ITTSB.EU Blog Forum
Significant information’s in favor of a professional Workshop => All about NiMH and Ni-CD chargers in European Union => Topic started by: Kiriakos GR on November 13, 2025, 03:26:43 PM
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Charge timer protection, this is a function, only available at no piss poor chargers.
Charge timer protection, this translates that there is a built-in IC timer control within the charger, this monitoring its one charging port.
In theory, charge timer this coexist with -dv detection circuit.
At the event that voltage alone cannot increase and fall for having a proper -dv detection (single or pair of batteries fully charged), then the timer IC this will turn off this charging slot, at a specific time limit.
Charge timer protection time limit.
I am a reasonable man, I do read the user manual of any electronics that I own, but its not possible to find one non written specification at the user manual. :P
Basically this problem starts with all those willing to become Chinese products sellers, and even OEM distributors, then a product this appears under their chosen branding.
These people, importers, they are clueless of electronics functionality and specifications.
And they do not demand so to receive detailed users manuals for the products that they are plan to sell.
In this case, the consumer he may find the truth, by combining information's of two or three rebranded imports of a single identical product.
At such poorly documented products, and if they do include a timer protection, the information of Max Hours as charging process duration for its type of a battery type, this might be this timer preset.
Example of product back plate:
AAA 5 Hours
AA 8 Hours
9V 10 hours
If the charge does not stop within these limits? The you do not own a charger with timer protection.
In some cases, the factory it might add a timer limit for all charging ports, this could be at 12 Hours up to 20 Hours.
And therefore, here is another example, of how to discover if there is a timer function at your charger.
Standard charge chargers these does not come with micro-controller and or, with out any sort of automation (built-in IC timer control).
Your brain cells, they are obligated to unplug the charger and to stop the charge by your self, after a period of hours.
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Built-in IC timer control, and time limit preset.
Time limit preset, this is a man made decision.
The electronics engineer and product developer, he calculates the time that the charger stays as On, according to DC current output magnitude of its charger.
Such a calculation it should take in consideration, the actual NiMH battery type and charging rate C limits.
Here we have an example of such choices:
velleman VL3969
Charging in pair slot AA: 260-320mA = 8h (timer control)
Charging in pair slot AAA: 110-130mA = 8h (timer control)
Single slot 9V cell: 14-18mA = No timer control
It is somewhat unorthodox, that technical community and product repairs specialists, we never receive any motivation from the battery chargers industry, about technical inspection of NiMH chargers.
What is best practice for us, so we to inspect built-in IC timer control good operation?
What is best practice for us, so we to inspect charging current?
All that we know with certainty, this is that we can measure charging current as soon the circuit this stabilizes, after of 30 minutes of time.
This is a basic rule at everything electrical and or an electronic circuit.
I am not a hater of China, but since the moment that they take over electronics development, they did distort or destroy, the concept of delivery of information for products servicing.
There is no supply of servicing manuals.
And products user manual, this is another example of poorly constructed documentation.
Us the older in age repair men, we have past made experiences, from 80S up to 90S, that everything were well documented.
The younger in age repair men, they must feel as totally lost, with out having any assistance, about how-to so to troubleshoot Chinese developed electronics.
European Union, this started forcing by law, legislation in favor of products repeatability, all manufacturers they are obligated to deliver, products servicing information to end users.
The new question is, of how many decades it will take, the Chinese industries them to start complying?
An better and more reasonable approach, Nothing to be imported at European Union, when this not including servicing documentation.
When EU legislation this is ignored, the fix this is to be added a pack of drastic measures, at EU borders.
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Year 2018 NiMH Battery Chargers Handbook and Application Manual
https://data.energizer.com/pdfs/charger_appman.pdf (https://data.energizer.com/pdfs/charger_appman.pdf)
74LV4799 Timer for NiCd and NiMH chargers / 1998 Apr 20
https://media.digikey.com/pdf/Data%20Sheets/NXP%20PDFs/74LV4799.pdf (https://media.digikey.com/pdf/Data%20Sheets/NXP%20PDFs/74LV4799.pdf)
ANSMANN 2004, BATTERY CHARGING GUIDE
https://docs.rs-online.com/1715/0900766b804bde6a.pdf (https://docs.rs-online.com/1715/0900766b804bde6a.pdf)
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VARTA 57688 this is another overpriced SCAM of a charger. :P
VARTA advertising, independent charging slot operation, but in the end, this charger does five slots monitoring by the use of five timers.
LCD screen charge level this is identical to four LED lights percentage.
Actual numbers, these are an internally calculated estimation.
Why this trash it is sold then from 50 ~ 35 Euros?