Use for the Tesla Switch

[Sobakin]

After my second phase of testing I had good results. Attached is an pdf file of my data. I am more comfortable with this data, and also I have an explanation of my previous anomalous "charging".

Reading your pdf I don't understand how batteries in parallel can have different voltages.

I ran a 20 watt load (halogen bulb) for 8.5 hours for this test. The batteries were very close in initial charge (average of 12.465 vs 12.46). The total loss after 8.5 hours for the tesla switch was .2025 volts vs .425 for batts in parallel. So again I got 2 times better run time for the TS.

Two times less in voltage drop didn't mean two times better run as voltage drop is non-linear for time. Also your measurements under load in 2-switch TS shows that batteries that befor swap under load had 12.0V and after swap shows 12.2V, they're really may be not charged after that, only stopped to discharge and load like charge-discharge is closer to simply no load, what's why their voltage 12.2 instead 12.0 under load, in parallel all batteries are under load, so this is my explanations of difference:
Before last swap You have:
12.06 12.34 12.16 12.24
and after 8:30 You have
12.38 11.95 12.36 11.97
if You swap batteries after 8:30 and connect load, Yoy could see what batteries which had 12.06 and 12.16 before last swap remain about the same charge, same like batteries before first swap and after second swap (12.02 became 12.04 and 12.05 became 12.04) - their voltages the same, because they didn't discharge.
lets combine this results:
12.06 11.95 12.16 11.97
With 4 in parallel after 8:30 You have:
11.84 12.04 11.88 12.06 - not so big difference, but looks like it has something, including some loss in transformer.

I noticed I regained some of the lost charge after letting the batteries rest for a short period of time. I think this is what happened in my last test. I did a battery swap before hour 4 in my last test, so the batteries were diconnected for perhaps long enough to regain some charge. Also my voltage drop for the last test was so small (.04 volts total) that it didn't take much to make it appear the batts were charging.

It will really good if after resting and voltage gain You could load it and without returning voltage to state just before of stop load in one minute, measure voltage w/o load has ho practical sence.

All what I write is my thinking about, it may be wrong, of course.

[Sobakin]

Sobakin what size batteries are you using and are they the regular flooded lead acid batteries? The sealed gel cell type batteries do not work well with the TS. Also your load has to be matched to the size of the batteries and the size of the transformer. I don't remember seeing anywhere what batteries or size of transformer you are using. I do know you can go too large with your load and then you will get charging on the top but drain the bottom batteries at a much faster rate so your total run time will be shorter. About 12 watts or so seems to be working for most people with the rewound Radio Shack transformer. Another thing to remember is that the best run times and charging will probably not be at the same tuning spot as the place with the most output. You may have to make a compromise.

Carroll

Hi Carroll,
I'm using two battery sets - 4x 1.3 A-h 12V SLA and 4x 4 A-h 12V flooded lead-acid for scooters.
Transformer is like Matt recommended, originally ~30W, rewired with ~90 turns each of primary and ~110 turns of secondary 20AWG.
Loads 6W bulb or 21W bulb.
Now I continue tests for different conditions and combinations.
Looks like I found something, need to repeat for confirm.

[citfta]

To tune for best charging takes a lot of patience. As you thought you just have to take readings over a period of time and see what is happening. Each set up will be a little different so you just have to keep working with it until you get a feel for what happens when you change this or that. A smaller load my help or a larger one. A shorter pulse or a longer one may do it. You just have to try different combos and see what happens. I usually will only change one thing at a time though and try it for a while and then go back and change something else. And be sure and keep good notes like you have been doing.

I don't know if Matt is still taking anyone into his private group or not. Maybe he will see this and answer you about that.

Carroll

PS You're welcome, glad I could help a little.

[jpolakow]

How to tune for best charging

Sobakin what size batteries are you using and are they the regular flooded lead acid batteries? The sealed gel cell type batteries do not work well with the TS. Also your load has to be matched to the size of the batteries and the size of the transformer. I don't remember seeing anywhere what batteries or size of transformer you are using. I do know you can go too large with your load and then you will get charging on the top but drain the bottom batteries at a much faster rate so your total run time will be shorter. About 12 watts or so seems to be working for most people with the rewound Radio Shack transformer. Another thing to remember is that the best run times and charging will probably not be at the same tuning spot as the place with the most output. You may have to make a compromise.

Hi Carroll,
How does one tune for the best charging? Do you just watch the voltage change on the tops batts as you alter the pulsewidth? Or do you have to take many readings over a period of time to see how the batteries charged? Just curious as that is the next phase of my testing. Also, is Matt still accepting members into his private group? I have some out of the box ideas that could help. Thanks so much for your help so far! It would have been difficult to get running without your expertise!

