HELP PLEASE WITH 12V ISSUE - HOW TO REDUCE CURRENT TO FRIDGE FAN
Baz421 said
06:55 PM Mar 10, 2019
Hi all..
As per a previous post my Danfoss BDF50 compressor fan packed it in on 43 deg C day.
Have had considerable problems getting replacement that has the required airflow in cfm. MOST fans don't deliver the 80cfm minimum.
Danfoss don't supply fans in Aust now - go buy one. typical.
Found one at about 138cfm. Great news. Fitted and runs great EXCEPT IT RUNS FOR <2 SECONDS AND fan and compressor shut down due overloaded fan 12v circuit.
Fan draws about 833mA and trips the compressor controller as it's rated as 1A start and 500mA running. Hence my problem.
Tried to use a relay but doesn't solve the problem
I need to reduce the amps without reducing voltage to fan circuit.
Can someone work it out please,,,,,, my brain is scrambled.
DeBe said
07:33 PM Mar 10, 2019
Depends on which controller. Showing the 2 different controlers using a relay with a diode fited across the relay coil.
so the current draw to relay is 42mA is that correct,,, I'm brain dead today
thanks for response Col
iana said
08:08 PM Mar 10, 2019
Since your fan is delivering nearly twice the required air flow, have you tried blanking of the face of the fan to reduce its air flow, hence reduce the load.
Baz421 said
08:15 PM Mar 10, 2019
iana wrote:
Since your fan is delivering nearly twice the required air flow, have you tried blanking of the face of the fan to reduce its air flow, hence reduce the load.
How will that help the load? Will just starve fan of air will it not,,, may run faster but how will the current be reduced??
iana said
08:19 PM Mar 10, 2019
Wrong wording, partially blanking off the inlet of the fan. The load of the fan would be related to the work each blade is doing, so I am saying as an experiment with say some cardboard, cut a hole in the cardboard of a reduced diameter to the fan and with the cardboard partially blanking off the face of the fan, measure and see if the milliamps have dropped. Its just a suggestion.
Baz421 said
08:32 PM Mar 10, 2019
iana wrote:
Wrong wording, partially blanking off the inlet of the fan. The load of the fan would be related to the work each blade is doing, so I am saying as an experiment with say some cardboard, cut a hole in the cardboard of a reduced diameter to the fan and with the cardboard partially blanking off the face of the fan, measure and see if the milliamps have dropped. Its just a suggestion.
Thanks Current draw is almost constant,,, so airflow changes wouldn't have any significant effect IMHO.
DeBe said
08:37 PM Mar 10, 2019
1N4004 diode available from Jaycar will do the job. The relay suggested by Old Col should be fine.
Baz421 said
08:40 PM Mar 10, 2019
DeBe wrote:
1N4004 diode available from Jaycar will do the job. The relay suggested by Old Col should be fine.
Thanks a lot DEBE,,, I went to Jaycar to see if they had a low draw relay for the control circuit,,, no was answer grrrr.
Ill try that relay first as everything else is in place and fan is great,,, keeps compressor cool at last.
Peter_n_Margaret said
05:28 PM Mar 11, 2019
Baz421 wrote:
iana wrote:
Since your fan is delivering nearly twice the required air flow, have you tried blanking of the face of the fan to reduce its air flow, hence reduce the load.
How will that help the load? Will just starve fan of air will it not,,, may run faster but how will the current be reduced??
Iana is correct. That will usually reduce the current draw of an axial fan.
Less work done = less energy required.
Cheers,
Peter
DeBe said
07:37 PM Mar 11, 2019
Not correct with Brushless fans, restrict the air flow the current actualy rises. Totally different to Brush type motors.
Alternately you could use a series resistor to reduce fan speed and current.
Ken
-- Edited by kgarnett on Tuesday 12th of March 2019 09:05:51 AM
Whenarewethere said
09:26 AM Mar 12, 2019
I put this 120mm fan in my 28L Weaco fridge to replace the 80mm fan. Been running it long enough now & am very happy will it. Mwave & Techbuy sell them. Good pressure & only draw 0.1amp 121m3/h.
