Power Supply + Charger for S800



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PeterLester

Member
Noisy is right...

Took one of these apart and adjusted the voltage outputs to maximum, then searched around for the negative DC ground/earth lead hoping to be able to isolate one PS DC output as per the following link http://www.tjinguytech.com/my-projects/server-ps. But the link describes this method only for the Dell 550W (model AA23300) and I have the Dell 700 watt (model NPS-700AB's). If my photos attached are showing the right DC earth point then I am set to go. Otherwise I might risk damaging one PS if I try to gues my way thru this..... (working without schematics). Any suggestions anyone?
The red multimeter probe shows the DC ground to earth connectionView attachment 7099
The last photo shows what happens when the case was opened.... a disconnected conector. Had to run a ground wire in to try to discharge all the capacitors before working the connector back on..... was nearly electrocuted by a TV power supply years ago doing this kind of thing! extremely painful experience!!! View attachment 7097View attachment 7098
 

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PeterLester

Member
Thanks for your concern.... This is not a task for just anyone hobbyist for sure!!!
While it is a simple and straight forward task to connect two 12 VDC batteries together to achieve the desired 24 VDC ouput.... that is not the case when using two power supplies fed from separate 120 VAC circuits. There are multiple ways in which one faulty or failed 12 VDC power supply can damage the other and/or the downstream connected load leading to a fire, shock hazard etc. e.g. what happens when one 15 amp breaker trips but not the other? The tjinguytech links attempts to explain these risks....

While it is easier to remove the AC ground connection from earth on one of the Power supplies, that creates a shock hazard requiring a warning neon bulb etc. Later the tjinguytech articles explain the much safer method of removing the DC output ground from earth on one of the two power supplied which provides a completely safe solution. What the articles fail to explain is the shock hazard risks when going in to do this simple task..... and there is a warning label on the outside of these units (certainly not very obvious) which must not be ignored.

In any case these are now closed back up and working fine and I was able to do the work w/o incident using insulated gloves, tools, grounding the caps first etc.
 
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kloner

kloner

Aerial DP
I just isolated my insides from the case and wired the dell ps in series... holds 23.9v at 30 amps off my charger.... been going for a year, charged an average of 15,000 mah 10-15 times a weekend when i go fly,,, no sparks, no fire, and i didn't get shocked
 


kloner

kloner

Aerial DP
ah, it never crossed my mind to run one...... made this double end plug for the wall that makes it so simple to plug and go,,,, but sometimes i'll charge mr tx batt, 4 cell nimh at .5 amp and wonder if it needs all that racquet to do it..... takes forever too cause it discharges then charges.

get you a cheap pelican knock off and mount it all up. makes a nice clean case

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Pelted

Member
I received my ebay HP power supplies yesterday and did the modification with no hiccups. Very easy conversion (I did not do the dual 24v version yet) and straight forward. But damn, for the price compared to the LHS units this just can't be beat. Thanks all for the tips and links.
 

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