Pulse Desulfators - Page 1
Forum section: electronics / general

author: sonicj
author_rank: Frequent Contributor
timestamp: January 28, 2011, 06:42:13 pm
content: I recently tested a commercially produced Lead Acid Battery Charger/Maintainer/Desulphator onanother forumand thought it might be of interest here as well... There is alot of experimentation and open designs for those interested in building their own. Here's agood place to start. Pretty interesting stuff!Pulse Conditioning Primer(copy & pasted from another forum)For this first experiment, I'm using the BatteryMINDer Plus Charger/Maintainer/Desulphator fromNorthern Tool. The test subject is a Sealed Lead Acid (SLA) battery from Power Sonic. It is listed at 12V with a capacity of 5 Amp Hours. Based on a "03" sticker attached to the bottom of the case, the year of manufacture is believed to be 2003. The small capacity battery was chosen for the practicality of measurement. As I understand it, results should scale proportionally with battery weight and conditioning duration. ie: as the battery increases in weight, so does the time required to pulse condition. The underlying principle of operation of this battery is the same as any deep cycle golf cart battery.I feel that the best method for measuring any gain (or loss) in performance of a SLA battery is to measure the current consumption of the battery over a constant current discharge until the voltage drops below a specified threshold followed by the same test performed after the conditioning period. For this test I have chosen to discharge the battery at a rate of 1C (aka: One Hour Discharge) which for this particular battery is 5A. The depleted threshold for the tests is set at 10.5V; widely considered to be the total completed discharge voltage for a typical 6 cell lead acid battery under load. These amperage and voltage settings will be used for both measurements.The equipment to be used for the discharge tests is a West Mountain Radio - CBA II - Computerized Battery Analyzer. The initial charge for the battery was performed by a IMAX B6 (clone) at a variable rate not exceeding 1A. Maximum charge capacity was determined by the charger. The battery was left to rest for approximately 8 hours prior to initial discharge test.

author: sonicj
author_rank: Frequent Contributor
timestamp: January 28, 2011, 07:25:22 pm
content: heres a screen shot of the pulse. i'm having a hard time getting the rigol to cooperate when zoomed out.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 28, 2011, 10:13:44 pm
content: It's possible to make a good desulfator/charger from a light dimmer, motor run capacitor, and bridge rectifier.

author: sonicj
author_rank: Frequent Contributor
timestamp: January 29, 2011, 01:26:20 am
content: Quote from: NiHaoMike on January 28, 2011, 10:13:44 pmhmm, i haven't seen this design before... sounds easy / dangerous!do you have any details?-sj

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 29, 2011, 02:14:06 am
content: The idea is that the light dimmer and capacitor in series make high current pulses which are then rectified for charging the battery.

author: Lightages
author_rank: Unknown
timestamp: October 10, 2011, 10:47:35 pm
content: I am visiting this old topic after seeing a reference to it in another thread.Could you please clarify the conditions and charging method for each of the tests as it is not quite apparent to me.

author: sonicj
author_rank: Frequent Contributor
timestamp: October 11, 2011, 01:45:24 am
content: Quote from: Lightages on October 10, 2011, 10:47:35 pmsure. i started with a old 12V 5Ah sealed lead acid battery. the charge for the initial discharge test was done on B6 clone charger @ 1A max with default cutoff settings. the battery was discharged at a rate of 5A until the 10.5V cutoff threshold was reached.(Black Line)the battery was then re-charged by the desulfator and was left attached for 2 weeks. after the 2 week conditioning period, the battery was subjected to the same discharge test as before.(red line)the result was roughly a 50% increase in capacity and roughly 0.25V higher voltage under load across the entire discharge.the final test (which i haven't mentioned in this thread yet) occurred approximately 1 month after the second test. the battery was left on the desulfator for entire time between the 2nd and 3rd tests.(green line)despite being on the desulfator for twice as long, the results were less profound than the difference between the 1st and 2nd tests, but did show gain in both capacity and voltage under load.-sj

author: Lightages
author_rank: Unknown
timestamp: October 11, 2011, 04:11:14 am
content: Thanks for the details.I can see where you might think that the desulphator is to be credited for the revival of this battery. Perhaps it was. It is difficult to tell without an identical test with and identical battery in identical condition left to sit for the same period of time on just a float charge.Some people have found that a few repeated equalization charge cycles can bring a battery back to some form of usefulness.You are discharging the battery at a 1C rate and I wonder what the difference would have been using a 20C rate as is the way a battery is normally specified.

author: sonicj
author_rank: Frequent Contributor
timestamp: October 11, 2011, 06:15:42 am
content: agreed. floating a battery in that condition might produce similar results. cycling as well... using a float charge on a similar battery would be needed to validate the desulfator as the source of the gain.i may have another battery of approximate vintage that i can repeat the tests on using a float supply.i think you meant to say 20hr rate as 20C would be 100Ai don't think the slower rate would reveal anything significantly different, but i agree, it would be interesting to see if it did.-sj

author: BravoV
author_rank: Super Contributor
timestamp: October 11, 2011, 06:52:05 am
content: Interesting thread, posting here to subscribe !Thanks for sharing it here sonicj !

author: saturation
author_rank: Super Contributor
timestamp: October 11, 2011, 07:53:29 pm
content: Not sure how I missed this thread, but I wasn't sure these really work for lead acid batteries. sonicj, the pulse is exactly 35Vpp DC or AC pulse? The Soneil charger begins each cycle with pulse cycle VDC to about 18V, and its similar but its only done of a few minutes are a 'preventive measure' to keep sulfation down.For the desulfator, the pulsing is continuous?? What duty cycle? and you maintain this for 2 weeks, but how long is the optimal time? Or do you keep just winging it until the batteries AH no longer improves?

author: sonicj
author_rank: Frequent Contributor
timestamp: October 11, 2011, 10:23:10 pm
content: uhmm... the voltage was at like 14V, so i guess 35Vpp would make it AC??the pulsing is continuous after the charger reaches full charge. i'll have to stick it back on the scope to find duty cycle. i believe 2 weeks was the recommended time from the product manual. word on the street is 1 day per lb to reach noticeable results. personally, i have been rotating the device between batteries (truck, motorcycle, tractor, golf cart accessory) every couple of weeks. many build standalone pulsers that hang on the battery 24/7.-sj

author: Lightages
author_rank: Unknown
timestamp: October 12, 2011, 04:46:58 pm
content: Quote from: sonicj on October 11, 2011, 06:15:42 amLOL, of course yes, I meant to say C/20.

author: saturation
author_rank: Super Contributor
timestamp: October 12, 2011, 07:03:38 pm
content: Is its true AC ? then its +/- 17.5V ? then its a type of "burp" or reflex charging, with negative or polarity reversals on the inputs. But it would be novel and unusual; its like charging a DC battery with AC. The desulfators I've seen are often just pulse VDC.Quote from: sonicj on October 11, 2011, 10:23:10 pm