Laptop power supplies as chargers..

Ypedal

Ypedal

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Still on my quest for a cheap, simple, small, 100v lipo charger.. this is like the pick 2 but not 3 deal with batteries.. frustrations..

Ok.. so after repairing a MW supply:
http://endless-sphere.com/forums/viewtopic.php?f=2&t=41160

I put 2 of them in series, set the voltage to 99.5v and hooked it up to a CA and a 24v cell pack.. all was well for 0.8ah at 8 amps until one of the units i " fixed " quit.. fan stopped and no output.. .. will deal with that some other day.

I happen to have a box full of these laptop power supplies, specifically a bunch of HP 18v 3.5amp units..
 

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The output wires are made of this stupid braided , shielded cable stuff, the braid i hate because you canot solder it ( i've tried .. not with a bigger iron yet.. but anyways.. not important ) .

see:
HP2.JPG

after much futzing i managed to crack one open using a dremel and a cutting wheel..

HP3.JPG

so i can un-solder the braid crap, and solder on some 14 awg silicone in there with andersons.. or similar..

I'm borderline electronics retard, so i got no clue, however, me think that if i hook 3 of these in series i get 60v, hook that in series with the non-dead MW 48v unit tuned down to a total of 100.0v i got myself a 3.5 amp 100v unit..

using 5 of these, would make a very small, compact, weatherproof on-board charger.. for opertunity charging ....

anyone ?.. yay.. nay ?
 
I have a shitpot load of Laptop chargers, at 10.8 volts. I seriesed 4 of them to charge 36V Battery. Works great to 42V HOC.

Did 3 the same way for 24V charge and 1 won't do the charge. Tried 3 different chargers, all do the same. These are NEW. :roll:
 
I have had good result using Del 3r160 supplies for the old dell optiplex compact desk tops. Been using them for about a year, 4 series to charge a 36 volt pack.
seems they may work well 9 in series for 100 volts.

You must cut the ground on all except for one, and all must be powered up at the same time

I wanted to post some pic and drawings for you, however can,t seem to make it happen! right now. I have posted much detail about the P S U in the past here.

Ask if your are interested, and ill post more info later
 
torqueon said:
I have had good result using Del 3r160 supplies for the old dell optiplex compact desk tops. Been using them for about a year, 4 series to charge a 36 volt pack.
seems they may work well 9 in series for 100 volts.

You must cut the ground on all except for one, and all must be powered up at the same timeI wanted to post some pic and drawings for you, however can,t seem to make it happen! right now. I have posted much detail about the P S U in the past here.

Ask if your are interested, and ill post more info later
Click to expand...

I was hoping someone would mention this part, i dont fully understand why this is, but i konw it's important .. " Isolated " .. vs " not isolated " ..

I thought this only mattered if the units had metal housings and made contact with each other? ( had this happen on nimh packs with Hi-Power chargers... blew fuses if the chargers touched ) ..

more info welcome !!!.. pls ! ( or i will be learning by experiments in the driveway and power bars... neighbors look at me with fear when i do this .. it happens quite a bit ! )
 
with the SMPS chargers the output is isolated from the input.

if the cord has a grounded lug on it, then you can check to see if the ground is connected to the negative ouput with an ohmmeter. i have seen this case with a three pronged plug charger.

if it is a two pronged plug, the output is isolated.
 
torqueon said:
You must cut the ground on all except for one, and all must be powered up at the same time
Click to expand...

Some of the more fancy laptop supplies (Dell) have a high-ohmic resistor between the input
and output side of the supply. I think this resistor is necessary for the startup, that some
sort of signals must be present at the output side for the input side to start and work.
I can imagine this is where the 'all must be powered up at the same time' comes from.
 
the resistor on the output is a draindown resistor across the output caps so there is no voltage remaining on the plug when off. of course if the 'adapter' is left plugged in then the charger pushes current equal to that draindown current all the time.
 
Cheap as you find those at the garage sales, too bad it's not simple enough for the likes of Dogman. Be nice to have an opportunity charger more built to get knocked around, and that cheap!

Can't solder a wire, that's why god made wire nuts. Or use a crimp connector.
 
I tell ya if someone got into the turn key, adjustable & affordable (re: no china shipping $$) 18s-24s Lipo charging business they'd make a killing... I'm at 18s now, but want to do 22s-24s since I have some extra packs, but I'm no good at modding stuff like meanwell 48s nor do I want to shell out for a couple additional ecitypower chargers set to one voltage...

