> You do not need those chips.š They may be implemented in software.
>
> Chargers from Astro Flight (http://www.astroflight.com) use a single PIC16C71-04 to
> monitor charge.š Capacity may be estimated by the current * time (which is
> tracked in the chip) to a reasonable degree.š We use these chargers to monitor
> our packs' life, actually.
>
> A friend of mine did the chargers.š Even the PWM (boost and buck) is generated
> by the PIC.
>
> BTW, the Astro chargers have single-button selection of slow/fast rates, LCD
> display of current, voltage, capacity, and time.š They are also rather
> inexpensive (US$110 typical).
>
> Andy
>
> "Milan Pavlica (YU7AEC)" <EraseMEmpavlicaspam_OUTTakeThisOuTPTT.YU> on 06/21/2000 02:37:44 PM
>
> Please respond to pic microcontroller discussion list <PICLISTspam_OUTMITVMA.MIT.EDU>
>
> šTo:ššššš @spam@PICLISTKILLspamMITVMA.MIT.EDU
>
> šcc:ššššš (bcc: Andrew Kunz/TDI_NOTES)
>
> šSubject: NiCd and NiMh charger with PIC
>
> Hi PICers...
> I have a problem..
> I need NiCd and NiMh charger which can charge them with fast and slow
> method - it can be selctable by one switch...
> Also i need auto detect of capacitance of battery...But it can be on
> fixed value.
> Problem is that i cant find here in YU MAX713 or SAA1501 IC circuit and
> i need those charger to build with a PIC..
> Does anybody can help me???
> THANKS!!!!!

>
> Chargers from Astro Flight (http://www.astroflight.com) use a single PIC16C71-04 to
> monitor charge.  Capacity may be estimated by the current * time (which is
> tracked in the chip) to a reasonable degree.  We use these chargers to monitor
> our packs' life, actually.
>
> A friend of mine did the chargers.  Even the PWM (boost and buck) is generated
> by the PIC.
>
> BTW, the Astro chargers have single-button selection of slow/fast rates, LCD
> display of current, voltage, capacity, and time.  They are also rather
> inexpensive (US$110 typical).
>
> Andy
>
> "Milan Pavlica (YU7AEC)" <RemoveMEmpavlicaTakeThisOuTPTT.YU> on 06/21/2000 02:37:44 PM
>
> Please respond to pic microcontroller discussion list <PICLISTEraseME.....MITVMA.MIT.EDU>
>
>  To:      EraseMEPICLISTMITVMA.MIT.EDU
>
>  cc:      (bcc: Andrew Kunz/TDI_NOTES)
>
>  Subject: NiCd and NiMh charger with PIC
>
> Hi PICers...
> I have a problem..
> I need NiCd and NiMh charger which can charge them with fast and slow
> method - it can be selctable by one switch...
> Also i need auto detect of capacitance of battery...But it can be on
> fixed value.
> Problem is that i cant find here in YU MAX713 or SAA1501 IC circuit and
> i need those charger to build with a PIC..
> Does anybody can help me???
> THANKS!!!!!

> Sorry, it's not something I developed.š A friend did it.
>
> It's a simple PCB, though - you could purchase one and reverse engineer it.
>
> Andy
>
> "Milan Pavlica (YU7AEC)" <RemoveMEmpavlicaEraseMEEraseMEPTT.YU> on 06/21/2000 03:01:20 PM
>
> Please respond to pic microcontroller discussion list <RemoveMEPICLISTspam_OUTKILLspamMITVMA.MIT.EDU>
>
> šTo:ššššš RemoveMEPICLISTTakeThisOuTspamMITVMA.MIT.EDU
>
> šcc:ššššš (bcc: Andrew Kunz/TDI_NOTES)
>
> šSubject: Re: NiCd and NiMh charger with PIC
>
> I need schematic diagram and software for it...Or only a algorythm...
> Thanks!
>
> Andrew Kunz wrote:
>
> > You do not need those chips.
>
> š ------------------------------------------------------------------------
>
> š They may be implemented in software.
> >
> > Chargers from Astro Flight (http://www.astroflight.com) use a single PIC16C71-04 to
> > monitor charge.š Capacity may be estimated by the current * time (which is
> > tracked in the chip) to a reasonable degree.š We use these chargers to monitor
> > our packs' life, actually.
> >
> > A friend of mine did the chargers.š Even the PWM (boost and buck) is generated
> > by the PIC.
> >
> > BTW, the Astro chargers have single-button selection of slow/fast rates, LCD
> > display of current, voltage, capacity, and time.š They are also rather
> > inexpensive (US$110 typical).
> >
> > Andy
> >
> > "Milan Pavlica (YU7AEC)" <EraseMEmpavlicaspamspamBeGonePTT.YU> on 06/21/2000 02:37:44 PM
> >
> > Please respond to pic microcontroller discussion list <RemoveMEPICLISTKILLspamMITVMA.MIT.EDU>
> >
> >š To:ššššš PICLISTSTOPspamspam_OUTMITVMA.MIT.EDU
> >
> >š cc:ššššš (bcc: Andrew Kunz/TDI_NOTES)
> >
> >š Subject: NiCd and NiMh charger with PIC
> >
> > Hi PICers...
> > I have a problem..
> > I need NiCd and NiMh charger which can charge them with fast and slow
> > method - it can be selctable by one switch...
> > Also i need auto detect of capacitance of battery...But it can be on
> > fixed value.
> > Problem is that i cant find here in YU MAX713 or SAA1501 IC circuit and
> > i need those charger to build with a PIC..
> > Does anybody can help me???
> > THANKS!!!!!

>
> For me it would be the opposite!
>
> The software is "easy" -
>
> 1  dump some charge into the pack at a known current.  Turn it off.
> 2 measure the pack voltage.
> 3 Repeat from 1 until the voltage drops slightly (NiCd drops more than NiMH).
> 4 Capacity is the sum of all the little charge (current x time)
>
> Caveats:
>
> a) Completely-discharged cells often "false-peak" early in teh charge cycle.
> It's easy to detect, though.  If you know the number of cells, the voltage will
> be much less than the expected full charge voltage.  You need to ride through
> this, usually done with a 30-second delay before looking for the true peak.
>
> b) Peak voltage will vary depending upon current, cell chemistry, and individual
> cell.
>