deleted_user_160
Yeah but you not dealing with a David Craig fan.
Slowbrick
A 940 fan startup current can exceed 40A depending on its condition. I run a 40A copper circuit breaker and have used the stock 940 relay which uses a two speed circuit. I have the fan start in the low speed mode which even with a 20A breaker would on occasion trip it. If the fan went mental a 40A breaker would still catch it. A breaker is good in this scenario as they are self resetting so if you stuffed up your wiring you can just break and reset instead of blow and change.
Yes I know...grow up. :p
OldnDecrepit
Well its been a couple of days and the 20A fuse hasn't blown yet. I am going to rewire some of it because the current power wires are getting too hot for my liking and I might go up to a 30A fuse.
My other concern is the drain on the battery. Time for a bigger alternator I think.
Slowbrick
I would use 12ga wire for all the power leads both + and -. The signal ground doesnt have to be too serious, something like 16ga will do .Did you just add a ring terminal to your battery post and fuse it from there? Also ensure you have a nice solid ground for your relay otherwise it wont have good flow and will just waste power as heat. Ensure your ground straps are nice and clean. Your alternator should be able to cope. I'm still running the OG 70amp alternator and have had my current battery for about 5 years with no issues.
deleted_user_160
Have you checked the condition of the fuse yet? And checked the heat in the wires?
deleted_user_160
If your going the thermo setup 100A alternator is the go.
If your wires are getting hot, the powered wires need to be bigger source some 40A 12v wiring. And they will cope, but still get warm.
That only needs to be for the wires that are powered, as aposed to the signal or ground.
Slowbrick
blondejay;46710 wroteIf your going the thermo setup 100A alternator is the go.
If your wires are getting hot, the powered wires need to be bigger source some 40A 12v wiring. And they will cope, but still get warm.
That only needs to be for the wires that are powered, as aposed to the signal or ground.
Good advice here. I've been coping fine with the 70A alternator but I have kept my grounds and connections nice and clean to ensure nice easy flow. When it comes to wiring and power, if in doubt go bigger. You would rather pay more for bigger fittings and cable than set your car on fire.
OldnDecrepit
Power and earth are wired to the battery but I intend to upgrade the power wires, fuse and the relay. The 80A alternator seems to be coping at this stage but I'd still like to replace it with new if not new and 100A.
deleted_user_160
The down side to sourcing power direct from the battery is that it will continuously run even when the car is off, as under convection (if I've use he term right) it will get hot again in the radiator 5-10mins after turning he car off.
Unless you run an ignition signal wire?
OldnDecrepit
Yes, I ran an ignition wire to the relay, just the power/earth directly from the battery to the relevant connections on the relay.
Vee_Que
80a alternator would be fine for the fan. 940s did run a 100a though so do any car with ecc.
OldnDecrepit
Voltage looks a bit sick when the fan kicks in - about 13V or less (gauge isn't calibrated between 10V and 16V).
Might get worse if I get stuck in traffic and it's not going to get better when I connect the secondary fan to run all the time when the ac is on!
I've never replaced the alternator so maybe a new/reconditioned 80A one will cope better.
Edit: By the way the 960 fan has 3 wires, one red one black and one green. The red and black are power & earth, what's the green one for?
Edit 2: Just did some further research on a Dave Barton page and the fan is supposed to be two speed, so I guess the green one is for the lower speed. Didn't work at all when I tested it, so I might test it again tomorrow.
Vee_Que
Yeah the other wire is low speed. The battery is usually the issue for drop im voltage but dropping isn't a problem unless it drops to 11v. My high beams do the same thing but it then charges back up. Not worth worrying about imo.
Slowbrick
OldnDecrepit;46819 wroteVoltage looks a bit sick when the fan kicks in - about 13V or less (gauge isn't calibrated between 10V and 16V).
Might get worse if I get stuck in traffic and it's not going to get better when I connect the secondary fan to run all the time when the ac is on!
I've never replaced the alternator so maybe a new/reconditioned 80A one will cope better.
Edit: By the way the 960 fan has 3 wires, one red one black and one green. The red and black are power & earth, what's the green one for?
Edit 2: Just did some further research on a Dave Barton page and the fan is supposed to be two speed, so I guess the green one is for the lower speed. Didn't work at all when I tested it, so I might test it again tomorrow.
Easiest and tidiest way of installing a 940 efan is to use the OEM relay and plugs. That way you only have to wire in your relay with the power and earth then just plug the fan in with the connector still attached into the relay. Then you use the two wire yellow plug to control the high and low speed and you are done. It also means if your relay ever went bang it would just be a matter of unplugging the connectors and plugging them back in. Literally a 5 minute job.
OldnDecrepit
Unfortunately I didn't get the relay with my fan, just the shroud.
I'll test the green wire again today to check that it works and maybe connect it up instead of the red. I'll be going to get some new relays and wires today.
Philia_Bear
Green wire is 50% speed
The fan should always run on the green wire for 60 seconds befor switching to the red wire to reduce start load
Philia_Bear
Above is from memory
OldnDecrepit
Checked the wiring today and the green one does work, so I'll wire that one up for a while instead of the red. It may be enough to keep the car cool as it is still stock. I'm going to wire the ac fan to come on whenever it is running so that might help too.
It will take a bit more wiring to set up both speeds.
Slowbrick
I would junk the AC fan and just wire the efan to cycle when the ac is on. Less wiring and reduces the number of things to go wrong.
deleted_user_160
i wouldnt worry about the low speed option unless or until you get the controller.
other davis craig controllers do this from the unit, with 2 wire fans. but its ultimatly much of a muchness. as majority of thermo fan universal set up's dont use them.
mine does drop as does everything (but it will generally only drop if im using the heater/ AC.
even then its only down to the 12-13v
dont stress too much.