Any reason not to gang universal laptop chargers together?

[John in CR]

Another member posted this $8 with free shipping 96W universal laptop charger http://www.ebay.com/itm/150716932513?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649. They're sold out now, but $8 ?????

I'm looking at it thinking that for $32 I can have 4 of them, which in series or parallel I could have a 375W charger capable of almost any voltage between 15V and 96V. $80 would buy 10 units, so I could have 2 full 20s bulk chargers that I could connect in parallel for a slick 83V cutoff and 8A charge current with a couple of spares in case any break.

Being the crude hacker I am, but interested in durability, I'd free them of their plastic cases, put 4 in a single case with one power cord and one charge wire, and add a fan to keep them far cooler than in their designed use. That could even reduce the overall size compared to 4.

In addition to having spares, the thing I really like about this over a charger like the cheapies from BMSBattery is not only that this is cheaper, but I get something I know I can tailor to exactly the cutoff voltage I want instead of receiving a charge I can't change and probably won't do the 82-83V cutoff I want.

Since they're switching supplies, there isn't anything wrong with series and paralleling them together is there?

 

[Gödel]

It might work with linear supplies. With switchers there will probably be unstable operation depending on how heavily the supplies are loaded.

 

[parabellum]

I have received similar one 2 days ago for testing, adjustable from 12-24V 90W. It turns off if the current draw is higher then max current. Actually it is continuously switching on/off trying to recover, do not think it is good for the supply. If current limiting is added it may work. I also believe 90W is not continuous rate, it gets hot quick delivering 80W.
http://www.ebay.com/itm/360292965945?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648#ht_948wt_1187

Happy Christmas!

 

[fechter]

Hiccup mode current limiting... not good for charging.

Some of these may also NOT be isolated on the output, so you'd have to check that before attempting to put them in series. That can usually be fixed if they aren't isolated, but the hiccup mode thing is a show stopper.

 

[ZOMGVTEK]

Switchers, especially cheap ones, tend to not like being run in parallel. They would need to be putting out damn near identical voltages for that to work out. Also, the thing isnt very likely to even charge a battery to begin with. It's very likely it will just cycle on and off, never really charging. Putting two '90W' units in parallel almost NEVER means 180W total.

Plus, I doubt these units could even take 90W. MAYBIE for brief periods. Run them for a few hours at 90W, and they might fail or shutdown. Never trust rated power outputs, they tend to not be achievable for very long in the real world.

 

[John in CR]

Thanks for the Christmas present guys. You saved me time and $, because I felt compelled to try what seemed almost too good to be true. I guess I just go lucky that my 36V Bosch chargers work so well in series and parallel....at least 2p2s does. I tried 3s, but that didn't want to work reliably.

What's the cheapest but reliable way to get 3-4A with a solid cutoff at say 82V? Throw smallest in the mix too, since portable would be nice.

John

 

[NeilP]

I would not give up on them yet John.
No for the parallel suggestion, and yes you would probably have to isolate the ground side , for series.
Only snag is getting a current limit in place. You only need to find one other type of supply that is CC limited and stick that in series too, then up the voltage with the cheapo ones,

I am doing similar with old PC PSU's. One Meanwell with current limit pot mod in series with as many PC supplies as required at 5volt each to get the volts I need. Each PC supply is good for a minimum of 25 amps at 5 volts. Trimming of the voltage then done with the Meanwell

OK, so this is not a compact soultion :lol: but can give you big current for almost free at any voltage you need.

 

[Harold in CR]

John, Remember those Laptop Chargers I told you I have ?? Here is a link to Ted Dillard 's charger project, using those same ones. He is using them on his Cafe' Racer Design Moto.

I know you said the voltage was not good for you, but, you might figure out what he is doing, and go from there.

here

I have 3-12V packs of "D" cell NiCd's, in series for 36V. I use 4 of these chargers to get a finish voltage of 40.9-41.0. When I put the charger on a 36V pack, if the cells are not equal, one of the 4 chargers will start blinking the red-green, then, they all blink. I usually wait an hour or so, then turn on the power strip. Usually, all 4 chargers give 4 red LEDs and the pack charges. When the pack gets close to charged, all 4 LEDs go to a yellow-green, then, will finally go full green.

I have several of these, so, if you want to play, I can send out a few and let you see if you can figure out something, so you can buy what you need. Read Ted's thread. It's only 3 pages.

 

[migueralliart]

This guy is using a similar approach but not with AC ones. He is using DC car laptop chargers

http://www.flyelectric.ukgateway.net/lithium-charger.htm#laptop1

I really think we should be able to grab one of these, modify it and add some sort of HVC and be done with it. Even at 96watts it is soo damn cheap.

 

[migueralliart]

Another member posted this $8 with free shipping 96W universal laptop charger http://www.ebay.com/itm/150716932513?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649. They're sold out now, but $8 ?????

Couple of cents more expensive but he has thousands of em
http://www.ebay.com/itm/250754529226?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

These are $1.5 more expensive ($9.56) but he is in the US so shipping will be faster.
http://www.ebay.com/itm/Universal-96W-Laptop-AC-Power-Adapter-Dell-Plug-/250948011750?pt=Laptop_Adapters_Chargers&hash=item3a6daac6e6

 

[SamTexas]

Couple of cents more expensive but he has thousands of em
http://www.ebay.com/itm/250754529226?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

These are $1.5 more expensive ($9.56) but he is in the US so shipping will be faster.
http://www.ebay.com/itm/Universal-96W-Laptop-AC-Power-Adapter-Dell-Plug-/250948011750?pt=Laptop_Adapters_Chargers&hash=item3a6daac6e6

All the generic power supplies I have used so far are not robust. They die within a month or two of constant use. If the voltage is right, I would buy genuine chargers from reputable companies like HP/Compaq or Dell.

 

[migueralliart]

Couple of cents more expensive but he has thousands of em
http://www.ebay.com/itm/250754529226?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

These are $1.5 more expensive ($9.56) but he is in the US so shipping will be faster.
http://www.ebay.com/itm/Universal-96W-Laptop-AC-Power-Adapter-Dell-Plug-/250948011750?pt=Laptop_Adapters_Chargers&hash=item3a6daac6e6

All the generic power supplies I have used so far are not robust. They die within a month or two of constant use. If the voltage is right, I would buy genuine chargers from reputable companies like HP/Compaq or Dell.

I agree with you but the OP is doing a test and is considering cheap chargers to attain a solution just trying to contribute over here