Recharging Batteries using only voltage spikes. A Results Log Thread

[nul-points]

hi Jeanna & crowclaw

thanks for your kind comments - appreciated!


i'll try & answer some of the points you raise:

> could you have missed capturing more?

i agree - there's a lot more going on in spikes than we usually see with our test equipment - and i suspect that this is exactly where all the interesting stuff is happening!!

i took a variety of scope 'snapshots' throughout the different tests i did with battery charging, to see what how my test circuit was operating with batteries compared to the usual resistive load - it looked pretty much the same (apart from the fixed voltage offset on the output caused by the output battery itself, of course!)

due to the nature of the energy conversion of around 4000 Watt-seconds total at only 160mW per second, each test took many hours (as you can see from the graphs) - so there was only so much data i could usefully capture with my 'scope in datalogging mode



> I wonder what would happen if you were to charge 4 batteries?  Would they charge as high as the 2AAA and in the same amount of time

i suspect not - i ran a test with two batteries in one of the two paths (ie direct pulse charge) and the same output energy as the single battery in that path just got divided between the two batteries


> What if you were to reverse your set-up?  Would your NiMH AAA be able to produce high enough spikes to charge your NiMH 8.4v cell?

unfortunately not - my test circuit is not a voltage-booster like the JT - the output voltage on the switched-charge circuit is always lower


> Another q is about the difference it would make if you were to recharge these in parallel?
Do you suppose the spikes could be caught better in a parallel arrangement?

well, the output batteries were 'in parallel' across the circuit - but each was receiving separate 'packets' of charge - so i guess you mean to have the output batteries exactly side-by-side (+ to +, - to -)

i did try this but, as i realised afterwards, this was never going to work:
  different batteries have slightly different characteristics and the battery which charges slower 'drags' any parallel batteries down to its terminal voltage - it 'holds back' other batteries from charging at their own individual rates

however, on the JT, since the secondary produces an AC waveform, you can connect two batteries in parallel across the secondary output - you have to connect them in opposite polarity, each with its own separate charging diode:

|  JT secondary o/p   |
|                              |
v                             v
|--------|>|---/-////+/-------|
|--------|<|---/+///-/--------|


> I am getting higher and more frequent voltage spikes from my jtc's than he gets from his SG wheel, so I should be able to recharge a lot of batteries... right?

i'd be interested to hear if you can get solid quanties of Joules (Watt-seconds) by using just large & more frequent spikes - the evidence i saw from the results i showed above was that the total area under the spikes (the power content) was what gave the actual charge in that test, no matter how many or their magnitude

having said that, i have a long-running test going at the moment to see if i can 'self-trickle-charge' an AAA NiMH driving its own VERY low-power circuit which pulses 3 LEDs in parallel and feeds the output current & flyback current back into the same AAA

the circuit SHOULD just discharge the battery (and will slowly discharge a cap) but i'm hoping that there might be some low-level charging action on the battery just from the spikes - the drain is probably a fraction of a micro-amp though, so it's going to take a looong time to find out if the battery is discharging! (been running a few weeks now, i think, at 1.260V!)


> Did you find the switching frequency important to the timed rate of charge

good question - since each test took many hours (followed by many more to recharge the input battery afterwards!) i didn't try altering the pulse rate very often!

i agree it's an important test to try - i'm interested to hear how you get on

i did try 8.4v to 8.4v recharging on my test circuit but (as i mentioned in answering one of Jeanna's qs above) the output voltage wasn't really sufficient and very little charge got transferred

> my 8.4 volt battery will charge from approx 0.99v (fully discharged) to 10 volts in approx 3 mins. But I still have to log discharge rates before we get to excited...

i agree - one thing i found was that the output battery rises to its final charged voltage very quickly but this doesn't give an indication of the charge it has taken

the batteries would stay at that voltage for hours whilst they received all their charge from the input

only the discharge test at the end showed just how much charge they could deliver back!   


sorry - bit of a marathon reply!!!

all the best in your investigations - keep it rolling!
sandy

[nul-points]

apologies - i drew the diodes the wrong polarity above!

