SLA Battery Conditioning Methodology?

[tphiau]

Hi there,
I'm new to the forum.
I've made a monopole, and a handful of operational SS Bendini type circuits, with some limited success in restoring a few sulphated batteries.

I have a question on the best way to condition a battery using this technology. Clearly many charge/discharge cycles are needed. Especially when conditioning a 'dead' battery. But what voltage should I charge to, to do this? 15v for first cycle?
And discharge to 12v (for 12v) batteries, at C20 rate.
What then?
15v again, or 14.4? or some other level?
And repeat.

Or is it something else entirely.
Any help would be appreciated. I have some circuits I've cobbled together for battery cutoff at high and low voltage, and would like to automate the cycling process.
Regards,


tphiau

[Sephiroth]

I have been obsessively studying the conditioning process for the last month and I can tell you a few things that I know from my observations.

When performing your discharge, you need discharge the battery VERY low. 10.5v has been mentioned but I haven't discharged that low myself, but my results show that the battery needs a deep discharge. There is alot more I can say about this but I'll leave it for another time

Constantly cycle the batteries. CONSTANTLY! When Aaron said that you shouldn't stop cycling for even a day I thought he was exagerating, so I let my battery rest for a day and it took a week to get the battery back to the same condition!

Maximum charging voltage is variable and primarily depends on what C-rate you are charging at. I am using close to C40 and I consider the battery to be fully charged when it reaches 13.55v or there abouts. After this point the battery voltage will rise sharply and perhaps have a few pseudo peaks until (many hours later) it levels out at around 16.2v then it starts dropping consistently. (side note. The maximum voltage reduces as the batteries condition.) I charge the batteries until the voltage levels out but I don't wait until the voltage starts dropping.

This is just for the conditioning process. Once the battery is over 13.55v the rest of the charge is "wasted" in the sense that it doesn't appear to contribute to the energy stored in the battery.

For the first cycle, charge the battery until it has peaked and then starts dropping again just so you know where that point is.

These observations have been taken from charging relatively new batteries so I am not sure how conditioning heavily sulphated batteries will effect it but I am pretty sure the same method will apply.

Over time you will see that the battery will start holding a higher and higher voltage during discharge but it's a slow process.

[ABCStore]

What about tractor batteries? 160CCA or 235CCA? And car batteries?

ABC

[Sephiroth]

I haven't tried car batteries yet but I think the method should still be the same except I don't think they are designed to be discharged as low as golf cart type batteries.

[theremart]

Top voltage.

I have found that the Joule thief charger is a REAL winner with 12 Amp hour batteries... as well as the Jetijs. But since I have had these batteries on Solid State charging I bring them up to 15 -16 V. It seems to get the most amp hours out with this sized battery you need to take them even higher than normal.

I started doing that when I read of Bedini taking his Large set of telcom batteries way over the normal charge value of that sized battery, and thought I would have a go at it since I was not seeing the results as Bedini showed.

Golf cart batteries need large energizers to charge, 3 amp + at 20 V...


I am now in the process of moving to Florida, soo I had to return all of my golf cart batteries back to my vendor ...... I still have my semi batteries, and I may be switching totatly to alum batteries charged with a Lister engine powered with used motor oil or vegi oil.

Ideally I would like a LARGE battery bank so I could charge the bank with the engine or with CO gas running a generator, which I have been starting to play with....

[tphiau]

Hi Sephiroth,
thanks for your reply.
How low do you take a battery in the discharge cycle? I presume you do this just once during the first cycle. Or do you do it for all the conditioning cycles?

I can believe the cycling process needs to be constant. I have seen the same effect you describe, and wondered what was going on at first.
How do you do the cycling? I'm working on a paired set of LM741 op amps to manage the upper and lower voltage. I have each working. Just joining them together now to do the cycle automatically. I hope!

How do you know when the conditioning cycle is over? What would you expect to see happen with the battery?
I'm hoping to see input amps less than output amps.

And one more question. What kind of charger are you using?
Thanks,


tphiau

[tphiau]

Hi Theremart,
what Joule Thief circuit are you using. I've played with a few, but have nothing big enough to charge a 12v battery yet.

I have found that the Joule thief charger is a REAL winner with 12 Amp hour batteries... as well as the Jetijs. But since I have had these batteries on Solid State charging I bring them up to 15 -16 V. It seems to get the most amp hours out with this sized battery you need to take them even higher than normal.

Thanks,


tphiau

[Sephiroth]

Hi Sephiroth,
thanks for your reply.
How low do you take a battery in the discharge cycle? I presume you do this just once during the first cycle. Or do you do it for all the conditioning cycles?

I can believe the cycling process needs to be constant. I have seen the same effect you describe, and wondered what was going on at first.
How do you do the cycling? I'm working on a paired set of LM741 op amps to manage the upper and lower voltage. I have each working. Just joining them together now to do the cycle automatically. I hope!

How do you know when the conditioning cycle is over? What would you expect to see happen with the battery?
I'm hoping to see input amps less than output amps.