Buy a solid state relay from Jay Car www.jaycar.com.au/pcb-mount-solid-state-relay-12v/p/SY4093 and wire the switch/control side as marked, + to + and - to - . The load side how ever is different, the + and - relate to the current flow and not to voltage. It you wire the relay in the positive wire, then the positive from the battery/fridge control feed goes on the relay load + terminal and the fan + goes on the relay load - terminal. The fan negative connects direct to the supply negative and not to the relay. Get that part wrong and you will need to buy a new relay, they are not forgiving, death of the relay is instant.
T1 Terry
Baz421 said
09:29 PM Mar 12, 2019
Whenarewethere wrote:
I put this 120mm fan in my 28L Weaco fridge to replace the 80mm fan. Been running it long enough now & am very happy will it. Mwave & Techbuy sell them. Good pressure & only draw 0.1amp 121m3/h.
Thanks . I asked local van supplier to source a genuine one - they found a sleeve type (read bush) $75. Can get em in Adelaide for <$10,, sent it back.
Danfoss told me genuine not available in Oz,, get one after market,, Danfoss agents appear to only be interested in 240v stuff
Interesting,, have 2 of these at top of fridge vent ie the top vent to exhaust for use on very hot days (we had 43C when fan failed and 47C next day),, but at 88cfm I'm told they just do the job,,, as a compressor fan.
Thanks again for info.
Alternately you could use a series resistor to reduce fan speed and current.
Ken
-- Edited by kgarnett on Tuesday 12th of March 2019 09:05:51 AM
-- Edited by Baz421 on Tuesday 12th of March 2019 09:57:09 PM
Baz421 said
09:56 PM Mar 12, 2019
T1 Terry wrote:
Buy a solid state relay from Jay Car www.jaycar.com.au/pcb-mount-solid-state-relay-12v/p/SY4093 and wire the switch/control side as marked, + to + and - to - . The load side how ever is different, the + and - relate to the current flow and not to voltage. It you wire the relay in the positive wire, then the positive from the battery/fridge control feed goes on the relay load + terminal and the fan + goes on the relay load - terminal. The fan negative connects direct to the supply negative and not to the relay. Get that part wrong and you will need to buy a new relay, they are not forgiving, death of the relay is instant.
T1 Terry
Thanks Terry I bought the relay recommended in prev post,, I can get relay to click in but no output. I can get my wiring to work with low wattage light globe so I know wiring is good just need relay - off to jaycar again
Whenarewethere said
08:41 AM Mar 13, 2019
Have you looked as RS-online they should have something.
Works well and is very quiet. Have used this type of fan for ten years in my frig, one replaced by another of the same type after 5 yrs. I don't fret that the CFM is very slightly lower.
You have to cut off the plastic connector on the new fan, trim back and insulate the unused yellow (tacho) wire, then crimp two female spade connectors to the new fan red and black wires, and then it just plugs directly in.
No need for any additional relay.
Fan airflow direction is outwards, ie away from the compressor.
For reference, the original fan with my BD50 was a Yate Loon type GP D12BM-12. Its spec is 72 CFM.
Good luck
-- Edited by Tech48 on Friday 15th of March 2019 02:33:15 PM
-- Edited by Tech48 on Saturday 16th of March 2019 09:48:29 AM
Baz421 said
08:30 PM Mar 17, 2019
Thanks all for your replies much appreciated.
Fitted a relay from Altronics works well.
Fan is rated at 48dB but I'm not sure. See how we go sleeping.
Whenarewethere said
11:28 PM Mar 17, 2019
If the fan is mounted on acoustic isolation blocks it will help. Also some butyl acoustic material on the flat surrounding surfaces, & some acoustic foam on top & also on the remaining surfaces. If
Hi all..
As per a previous post my Danfoss BDF50 compressor fan packed it in on 43 deg C day.
Have had considerable problems getting replacement that has the required airflow in cfm. MOST fans don't deliver the 80cfm minimum.
Danfoss don't supply fans in Aust now - go buy one. typical.
Found one at about 138cfm. Great news. Fitted and runs great EXCEPT IT RUNS FOR <2 SECONDS AND fan and compressor shut down due overloaded fan 12v circuit.
