Post by thread:Batteries

At 13:18 07/04/97 -0600, you wrote: >We have a project that requires -40 degree (C or F, you choose) operation. >Anyone know of a battery supplier that provides something that works >reliably at that temperature? > <.....edtoddKILLspam@spam@sni.net> Ed Todd How much power do you need? If your power requirements are small there are quite a lot of lithium/thionyl chloride batteries available. Some are specified to operate down to -55C (Saft and Crompton both make them). Lithium/Iron Sulphide batteries will also operate down to -40 and offer higher peak currents but lower total capacity. Whichever you choose, remember that the capacity and voltage both drop dramatically at low temperatures. (I guess you've discovered that already :) Hope this helps, Keith. ========================================================== Keith Dowsett "Variables won't; constants aren't." E-mail: kdowsettKILLspamrpms.ac.uk WWW: http://kd.rpms.ac.uk/index.html

At 01:18 PM 4/7/97 -0600, you wrote: >We have a project that requires -40 degree (C or F, you choose) operation. >Anyone know of a battery supplier that provides something that works >reliably at that temperature? > <.....edtoddKILLspam.....sni.net> Ed Todd > > I found a batteries that can help you: look for Cyclon made by Hawker Energy Products. It can operate from -65 C to 65 C. =================================================== Alboni Giorgio Faenza (Ra) ITALY E-Mail: EraseMErac1337spam_OUTTakeThisOuTracine.ravenna.it www.geocities.com/SiliconValley/Heights/5444 =================================================== Per e-news by geocities: http://www.merc.com/cgi/geocities.cgi Per aggiungere link in Lycos: http://www.geocities.com/BHI/search.html Da vedere: === Andrew Warren - fastfwdspam_OUTix.netcom.com === Fast Forward Engineering - Vista, California === === Custodian of the PICLIST Fund -- For more info, see: === http://www.geocities.com/SiliconValley/2499/fund.html Piclist sul web: http://www.428main.com/piclist/ DA FARE VOL: Per aggiornare i tuoi dati collegati alla alla URL: http://www.volftp.vol.it/IT/IT/MAIL/index.htm e utilizza i seguenti dati per accedere alla tua scheda personale: Email: @spam@rac1337KILLspamracine.ravenna.it Password: GFBAEGD

Ciao, forse per sbaglio, ma hai mandato in giro questa roba, sara` il caso che cambi la password ? {Quote hidden}> > =================================================== > Alboni Giorgio > Faenza (Ra) ITALY > E-Mail: KILLspamrac1337KILLspamracine.ravenna.it > www.geocities.com/SiliconValley/Heights/5444 > =================================================== > Per e-news by geocities: http://www.merc.com/cgi/geocities.cgi > > Per aggiungere link in Lycos: http://www.geocities.com/BHI/search.html > > Da vedere: > === Andrew Warren - RemoveMEfastfwdTakeThisOuTix.netcom.com > === Fast Forward Engineering - Vista, California > === > === Custodian of the PICLIST Fund -- For more info, see: > === http://www.geocities.com/SiliconValley/2499/fund.html > > Piclist sul web: http://www.428main.com/piclist/ > > DA FARE VOL: > Per aggiornare i tuoi dati collegati alla alla URL: > http://www.volftp.vol.it/IT/IT/MAIL/index.htm > e utilizza i seguenti dati per accedere alla tua scheda personale: > Email: spamBeGonerac1337spamBeGoneracine.ravenna.it > Password: GFBAEGD ^^^^^^^ Ciao Luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: TakeThisOuTluigiEraseMEspam_OUTiet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________

Date: Sun, 20 Apr 1997 17:10:56 +0200 To: pic microcontroller discussion list <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> From: Giorgio Alboni <rac1337EraseME.....racine.ravenna.it> Subject: Re: Batteries In-Reply-To: <EraseME199704071917.NAA03625mailrelay.csn.net> I found a batteries that can help you: look for Cyclon made by Hawker Energy Products. It can operate from -65 C to 65 C. =================================================== Alboni Giorgio Faenza (Ra) ITALY E-Mail: RemoveMErac1337EraseMEEraseMEracine.ravenna.it www.geocities.com/SiliconValley/Heights/5444 =================================================== At 01:18 PM 4/7/97 -0600, you wrote: >We have a project that requires -40 degree (C or F, you choose) operation. >Anyone know of a battery supplier that provides something that works >reliably at that temperature? > <RemoveMEedtoddspam_OUTKILLspamsni.net> Ed Todd > > =================================================== Alboni Giorgio Faenza (Ra) ITALY E-Mail: RemoveMErac1337TakeThisOuTspamracine.ravenna.it www.geocities.com/SiliconValley/Heights/5444 ===================================================