And one more question. What kind of charger are you using?
Thanks,


tphiau

My discharges are done "casually" meaning I don't have a fixed voltage that I cut it off at and start charging again. I do this for three reasons. The first is because I am using a "useful" load, my halogen desk lamp. So generally I use it for as long as I need it.

Secondly, because of the time scale involved, I can't be around to cut the battery off at a certain point.

Thirdly, because I am studying it I started off using relatively brief load periods of just a few hours. I did this for a couple of cycles and then I started doing lower discharges, and the discharge curves are VERY interesting and I will share them when I have enough data to do a proper write up.

Generally, I discharge them to around 12.4 - 12.5... ish

You need to load the battery deeply every time... deeper than I am really. So charge the battery up to its max voltage and then discharge the batteries then repeat.

I suppose the conditioning will be over when you stop seeing improvement in the battery. Over time the battery will power an identical load at a higher voltage, and the max voltage it will charge to will drop. When these level out then the battery should be fully conditioned.

I am using an 8 strand solid state oscillator with an iron filing core using MJL21194 transistors with 3 diodes in parallel coming off each winding (24 diodes in total) Coil resistance is 0.25 ohms. I have it tuned to around 5khz and it draws 800ma. I am charging 2 x 24ah deep cycle batteries in parallel and I have two other identical batteries that I am not charging to use for comparison with the conditioned batteries.

But I want to make it three time bigger I am gathering the components to take it up to a 24 strand oscillator with 41 milliohms resistance!

It's going to be a beast!!!

[tphiau]

Hi Seph,

I have been discharging to 12v, at the C20 rate for the batteries I'm using

Generally, I discharge them to around 12.4 - 12.5... ish

I suppose the conditioning will be over when you stop seeing improvement in the battery. Over time the battery will power an identical load at a higher voltage, and the max voltage it will charge to will drop. When these level out then the battery should be fully conditioned

I plan to get my charger/discharger going in the next few days, then let it run to see what results I get. I'm trying to do things I can repeat to see what works.
I am making two, so can run two tests in parallel.

[QUOTE=Sephiroth;51591]I am using an 8 strand solid state oscillator with an iron filing core using MJL21194 transistors with 3 diodes in parallel coming off each winding (24 diodes in total) Coil resistance is 0.25 ohms. I have it tuned to around 5khz and it draws 800ma. I am charging 2 x 24ah deep cycle batteries in parallel and I have two other identical batteries that I am not charging to use for comparison with the conditioned batteries./QUOTE]

Cool. What wire size? And how long approx to give 0.25 ohms?
I measured one of my coil windings, and it was 3.75 ohms. .56mm diam (24awg) wire and 250 grams. 100 mt, I think.

But I want to make it three time bigger I am gathering the components to take it up to a 24 strand oscillator with 41 milliohms resistance!

It's going to be a beast!!!

Outstanding! I'm gathering for a larger model too. Just trying to settle on the final design. I want to do bigger batteries, and see where that takes me.
And why, pray tell, have you chosen 41 mohms as the target?

Cheers,


tphiau

[Sephiroth]

I am using 22 guage wire. Each strand is about 2 ohms so I reckon they are about 125 feet long.

41 milliohms isn't really a precise target. It's just a target I know I can achieve. The reason I am trying to get as low a resistance as possible is so it is more efficient (obviously) but also for impedance matching.

My batteries are rated at 9 milliohms internal resistance and with two of them in parallel the battery bank has 4.5 milliohms internal resistance. I want to get as close to that figure as possible but it is practically impossible!

I believe this is what John means when he uses the term Impedance Matching.

Maximum power theorem - Wikipedia, the free encyclopedia

Impedance matching - Wikipedia, the free encyclopedia

[ABCStore]

Speaking of batteries, is there a good rule of thumb of calculating Ah from known CCA rating? Right now I have 160CCA, 235CCA, 265CCA tractor batteries, 550CCA car battery etc
I've read somewhere to divide CCA by 20 but that's not always the case

ABC

[sucahyo]

I found that SLA can develop phantom emptyness. The battery show empty behaviour and then suddenly show full charge a minute later.

I think this is because I keep charging it without ever discharging it. This is my second battery that show this behaviour.

YouTube - phantom empty

[nvisser]

I am using an 8 strand solid state oscillator with an iron filing core using MJL21194 transistors with 3 diodes in parallel coming off each winding (24 diodes in total) Coil resistance is 0.25 ohms. I have it tuned to around 5khz and it draws 800ma.

Hi Sephiroth
I found that on the solid state at such a high frequency I get better charging without the core. Iron cores are mostly used for 60Hz applications and are also needed to run a wheel.
I can see the surface voltage on the battery going up while charging when I pull the core out of the coil.
I got some questoins
Do you charge the batteries directly with the spikes or do you use a cap pulser?
Do you introduce resting time after each charge before discharging and how long?

[sucahyo]

Here is what my radiant charger do to my SLA:

YouTube - Loaded battery fluctuation, broken by radiant charger

It periodically darken.

[SkyWatcher]

Hi sucahyo, i've seen that very thing with a 12v 7ah sla. It needs more conditioning, if it can be recovered. One or more cells are shorting when it drops like that, i think.
peace love light
Tyson