Toronto Electric Model Aviation Club Forum

Toronto Electric Model Aviation Club (TEMAC) => General Discussion => Topic started by: gordonbw on March 24, 2013, 08:46:27 PM

Title: Power Supplies
Post by: gordonbw on March 24, 2013, 08:46:27 PM
What are people using to power their chargers these days?  Many years ago I converted an old AT computer power supply, and it served me well for a long time.  Now, with higher voltage and capacity batteries, it no longer does the job, so I need an upgrade.  Are you guys using the newer ATX power supplies, server power supplies, or dedicated bench supplies... And where are you buying them?
Title: Re: Power Supplies
Post by: Andy Hoffer on March 25, 2013, 04:11:49 PM
Quote from: gordonbw on March 24, 2013, 08:46:27 PM
What are people using to power their chargers these days?  Many years ago I converted an old AT computer power supply, and it served me well for a long time.  Now, with higher voltage and capacity batteries, it no longer does the job, so I need an upgrade.  Are you guys using the newer ATX power supplies, server power supplies, or dedicated bench supplies... And where are you buying them?

I have always been a big fan of ATX power supplies.  They have always filled the bill for me.  I get mine from old PC's at curb side or from the Gorilla Store (Active Surplus) on Queen Street West.  They come in all sizes and are very reasonably priced.  Not sure if they carry server power supplies, but I would not be surprised.

Andy
Title: Re: Power Supplies
Post by: gordonbw on March 26, 2013, 08:43:07 AM
Andy, how much power are you asking your ATX supply to deliver?  My old AT supply seems to have a top end of 3.5 amps, above which it will not operate the charger.
Title: Re: Power Supplies
Post by: Andy Hoffer on March 26, 2013, 09:02:07 AM
Quote from: gordonbw on March 26, 2013, 08:43:07 AM
Andy, how much power are you asking your ATX supply to deliver?  My old AT supply seems to have a top end of 3.5 amps, above which it will not operate the charger.

Hi Gordon:

I have one ATX supply that provides 4.2 amps @ 12 volts, another that provides 16.0 amps at 12 volts.

Andy

Title: Re: Power Supplies
Post by: sihinch on March 26, 2013, 11:11:52 AM
I have a 200 watt HobbyKing power supply and a 350 watt Progressive RC power supply.
Title: Re: Power Supplies
Post by: Bobmic on March 26, 2013, 04:11:42 PM
Unless you charge at low currents 12v ~15Amp power supplies will not be enough - you are looking at under 180W.
Most of the chargers today are between 200-400w.
It all depends on the batteries and chargers you are planning to use.
If you have a larger PS you can always use multiple chargers. I am using 350w PS from hobby partz which was relatively cheap and is working well. Most of the newer PC power supplies will be good and server ones will be even better.
Title: Re: Power Supplies
Post by: Andy Hoffer on March 27, 2013, 12:21:17 AM
Anyone know if you can safely wire two smaller 12 volt power supplies in parallel for greater current capacity to power larger chargers?  Any technical issues with doing so?

Andy
Title: Re: Power Supplies
Post by: Ededge2002 on March 27, 2013, 10:35:13 AM
I have a mean well 320W one that I no longer use. Its a solid unit but is 17.5-27Volts. Some of the newer chargers are 18 volts in. Please check your application.

$40

http://ca.mouser.com/Search/m_ProductDetail.aspx?Mean-Well/S-320-24/&qs=moO/8p2KOt%252b2QRvG/65Ryg== (http://ca.mouser.com/Search/m_ProductDetail.aspx?Mean-Well/S-320-24/&qs=moO/8p2KOt%252b2QRvG/65Ryg==)
Title: Re: Power Supplies
Post by: gordonbw on March 28, 2013, 01:42:15 PM
Ed -- thanks, but all my current chargers are 12v.
Title: Re: Power Supplies
Post by: Tom on April 06, 2013, 10:26:05 AM
I just ordered this power supply from eBay...
http://www.ebay.com/itm/12V-29A-350W-AC-DC-Universal-Regulated-Switching-Power-Supply-/350589142705?ssPageName=ADME:L:OC:CA:3160 (http://www.ebay.com/itm/12V-29A-350W-AC-DC-Universal-Regulated-Switching-Power-Supply-/350589142705?ssPageName=ADME:L:OC:CA:3160)

$28 including shipping.
I'll let you know how it works out.
Title: Re: Power Supplies
Post by: Tom on April 06, 2013, 10:33:31 AM
Quote from: Andy Hoffer on March 27, 2013, 12:21:17 AM
Anyone know if you can safely wire two smaller 12 volt power supplies in parallel for greater current capacity to power larger chargers?  Any technical issues with doing so?

Andy

Power supplies typically don't like to be paralleled - unless they were specifically designed to do so.  I don't believe ATX power supplies will work in parallel.
Title: Re: Power Supplies
Post by: Andy Hoffer on April 06, 2013, 12:10:59 PM
Thanks Tom.  Much appreciated.

Andy

Quote from: Tom on April 06, 2013, 10:33:31 AM
Quote from: Andy Hoffer on March 27, 2013, 12:21:17 AM
Anyone know if you can safely wire two smaller 12 volt power supplies in parallel for greater current capacity to power larger chargers?  Any technical issues with doing so?

