Dual batteries

Fawk.

You guys like complicated wiring or what ?

Get a Volvo relay unit. It's got :

- pwr in
- pwr out to speed1
- pwr out to speed2
- gnd trigger for speed1
- gnd trigger for speed2

Send the pwr in to a battery through a Mega fuse (40amp) and done.

If you have 2 fans, duplicate it side by side but merge both gnd triggers together.

Simplest wiring ever.
 
Bebop said:
Fawk.

You guys like complicated wiring or what ?

Get a Volvo relay unit. It's got :

- pwr in
- pwr out to speed1
- pwr out to speed2
- gnd trigger for speed1
- gnd trigger for speed2

Send the pwr in to a battery through a Mega fuse (40amp) and done.

If you have 2 fans, duplicate it side by side but merge both gnd triggers together.

Simplest wiring ever.
Click to expand...
Noted for future junkyard finds
 
marty79 said:
Noted for future junkyard finds
Click to expand...

Before frying something when you wire it wrong, remember this relay will work well on a taurus/volvo fan or any dual speed internally wired the same way. Not ideal when running 2 single speed fans side by side or a dual speed that requires a dual feed etc...
 
Ran 2 Tauraus fans and 2 relays on my duramax back in the day.

20200902_105130.jpg
 
Mac5005 said:
I don’t remember the full schematic from when I did this.

Small orange and blue wire are the lo/high speed wires that are grounded based on preset temps by the gauge.

Medium orange is the 12v from ignition relay.

It took 3 relays to make it work properly, wouldn’t do what we wanted with 2 relays.

<180° no fan
>180<200 low fan
>200 hi fan.

IIRC, one relay triggers the ST85 solenoid for High Speed.

One relay is for Low speed fan

One relay shuts off low speed when high speed it triggered.

Bc it’s all done thru the ground on the gauge trigger side, it needed the extra relay.

4th relay is a spare. Plus fuses for the relays and the 100a breaker for the load side.

The trigger wires are crimped, the load side is all solder with wire large enough to handle the current.

All mounted in front of radiator behind grill so the relays stay cooler and avoid heat soak.
Click to expand...


Similar to my setup... tried & true for years!
"Complicated", maybe?
Easier to find replacement relays than the Vulva version in the crapholes surrounding most wheeling venues, absolutely!

Dual 50A relays for High side and a single 50A for the Low (using pull-a-part GM sealed relays $1 for both relay & sealed base)... wired so that the energized speed locks out the other. Powering both speeds of a Taurus fan at once = lets ALL the smoke outta the fan motor
 
If you're in the middle of the boondocks and your relay fails, you just jump it until you're back home and done.

We can argue eternally, but at the end of the day, both solutions work. They are just another way to skin the same cat.

I just like the simple, less components, easier to troubleshoot, approach.
FYI, I've never had a Volvo relay fail. Ever.

My preferred solution isn't even one of the 2 posted above, but I didn't want to derail this thread more than what it is already.
 
Bebop said:
dual speed that requires a dual feed etc.
Click to expand...
How do I know if dual speed fans are wired dual feed? I'm pretty sure my fans are dual speed, and even though they cool fine on I guess low speed, what's needed to get that high speed?
 
marty79 said:
How do I know if dual speed fans are wired dual feed?
Click to expand...

Research.
Before wiring anything (especially stuff salvaged from the JY) you should spend time reading the donor vehicle diagrams in order to determine what are the power dynamics in and out of the component, the amperage that's being pulled, yada yada

I'm pretty sure my fans are dual speed, and even though they cool fine on I guess low speed, what's needed to get that high speed?
Click to expand...

If you have Taurus fans, they are in fact dual speed. But not dual feed.
If you want to wire both speeds, just find a volvo relay (see pic with part number above) and wire them as I posted above.
 
I can't believe y'all are going to make me respond to a Fuller thread.

1. It sounds like @marty79 has the 96+ (bubble taurus as I call them) taurus fans. The fans and motors are identical to the earlier squared off 89 to 95 fan but there is no shroud which sucks. That's because the bubble taurus radiator mounted in front of the core support which was fiberglass and the 2 fans bolted directly to it, using the core support as a shroud. @Jody Treadway posted the pic of a 95 and older fan which is the desired one because shroud.