[jpolakow]

Test 2

After my second phase of testing I had good results. Attached is an pdf file of my data. I am more comfortable with this data, and also I have an explanation of my previous anomalous "charging".

I ran a 20 watt load (halogen bulb) for 8.5 hours for this test. The batteries were very close in initial charge (average of 12.465 vs 12.46). The total loss after 8.5 hours for the tesla switch was .2025 volts vs .425 for batts in parallel. So again I got 2 times better run time for the TS. This is good. I think I can do better though. So far I have only been tuning for best output voltage. Next I will tune for best charging as well.

I noticed I regained some of the lost charge after letting the batteries rest for a short period of time. I think this is what happened in my last test. I did a battery swap before hour 4 in my last test, so the batteries were diconnected for perhaps long enough to regain some charge. Also my voltage drop for the last test was so small (.04 volts total) that it didn't take much to make it appear the batts were charging.

Anyways attached is my data if you want to take a look.

[citfta]

Sobakin what size batteries are you using and are they the regular flooded lead acid batteries? The sealed gel cell type batteries do not work well with the TS. Also your load has to be matched to the size of the batteries and the size of the transformer. I don't remember seeing anywhere what batteries or size of transformer you are using. I do know you can go too large with your load and then you will get charging on the top but drain the bottom batteries at a much faster rate so your total run time will be shorter. About 12 watts or so seems to be working for most people with the rewound Radio Shack transformer. Another thing to remember is that the best run times and charging will probably not be at the same tuning spot as the place with the most output. You may have to make a compromise.

Carroll

[Sobakin]

Well I'm definitely going to have to disagree with you there Sobakin. I have proved it to myself the tesla switch gets better runtimes than 4 batteries in parallel. I think you missed the point of the switch- to run a load and use the current to charge another battery instead of just running it to ground and permanently losing that charge. That's why the TS gives better run times. I'll post my test 2 data tomorrow so you can see for yourself.

Oh, I forgot to mention what I'm writing about results FROM MY EXPERIMENTS only - that's I mean.
I read about good results, what's why I resume TS-building and testing, first (6-switch) I built more than halfyear ago and didn't get positive results.
I understand the idea of TS, but didn't see it myself yet.

[jpolakow]

4 batts in parallel gets definitely longer time than any TS with transformer - transformer with load takes more input current than pure load (bulb), in my case with 21W bulb load 1.9A input vs 1.6A output, for 6W bulb 0.55A input vs 0.45A output, it is because secondary windings has more turns than primary.
What's why I did another baseline test - with transformer, but instead TS I used full bridge DC/AC converter, but 6-switch TS runs same time. And Matt's 2-switch too, I only need to swap batteries.

Well I'm definitely going to have to disagree with you there Sobakin. I have proved it to myself the tesla switch gets better runtimes than 4 batteries in parallel. I think you missed the point of the switch- to run a load and use the current to charge another battery instead of just running it to ground and permanently losing that charge. That's why the TS gives better run times. I'll post my test 2 data tomorrow so you can see for yourself.

[Sobakin]

Pardon me if I'm wrong, but I think your baseline test to compare against is 4 batteries in parallel. Not another tesla switch. If you do that you may see better results

4 batts in parallel gets definitely longer time than any TS with transformer - transformer with load takes more input current than pure load (bulb), in my case with 21W bulb load 1.9A input vs 1.6A output, for 6W bulb 0.55A input vs 0.45A output, it is because secondary windings has more turns than primary.
What's why I did another baseline test - with transformer, but instead TS I used full bridge DC/AC converter, but 6-switch TS runs same time. And Matt's 2-switch too, I only need to swap batteries.

[jpolakow]

Thanks for your words,
Just finished test with TS on MJLs - the same working time as mosfet TS and 6-switch TS with transformer, only MJLs version average output voltage was 1V lower.
6 hours from full charge to 12V average, used 1.3 A-h batteries and 6W bulb as load.

Pardon me if I'm wrong, but I think your baseline test to compare against is 4 batteries in parallel. Not another tesla switch. If you do that you may see better results

[Sobakin]

Hi Sobakin,
I guess I don't know what to tell you. It looks like you have done a good job. You obviously know more about electronics than I do. I guess the only thing I can offer is that I will be doing a writeup of my build for others to see and maybe possibly build exactly that? I don't know. I'm def no expert. But good luck. Keep on trying.

John

Thanks for your words,
Just finished test with TS on MJLs - the same working time as mosfet TS and 6-switch TS with transformer, only MJLs version average output voltage was 1V lower.
6 hours from full charge to 12V average, used 1.3 A-h batteries and 6W bulb as load.

[jpolakow]

Hi Sobakin,
I guess I don't know what to tell you. It looks like you have done a good job. You obviously know more about electronics than I do. I guess the only thing I can offer is that I will be doing a writeup of my build for others to see and maybe possibly build exactly that? I don't know. I'm def no expert. But good luck. Keep on trying.

