Ultimate UPS Mod

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So my weeny UPS battery was causing the UPS to spit out error beeps meaning I won't have battery protection anymore, oh well.

Properly dispose battery and cut existing spade leads
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I had lame wire crimps so I had to open the case to extend the wire leads. I also had the same color wire so I tagged the B+ lead with electrical tape.
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Removed the annoying buzzer. I still need to game on even the power cuts out still.
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Obtain large european car group 49 battery and install battery terminal leads. I bought it used for $40 and battery puts out a lot of CCA and has lots of RC for extended runtime when posting stuff at BITOG.
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Crimp ring terminals to ends of wires and connect to battery...

BZZZZT!!!!

Realise you did not have adequate lighting and cross-connect the terminals. So much for trying to complete this project at night while tired from work.

Luckily the unit was fused so all I had to do was replace the fuses. Interestingly for something so simple the fuses were made in Japan. Perfect for a JDM car yo.
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Then find out the fuses were soldered to the unit. Non-serviceable parts my cinnamon buns. I would've tossed this unit in the trash if I was not skillful.
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A little detail goes a long way. Text all lines up like a book. Screw that caution warning I've been in near death situations and I'm not letting that scare me.
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Strap em together and look how it's a ridiculously hideous mod. Also added a voltmeter for realtime voltage monitoring.
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Awesome
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I did something similar about a decade ago with an old APC Smart-UPS 1000XL. I had two large (650CCA) car batteries hooked up to it and it had insane runtime.
 
Bbeen there and done that. Cheap upgrade. But, light duty ups's aren't meant to run indefinitely on big batteries.
 
I did that for pretty much all the reasons you did. You know car batteries give off hydrogen which is a flammable thing and not UL approved etc. I used a $15 walmart lawn tractor lead acid battery, cheezy cranking amps but still plenty of reserve capacity.

PS that voltmeter is sweet, I love little LED whatzits from dealextreme or wherever.
 
Originally Posted By: Greasymechtech
But, light duty ups's aren't meant to run indefinitely on big batteries.


You have to watch this one. Decent UPS which are designed for long runtimes have adequate heatsinking and at least one fan to keep the temps in check on the switching transistors. Little units like the one shown have weeny heatsinks that are not designed for convective cooling, but simple small thermal mass. They will eventually overheat and fail (best case), or set fire to the case (worst case). In addition to the transistors, the transformers are usually designed "on-the-limit" and are a *lot* harder to keep cool. They heat up slower, but they just keep heating up until something melts.

If you plan on actually using more than 5 minutes of that battery capacity, pop a fan in there forcing air over those heatsinks and you'll have more of a chance of it surviving more than 5 or 10 minutes at a decent load.

Other than that, nice job. Double check your charging float voltage though. It's not unheard of for UPS units designed for SLA batteries to boil flooded batteries dry.
 
That battery inside my home would make nervous. It appears like a fire hazard to me but nifty idea.
 
The original battery was designed to die before the unit could get hot enough to cause damage. Now you have enough juice to melt plastic to let the smoke out of your transistors and VRs. Be careful.
 
Originally Posted By: rjundi
That battery inside my home would make nervous. It appears like a fire hazard to me but nifty idea.


Yep, looks cool but its a fire hazard.
 
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