...there must be something out there to cheaply fill out needs. *sigh*
 
The dell 3r160 are good for 8 amps, and you can vary the volts from 3.6 to 12 volts by installing a poteniometer, so no need for a meanwell. Had 6 units shipped to my door for $30.00 + 3 that i found in the trash.

There are 6 wires on the output side, (red and brown, are +) (black and white, are -) Yellow and green are sense wires

Wire in a potentiometer, wiper to the sense wire and you got yourself a 3.6 to 12 volt supply

These units will cut out if over loaded, if that happens remove load and reset the dells by powering off, about 10 seconds, power back up and reset to a lower voltage and try again. An ampmeter a big help here.
The power output will drop as the batteries charge and as the dells warm up, so you have to readjust the pots through out the charge.

To the credit of E S I have managed to build a circiut to maintain constant current, still work in progress.
 
cwah said:
why do we need current constant for charging?
Click to expand...

Reason i'm using these in series with a meanwell is that the laptop supplies will max out at 3.5 amps and keep the meanwell from overloading and melting down. ..

The Nano packs can take the current ( like.. 5C on a 13ah pack = 60 amps if i could afford that big of a supply ) but 3.5 amps is good enough for me and healthy for the pack.

the point here is to get it done ( reliable ) , and do it cheap.
 
ok.. so update time.

I soldered a + and - lead to the units ( using recycled andersons from my stash of cut-wires, this is a " cheap and recycle " project after all ) ..

View attachment 2

put the plastic housings back on and used filament tape to keep them tight, i figure the plastic needs to make contact with the metal shell to shed heat.. and air gap would be bad..

hooked it all up in series on a power bar, ( one of the 3 units has the ground pin missing already, the other 2 have them, and i left them be for now ) ..

I have a 12ft lenght of 10 awg silicone wire going on here, as i plan to put the charger on the shelf and run the wire down to whatever bike i'm charging from the garage..

HP7.JPG

and, so far, cha-ching !

HP8.JPG
 
CA just hit 0w and put 2.7xx ah back into the pack.

View attachment 1

the hottest the laptop units got was 62 celcius :shock: but they kept on ticking...

cell voltages range 4.11 to 4.17v ( from a well worn out pack, 8 of these cells have been pricked with a needle and de-puffed about a month ago.. still running them in 100v 5ah at 100 amps on a 9C setup ( full 20C rate ) ..

HP11.JPG
 
dnmun said:
what did you use to seal the hole from the needle? did they puff up again after that or stay flat?
Click to expand...

I used a tuck tape ( the red stuff used on home vapor wrap, very strong red tape ..

http://indoorgardensolutions.com/index.php?l=product_detail&p=332

After pushing the gas out using a piece of wood, sealed the pinhole, then put back in the shrink wrap shell, taped that, then put the 4x 6S packs in compression and tapped the mass into a solid pack, it still swells a bit but has been working ( hard ) for the last bit, no trouble yet.
 
i seem to have misplaced my digicam, :evil: .. but i'm sure it will eventually show up.. it's a sign that i need to stop everything and start cleaning.. but so many projects near completion.. while so many others waiting to be started... means cleaning and organizing are low on the priority list.. i'm not proud of it.

So since i now have 3 charge cycles from the franken-charger and it looks like a stable 4.5amp 100v ( 450w ) unit, i went digging and found 3 identical cpu heat sinks, nice chunky aluminum, one for each laptop unit....also got some aluminum stips and once i tidy up the wires .... should be golden.. i can then start work on another unit ( so many 100v bikes, so little time )
 
Found my camera !!!

I hope this helps keep them suckers cool enough to keep on running....

Used some thermal paste, clamped them down and jbweld on the edges to keep them in place..

then I plan to make some sort of bracket to secure them to the MW unit.
 

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dnmun said:
with the SMPS chargers the output is isolated from the input.

if the cord has a grounded lug on it, then you can check to see if the ground is connected to the negative ouput with an ohmmeter. i have seen this case with a three pronged plug charger.

if it is a two pronged plug, the output is isolated.
Click to expand...

I just checked this, and Yes, if i check Ohms from the AC ground to output Negative, i get 3.6k so these are NOT isolated...? right?

So now that i've removed the top half of the plastic shell, and attached heat sinks, does this mean the heatsinks can not be allowed to touch ? or do i zap myself if i put my hand on the unit ?

I plan to cut the power cords from all 3 units, solder the Live and Neutral's together, tie them to the L and N from the meanwell , leave the ground out of it ?..

suggestions anyone ?
 
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