AC DC Adaptor fail

Finally seeing water levels dropping. I would rate that as very rapid and caused by excessive voltage/amperage or wattage. I had excessive water levels and losing some was wanted. But I will be more cautious using the high power adaptor. It will be more useable once I have the PWM controller to tune it down. Currently charging with the low power adaptor.

Battery state:
13.67V while connected to charger, draw from mains 1.2W, feed to battery 40mA average
13.58V stand alone
13.2 m-Ohm internal resistance
15% wear life
196 CCA, Spec: 640 CCA, type 096
 
Here's a couple of videos containing useful background information. However, I only play with the charging process according to my own experience, and tools at hand. I do find affinity with the information in the videos. My goal is to attain 16V stand alone voltage on a battery without creating electrolysis. I need this done via the mains. This voltage level is known to be possible on both the 096 and 075 batteries while connected to a (up to) 23v (up to) 250mA china solar panel in different cars while loaded by the car's engine off current draw.

It is confirmed 18V 40mA average sine wave mains charging is harmless to the batteries. This contradicts the belief that excessive charging voltage is bad. In the right setting and current, it is good. It is confirmed audible bubbling in the electrolyte is bad because of rapid loss of water. Water could be replenished on very old batteries. But, all new batteries are physically sealed to prevent maintenance.


 
The charging did no further good. So I am pressing the battery into service. Since I am deliberately looking for it, I can perceive a very light hesitation on starting the engine. This is expected given the low capacity. The battery should do fine while supplied by the summer sun. I only use the car to get to destinations and don't need capacity for things while the car is not running.

Battery state:
13.72V while connected to charger, draw from mains 1.2W, feed to battery 40mA average
13.67V stand alone
13.14 m-Ohm internal resistance
16% wear life
197 CCA, Spec: 640 CCA, type 096
12.71V engine off, 14.2V engine on, 8.33V engine start


The switched out battery is a reconditioned ebay unit at a bargain price, on the second year of winter service. Last OCT/NOV it was at 100% wear life and the CCA was 600, higher than the seller spec. This will be left charging with the low power adaptor unattended. The battery is a sealed unit and unsuitable for charging that cause continuous bubbling. I believe intermittent bubbling might be OK - the hydrogen could recombine into the electrolyte by itself.

Battery state:
Draw from mains 1.2W, feed to battery 50mA average
12.04V stand alone
6.46 m-Ohm internal resistance
64% wear life
401 CCA, Spec: 550 CCA, type 027
11.84V engine off, 14.2V engine on, 9.07V engine start
 
Could not resist taking a peek, and the progress is good.

Battery state:
12.32V while connected to charger, draw from mains 0.9W, feed to battery 40mA average
12.32V stand alone
5.81 m-Ohm internal resistance
80% wear life
446 CCA, Spec: 550 CCA, type 027
 
Progress continues to be made. The battery is a good'en. Up to now, the wear life numbers were based on a 500 CCA battery. So they were inaccurate. But, I will continue this error. This number is less critical compared to the measured CCA which is the actual usable CCA the battery has.

Battery state:
12.37V while connected to charger, draw from mains 1.2W, feed to battery 40mA average
12.37V stand alone
5.37 m-Ohm internal resistance
93% wear life (over-stated)
483 CCA, Spec: 550 CCA, type 027
 
Progress slowed but continues. Stating proper wear life level from now on. Re-attaining 100% wear life or greater looks likely.

Battery state:
12.45V while connected to charger, draw from mains 0.9W, feed to battery 40mA average
12.44V stand alone
5.05 m-Ohm internal resistance
87% wear life
513 CCA, Spec: 550 CCA, type 027
 
Progress slowed to a crawl. It feels as if the adaptor doesn't quite have the umph to give me the final cca's. The observations suggest either the amperage or voltage needs to be higher when the battery approaches fully charged. The final state of the battery will be 13.5V. Based on the present level, this means that there is plenty of head room for more cca's.

Battery state:
12.56V while connected to charger, draw from mains 0.9W, feed to battery 40mA average
12.56V stand alone
4.93 m-Ohm internal resistance
92% wear life
526 CCA, Spec: 550 CCA, type 027
 
The china PWM motor controller arrived, and I put it to use immediately. I set it up to use with the high power adaptor. The results are very encouraging. The controller has a duty rate of 5%-100%, meaning power is output from the controller 5% to 100% of the time variable by a manual dial. It is not known at what frequency the output pulses. The controller turns my adaptor into a pulse charger, pulsing 21V, 1A, at an unknown frequency. I set the duty rate at the minimum and could not hear any electrolyte bubbling. Effectively I am charging at 21V with no perceivable gassing. This is going to be good.