John

[Sobakin]

You stated previously that you connected the two primaries in parallel. I think that would definitely not work. The two pulsewidths would be fighting each other.

I connected two primaries in parallel when I drive transformer by H-bridge (or 6-switch TS), in such cases I need only one primary, so I parallel them for lower resistance (this gian output voltage by 0.1V), when I power transformer by Matt's 2-switch TS, I didn't parallel primaries, OF COURSE. I understand (or, at least, try to) what I am doing, maybe this is my biggest problem - I have many questions to Matt without answers. Matt only says "do as I said"
For example, I still want to know, which role in Matt's TS plays transformer - is it for simplifier wiring, or it has some key property like collecting additional energy. And why 2-switch is better than 6-switch. I didn't see answers from my experiments, so maybe Matt could answer?

[Sobakin]

Hi Sobakin,
Also I don't think there are any "magic" properties of the MJL.

I don't think so too, but this is last idea in my head, all another methods I've done.

I don't think the component used for the switching matters so much as long as it can keep up with the switching speed and the amp draw.

My wiring is exactly like in Matt's drawing, mosfets as swithes. It works good, but hasn't positive effect, i.e. longer run. Now I built same this MJLs, just started testing.
Across IRF540N mosfets I had about 0.01V drop, across MJL21194 I have about 0.9V drop, transformer's output voltage also drop by 1V.

I think more what you should be concerned about is the EXACT wiring of the batteries to the transformer. Following the safety checklist should verify this. Also I don't know what an H-bridge generator is- is that what you are using to generate the pulsewidths? Matt definitely specified using a microprocessor so you may have better luck with that. The Stamp one that he (and me) used are only like $40.

My wiring is EXACT like in Matt's pdf.
Few pages above I posted my scheme:



I don't use microcontroller, but another square wave analogue IC-based generator.

H-bridge is DC/AC pulse converter for drive transformer.

Here are the things I deemed critical from Matt's specifications, or that would make the build as easy as possible. I would try to stick as closely as possible to these:
1. Wind the transformer with equal primaries, and a secondary that is 20% longer. Make sure to note the start and end of each wire. -You stated previously that you connected the two primaries in parallel. I think that would definitely not work. The two pulsewidths would be fighting each other. Also make sure there are no shorts in the transformer by performing continuity tests between the windings.
2. Wiring up the batteries to the transformer EXACTLY as specified by Matt. Also noting that the start of the wires in the transformer(the first layer that is wound) go to the correct side in the schematic.
3. Make sure all batteries are equal.
4. Use an incandescent bulb as a load.

I think that's all for now. If any of these things are different from your build you may want to correct them. Again I don't think the switching component matters so much, but more the correct wiring of the circuit and proper configuration of the transformer.

I did all of that.

[jpolakow]

Congratilations!
But for clear result can you do baseline test from full charged to, say, 12V (under load), and the same for TS (with swap batteries several times or one time after top pair low to 12V) ?
I just tested my batteries (in parallel) with same transformer at same frequency and load with H-brigde generator, and working time from full charge to 12V was the same as with 2-switch mosfet TS.
Now I building TS with MJLs.

Hi Sobakin,
Yes I am going to do more clear testing from fully charged to at least .5 volts discharged. Hopefully more like 1 volt discharged. My second tests will begin tomorrow.

Also I don't think there are any "magic" properties of the MJL. I'm not even using them, I'm using solid state relays. The part number is the one Matt specified in his schematic- CPC1718 I believe. I don't think the component used for the switching matters so much as long as it can keep up with the switching speed and the amp draw. I think more what you should be concerned about is the EXACT wiring of the batteries to the transformer. Following the safety checklist should verify this. Also I don't know what an H-bridge generator is- is that what you are using to generate the pulsewidths? Matt definitely specified using a microprocessor so you may have better luck with that. The Stamp one that he (and me) used are only like $40.
Here are the things I deemed critical from Matt's specifications, or that would make the build as easy as possible. I would try to stick as closely as possible to these:
1. Wind the transformer with equal primaries, and a secondary that is 20% longer. Make sure to note the start and end of each wire. -You stated previously that you connected the two primaries in parallel. I think that would definitely not work. The two pulsewidths would be fighting each other. Also make sure there are no shorts in the transformer by performing continuity tests between the windings.
2. Wiring up the batteries to the transformer EXACTLY as specified by Matt. Also noting that the start of the wires in the transformer(the first layer that is wound) go to the correct side in the schematic.
3. Make sure all batteries are equal.
4. Use an incandescent bulb as a load.

I think that's all for now. If any of these things are different from your build you may want to correct them. Again I don't think the switching component matters so much, but more the correct wiring of the circuit and proper configuration of the transformer.