEING WATCHED. AS SOON AS IT HITS 1.1 V PER CELL OR 6.6V , THE CHARGER IS REMOVED. At 1.1V, the voltage drop in nicads accelerates.

     There must be a way to stop the discharge by itself without having to plunge P2k to P3k on a TLP charger(I have one). I have seen one style used in AA nicads. A diode of sufficient current rating shorts out the cell. Usually it is done on spent battery so the current is now weak. The diode will not let the V go below .7V. so, the cell is not fully zapped. Then it is charged. Well, how do we do this on a 4 cell pack. Threshold V is 4.4V, so we divide that by .7 and get 6 diodes in series. 6 x .7 is 4.2 volts. So the battery will be discharged to 4.2V before charging. if you want to discharge high current, used big diodes but better to series an auto bulb to limit the discharge rate. When it is out, the discharge is complete.

[bravokilo]

Now, the moment you want to raise the charging rate, just extrapolate the current. If you want to charge in half the 15 hours, double the current., etc. BUT YOU HAVE TO PUT A TIMER SINCE YOU WILL BE OPEN TO OVERCHARGE! In RC cars, we had fast chargers with a 15 minute timers. You can use the timer of the oven toaster. So, 15 hours is 15 x 60 minutes, right? divide that by 15 to get the factor with which to multiply the charging rate. Usually the car battery is the source to charge the nicads in the field. Make sure you have nicads ok for fast charging.   

FURTHER NOTE ON MAKING 2 CHARGERS FROM ONE TRAFFO\

     Let us go back to the Futaba charger for 4 cells and for 8 cells at the same time. We said, use 1 and 2 for the 4 cells. We then use 1 and 3 for the 8 cells BUT WE HAVE TO USE THE OPPOSITE PHASES TGO CHARGE THE 4 CELLS AND THE 8 CELLS.

     Use 1 and 2 for the 4 cells and put the a diode on 2 to obtain a plus.  1 therefore is minus. For the 8 cells, use 1 and 3 but the diode on 3 is inverted to produce a minus. 1 therefore is common but is minus for the 4 cells and is plus for the 8 cells. In short, they are "OFF phase". One phase of the traffo charges the 4 cells and the other phase the 8 cells. In short, they are not in actuality being charged at the same time but alternately. So, you see 1 and 2 is never really used twice.

CONSTANT CURRENT CHARGER

     If you look up the datasheet for any voltage regulator, they can be configured to become current regulators. The circuits shown in this thread using VRs are examples. Notice, the battery being charged is placed in series from ground to the reference pin of the regulator. For 78xx VR, Pin 2 is the ref pin. As the battery gets charged, the internal resistance drops. It adjust the V and let the curent remain the same. A constant current charger can charge at C10 but for 10 hours. Interpolate from there if you want a fast charger.

BK

[bravokilo]

[efren]

nice, thanks for the schematics sir BK +1

[bravokilo]

Yep, Efren, mayroon pa ako nakita magandang charger , hanapin ko

BK