2. @Mac5005 sounds like he has what's called a series/parallel fan setup. That's an awesome way to run 2 SINGLE speed fans with 2 speeds using 3 relays. Ground 1 relay fans run in series so each motor gets 6v, ground all 3 relays fans go parallel for full voltage, that's how gm used to do their fans. I set up Dad's c10 that way. But it's not relevant here because taurus fans are dual speed with dual windings, bringing us to number 3.

3. @Bebop is right the Volvo relay is the shit for taurus fans. It's rated for 70 or more amps because the volvo fan is basically a taurus fans with a different shroud. It's 5 wire hook up is simple. One fused feed in, 2 large wires out to fan, one for each speed. And 2 small triggers, ground one for low, the other for high, and as a bonus the low can stay grounded on high because the relay itself prevents both windings from being powered at once, which is hard on the motor and actually causes it to run slower.

The solenoid looking relay will also work good but the Volvo relay is my preference because theres no exposed hot terminals.
 
I really like the Volvo fans more than the Taurus ones. They bolt flat to your shroud and done.

But this is all old tech. Brushless fans and PWM commands are the future, gotta keep up with the times lol
 
Tim C said:
The solenoid looking relay will also work good but the Volvo relay is my preference because theres no exposed hot terminals.
Click to expand...
This is the only thing I'm still trying to understand..is it because a solenoid can provide big amount of amps to a circuit and that's why it's better than a relay or is it added on to relays.
 
Thank you everyone for all the input, I now know more than ever on fans, relays and wiring them up. Thanks for bearing with me on my learning curve lol
 
My setup is on my dads 2 speed early Taurus fan. I used to run it, but I have since gone back to mechanical fan.

Single fan, two speeds.

The reason his(my) setup was so complicated is in how the autometer triggers through the ground.

It did not function the way you would think it would, using two relays.

It has to do with the autometer settings on/off/on, off/on/on, off/off/on etc.

So yes it makes it more complicated but to me not that complicated if you have a good understanding of electrical and why/how to switch things on the ground side so the switch sees no current vs switch on the 12v side.

The exposed terminals don’t bother me where they are located just above the winch behind the grill and front tube work, in front of rad.

If something gets in there and destroys or shorts them, the nose of the buggy would have to be totaled.
 
Tim C said:
I can't believe y'all are going to make me respond to a Fuller thread.
Click to expand...


I'm glad you did. I learned some good stuff from this thread.
 
Mac5005 said:
3d2fcfaf3c2a63a1b4e6b33f02eedda8.jpg


I don’t remember the full schematic from when I did this.

Small orange and blue wire are the lo/high speed wires that are grounded based on preset temps by the gauge.

Medium orange is the 12v from ignition relay.

It took 3 relays to make it work properly, wouldn’t do what we wanted with 2 relays.

<180° no fan
>180<200 low fan
>200 hi fan.

IIRC, one relay triggers the ST85 solenoid for High Speed.

One relay is for Low speed fan

One relay shuts off low speed when high speed it triggered.

Bc it’s all done thru the ground on the gauge trigger side, it needed the extra relay.

4th relay is a spare. Plus fuses for the relays and the 100a breaker for the load side.

The trigger wires are crimped, the load side is all solder with wire large enough to handle the current.

All mounted in front of radiator behind grill so the relays stay cooler and avoid heat soak.
Click to expand...


Get the coil-side hot wire for the low speed relay from the NC contact on the high-speed relay. When the high-speed relay turns on, it cuts power to the low-speed relay. ;)

If you didn't care about turning it on at 180F, you could do all of the control switching with one Bosch-style relay.
 
marty79 said:
This is the only thing I'm still trying to understand..is it because a solenoid can provide big amount of amps to a circuit and that's why it's better than a relay or is it added on to relays.
Click to expand...
Solenoids and relays are essentially the same thing and can generally be used interchangeably. They function the same but in automotive terms a solenoid usually refers to the round metal can style with exposed terminals (think ford starter solenoid) and a relay is usually referring to the square black kind with terminals or a plug on the bottom.
 
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