Help on wiring a 12v 1.5amp dc van into my ice cream cart bike freezer

[Thecreamist]

Hello Forum!

Yes I have an ice cream cart bike that is battery powered and yes I regret purchasing it! I have attached a generic picture of it to this post.

I need some help replacing a cooling fan on the condenser coils in the freezer because its really poorly designed. I'll try to give as much relevant information as possible.

Issue: I am replacing a 12v .25 amp cpu fan with a 12v. 1.4amp cpu fan. The 1.4 amp fan does not turn on at all when installed into the wiring of the old fan.

Details:

The whole bike is a DC powered, including the freezer and all of its components, the whole bike is powered by this battery:

https://www.amazon.com/LiFePO4-Battery-2000-5000-battery-Off-Grid/dp/B08FMTRYPT/ref=sr_1_2?crid=26SQQIPOVZCWX&keywords=chins+battery+100+ah&qid=1661206991&sprefix=chins+battery+100+ah,aps,126&sr=8-2

We use this fuse box: https://www.amazon.com/WUPP-Blade-Warning-Indicator-Damp-Proof/dp/B07GBV2MHN/ref=sr_1_4?crid=M2LVV5SG6WE6&keywords=dc+fuse+box&qid=1661207206&sprefix=dc+fuse+box,aps,136&sr=8-4

This is the compressor inside the freezer: https://www.coowor.com/p/2016120514...or-automobile-freezer-solar-battery-power.htm

I'm trying to find a diagram of the controller but I can't seem to find it right now.

Here is a picture of the old fans wiring:

Here is a picture of the wiring going into the compressor:

Old fan (Chinese website, impossible to find any info on this fan): https://world.taobao.com/item/557888361371.htm

New Fan I want to put in the bike: https://www.amazon.com/EZDIY-FAB-4000RPM-Cooling-FFC1212DE-Computer/dp/B079NXYC7H/ref=sr_1_4?crid=OVLP318YBMIT&keywords=12+v+1.4+amp+cpu+fan&qid=1661208308&sprefix=12+v+1.4+amp+cpu+fan,aps,121&sr=8-4

I don't understand why this fan isn't working. The wiring is a thick enough gage to handle the amp increase. The battery is super powerful and provides 100 amp/hrs.

The only things that my techs have brought up as a possibility is that there is a resistor built into the compressor controller to only out put .25 amps to the fan. Or its possible that the new fan needs a dioder to direct the 12v's into the fan. Both answers don't really make sense to me.

If there is any other information that is needed please let me know!

Any and all help on this issue is greatly appreciated! Thank you!

 

[Lucien Nunes]

Hi there. The fan output from the compressor control box is likely to be protected against overload, possibly by a self-resetting electronic or PTC fuse. This might react at quite a low current to prevent damage to the output switching transistor that turns the fan on when needed. The new, larger fan might be tripping this overload protection.

I assume that you have checked that the new fan works when connected to 12V. Does the original fan still work when connected to the compressor? Does the voltage switch from near zero to near 12V when tested with a multimeter? If so, you could use the output to control a relay to switch the new fan. The relay coil must be suppressed with a diode to prevent possible damage to the output. We can advise on this if required.

A 12V 1.4A (17W) fan is going to be noisy!

 

[brianmoooore]

Hi there. The fan output from the compressor control box is likely to be protected against overload, possibly by a self-resetting electronic or PTC fuse. This might react at quite a low current to prevent damage to the output switching transistor that turns the fan on when needed. The new, larger fan might be tripping this overload protection.

Instructions for the compressor give max. fan current of 0.5A after start up.

 

[Thecreamist]

Hi there. The fan output from the compressor control box is likely to be protected against overload, possibly by a self-resetting electronic or PTC fuse. This might react at quite a low current to prevent damage to the output switching transistor that turns the fan on when needed. The new, larger fan might be tripping this overload protection.

I assume that you have checked that the new fan works when connected to 12V. Does the original fan still work when connected to the compressor? Does the voltage switch from near zero to near 12V when tested with a multimeter? If so, you could use the output to control a relay to switch the new fan. The relay coil must be suppressed with a diode to prevent possible damage to the output. We can advise on this if required.

A 12V 1.4A (17W) fan is going to be noisy!

Hey Lucien,

Thanks for the reply. The new fan does indeed work when I plug it into my computer. The original fan does work but it does not have enough CFM to cool down the compressor coils. Voltage does go from 0-12 when it gets turned on.

I'd love some instructions on how to use an output to control a relay to switch on the fan. I have very little electrical knowledge but I can solder, or I can get my fridge tech out here if its too complicated and he can wire it in.

Yes the 12v 1.4a fan is amazing, it pulls so much CFM! Since the fan is located on the bottom of the bike I don't think the noise will be an issue for customers

Thanks for any help!

 

[Thecreamist]

Instructions for the compressor give max. fan current of 0.5A after start up.

Hey Brianmooore,

Thanks for the response. That is sad, that isn't enough power to cool down the coils. I need way more CFM that what a cpu fan at 0.5 amp can pull. Too bad this freezer is really poorly designed. This is the second compressor going into the bike and I'd like to avoid doing it again