If the PWM is not supplied from the mains, it will draws 45mA from the battery. This is a feature I wasn't expecting but actually wanted. I believe having a nett power draw phase during the charging process is critical for battery revival. This feature will be used with a timer switch. This feature is not currently being used.

pwm.png
 
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The charging was going great, then during the process something triggered the PWM controller to ignore the manual dial and go full throttle. I could tell from the draw on the mains. This resulted in the battery bubbling. The trigger might have been time or heat. The controller looks bugged, and it's not hard to imagine they never planned for anyone to use it for long durations. I was definitely on the right track and will order a new controller of different make. I will get a 0%-100% duty rate controller. Even at 5% duty rate, the bugged controller was pulling 9W from the mains, which was higher than I like. I will repurpose the controller for controlling PC fans, which will be under constant passive observation during use.

Last night the battery was at 551cca and everything was ticking along very nicely. Today, it was back to 500cca and bubbling. Bubble is bad, very bad.

For luck, I have put some thermal conductive silicone under the controller's heat sink and giving it one more go.
 
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The PWM controller is definitely broken in some way. It would enter full throttle at random moments. But all is not lost. It works with the low power adaptor fine and makes it work better. The battery CCA may have hit the wall. I will give it a couple of more days to see if it's really done. In the past the battery had around 600 CCA. It's not a big deal if this can't be reattained. It is also possible the high power adaptor may have some effects on it once I have a new controller.

Battery state:
13.19V while connected to charger, draw from mains 1.8W, feed to battery 18V 4mA pulses of unknow frequency and width
13.09V stand alone
4.71 m-Ohm internal resistance
100% wear life
551 CCA, Spec: 550 CCA, type 027
 
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There's more progress. The charging continues until the progress stops. It looks hopeful 600CCA could be attained.

Battery state:
13.03V while connected to charger, draw from mains 1.8W, feed to battery 18V 4mA pulses of unknow frequency and width
12.98V stand alone
4.53 m-Ohm internal resistance
100% wear life
573 CCA, Spec: 550 CCA, type 027
 
The battery was bought to be used interchangeably between 2 cars. I gave it a test fit on a micra and it was fine. The battery was 2 sizes bigger than original and needed for an infrequently driven car. The battery powered some test starts and DIY MOT lights assessment. After that, the battery was put back into charging. The CCA went up and down for a few days before settling back on an upward trajectory. The final stretch of the charging process will likely to take a long time. The target is ~13.5V connected to charger and 595 CCA. The CCA number was what the battery had before the last winter. If the number could be regained, that would indicate the battery suffered no deterioration in 5 months of winter use. Most of that time, the battery was in moderate to bad drained state.

Battery state:
13.21V while connected to charger, draw from mains 1.8W, feed to battery 18V 3mA pulses of unknow frequency and width
13.1V stand alone
4.4 m-Ohm internal resistance
100% wear life
589 CCA, Spec: 550 CCA, type 027
 
The new PWM controller came by fast boat in 8 days. I put the battery aside to experiment with the new controller. Still waiting to see if it will break like the last one. Performance-wise, it's disappointing. It super charged my low power adaptor and caused it to create bubbles.

Surprisingly, the battery I put aside for a couple of days continued to charge without being connected to anything. This phenomenon was described by the video I posted earlier. The battery reached my target and I will store it away for the winter. There may be more capacity to be gained, but I don't really care. The battery has gone back to the like-new state, and that's all it mattered.

Battery state:
12.85V stand alone
4.33 m-Ohm internal resistance
100% wear life
599 CCA, Spec: 550 CCA, type 027
 
DiyNutJob said:
Battery state: 16 Apr 2023
13.4V while connected to charger, draw from mains 1.2W, feed to battery 40mA average
13.4V stand alone
6.57 m-Ohm internal resistance
62% wear life
395 CCA, Spec: 430 CCA, type 075
Click to expand...

I took out the less valuable and previously charged battery for experimentation with the PWM controllers. After plenty of electrolyte bubbling and head scratching, the solution was discovered to finely tune the charging process.

Came out of storage battery state:
12.88V stand alone
6.92 m-Ohm internal resistance
374 CCA, Spec: 435 (correction) CCA, type 075

Battery state after a few days of non-productive experimental play:
13.36V while connected to charger, draw from mains 1.2W, feed to battery 18V 4mA pulses at 22.5kHz of minimal duty rate
13.29V stand alone
6.57 m-Ohm internal resistance
69% (correction) wear life
395 CCA, Spec: 435 CCA, type 075
 
Finally, an unexpected breakthrough. Since I started playing with this battery, it had never went beyond 395 CCA. Now it has, proving the value of PWM controllers, and high voltage. It is now possible for me to select the amperage the battery receives. The precision I have is +/- 5mA. The bubbling caused by the high voltage is an issue. This could be countered with rest or nett-draw intervals during the charging process. I speculate the bubbled up gases would recombine into the electrolyte during these intervals. The intervals are not currently used.

Battery state:
13.74V while connected to charger, draw from mains 1.5W, feed to battery 18V 23mA pulses at 23.16kHz of duty rate proportional to the amperage
13.62V stand alone
6.44 m-Ohm internal resistance
86% (correction) wear life
402 CCA, Spec: 435 CCA, type 075
Bubbling rate closest to ear at 1 inch distance: 10 per second, subjective
 
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