Hey gang,

I finally scrounged all the parts I needed to finish this one up.


My thoughts when starting and thinking about this project was originally just a convenient way to keep my power supply connected and with in easy reach of my chargers. In light of the recent incident involving one of our RCG friends house, I rethought the design slightly.

Pressure containment is not a concern here, only the containment and suppression of flames should a pack run away. Also I wanted something that looked nice to take to the field with me.

I started with a metal heavy gauuge tool box. I checked at HarborFreight first, looking for a deal. They wanted $31 for a lighter gauge box than this. The box was just plain flimsy. I found this one for $24 at the local Tractor Supply Co. A bit more than I wanted to pay, but I was lucky it was the only money I spent on this project.

The Ability to charge with the lid closed if I choose to was important. I started with Dremeling out holes for a AC and DC connection
[IMG][/IMG]

After mounting the two connections, I mounted the power supply using velcro to the bottom of tool box. This isw a modded ATX power supply, putting out almost 13vdc rated at 30A
[IMG][/IMG]

Next step was cutting the plexi shelf in the same dimension as the original metal tray I have since discarded. I will be running 2 chargers in this box, I wanted to add a ammeter so I could keep track of what the charger is actually putting out in DC.

Laying out the design


Inginuity is the key when doing hobby stuff. I couldn't find my circle cutting attachment for my Dremel, so A chunk of wire, a binding connector and a stak-on make the perfect circle tracer.


Next was using the binding connectors for a template and mount them into the plexi.


From there it's just wiring and assembly.The upper 2 binding posts are 12VDC, the lower one that's revearsed is the feed from the 5VDC rail. This allows me to test servos and reveivers without having to hook up a bettery pack.


The only thing left to do, and it was getting too cold in the garage to do it tonight, is mount the temp probe. I'm going to Dremel a channel in the plexi and recess the temp probe, so the battery can be simply layed on top of it and were ready to go.


I'm debating, I may also line the lid above where the batteries are with some Ka-wool, should a battery go off, i"m pretty sure it won't burn through the metal as is, but some ka-wool would insure it would remain contained.

I may also do a bit of "case modding" by adding some cold cathode lighting under the plexi or something like that, just cause I can. I have enough parts left to make a few more of these. I may make them up and sell em off, I haven't decided yet.

Let me know what you all think of it.

Bill


short video

http://www.youtube.com/watch?v=2onraahVedA

I like the in-line ammeter... I was just thinking about that earlier this week.
Do you have it between the PS and both chargers?
(i.e. displays how many total amps both chargers are pulling)

Nice work!
n8

Yea the ammeter is on the 12vdc rail between the power supply and the banana plugs.

I have the banana plugs wired in parelle, and also have the 12vdc wired in paraelle with the ammeter between. This way whether I'm drawing off of the power supply, or running off a deep cycle battery via the external plugs I can see how many amps i'm drawing.

Thanks
Bill

Sounds similar to what I did, except I used an old Dell appliance face plate as a charging "bus", and just connected all of the banana plugs in parallel on the back.
http://www.rcgroups.com/forums/showthread.php?t=1204600

Like your setup, I can power up the bus from the Power Supply or a car battery quickly and all four chargers are ready to go. So I just need to drop the ammeter in between the PS/batt and the bus.

Nice job I like it.
well done.

Great job! I'm going to find a heavy gauge plastic toolbox and try my hand at the same thing. A metal box kind of worries me a bit around exposed male charge leads. Cutting holes in the plastic box will be easier for me .... but definitly not as strong as steel.

Thanks for sharing!!

Bob

seems like a cool idea for a portable charging station. Especially if you could put some sort of 12v battery source inside or had 110v at the field.

But for home charging, to me, it seems like a bit of overkill.

one last thing, you allowing the PC power supply to have cooling air down under? I didn't see any vent holes in the plexi or in the case.

Originally Posted by cryhavoc38

one last thing, you allowing the PC power supply to have cooling air down under? I didn't see any vent holes in the plexi or in the case.

Funny I just got done picking through the cabinets at work for another fan. I couldn't find anything of decent size so I'll have to tear apart another power supply to get one. I'm going to mount another fan on the right side of the box to aid in cooling. There is a air gap all the way around the plexi currently to allow hot air to escape, but some forced cooling would be super easy to do since I have access to 12v down there.

