How does my charger ...?

[Boatman]

Strange question but, how is it that I can run my charger on a 12V power supply and it is able to produce enough voltage to charge my 22.2V packs?

I know transformers (not optimus prime) can lower voltage like from 120 to 24V but how do they up the voltage? Is it similar to a capacitor in some way? Just wondering. :confused2:

[Diesel6401]

Strange question but, how is it that I can run my charger on a 12V power supply and it is able to produce enough voltage to charge my 22.2V packs?

I know transformers (not optimus prime) can lower voltage like from 120 to 24V but how do they up the voltage? Is it similar to a capacitor in some way? Just wondering. :confused2:

Just a shot in the dark and myabe wrong, but I think they use a voltage mulitpliers to double or triple the voltage depending on which size power supply you have. Voltage multipliers and like a cocktail of caps, diodes and rectifiers. I have a old electrical textbook with a bunch of stuff like that in it. I need to find it.

[ozzie-crawl]

think that the power supply only giving out 12 volts but its in coming voltage is 110-240v, it turns the high voltage in to higher amps,then the charger uses the extra amps to convert the higher amps in to voltage.
i think thats rite.
from memory power lines for our houses have very high voltage like 100,000 volts
but very little amperage the transformers convert the high voltage down and lifts the amperage up, the power may go threw multiple transformers before it gets to your house.

[Boatman]

HA! Thanks guys. Sounds complicated. I just always wondered. I always thought the electric coming into the house was at like 440 and was split down the middle for 220 buss bars on each side thus creating 120or 220 circuits. I know it can get tricky but just wondered if anyone else had the same question.

[Joe Friars]

That is an interseting question. I use a Hyperion charger the is AC/DC. I have a 12v gel battery out of a traffic signal back up system that I use. I often wondered how it could charge 2 - 6 pack nihms or 2 - 2s lipo packs at 14+ volts. :confused2:

[line6]

Basically your putting Mah back into the battery not 12v. as you put Mah back into the battery volts go up till the battery is fully charged.

[Diesel6401]

At 1c charge rate 2s pack will charge at close too or over 8v. A 3s will charge at like 12+v and so on. So when you at a 2s or 3s pack the chager input voltage is still = too or more then the needed out voltage. When you charge a bigger pack 4s which would be like 16v+ and up the input voltage is less than (12v) what is needed to charge to the voltage needs (16v) to be stepped up to satisfy the charge needs of the 1c charge rate. For bigger packs voltage has to be stepped up for a 1c charge rate which is where the voltage multipliers come into effect. That's why its so important to to set the charge amps correct on your charger because if you try and charge a 1c rated lipo at a 2c rate the voltage into the pack becomes more than it can handle. At least I think that's how it works I may be wrong its late.

[ozzie-crawl]

i am no electrician but as far as i know with a car battery because it has high amps available it can convert it to higher voltage less amps basically the opposite of a transformer working of your home were it takes high voltage low amperage and converts it to low volts high amps.you can buy converts to run 240 volts of a 12v car battery.
thing with lipo chargers don't they switch from constant voltage to constant current or vise verse
sure one of the guys on here can explain how it works properly :biggrin:

[CornelP]

It is quite easy.... see the link, gives you an idea. In the charger there's different story, mainly done with IC, but the idea is the same:
http://en.wikipedia.org/wiki/Voltage_multiplier

[AndyKunz]

That wiki example is a low-current one. For high current applications (like ours), typically the input DC is pulsed. The pulsed DC goes into an inductor. When the pulse is turned off, the BEMF of the inductor causes a higher voltage (lower current) to come out.

Alternatively (pun), the pulsed DC can go into a transformer just like AC.

The actual topology chosen depends on the requirements of the application. Basically they all use a pulsed DC, magnetics, and output conditioning circuitry.

