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Intelligent battery charger circuit

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Hello Dexter Dude,
This applies only if you've got some space left in program mem. of course..
Have you ever thought of doing some kind of "health" check on a battery, after it is charged up? Without using extra buttons, you could do a discharge for a fixed time (maybe 5 or 10secs) and translate the resulting drop in voltage into a number for display, to get a relative indication of how good the battery holds the charge.
If this action also is performed at start-up, you could check at any moment, and then abort the rest of the proces (by removing the battery).
For a better (time consuming) check, a suspected battery could be left in the charger and (after charging) this "drop" check could be repeated every hour automaticly (and recorded).
This way the batteries can be labeled with a (quality) number (9 to 1) and the 'lesser good' ones will get sorted out.
You did a nice job, greetings, At.
 

I tested an old NiMH 1600mA battery which I know it is in bad shape .This battery holds the charge perfectly for 1day but after that it's capacity starts rapid declining . So this method of sorting out bad batteries may not work as expected .
 
Dexter Dude said:
.. // So this method of sorting out bad batteries may not work as expected .
Click to expand...
You are right Dexter, it's difficult to find a reliable indication, i think usually people just throw them away if this happens, but I often find it's one or two in a string of batteries that spoil the whole pack.
What I suggested is actually some kind of Ri test on the battery. Directly after charging "things look ok", then it starts to decline on older (or mistreated) ones. Maybe a (first) test should start after an hour. I could notice the difference between bad and better ones, already after some hours.
And after 2 or 3 day's it is clear if they are worth to be saved.
At.
 

Dexter's schematic for charging NiCd/NiMH is best for 1, 2 or 3 cells, how can we improve that for 6-8 NiCd cells connected in series, each of about 2800mA...
Thanx in Advance...
 

Re: intelligent battery charger circuit

hi
i think you must check this link

(**broken link removed**)
 

Re: intelligent battery charger circuit

qayyoum said:
hi
i think you must check this link

(**broken link removed**)
Click to expand...

Well Qayyoum, this link don't work, do you have alternative link or can you plz give me that schematic/detail or whatever in some other format.....!!!
 

Re: intelligent battery charger circuit

come on Qayyum, could you help me fix this...:|
 

Re: intelligent battery charger circuit

But I have a doubt. Why not use Power Management ICs for charging and Discharging batteries in efficient way. There are so many chips in the market.
 

Re: intelligent battery charger circuit

FreeMAn0110 said:
But I have a doubt. Why not use Power Management ICs for charging and Discharging batteries in efficient way. There are so many chips in the market.
Click to expand...

Can you give some of those... for high current and multiple NiCd cells to be charged in series ...?
 

Re: intelligent battery charger circuit

Can you please let me know what current rating you looking at. Also the number of cells.
 

Ya got it. But what I meant was what current rating you want as output. Depending on that there will PMIC. Charging current would be managed by the PMIC itself.
 

can you please check powerful PMIC launched by Linear Technology.
**broken link removed**
 

Hi, guys. I make a simple PCB for Dexter's charger
here is how it looks.
**broken link removed**


Dexter, what do you think to use 2 Mosfets for discharge. one is for the fast discharge when charging, and one for discharge before charging. Right now when you discharge the battery before charging, the current is too big. Using smaller resistor is option, but better is to use 2 independent circuits.

Niki
 

Hallo niki (fena),
Can you show a PDF or BMP version of your PCB? (Traces only).

note: If you want another discharge circuit, it also implies other software. Probably Dexter doesn't like that.

At.
 
Last edited:

Hello, T.

I made this charger, but I don't like it. I don't think that this is a good charger. In this case, please find some better alternative.

Niki
 

Hi everyone

Is there anything in this thread that can help me build an intelligent SLA battery charger?

I'm trying to build a smart charger on which you can actually choose the voltage of battery to be charged (common SLA : 6V,12V,24V); and charging the battery using 3 stages method (constant current, constant voltage, float charge).

Could anyone here help me with this?

Thanks in advance ;-)

Amir
 

I found that there are several different methods to determine battery health.

In the case of lead acid batteries, internal resistance is a rough and ready indication,

Impedance measurement: an AC load is applied to the terminals of the battery and the response (instantaneous volts, phase angle) is measured **broken link removed**, apologies to the designer of this circuit, whose site I cannot find again.. US Patent No 5773978 describes a similar circuit.

Similar methods involve measuring the internal battery resistance by briefly switching a large DC load across the battery and measuring the response, a smaller load may be placed across the battery to remove "surface charge" first. Ford describe a 1973 patent that uses specific timings USPNO3857087.

The Cold Cranking Amps method does this, albeit for a longer amount of time (as long as the button is pressed). A cooled load resistor and basic voltmeter are all that is required. This method is reasonable for identifying end-of-life batteries without too much interpretation.

Most modern methods use a range of frequencies and determine health against a "matrix" of multiple parameters that have been previously determined from the same model of battery.

Different battery chemistries require different approaches.
 

Salutare. Dexter poti sa pui undeva hex-ul de la incarcatorul cu pic16F628. Vreau sa-l fac dar nu-l mai gasesc nicaieri. Multumesc
 

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