Overkill? Probably , but its nice to just grab the box, plug it in and charge. When I'm done I can get it off the bench to free up more room. Btw ignore the mess on the work bench. Its normally not like that.... I swear We were in the process of going through crap, and hanging more peg board. It looks like a tool box threw up on my bench right now. That's this weekends project.

Bill

forced air with another 120mm fan (nice and quiet) would be a good idea.
Cut some vent channels in the case with a router, or you could go simple and router in some vents in the plexi to allow for the heat to rise up and out.
As far as charging with the lid down, I'd recommend against that unless you had full case forced air cooling with exhaust vents.

Overall its a great idea. congrats.

Originally Posted by Dirt Brakes

Funny I just got done picking through the cabinets at work for another fan. I couldn't find anything of decent size so I'll have to tear apart another power supply to get one. I'm going to mount another fan on the right side of the box to aid in cooling. There is a air gap all the way around the plexi currently to allow hot air to escape, but some forced cooling would be super easy to do since I have access to 12v down there.

Overkill? Probably , but its nice to just grab the box, plug it in and charge. When I'm done I can get it off the bench to free up more room. Btw ignore the mess on the work bench. Its normally not like that.... I swear We were in the process of going through crap, and hanging more peg board. It looks like a tool box threw up on my bench right now. That's this weekends project.

Bill

Nice job!! but don't go tearing apart a power supply just to get a fan !

http://www.frys.com/product/4722179?...H:MAIN_RSLT_PG

This seems like a pretty good idea to me. A couple of questions, though:

Is there any reason you didn't just cut a full size hole on the side and install the PSU just like you would in a PC case? The only thing I can think of is maybe weight balance?

That way you could use the plug (and maybe power switch, if your PSU has one) that are built right into the PSU, instead of extending it stuff. The PSU fan would also vent directly out the side of the box, and you could cut another hole on the opposite end and install a grille to get better airflow. You could even put a filter on the grille, if you were feeling ambitious.

What are the dimensions of the box? It looks like you could possibly fit some 12V SLA batteries down with the PSU too, so you could run it without having to haul a big deep cycle around. Obviously this idea might affect airflow (and weight!) a bit.

Originally Posted by Ezrem

This seems like a pretty good idea to me. A couple of questions, though:

Is there any reason you didn't just cut a full size hole on the side and install the PSU just like you would in a PC case? The only thing I can think of is maybe weight balance?

That way you could use the plug (and maybe power switch, if your PSU has one) that are built right into the PSU, instead of extending it stuff. The PSU fan would also vent directly out the side of the box, and you could cut another hole on the opposite end and install a grille to get better airflow. You could even put a filter on the grille, if you were feeling ambitious.

What are the dimensions of the box? It looks like you could possibly fit some 12V SLA batteries down with the PSU too, so you could run it without having to haul a big deep cycle around. Obviously this idea might affect airflow (and weight!) a bit.

Yes balance was the main issue. Although if you added a battery to the other side it would prolly balance nicely.. In hind sight mounting the power supply would have prolly worked better, and eliminated the need for an additional fan in the bottom of the bow.

I don't normally charge at the off of 12v field, and in the few occasions I do, i have a plug made up the plugs into the power in my trailer plug, then into the plugs on the side of the box. It seems to work fine as I don't charge many large batteries at one time. I can't justify the added weight or maintenance of SLA batteries for that reason.

Bill

Bill,
Would it not be a good idea to make a fireproof battery tray to protect all the equipment in case a battery decides to blow.
I was thinking you could use the discarded upper tool tray, if it allows, or some spare sheet metal.
You could cut it to between one third to a half length, leaving some of the floor of the tray to the left side. Fold this side piece up so as to create an open topped box and a firewall between the battery and the charger unit.
Basically your making a square cake tin or baking tray.
You could then drill holes and grommet them, for the charger cables, or have binding posts, on extension leads from the charger, mounted in the firewall.

Tom.

Yea I suppose it wouldn't be a bad idea. I had considered it, but haven't implemented anything.

I have also thought about adding a partition of some sort between charger and where batteries go then lining with kawool. that would also be effectively fire proof. the metal tray could be used or even simple drywall would Do the job for fire reduction just fine.

Bill