SHOULD be:-

|  JT secondary o/p   |
|                              |
v                             v
|--------|<|---/-////+/-------|
|--------|>|---/+///-/--------|

[jeanna]

Hi everybody,
I have just added another duracell to my battery recharging "wheel".
I noticed that I was discharging longer than I was recharging so today is the first full day of discharging 2 while charging only one.
It is still lopsided, but the duracell's are taking a charge, and while the voltage level SEEMS to be less than usable, I am nevertheless, able to run a jtc with one of them for 10 hours or more.

Also, the Nicd 500mAH AA is probably fully restored at this point.
It runs a jtc for 8 hours and then goes into blink then recover mode at around 10 hours. This means it never fully goes out because it seems to be able to blink and recover for hours and never go below 1.0v after the moment of recovery.
This seems strange for any battery, but I am just saying what I am seeing.

So, it looks like this is really working.
Next, I want to charge something that is a higher normal voltage than the AA that is running the jtc charger, because that would be very cool.
Unfortunately, I only have one loose 12v battery and it is always fully charged.
I guess it is time to find a bad battery and fix it with my joule thief, isn't it?

jeanna

[jeanna]

Hi everybody,

Circumstances have pushed me to do this in a big way.
It was crazy this week.
I might have 3 bum chargers, or 12 bum batteries, or both . But lets see if the jtc can either condition or fix em.

I decided to recharge a pair ofAAA  batteries in an old led nite lite I made years ago.

The charger refused the batteries...

I  pulled out the jtc battery charger that has appeared in this thread, added a new run battery and put both batteries into a 2 battery pack for 15 minutes.
Then the charger took the batteries and charged them in less than 20 minutes.
This is record time. It is a fast charger but this usually means 2  hours.

I had tried other batteries earlier when I couldn't get the first 2 into the charger and they wouldn't go either, and
to make a long story short...
I ended up using the jtc charger to condition a total of 8 batteries 4 AAA and 4AA, and they all ended up in the charger in record time and they look great right now.

Wow.


Now, for the 12v power pack.
In 2007 I bought a 12v xantex power pack on a wheely device. I actually bought 2 similar devices of different capacities.
1 with a 1500w inverter and one with a 350w inverter. I have used the smaller one several times to fill tires etc, but just small jobs and then I top off the battery and leave it to trickle charge.
Same for the big one, except I never used it. It still had tape covering the ac switch.

Well, last week the charger for the big one started to run, and instead of stopping after 10 minutes, it kept on, and I pulled the plug after 5 hours, The battery was at 9.05v     

So, today I took the big one apart and found 3 parallel 12v batteries inside!
I undid the connectors and all 3 were in the 9v range, but the lowest one is the one I figure was bringing them all down, so I am now watching as the jtc charger is conditioning the 12v battery.

I'm crossing my fingers!

jeanna

There is another story with the 350w power pack, but I will save that for later.

[stevensrd1]

Maybe its the voltage spikes from my experiment thats allowing me to recharge so many batteries using only 2 batteries. I called it the overunity pulse motor and posted a few threads in the news section. Essentially what I did was modify a motor by breaking off one of the three contacts on the motors rotor inside it. That makes it a pulse motor that pulses power on and off as it spins. So I made several experiments,,where I recharged 2 batteries with 2 batteries,,then recharged 3 batteries with 2 batteries,,then recharged 4 batteries with 2 batteries, and lastly my present running experiment is recharging 5 batteries with 2 batteries, also running the pulse motor at the same time, placed a few of the videos on youtube as well,,the links are in my postings in the news section of this site on the overunity pulse motor. But after reading here,,it may be that its voltage spikes that allow me to do this,,from the motor.