SAFT NiCd "block" battery high cell voltage

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Subject Author Date SAFT NiCd "block" battery high cell voltage Bob F 01-29-2008  Re: SAFT NiCd "block" battery high cell voltage Neon John 01-29-2008  Re: SAFT NiCd "block" battery high cell voltage Solar Flare 01-29-2008  Re: SAFT NiCd "block" battery high cell voltage Bob F 02-04-2008
Posted by Bob F on January 29, 2008, 6:56 pm Please log in for more thread options Any experts here on large nicads? I just picked up 45 used SAFT SBM43-2 NiCd "block" batteries. Each battery appears to be 2- 43 AH cells with a jumper bar attached between the two cells putting them in series electrically. Each battery measures 3.4-3.62 volts, which seems on the high side for 2 cells voltage. According to the technical manual, they should be charged at 1.7V/cell max, which would produce 3.4V / battery. Could the higher voltage be indicative of batteries near their life end? Or were they last charged at too high of a voltage? Or?? Cost - 20 mile drive each way. http://www.saftbatteries.com//130-Catalogue/PDF/tm_bb_en.pdf http://www.saftbatteries.com//130-Catalogue/PDF/com-data_bb_en.pdf Posted by Neon John on January 29, 2008, 9:00 pm Please log in for more thread options >Any experts here on large nicads? Don't know about expert but somewhat experienced. > >I just picked up 45 used SAFT SBM43-2 NiCd "block" batteries. Each battery >appears to be 2- 43 AH cells with a jumper bar attached between the two cells >putting them in series electrically. Each battery measures 3.4-3.62 volts, which >seems on the high side for 2 cells voltage. According to the technical manual, >they should be charged at 1.7V/cell max, which would produce 3.4V / battery. >Could the higher voltage be indicative of batteries near their life end? Or were >they last charged at too high of a voltage? Or?? Wet NiCads are almost impossible to kill and their lives are measured in half-centuries. My oldest wet battery is a Korean-war-vintage 28 volt aircraft starter battery. Still at full rated capacity. I've had to change the electrolyte (KOH) a couple of times, as CO2 from the air slowly neutralizes it, but other than that and an occasional watering, nothing else done. You can't hurt a wet NiCad with moderate over-charging or discharging. In fact, the usual storage configuration for wet cells is fully discharged and shorted. All they do on over-charge is get warm and use more water. The plates will NOT lose active material like PbAs do. Moderate over-charge of a series string is necessary for proper equalization. I suggest putting some cells through charge/discharge cycles and see what you get. I think that SAFT adds something to their electrolyte that raises the voltage a tiny bit. That may be the root of what you're seeing. You might drop SAFT a note and ask. SAFT says not to change the electrolyte but that may be necessary if these cells were not stored properly. Again, they can tell you for sure. > >Cost - 20 mile drive each way. I'm green with envy :-) John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN Better remain silent and be thought a fool than to cite Wikipedia and remove all doubt. Posted by Solar Flare on January 29, 2008, 9:03 pm Please log in for more thread options I maintained a few ni-cad banks years ago. 1.22, 1.33 & 1.44 volts per cell rings a bell. I think that was nominal, float and equalize voltages. You really need a constant current charger as the voltage is a really nonlinear curve to their charge. Things I remember - we used them in outside stations as their cold curve was much better - they had small capacity per size compared to lead/acid units - we got rid of them all - chargers like to "hunt" or oscillate if you try to charge them with a voltage unit. Touching feedback damping was the key to prevent it. Most chargers these days have never heard of this adjustment Have fun. > Any experts here on large nicads? > > I just picked up 45 used SAFT SBM43-2 NiCd "block" batteries. Each > battery appears to be 2- 43 AH cells with a jumper bar attached > between the two cells putting them in series electrically. Each > battery measures 3.4-3.62 volts, which seems on the high side for 2 > cells voltage. According to the technical manual, they should be > charged at 1.7V/cell max, which would produce 3.4V / battery. Could > the higher voltage be indicative of batteries near their life end? > Or were they last charged at too high of a voltage? Or?? > > Cost - 20 mile drive each way. > > http://www.saftbatteries.com//130-Catalogue/PDF/tm_bb_en.pdf > http://www.saftbatteries.com//130-Catalogue/PDF/com-data_bb_en.pdf > Posted by Bob F on February 4, 2008, 8:53 pm Please log in for more thread options > Any experts here on large nicads? > > I just picked up 45 used SAFT SBM43-2 NiCd "block" batteries. Each battery > appears to be 2- 43 AH cells with a jumper bar attached between the two cells > putting them in series electrically. Each battery measures 3.4-3.62 volts, > which seems on the high side for 2 cells voltage. According to the technical > manual, they should be charged at 1.7V/cell max, which would produce 3.4V / > battery. Could the higher voltage be indicative of batteries near their life > end? Or were they last charged at too high of a voltage? Or?? > > Cost - 20 mile drive each way. > > http://www.saftbatteries.com//130-Catalogue/PDF/tm_bb_en.pdf > http://www.saftbatteries.com//130-Catalogue/PDF/com-data_bb_en.pdf > Thank you both for the info. Bob F Similar Threads Posted Re: burst nicd ! August 1, 2007, 4:09 pm High efficiency energy converter October 30, 2007, 2:36 am high output, externally regulated alternator recommendations? August 16, 2007, 1:45 am DC to the load - what voltage do you use? July 11, 2008, 5:49 pm Re: DC to the load - what voltage do you use? 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