Mass USB charging

D3x! said:
dude I have been saying that since the beginning :D

it will be simpler, possibly cheaper and more effective :/
Click to expand...

Eventually this needs to be managed by someone other than myself, so flicking switches is a problem when you task someone else with it.

Otherwise it can be left on to save the hassle.

Sent from my HTC Desire using Tapatalk 2 Beta-5
 
Cloud said:
Eventually this needs to be managed by someone other than myself, so flicking switches is a problem when you task someone else with it.

Otherwise it can be left on to save the hassle.

Sent from my HTC Desire using Tapatalk 2 Beta-5
Click to expand...

If you are hiring people who can't turn on or off switches, well then I just don't know anymore buddy
 
Cloud said:
I ran into a bit of a problem with a project I am working on and wonder if anyone has any ideas.

I bought a 36 port USB hub that comes with a 5V 4A power supply. After plugging in 25 Huawei S7 tablets the poor power supply nearly melted (in fact, it did become soft in parts) and shut itself down after about 15 mins.

After doing some research I noticed that the max output for one USB port is supposed to be 500mA, which means the max the 36 port hub can charge is 8 (500mA x 8 gives 4A). This is a bit of a bummer, as I need to be able to charge 34 simultaneously :P

Common sense (and that's all it is, have no formal education in electronics) says I need to find a 5V 17A power supply to charge the hub as this should give each port at least the 500mA it needs.

But that is easier said than done, most hubs come with underpowered power supplies and I have yet to find a 5v supply with anything more than 4A.

Any ideas or suggestions?
Click to expand...

Yes, give me one of those tablets and it will lessen your burden... :)
 
Last edited:
henry1103 said:
What is your price range?

I saw another one here at half the price mentioned:
http://www.amazon.com/Multiport-Recharges-Powers-Glasses-Devices/dp/B004X24KPM

if looking for a cheapie, then its probably best to build your own...
Grab a 12V car battery, some fuses, grab some resistors, and build...

An alternative would be buying multiple of these:
http://www.amazon.com/Cosmos-Adapter-Charger-shuffle-classic/dp/B0052RM8T2/ref=pd_cp_cps_0
Click to expand...

Considering perhaps building something, but otherwise just use some locally available 4 ports.
 
D3x! said:
If you are hiring people who can't turn on or off switches, well then I just don't know anymore buddy
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The person managing the tablets will be doing me a favour initially. Perhaps when I start paying them I can ask them to flick switches :P
 
Cloud said:
How much would something like this cost?
Click to expand...

Depends. You can parallelise it but if I said 1 transformer with 2 SMPS modules you'd probably end up spending about R350 total.

bdt said:
^ now that's some ghetto/redneck action right there! :rolleyes:
Click to expand...

No, that's electronic engineering. Why put up with someone else's crap when you can make it yourself :) Though as someone mentioned earlier, you might as well just get a PC PSU, short the pins below the clip on the ATX connector and simply make a breakout for the chargers. That's the cheapest solution provided you already have one laying around. If you don't, the one I suggested might turn out to be cheaper since you want a good PC PSU.
 
@Cloud: If this is the hub you are considering, there are some reviews on Dealextreme. They seem to sell several similar types.
http://www.bidorbuy.co.za/item/6336...80_Mbps_transfer_speed_Excellent_Special.html
http://club.dealextreme.com/forums/Forums.dx/threadid.634655
http://club.dealextreme.com/forums/Forums.dx/threadid.433192?page=1

In general cheap Chinese switching power supplies are very poorly designed and can easily damage any equipment that is connected to them when they malfunction. In your case this could mean 30+ tablets get detroyed instantly. Considering the replacement cost of the tablets you really need to use a high quality PC supply or an industrial grade 5V PSU unit. If that 10 port hub is screwed together you could consider opening it, removing the circuit board and rewiring or replacing the connectors. You can buy USB sockets from Mantech, Rabtron etc. for <R5. You could also install fuse holders for each port as a safety precaution.
http://shop.rabtron.co.za/catalog/ieee-connectors-c-126_243.html?osCsid=dqr9oj9umke5qqd2icpl2j8o91
 
Yotch said:
@Cloud: If this is the hub you are considering, there are some reviews on Dealextreme. They seem to sell several similar types.
http://www.bidorbuy.co.za/item/6336...80_Mbps_transfer_speed_Excellent_Special.html
http://club.dealextreme.com/forums/Forums.dx/threadid.634655
http://club.dealextreme.com/forums/Forums.dx/threadid.433192?page=1

In general cheap Chinese switching power supplies are very poorly designed and can easily damage any equipment that is connected to them when they malfunction. In your case this could mean 30+ tablets get detroyed instantly. Considering the replacement cost of the tablets you really need to use a high quality PC supply or an industrial grade 5V PSU unit. If that 10 port hub is screwed together you could consider opening it, removing the circuit board and rewiring or replacing the connectors. You can buy USB sockets from Mantech, Rabtron etc. for <R5. You could also install fuse holders for each port as a safety precaution.
http://shop.rabtron.co.za/catalog/ieee-connectors-c-126_243.html?osCsid=dqr9oj9umke5qqd2icpl2j8o91
Click to expand...

Destroyed... instantly... o.O Yeah, that would be a disaster. So building something is safer you think?
 
This video shows a Huntkey 550W PC PSU fail during a reliability test. I wonder how many of your tablets would have survived ...
http://www.youtube.com/watch?v=XglUdm25Bxo

I have had a cheap ATX supply blow on me before and destroy a motherboard and several peripherals. If you choose the PSU yourself you can be sure that there is sufficient capacity to supply all of the devices provided that you know the maximum current draw of one device. There are many reviews of various PC PSUs at www.hardwaresecrets.com during which the supplies are subjected to numerous torture tests to evaluate their performance which might be of interest.
 
Yotch said:
This video shows a Huntkey 550W PC PSU fail during a reliability test. I wonder how many of your tablets would have survived ...
http://www.youtube.com/watch?v=XglUdm25Bxo

I have had a cheap ATX supply blow on me before and destroy a motherboard and several peripherals. If you choose the PSU yourself you can be sure that there is sufficient capacity to supply all of the devices provided that you know the maximum current draw of one device. There are many reviews of various PC PSUs at www.hardwaresecrets.com during which the supplies are subjected to numerous torture tests to evaluate their performance which might be of interest.
Click to expand...

Thanks.

Sent from my HTC Desire using Tapatalk 2 Beta-5
 
This one is a bit cheaper R300 odd.
It is a ten port.

http://www.vantecusa.com/en/product/view_detail/465

Features:
Expand Your Computer With 10 USB 2.0 Ports
Backwards Compatible With USB 1.1 Devices
Hot-Swapping Feature: Allowing You To Connect/Disconnect Devices Without Powering Down System
No Drivers Required -- Plug & Play
AC Adapter Providing Extra Power To All USB Ports
LED Indicators
 
droid said:
This one is a bit cheaper R300 odd.
It is a ten port.

http://www.vantecusa.com/en/product/view_detail/465

Features:
Expand Your Computer With 10 USB 2.0 Ports
Backwards Compatible With USB 1.1 Devices
Hot-Swapping Feature: Allowing You To Connect/Disconnect Devices Without Powering Down System
No Drivers Required -- Plug & Play
AC Adapter Providing Extra Power To All USB Ports
LED Indicators
Click to expand...

How much power though, doesn't give the exact spec :(

Sent from my HTC Desire using Tapatalk 2 Beta-5
 
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