Andy

[line6]

At 1c charge rate 2s pack will charge at close too or over 8v. A 3s will charge at like 12+v and so on. So when you at a 2s or 3s pack the chager input voltage is still = too or more then the needed out voltage. When you charge a bigger pack 4s which would be like 16v+ and up the input voltage is less than (12v) what is needed to charge to the voltage needs (16v) to be stepped up to satisfy the charge needs of the 1c charge rate. For bigger packs voltage has to be stepped up for a 1c charge rate which is where the voltage multipliers come into effect. That's why its so important to to set the charge amps correct on your charger because if you try and charge a 1c rated lipo at a 2c rate the voltage into the pack becomes more than it can handle. At least I think that's how it works I may be wrong its late.

if you have a 50w charger u cant charge a 5000mah 4s pack at 1c
16.8 * 5.0amp(1c) = 84w So, a 50 watt charger cannot charge your battery at a full 1c
it will still charge all the way it just takes longer. the most u can charge that pack is around 3amp
50/16.8 = 2.97 .6c

just something to consider when looking to get a charger

[befu]

I thought Lipos were charged through thier charge jack, not the power jack? (I do not know the proper names of the leads) If each cell is charged, ballanced and peaked individually, they are all charged at the 3.7 volt.

A 22.2 volt lipo is 6 seperate batteries in series, which you can measure on the pair of large power wires.
I think the multi small gauge wire seperates each cell so they are charged in parrallel, or 3.7 volts each.

Of course, this doesn't help the Nimh pack question.

House voltage next.

[befu]

HA! Thanks guys. Sounds complicated. I just always wondered. I always thought the electric coming into the house was at like 440 and was split down the middle for 220 buss bars on each side thus creating 120or 220 circuits. I know it can get tricky but just wondered if anyone else had the same question.

In america: The power companies do run the power lines at thousands of volts. Your power loss from transmitting has an I squared function in it, basically it has the square of the current. So if you can drop your current, the power company becomes much more efficient. Power as we know is current times voltage. Up the voltage, current drops linear, but the power loss from the lines drops by the square. That is one reason AC power won out over DC power. Very efficient to step the voltage up and down for transmitting.

Now that garbage can looking thing up on the pole is the transformer and it drops the voltage down to what you need. For industrial uses, it is typically 480 volts - 3 phase (some places still run the 240 - 3 phase, but that is beyond this discussion) You have 3 power legs, each of them is at 277 volts to ground. Because each leg is 120 degrees out of phase with another, you get 480 volts across the legs. That is why you get 480 motors running all three phases, but you can also run the shop lights off of 277 volts.

Now your house power is 240 single phase. I know what you are saying, but my house has 220 made up from two 110 volt lines that are 180 degrees out of phase. That is from your point of view. The power company calls it 240 single phase because it is generated off of one of thier lines, which is a single phase. (It is always all about them, isn't it?) The transformer splits it on your side to two - 110 volts lines to ground. They are only 220 between the lines because they are 180 degrees out of phase.

Your typical little wall plug transformer is just that. It takes the 110 volts and steps it down to a lower AC voltage. It is then run through a capacitor/resistor/diode circuit to turn it into DC power and filter it down. Been a long time since I had to work that circuit in college classes, glad I went the mechanical engineer route as electrical stuff pretty much baffles me.

You gotta be careful asking a techincal question anywhere an engineer might show up...... :blah: :blah: :blah:

Brian

[ozzie-crawl]

I thought Lipos were charged through thier charge jack, not the power jack? (I do not know the proper names of the leads) If each cell is charged, ballanced and peaked individually, they are all charged at the 3.7 volt.

A 22.2 volt lipo is 6 seperate batteries in series, which you can measure on the pair of large power wires.
I think the multi small gauge wire seperates each cell so they are charged in parrallel, or 3.7 volts each.

Of course, this doesn't help the Nimh pack question.

House voltage next.

3.7v is there nominal voltage,charged cell is 4.2v
i only have 2s packs that i run in series for 4s, i very rarely balance them.
when charging this way there charged threw the main power wires not the balance taps,but i do plug the balance plugs in to monitor voltage.

[Boatman]

You gotta be careful asking a techincal question anywhere an engineer might show up...... :blah: :blah: :blah:

Brian

Yeah, thats why I could not ask my father! I would have been setting on his couch alll night:tongue_smilie:

Great info though. I guess I should just be glad someone came up with the parts of our chargers and now I understand that I will pay almost anything for a quality charger.