Fan draws about 833mA and trips the compressor controller as it's rated as 1A start and 500mA running. Hence my problem.
Tried to use a relay but doesn't solve the problem
I need to reduce the amps without reducing voltage to fan circuit.
Can someone work it out please,,,,,, my brain is scrambled.
www.jaycar.com.au/12v-dpdt-special-pc-mount-relay/p/SY4052
draws about 0.04211 amps at 12v
DeBe
101N0220 is the one. What are the values of the relay and diode???
I see what you are doing where do I getthe bits please.
Baz
so the current draw to relay is 42mA is that correct,,, I'm brain dead today
thanks for response Col
How will that help the load? Will just starve fan of air will it not,,, may run faster but how will the current be reduced??
Thanks Current draw is almost constant,,, so airflow changes wouldn't have any significant effect IMHO.
Thanks a lot DEBE,,, I went to Jaycar to see if they had a low draw relay for the control circuit,,, no was answer grrrr.
Ill try that relay first as everything else is in place and fan is great,,, keeps compressor cool at last.
Iana is correct. That will usually reduce the current draw of an axial fan.
Less work done = less energy required.
Cheers,
Peter
Not correct with Brushless fans, restrict the air flow the current actualy rises. Totally different to Brush type motors.
You could always purchase a genuine replacement fan from CaravansPlus as per the link below.
https://www.caravansplus.com.au/4441200001-fan-bd35-50-cool-unit-p-14018.html
or Jaycar have this one:
https://www.jaycar.com.au/ip55-rated-120mm-12v-dc-ball-bearing-fan/p/YX2522
Alternately you could use a series resistor to reduce fan speed and current.
Ken
-- Edited by kgarnett on Tuesday 12th of March 2019 09:05:51 AM
I put this 120mm fan in my 28L Weaco fridge to replace the 80mm fan. Been running it long enough now & am very happy will it. Mwave & Techbuy sell them. Good pressure & only draw 0.1amp 121m3/h.
https://noctua.at/en/nf-f12-industrialppc-2000/specification
T1 Terry
Thanks,, looked at these when you posted before,, not quite min airflow I think, but close
-- Edited by Baz421 on Tuesday 12th of March 2019 09:57:09 PM
Thanks Terry I bought the relay recommended in prev post,, I can get relay to click in but no output. I can get my wiring to work with low wattage light globe so I know wiring is good just need relay - off to jaycar again
Have you looked as RS-online they should have something.
https://au.rs-online.com/mobile/c/hvac-fans-thermal-management/fans/axial-fans/?applied-dimensions=4294440647,4294531136,4294644631
This the one I bought,,
https://www.altronics.com.au/p/f1165-sunon-120mm-12vdc-maglev-bearing-fan/
can't see it in rs pages. Thanks for link
The simplest & cheapest way is a relay connected as per JB's post.
yeh I'm trying to source one with low enough (<500mA) control circuit,,, think I've found one.
Hi Baz
I use this fan with my BD50 based frig, as a direct replacement.
Jaycar YX-2584, 120mm, 12V, 0.22A, (220mA) 64 CFM.
Works well and is very quiet.
Have used this type of fan for ten years in my frig, one replaced by another of the same type after 5 yrs.
I don't fret that the CFM is very slightly lower.
You have to cut off the plastic connector on the new fan, trim back and insulate the unused yellow (tacho) wire, then crimp two female spade connectors to the new fan red and black wires, and then it just plugs directly in.
No need for any additional relay.
Fan airflow direction is outwards, ie away from the compressor.
For reference, the original fan with my BD50 was a Yate Loon type GP D12BM-12.
Its spec is 72 CFM.
Good luck
-- Edited by Tech48 on Friday 15th of March 2019 02:33:15 PM
-- Edited by Tech48 on Saturday 16th of March 2019 09:48:29 AM
Thanks all for your replies much appreciated.
Fitted a relay from Altronics works well.
Fan is rated at 48dB but I'm not sure. See how we go sleeping.
If the fan is mounted on acoustic isolation blocks it will help. Also some butyl acoustic material on the flat surrounding surfaces, & some acoustic foam on top & also on the remaining surfaces. If