Andy

Power supplies typically don't like to be paralleled - unless they were specifically designed to do so.  I don't believe ATX power supplies will work in parallel.
Title: Re: Power Supplies
Post by: bfeist on April 06, 2013, 06:31:01 PM
Hi Andy,
I modded some high current server power supplies a couple of years ago. Each one is different. I suggest you don't series or parallel any of them together unless you can find someone else who has done so on rcgroups.

The PSU I converted is capable of 980W with 120V AC input, and 1300W with 240V input. It was $30 or so from a surplus place. Takes some tinkering though. You can see it here http://temac.ca/smf/index.php/topic,3514.msg16721.html (http://temac.ca/smf/index.php/topic,3514.msg16721.html)

Ben

Quote from: Andy Hoffer on April 06, 2013, 12:10:59 PM
Thanks Tom.  Much appreciated.

Andy

Quote from: Tom on April 06, 2013, 10:33:31 AM
Quote from: Andy Hoffer on March 27, 2013, 12:21:17 AM
Anyone know if you can safely wire two smaller 12 volt power supplies in parallel for greater current capacity to power larger chargers?  Any technical issues with doing so?

Andy

Power supplies typically don't like to be paralleled - unless they were specifically designed to do so.  I don't believe ATX power supplies will work in parallel.
Title: Re: Power Supplies
Post by: Andy Hoffer on April 06, 2013, 09:16:04 PM
Thanks so much Ben. Looks like a good investment.  And to boot, I now understand the correlation between your days at the field and the load dispatch patterns at the Pickering Nuclear genearting station.

Keep up the good work!

Andy
Title: Re: Power Supplies
Post by: gordonbw on May 01, 2013, 01:12:17 PM
So I read Ben's post -- looks like a great solution but a little more complex than I want to undertake. I have acquired a 350W, 29A Mean Well PS that looks like the attached. I want to set it up in a safe enclosure with a power switch and proper connection points so that I can use it with any of my chargers. 

As my electrical engineering knowledge is tenuous, I wanted to seek feedback on my plan.  Here's what I'm thinking:

- Mount the PS in an appropriately sized project box from Sayal, adding ventilation holes
- Mount a power switch, 120v bucket receptacle, LED and banana receptacles on the outside of the project box
- Connect the external components to the PS using 12 ga. wire.

Does this sound like the right approach?

Also, the PS has three pairs of -ve and +ve 12V connection points.  Should I gang these together, activate only one, or have a separate input for each of the pairs?
Title: Re: Power Supplies
Post by: Ededge2002 on May 01, 2013, 01:57:56 PM
All the requested items could fit within the Mean Well case. I just opened one up and looked.
If your not interested in undertaking it yourself I would do it for you with a pick up/ drop off at the field. I have a lot of experience with this type of modification and it would take about an hour.
If the unit is a single output all the output terminals are just paralleled.

Will post photos tonight of one I've converted.
Title: Re: Power Supplies
Post by: Ededge2002 on May 01, 2013, 05:45:30 PM
Mean Well  S-320-24 power supply i looked inside to see there is space.
Glorified FPV station that I modify to have the power supply inside (they are sold with them outside so they dont need to be UL inspected)
Converted computer power supply showing use of proper spacing of banana plug outlets so that Pamona electronics type banana plugs line up.
Converted Motorola power supply
Title: Re: Power Supplies
Post by: gordonbw on May 01, 2013, 06:15:54 PM
Ed, I would like to take you up on your generous offer to help with the conversion.  I will bring the PS and some compoents to the field on Saturday.  What's your preferred brewski?
Title: Re: Power Supplies
Post by: Ededge2002 on May 01, 2013, 07:34:26 PM
Were you set on going Saturday?  I'm trying to arrange that I can make it Sunday if at all this weekend.  If need be I'm sure there will be repeat visitors this weekend!
Title: Re: Power Supplies
Post by: Bobmic on May 02, 2013, 07:41:15 AM
Where can I find a server power supply? I had a PC one but it was not powerful enough.

thx,
Bobby
Title: Re: Power Supplies
Post by: gordonbw on May 02, 2013, 03:09:53 PM
Ed... I'll probably make it out on Sunday.
Title: Re: Power Supplies
Post by: Ededge2002 on May 06, 2013, 11:29:26 PM
I'm sorry I missed you Sunday. I arrived late as I had obligations. I will possibly be there Wednesday and one of the days this weekend. Let me know
Title: Re: Power Supplies
Post by: gordonbw on May 07, 2013, 09:02:57 PM
No worries Ed -- we cab try again on the weekend.   I heard you did some awesome rescue / recovery work on Sunday!
Title: Re: Power Supplies
Post by: Ededge2002 on May 21, 2013, 05:12:02 PM
I picked up the power supply on the weekend and took a few moments last night to get it set up.  Nothing complicated just add banana power output terminals, on/off switch and power cord.  As the photos show I didn't have any black wire on hand the right gauge so the banana terminal wires are all red with three thinner wires per terminal making it easier to have the wires flex and still have more than enough gauge.  With the terminal strip removed and the wires soldered directly I used a little drop of epoxy to cover each wire from the top for safety. 
Title: Re: Power Supplies
Post by: gordonbw on May 21, 2013, 05:19:56 PM
How cool is this?  Ed, you are a total mensch.  What are you drinking?