Underrated Charger In Car Toy Solved
This is my first article on this blog; I wish it will be beneficial and pleasant. One of my friends, head of the postal center in my village, asked me if I can repair his son’s toy car because he can not charge it. I bring it back with me and when I unscrew and remove the lid, I immediately see a slot at each of the positive and negative connectors on the toy circuit.
As indicated by the red arrows , I reweld the broken tracks .
Comparing the output of the charger to the voltage of the battery, I realize that the nominal voltage of each is the same 3.6 volts, while the charger must have an output higher than the battery voltage to allow the charging current flowing, as evidenced by the charger plug itself through its indication shown on the toy’s bottom: DC 4.8 V.
Battery’s Capacity and voltage
The unsuitable original charger with its small voltage and current
The required voltage for the charger as indicated on the toy’s bottom
I look in my gadgets for a suitable charger and I find this beautiful one which I bought a few years ago in the scrap market for only 0.5 USD. It has a 5-10 V output and 750mA max .
The capacity of the battery is equal to 700 mAh. The 210 mA current is an appropriate charging current to prevent overheating; From the hour of 16 o’clk , I let the battery finish its charge for an estimated time of 3 h 20 min (the charging time is calculated from 700 mAh / 210 mA = 70/21 = 3.33 h). When I resume the repair I see that the charger LED is still red and the DMM showed no signs of charging, I disconnect the charger from the mains and the light turns green, sign that the battery discharges via the charger!
To remedy this abnormal state I put a diode between the circuit and the positive wire so as to block the discharge of the battery and allow the charging current.
Once the charger is connected to the mains the DMM displays 30 mA and the LED shines in orange in sign that the battery is about to saturate.
A few minutes later, the current drops to zero and the green LED lights up…
The voltage reached 4,08V indicating a full battery charging.
The next day I brought the toy to Khalid : here is the toy repaired with its replacement automatic charger, he asked me how much he owes me but I replied smiling: do not worry my reward is the joy of your son with his repaired toy…
This article was prepared for you by Abdellah Kamli from Morocco. He is an electronic hobbyist and followed a training of higher technician patent at Educatel and he repair electrical and electronic devices.
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Jestine Yong works as an Electronics Repair Lecturer in Kuala Lumpur Malaysia and his training website is http://www.NoahtechElectronicsTraining.com. You can check out his repair blog at http://www.JestineYong.com
13 comments on “Underrated Charger In Car Toy Solved”
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Well done keep sharing
Thank you Grahame for your encouraging comment,
congratulations on your first article. looking forwards to sharing information with you. have a blessed day
Hi Waleed, I follow your articles and you are welcome,I hope to exchange ideas with you, greetings
Good job, Abdellah. Yes, there is no charge worth as much as the smile on a babies face when they get their toy fixed!
Good job! Sir
Good job Abdellah. I understand that the toy is a 2.4GHz controlled car? It looks like it uses the same 16 pins chip that is used in many other RF controllers too. I recently opened up the remote of a 2.4GHz Eachine E58 drone from Banggood (I couldn’t read any chipmarking on it, so its type is still unknown). Sadly these controllers are close to useless when these toys are operated in areas where lots of 2.4 GHz Routers are active. For instance in my neighbourhood I count about 80 of those Internet Routers alone which makes flying my Drone close to impossible to do without losing control. And all advertising on this good looking but uncontrollable E58 Eachine Drone is therefore highly over-exaggerated. The Drone itself looks good but even when there is just a little wind it can’t be flown safely because of its poor RF control. It could be that my Drone was fake or a mismanufacturing but it was not at all as all videos on this model had shown.
hi albert, thank you for your comment, I think that the poor control of your drone is due to a communication failure between the radio and the drone, I recommend checking their electronics if not, contact Banggood for replacement or refund, good luck.
Welcome, and thanks for your first article Abdellah.. a job well done.
Good repair Abdellah. Congratulations.
Welcome, Abdellah. It was very pleasant to read your first article. Just a comment: if you put a diode in series with the charger, you must take into account the voltage drop on it, that reduces the output voltage. In case of a silicon diode (the most common), you must have 4.8 -0.7 = 4,1 V. Less, but enough to charge the battery (perhaps in more time than that figured out).
Hi Henrique,
yes indeed the silicon diode drops the output voltage by O,7V, the charger displays 5,6V under 220 VAC, however the voltage role is to trigger charging process but do not affect its time, the charging time only depends of current and is ratio of battery capacity and charging current:
Q=I*T so T=Q/I
Thank you for starting to share.