4056 in series (I guess)

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FireFrog

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Jan 22, 2017
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So currently I have 9 tp4056 modules connected to a 5v cable from a old power supply
Is the current affected at all from the single 5v line?
Is voltage affected?

I'm trying to figure out how electricity would flow through them so I can make a smaller one that's more portable
 

Korishan

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As mentioned in the other post with your setup, you will lose some voltage/amperage.

The best way to check what you have losing, is to put your voltmeter on the rails and turn on each unit one at a time and see how much drop in voltage there is. Likewise, put in line so you can measure amperage (unless you have a fancy one that can check amperage via voltage usage) and repeat the process.

The computer psu should be able to handle quite a bit of voltage/current draw without much of a problem. The limitation will be the wires coming "from" the psu. So I would connect several black and red, or take and solder in a heavier cable that you know for sure will handle the heavier loads.
 

station240

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Some of the power supplies show the current output for each rail.
eg: +12V 28A, +5V 32A etc.
So in theory you can count up how many red wires (5V) there are, gives you some idea of how to best distribute your load of 9A (45w).

At a guess, two red and two black wires should be enough
 

Rerouter

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I agree, 2 of each should be sufficient to reduce the voltage drop,

the charging modules have a 30mV internal drop, so you can still charge at an amp as long as the voltage is greater than 4.19 + 0.03, so 4.22V, which would be a pretty horrible drop for a ATX power supply.


Wait, not in series, in parrellel, series would not work out.
 

FireFrog

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Jan 22, 2017
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Oh so I have the 4056 modules in parallel

Ok I'll check out the psu for info
I was thinking of taking a phone or tablet charger and soldering the chips so I can plug in anywhere instead of hauling a psu around, hahaha

So it depends on the power supply's current rating and voltage to deliver the needed current and voltage, got it
Thanks guys


Can I have two phone chargers in parallel for more amperage but just one connection to the outlet? I'm assuming adding a diode to keep it from messing up the second charger.
 

Korishan

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Connecting 2 DC wall adapters will increase amperage output. Diodes won't make much of a difference. I guess you could put 2 diodes on, one on each + leg, but I doubt it'd make much of a difference

I had connected 2 5v wall chargers (1x 1000mah, 1x 1500mah) so I could charge my tablet because it used a different connection than usb and I didn't have any chargers for that tablet. Had to fabricate one till I got the charger in the mail. If I recall, the two, or more, adapters in parallel don't always add to the sum of their ampacity ratings. Not sure why, tho.

However, if you add 2 adapters in parallel and each are 1500mah, and you use 3 4056's each pulling 1000mah, then you'll be border line of what they can handle. Make sure the rated amperage output is 20% higher than what it required by your max draw. You can quickly overheat an adapter and start a fire if you pull 100% load for too long a period. I almost made that mistake a few weeks ago with another project. I just happened to walk past it while it was running and things didn't quite smell right. I felt the adapter and immediately pulled the plug. I couldn't even keep my hand on it it was so hot.
 

FireFrog

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Jan 22, 2017
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I'll keep that in mind
Maybe run to the nearest thrift shop for some cheap Dc adapters to test before I do anything


What Meters do you guys use?
I'm looking to upgrade mine it doesn't measure current for some reason
 

Korishan

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I primarily use a Harbor Freight special. To measure current you have to put the red probe in the correct port. It's NOT the same port as voltage and resistance/ohm is read from. Then amperage is measure 'through' the meter; in other words, connected in series.

Now, I will be upgrading to a newer/better multimeter later when I need better precision. But the HF multimeter works for rough numbers for preliminary results.
 

FireFrog

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Jan 22, 2017
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I tried that
The manual said the same thing but I get 0.00

Maybe mine was a off one
 

Korishan

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On mine there are 3 settings for Amperage readings. 1 is for AC Amps, and 2 are for DC amps; one of which is for milliamps, and the other for picoamps. Though, I've never used the latter 2 since I was always measuring AC amps and greater than 1 Amp at that.

Not sure if while in DC mode it has to be wired a certain way. ie: red goes to power positive and black to load, or visa versa.
 

station240

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Yeah for DC current, red goes to power positive (eg charger) black goes to load positive (eg battery).
If you tap into the negative rail the colours are reversed.
 

Rerouter

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Ok, time to clarify, and play electronics 101, you cannot test the current capacity of a power supply by turning it to amps and putting your leads across + and -, you need a load for 1A, you would look for a 4.7 ohm 10W resistor, plug your multimeter probes into 10A and common, your black lead to negative of the supply, your red lead to one side of the resistor, and the other side of the resistor to + of the supply,

You would preferably at the same time have another meter measure the voltage across supply + and -, a cheaper charger intended for phones will generally have its output voltage just crash down once loaded to 1A,

For your chargers, if you power the chargers in parallel, you just need a supply that can give out 1A per circuit, each charger consumes up to 1A, internally its regulating it to follow the charge curve. for this you have 2 options, buy an AC brick that gives out 5V at 10A, or grab a laptop power brick and a DC-DC converter that can take in the laptop brick output and supply enough amps at 5V,

I would guess the laptop brick option will be the most compact and cheap option, your using 5Vx9A = 45W, assume a rather cheap DC-DC and lets say 52W input (efficiency losses), so a laptop 16V brick capable of atleast 3.25A


Also if you tried to measure the current while your leads where in the voltage position, try and measure a resistance, you may have blown the 250mA fuse for the mA/V/Ohm range.
 

Sean

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Rerouter said:
Ok, time to clarify, and play electronics 101, you cannot test the current capacity of a power supply by turning it to amps and putting your leads across + and -, you need a load for 1A ....

Of course you can, the shunt within the ammeter is the load.

You just need to make sure the tester is rated in excess of the power supplys max current.
 

Rerouter

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well i am speaking to who i assume is a beginner, equally in this case, when describing working with a multi meter, it wont really work out...

a generic multi meter is likely to have a 10 ohm 1W Resistor for the milliamp range = puff of smoke (5V / 10Ohm = 0.5A, 0.5A x 5V = 2.5W)

and a 0.1 ohm current shunt for the 10A range = popped fused or over current shutdown of power supply (5V / 0.1Ohm = 50A, fuse pops in less than 2 seconds for most)
 

station240

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Current inputs on multimeters are usually fused, though the cheap ones only have a fuse on the high current (10A) input.
If your going to use them to measure short circuit current, have spare fuses handy.

Another thing to consider is you also need to measure the voltage at the same time, so you need two multimeters.
No point finding out a PSU can supply 30A, if the voltage drops to 4.2V or something.
 

FireFrog

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Jan 22, 2017
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The meter works!
i opened the back to see if the fuse blew and it did, so after watching some of AveRage Joe fuse testing i grabbed a resistor and cut the end off to use for a fuse

thanks AveRage Joe for the idea
 
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