Hi All! I'm working now at one project, using C73, powered from Panasonic 3.6V 300mAH NiCd (from cordless phones) with MAX631 (3.6->5v convretor). The average current from the battery is 30 mA. I have LCD display and one free C73's ADC input, and I want to display the "Low Battary" symbols in 3 steps : full,middle, low. Now I connected ADC input to battary, and the problem is what values a must have as a limit to each step? Another problem - this project must be as cheaper as possible, so I need very very simple charger. What happens, is I use simple AC-powered 12v supply and connect it with then battery with (how?)mA current source ? --------------------- Alex Torres, EraseMEaltorspamspamBeGonecook.kharkov.ua Kharkov,Ukraine --- GoldED 2.50.A0531+

Alex I. Torres wrote: > > Hi All! > > I'm working now at one project, using C73, powered > from Panasonic 3.6V 300mAH NiCd (from cordless phones) > with MAX631 (3.6->5v convretor). > The average current from the battery is 30 mA. > I have LCD display and one free C73's ADC input, and I > want to display the "Low Battary" symbols > in 3 steps : full,middle, low. > Now I connected ADC input to battary, and the problem is > what values a must have as a limit to each step? You will have to get the manufacturer's discharge curve for 30mA. Measuring the voltage is not a good indicator, however. > > Another problem - this project must be as cheaper as > possible, so I need very very simple charger. What happens, > is I use simple AC-powered 12v supply and connect it with > then battery with (how?)mA current source ? There is no easy way. The simplest method would be a constant current source with a voltage setpoint charge stop. Remember, however, that you need enough current to overcome the reverse charge when the battery is flat. This current can also be enough to overcharge the battery, so a fast charge/trickle charge works best. You could do it with a transistor, an opamp, a zener, and a few resistors. The easiest way to destroy NiCds is to overcharge them. -- Friendly Regards Tjaart van der Walt RemoveMEtjaartKILLspamwasp.co.za _____________________________________________________________ | WASP International http://www.wasp.co.za/~tjaart/index.html | | R&D Engineer : GSM peripheral services development | | Vehicle tracking | Telemetry systems | GSM data transfer | | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973 | | WGS-84 : 26010.52'S 28006.19'E | |_____________________________________________________________|

In order to reliably determine battery life, you really need to be able to briefly switch a load across the battery which draws a predetermined current and then measure the battery voltage. Battery manufacturers can supply voltage/time curves for a given load, if you ask. {Quote hidden}> ---------- > From: Alex I. Torres[SMTP:altorSTOPspamspam_OUTCOOK.KHARKOV.UA] > Reply To: pic microcontroller discussion list > Sent: Tuesday, November 25, 1997 4:10 AM > To: spamBeGonePICLISTSTOPspamEraseMEMITVMA.MIT.EDU > Subject: Batteries > > Hi All! > > I'm working now at one project, using C73, powered > from Panasonic 3.6V 300mAH NiCd (from cordless phones) > with MAX631 (3.6->5v convretor). > The average current from the battery is 30 mA. > I have LCD display and one free C73's ADC input, and I > want to display the "Low Battary" symbols > in 3 steps : full,middle, low. > Now I connected ADC input to battary, and the problem is > what values a must have as a limit to each step? > > Another problem - this project must be as cheaper as > possible, so I need very very simple charger. What happens, > is I use simple AC-powered 12v supply and connect it with > then battery with (how?)mA current source ? > > --------------------- > Alex Torres, KILLspamaltorspamBeGonecook.kharkov.ua > Kharkov,Ukraine > > --- GoldED 2.50.A0531+ >

Andrew Mayo wrote: > > In order to reliably determine battery life, you really need to be able > to briefly switch a load across the battery which draws a predetermined > current and then measure the battery voltage. Battery manufacturers can > supply voltage/time curves for a given load, if you ask. This is exactly what we do to determine a 6 cell NiCd pack's state. I discharge it over a 47E resistor for 10s and measure the voltage under load. A few people have asked about good batteries to use lately. A very nice battery (but a bit expensive) is the Hawker (previously Gates) Cyclon 2V lead acid cells. They combine all the nice features of lead acids and NiCds. -- Friendly Regards Tjaart van der Walt EraseMEtjaartEraseMEwasp.co.za _____________________________________________________________ | WASP International http://www.wasp.co.za/~tjaart/index.html | | R&D Engineer : GSM peripheral services development | | Vehicle tracking | Telemetry systems | GSM data transfer | | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973 | | WGS-84 : 26010.52'S 28006.19'E | |_____________________________________________________________|

