Sly_Jeeper Posted July 22, 2020 Share Posted July 22, 2020 What size fuse should i use inline? Simple ground to battery ground, positive coming from battery with fuse holder inline and a switch by the grill? It blew a 10 amp fuse thanks guys 1989 4.0 Renix Scratchy Ba/10 2wd Stock Short bed base Link to comment Share on other sites More sharing options...
AZJeff Posted July 23, 2020 Share Posted July 23, 2020 The fan specification should tell you the current draw or the power draw (in watts). Take the wattage and divide by twelve (battery voltage) to determine current draw. Caution—startup surge current can be much higher than steady state current. Take the steady state current and add 25-30% to that when selecting a fuse. actually, I prefer self-resetting circuit breakers over fuses for cooling fans. Nothing sucks more than to be stuck by the side of the road because your fan won’t run because of a 25 cent fuse That failed due to fatigue. Link to comment Share on other sites More sharing options...
Sly_Jeeper Posted July 23, 2020 Author Share Posted July 23, 2020 Thanks for the information and the tip 1989 4.0RenixScratchy Ba/102wdStock Short bed base Link to comment Share on other sites More sharing options...
yxmj Posted July 23, 2020 Share Posted July 23, 2020 If this is the fan.... https://www.summitracing.com/parts/hda-3680 It says it would only have a 8.8 amp draw. If you blew a 10 amp fuse why not try just going up to a 15 and see if that is enough Link to comment Share on other sites More sharing options...
Sly_Jeeper Posted July 23, 2020 Author Share Posted July 23, 2020 If this is the fan....https://www.summitracing.com/parts/hda-3680 It says it would only have a 8.8 amp draw. If you blew a 10 amp fuse why not try just going up to a 15 and see if that is enough I will be trying that today thank you. Hopefully this helps with little heat at idle1989 4.0RenixScratchy Ba/102wdStock Short bed base Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted July 23, 2020 Share Posted July 23, 2020 1 hour ago, yxmj said: If you blew a 10 amp fuse why not try just going up to a 15 and see if that is enough An important aside to this: What size wires are you running? Don't up the fuse rating until you know FOR SURE that your wires can handle the load. Asking for a bonfire if this gets messed up. And my apologies if you already thought of this. I felt it had to be said, just in case. Link to comment Share on other sites More sharing options...
AZJeff Posted July 24, 2020 Share Posted July 24, 2020 On 7/23/2020 at 10:35 AM, JustEmptyEveryPocket said: An important aside to this: What size wires are you running? Don't up the fuse rating until you know FOR SURE that your wires can handle the load. Asking for a bonfire if this gets messed up. And my apologies if you already thought of this. I felt it had to be said, just in case. VERY good point. If you put in a large fuse, yet use (relatively) small guage wires, you wind up using the wires as the fuse element. Link to comment Share on other sites More sharing options...
Sly_Jeeper Posted July 28, 2020 Author Share Posted July 28, 2020 An important aside to this: What size wires are you running? Don't up the fuse rating until you know FOR SURE that your wires can handle the load. Asking for a bonfire if this gets messed up. And my apologies if you already thought of this. I felt it had to be said, just in case. The wires are 12 gauge, i am using a 15amp fuse now and has not blown. Do y’all think maybe i should use bigger wires?1989 4.0RenixScratchy Ba/102wdStock Short bed base Link to comment Share on other sites More sharing options...
AZJeff Posted July 28, 2020 Share Posted July 28, 2020 Let’s go back to specifications—what is the STEADY STATE draw of this fan you have chosen? Then add 20% for start up surge current to figure out peak current. Now how long are the wires from the 12v source to the fan motor? Now figure out the voltage drop for a given wire gauge and wire length using the below simple calculator: https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html you want your voltage drop to be 0.25vdc or less, so adjust your wire gauge accordingly. Link to comment Share on other sites More sharing options...
Sly_Jeeper Posted July 28, 2020 Author Share Posted July 28, 2020 Let’s go back to specifications—what is the STEADY STATE draw of this fan you have chosen? Then add 20% for start up surge current to figure out peak current. Now how long are the wires from the 12v source to the fan motor? Now figure out the voltage drop for a given wire gauge and wire length using the below simple calculator: https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html you want your voltage drop to be 0.25vdc or less, so adjust your wire gauge accordingly. I think ive got this in here right1989 4.0RenixScratchy Ba/102wdStock Short bed base Link to comment Share on other sites More sharing options...
derf Posted July 28, 2020 Share Posted July 28, 2020 Current type should be DC. Link to comment Share on other sites More sharing options...
Sly_Jeeper Posted July 28, 2020 Author Share Posted July 28, 2020 Current type should be DC. Thank you, it turned out to be 0.131989 4.0RenixScratchy Ba/102wdStock Short bed base Link to comment Share on other sites More sharing options...
zomeizter Posted July 29, 2020 Share Posted July 29, 2020 Go overkill with the leads if you have them... Link to comment Share on other sites More sharing options...
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