Author Topic: Running 24 VDC Freezer off 48 VDC Battery Bank  (Read 830 times)

0 Members and 1 Guest are viewing this topic.

armadillo

  • Jr. Member
  • **
  • Posts: 64
Running 24 VDC Freezer off 48 VDC Battery Bank
« on: September 20, 2017, 04:31:40 PM »
I have a Sundanzer DCF 165 chest freezer and I was wondering if it could be powered from a 48 volt battery bank using some kind of step down converter like this:  http://www.samlexamerica.com/documents/product-specs/12004-IDC-360C-24-0516_Hrez.pdf   Does that sound like a good idea or is there a more efficient step down converter available?

Sundanzer told me it would need one capable of 10 amps, which seems awfully high.

dnix71

  • SuperHero Member
  • ******
  • Posts: 2268
Re: Running 24 VDC Freezer off 48 VDC Battery Bank
« Reply #1 on: September 20, 2017, 05:21:29 PM »
The Samlex would work. The 10 amp requirement from Sundanzer is probably startup current, not running current.
How much is the asking price for the Samlex? VICOR makes a 500 watt 48>24vdc stepdown that sells on eBay for $110.

armadillo

  • Jr. Member
  • **
  • Posts: 64
Re: Running 24 VDC Freezer off 48 VDC Battery Bank
« Reply #2 on: September 20, 2017, 05:41:03 PM »
The Samlex would work. The 10 amp requirement from Sundanzer is probably startup current, not running current.
How much is the asking price for the Samlex? VICOR makes a 500 watt 48>24vdc stepdown that sells on eBay for $110.
Thanks for your reply, Dnix. The Samlex is about $270 and only 85% efficiency. Their 8 amp is $140  http://www.samlexamerica.com/documents/product-specs/12004-IDC-200C-24-0315_Hrez.pdf  A freezer converter needs to be a good one because it might take several days for me to notice when it quits. I don't think the danfoss compressors in those freezers have much of a start up surge.


Does the converter need to fully isolated (whatever that means)?

dnix71

  • SuperHero Member
  • ******
  • Posts: 2268
Re: Running 24 VDC Freezer off 48 VDC Battery Bank
« Reply #3 on: September 20, 2017, 05:57:29 PM »
http://www.ebay.com/itm/VICOR-V48A28C500AL-DC-DC-CONVERTER-MODULE-48V-IN-28VOUT-500-WATTS-/232110985228

$110 for a 500 watt Vicor 48>24vdc converter. These can be paralleled.

Isolation is desirable. It protects the fridge from faults that might occur on the battery bank side and from other things that are connected the bank at the same time.

armadillo

  • Jr. Member
  • **
  • Posts: 64
Re: Running 24 VDC Freezer off 48 VDC Battery Bank
« Reply #4 on: September 20, 2017, 06:38:13 PM »
http://www.ebay.com/itm/VICOR-V48A28C500AL-DC-DC-CONVERTER-MODULE-48V-IN-28VOUT-500-WATTS-/232110985228

$110 for a 500 watt Vicor 48>24vdc converter. These can be paralleled.

Isolation is desirable. It protects the fridge from faults that might occur on the battery bank side and from other things that are connected the bank at the same time.
Better price than Samlex and higher efficiency rating. It does use 10.5 watts no load, though. https://www.powerstream.com/p/V48A28C500AL-Vicor.pdf

Samlex draws <25mA.

joestue

  • Hero Member
  • *****
  • Posts: 1424
Re: Running 24 VDC Freezer off 48 VDC Battery Bank
« Reply #5 on: September 20, 2017, 08:42:05 PM »
I made a buck converter with two irfz46 fets and it turned 50v at 5 amps into 24v at 10 amps iirc, running on a fixed 50% duty cycle, so thats 97% approximately.

You could probably find a pwm generator board on ebay for 3$ and the rest of the components could be found from scrap electronic crap. If you could find a 5v cellphone charger to supply 5v to the pwm board from a 48v bank you could wouldnt have to build a linear regulator to do it, saving a couple bucks

armadillo

  • Jr. Member
  • **
  • Posts: 64
Re: Running 24 VDC Freezer off 48 VDC Battery Bank
« Reply #6 on: September 20, 2017, 09:59:25 PM »
I made a buck converter with two irfz46 fets and it turned 50v at 5 amps into 24v at 10 amps iirc, running on a fixed 50% duty cycle, so thats 97% approximately.

You could probably find a pwm generator board on ebay for 3$ and the rest of the components could be found from scrap electronic crap. If you could find a 5v cellphone charger to supply 5v to the pwm board from a 48v bank you could wouldnt have to build a linear regulator to do it, saving a couple bucks
I'm not an electronics guy by any stretch of the imagination. You're way over my head.  Thanks for your reply.

kitestrings

  • Hero Member
  • *****
  • Posts: 776
Re: Running 24 VDC Freezer off 48 VDC Battery Bank
« Reply #7 on: October 13, 2017, 12:28:38 PM »
We use a couple of these converters to power a 24V Steca freezer & 12V fridge off 48V bank:
http://www.solarconverters.com/products/constant-voltage-regulatordc-dc-transformer/step-dc-dc-transformer-2/

Good quality, inexpensive, good support, but poor website.  You can get more info and cost at several online sites like Kansas Wind, AltE, Drake Solar Seller.

Good luck, ~ks