Scott Walsh wrote: > > About putting a known load on the battery ... can you do this while > the product that is running from the battery is still working? > > regards, > SW. You could, but not with lead-acids. Also be carefull to not charge while you discharge. Put your product in a known state so it will always draw the same current when you test the battery. -- Friendly Regards Tjaart van der Walt @spam@tjaart@spam@spam_OUTwasp.co.za _____________________________________________________________ | WASP International http://www.wasp.co.za/~tjaart/index.html | | R&D Engineer : GSM peripheral services development | | Vehicle tracking | Telemetry systems | GSM data transfer | | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973 | | WGS-84 : 26010.52'S 28006.19'E | |_____________________________________________________________|

Pardon me for asking what may be a simple question. If you discharge the 7.5 V nicads into 47R (160mA) for 10 seconds what would you expect to see in a good / marginal / bad battery for voltage? Does the manufacturers data indicate these values? If I had a 12 volt lead-acid battery at 1AH and I discharged it at X mA would I discharge a 10 AH 12 V lead acid cell at 10X for the same indication of battery condition. Could I use the PWM O/P (set at 10% or 100%) of a PIC to control the load via a FET for both of these tests or would I require two separate loads? Thanks in advance for any assistance. Guy ---------- {Quote hidden}> From: Tjaart van der Walt <spamBeGonetjaartKILLspamwasp.co.za> > To: .....PICLISTspam_OUTMITVMA.MIT.EDU > Subject: Re: Batteries > Date: Tuesday, November 25, 1997 9:45 PM > > Andrew Mayo wrote: > > > > In order to reliably determine battery life, you really need to be able > > to briefly switch a load across the battery which draws a predetermined > > current and then measure the battery voltage. Battery manufacturers can > > supply voltage/time curves for a given load, if you ask. > > This is exactly what we do to determine a 6 cell NiCd pack's state. I > discharge it over a 47E resistor for 10s and measure the voltage under > load. > > A few people have asked about good batteries to use lately. A very nice > battery (but a bit expensive) is the Hawker (previously Gates) Cyclon > 2V lead acid cells. They combine all the nice features of lead acids > and NiCds. > > -- > Friendly Regards > > Tjaart van der Walt > TakeThisOuTtjaart.....TakeThisOuTwasp.co.za > _____________________________________________________________ > | WASP International http://www.wasp.co.za/~tjaart/index.html | > | R&D Engineer : GSM peripheral services development | > | Vehicle tracking | Telemetry systems | GSM data transfer | > | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973 | > | WGS-84 : 26010.52'S 28006.19'E | > |_____________________________________________________________|

Guy Farebrother wrote: > > Pardon me for asking what may be a simple question. > > If you discharge the 7.5 V nicads into 47R (160mA) for 10 seconds what > would you expect to see in a good / marginal / bad battery for voltage? Take the difference as a percentage of the first voltage. Fully charged batteries will be > 90% Marginally charged batteries will be > 80% This will indicate the charge level only. If you want to determine the state of the battery (good, bad, or ugly), you'll have to charge them fully before discharging. This will give you an indication of remaining capacity. VERY IMPORTANT : Make it impossible for the battery to discharge for longer than 10s. If your software goes haywire, the resistor will unsolder itself with disasterous effect (fire & brimstone) !! > Does the manufacturers data indicate these values? No - unfortunately not. I think it is for safety reasons (see the warning above) > If I had a 12 volt > lead-acid battery at 1AH and I discharged it at X mA would I discharge a 10 > AH 12 V lead acid cell at 10X for the same indication of battery condition. > Could I use the PWM O/P (set at 10% or 100%) of a PIC to control the load > via a FET for both of these tests or would I require two separate loads? This test will not work for Pb batteries. The internal resistance is a very poor indication for a Pb cell. The voltage drop vs capacity, however, is a lot 'better' than a NiCd for capacity measurement. Very important : Never let a Pb battery discharge completely - it will cost you a fortune in replacements. If you absolutely have to, the ONLY Pb battery in the world that can handle it, is at http://hepi.com > > Thanks in advance for any assistance. No problem -- Friendly Regards Tjaart van der Walt TakeThisOuTtjaartKILLspamspamwasp.co.za _____________________________________________________________ | WASP International http://www.wasp.co.za/~tjaart/index.html | | R&D Engineer : GSM peripheral services development | | Vehicle tracking | Telemetry systems | GSM data transfer | | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973 | | WGS-84 : 26¡10.52'S 28¡06.19'E | |_____________________________________________________________|