# Low voltage, high amperage transformer?

Hi! I would like to make, buy, or find, a low voltage high amperage transformer to power an electrolosis cell. I like playing with the hydrogen-oxygen gas produced. From what I have read, I only need about 1.8 volts for electrolosis, so I'd like a circuit or transformer that could take the power from preferable a 9 volt battery and convert it to 1.8v at as high an amperage as I can get. Thanks : )

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akelsey says: 2 years ago
Don't use batteries it will suck them dry very quickly. And besides transformers only function with AC power, which you would need an inverter to run from a battery.
If you had to use a battery you would want a car battery, you could probably find one easily, and they can put out HIGH amperages for short periods of time. If the 12V is just overkill you can spread it out over several cells like Christmas lights.
akelsey in reply to akelsey2 years ago
just the other day, i rewound a Microwave transformer. its not very hard to do, and it does product the desired current and voltage. UNFORTUNATELY AC current does not split the H2 and the O2. DC is required.
Zilliquister in reply to akelsey1 year ago
You need a bridge rectifier to convert the AC voltage to DC Voltage . on the secondary windings of the transformer in order to produce the DC required for electrolysis. A bridge rectifier is simply a set of 4 diode connected in a square with the poles facing "+" to "+" on one side and "-" to "-" on the other then joined together on the other ends. Like so:
T1
++
/ \
- -
L1 ____ + +____L2
\ /
- -
T2

L1 and L2 are the line voltage AC coming in
T1 and T2 are the DC output.

BTW high amps can kill you.
rocketman221 says: 4 years ago
you could re wind a microwave oven transformer to put out low voltage at very high current. at 1.8v one could give you 400 - 500 amps.
fozzy13 (author) in reply to rocketman2214 years ago
That sounds great! How would a go about rewinding one, after I find it?? What gauge wire would I have to use?? Would I be able to get that much from a 9v? Would the battery die almost instantly?? Sorry about all the questions, thanks a lot! : )
rocketman221 in reply to fozzy134 years ago
You can get the transformer from a dead microwave (you should be able to get one from craigslist for free) the higher wattage the microwave is the more power you will get out of the transformer.

Microwave ovens have a large capacitor you have to discharge before touching any of the wiring; you don’t want to get zapped by it.

Once you get the transformer out you will want to cut off the secondary winding (the large coil of thin wire) but don’t damage the primary winding (the coil of heavy wire) you will wind some heavy wire where the secondary was. The voltage is typically .8 to 1.2 volts per turn on the secondary (depending on the transformer) you will want 3 to 6 volts for your hydrogen generator.

8 or 10 gauge wire should be heavy enough for what you need. That should give you 30 to 50 amps (more than enough for a large hydrogen generator) but heavier wire could be used for more current.
The output will be ac which will be fine unless you want to collect the hydrogen and oxygen separately.

Be sure to put a fuse on the primary and secondary of the transformer.
The transformer should be placed in an enclosure to prevent anyone from coming into contact with the dangerous voltage on the primary.

Google "how to rewind a microwave transformer" and you will find a lot of info.

This instructable gives some onfo on rewinding a microwave transformer.

rexflash in reply to rocketman2213 years ago
sorry to add up the comment in btwn but i have a question ... what if i wanted to have a same voltage like around 3 to 10 volt but way more higher current .. like around 20,000 to 40,000 amps ... is it possible to get something like this from microwave transformer ?? or can i just add few more transformers in series and obtain more current? plz let me know as i m working in a project that requires amps in k .. so any thing starts with 20k amps works ... thank you and i m in time line to finish this project up .. so help me out over here and i'll really appreciate it ;) thanks
fozzy13 (author) in reply to rocketman2214 years ago
Thanks! : ) There's a lot of helpful stuff there.. So, what I'm thinking, is that I'm going to take a 9v battery, through a 555 timer for oscillation, and put it through this modified MOT and that will give me the power I'm looking for?? Or you're thinking I'm running the transformer from 120v AC and I have it all wrong?? : ) Thanks, this is a lot of help. Sorry about all the questions..
rocketman221 in reply to fozzy134 years ago
The mot runs off of 120v ac (or 220 depending on where you are). A 9v battery won't provide more than a few watts of power. If you needed the hydrogen generator to run off of a battery and produce a usable amount of gas you would need a car battery.
11010010110 in reply to fozzy134 years ago
use few turns of very thick wire a 9 V is not anywhere close to that. 500 9Vs in parallel maybe
muttyfutty says: 4 years ago
batteries? *pfftt...
Try re-winding a MOT (microwave oven transformer) with about 3-4 turns or REALLY thick wire, I've seen people get Hundreds of amps out of it
see http://www.instructables.com/id/Homemade-Spot-Welder/?ALLSTEPSJust look at the transformer.

if thats too much of a hassle you can use a PC (AXT) PSU like http://www.instructables.com/id/Computer-Power-Supply-to-Bench-Power-Supply/ And make it http://www.instructables.com/id/Convert-an-ATX-Power-Supply-Into-a-Regular-DC-Powe/?ALLSTEPS

hope i helped
pyper says: 4 years ago
9v batteries are piss poor for high current applications, you would be better off with 2xNiMH "D" cells or a small Ld-Acid battery, You can buy singly cell Ld acids that put out 2v with whatever A/h your prepared to pay for. As for using a transformer with a battery it's more trouble than it's worth, you would basically be building a small inverter, you can get single chip voltage regulators if you want to control the voltage but they arn't much good for high current applications.
fozzy13 (author) in reply to pyper4 years ago
Ok...where can I find the MiMH batteries, or the Ld ones?? I realize I'd be building a small inverter, which I think would be fun if I got it right. A voltage regulator wouldn't increase my amperage would it?? I have never used or seen one, so I don't know.. Thanks a lot : )
11010010110 in reply to fozzy134 years ago
rechargeable AA batteries are nimh car battery is ld. there are smaller lds (sealed lead acid battery) you understand the inverter and volt reg part correctly
fozzy13 (author) in reply to 110100101104 years ago
Thanks again : ) Where would I be able to find a smaller ld battery, like you suggest?? I'm assuming it's going to be rather expensive, heavy, and can't be salvaged from anything I could find easily?? Thanks!
11010010110 in reply to fozzy134 years ago
they are used mostly in computer UPS / some emergency lighting fixtures / other emergency related stuff they can give about 10 - 40 A (depends on exact battery) without damage (they can much more but will have short life) they dont have very much life in them especially if you discharge them a lot. (most are designed to wait all their life to emergency that never happens). and you need to bother about charging etc its better to use line powered power supply like the microwave transformer or computer power supply
fozzy13 (author) in reply to 110100101104 years ago
sorry i missed this one : ) thanks! 40A would be amazing.. I think I've got what I need, thanks a lot!
11010010110 says: 4 years ago
use a computer power supply. you have 3.3 / 5 / 12 V DC at tens of amps each
fozzy13 (author) in reply to 110100101104 years ago
Thanks : ) would that be from 120v AC though?? I'm a noob at all the circuiting stuff...
11010010110 in reply to fozzy134 years ago
yep it plugs to ac
fozzy13 (author) in reply to 110100101104 years ago
Thanks! But I was thinking portable : )
11010010110 in reply to fozzy134 years ago
then go for sealed lead acid batteries (what pyper called LD)
fozzy13 (author) in reply to 110100101104 years ago
ok, thanks : )..from what I'm seeing, they're pretty expensive, thanks though!