Fuel system is done

[QtrHorse]

So you are saying I should fire a seperate relay for each pump. I am assuming the little cube relays that are used for everything else.

Yes, I would use a relay for each pump. You can use the factory harness to operate both relays though. Yes, I'm talking about the little cube relays.

I say to use a relay for each pump because one pump might lock up and it could heat up the relay because it will start to pull more amps. If this happens, you would lose both pumps if the relay fails. If you have a relay on each pump, this would not happen.

See the link below for the type of relays I'm talking about.

You can also take a look at www.bcae1.com website, it has a lot of good 12V electrical information. There are sub forums for specific items such as relays, switches and etc..



40A Relay

 

[TARM]

Do not skimp at all on relays or your wiring. Get 30 amp inline fuses or breakers. Use only 10 g ultra fine strand wire. The strands should be as thin as hair. It should be very soft and flexible. If it stiff its not ultra fine. What you are trying to do is prevent as much voltage drop as possible from the battery to the pumps. 1 volt drop is 10gph on average from what I have seen. You want to be as close to 13.7 as possible. Same goes for the relays/ Good ones like Bosch will not leak voltage on you.

Get a distribution board and you can run your factory wire to it on one side and then run two wire one to each relay off the other side of each. TO wire the relay is:

Blade 85: negative from factory wire (black wire from harness)
Blade 86: positive from factory wire (red from harness)
Blade 87: positive from battery (wire from + post of battery)
Blade 30: positive to pump ( positive to pumps + connection post)
Put the inline fuse between the + battery post and blade 87

Blade 85 and 86 are across from each other and blades run in same direction
Blade 87 forms the top of a T with Blade 30 being the post of the T and they are directly across from each other but blades run perpendicular to each other forming a T

 

[QtrHorse]

Do not skimp at all on relays or your wiring. Get 30 amp inline fuses or breakers. Use only 10 g ultra fine strand wire. The strands should be as thin as hair. It should be very soft and flexible. If it stiff its not ultra fine. What you are trying to do is prevent as much voltage drop as possible from the battery to the pumps. 1 volt drop is 10gph on average from what I have seen. You want to be as close to 13.7 as possible. Same goes for the relays/ Good ones like Bosch will not leak voltage on you.

Not that this pertains to this thread but the ultra fine statement is not needed. You could always go down in size if surface area of each strand is a concern. Instead of using 12ga, go to 10 and etc.. The only crowd that seems to be concerned with ultra fine strands and lots of them is the audio crowd because it translates into very flexible wire.

I'm not a big fan of breakers because they take longer to trip than a fuse takes to burn/ break the circuit. Also, over time the circuit breaker will eventually have poor contact/ a higher restance than when it was new. This normally happens when they are exposed to the elements such as under the hood or under the vehicle. They are better used out of the elements.

 

[TARM]

All I know is I have run both the fine strand and ultra fine strand and I picked up close to a .5 volt switching between the two and both were 10 g. So for the small amount of extra cost plus how much easier it is to bend and work with I prefer it.

I did not know that about the breakers vs the fuses. That is good to know as I was going to switch to make it easy to take care of a issue as you woudl not have to have spare fuses.

 

[Arisley]

I am going to run 4G from the batt to the terminal strip. From there, 12G to each relay and from the relay to the pumps. There will be a 30Amp fuse on each pump. I have a couple little sets of vise grips to shut off fuel flow to a pump in case one dies, I will eventually put some ball valves to do the same thing.

This is a phased plan, it started years ago when I Hutched and Harpooned, it will not be finished until I put my sump in, delete the bowl and redo the supply and return lines.

 

[QtrHorse]

Yes, the finer stranded wire is normally a better quality wire and therefore is more true to the ga size chart plus it has more surface area. Normally the finer stranded wire is more expensive than just going to the next size lower. It is also hard to find good quality small gauge wire. Your best bet would be to buy it from a boat supply store because it will be tinned wire and quality wire.


Tarm,

If possible, use Maxi fuses or ANL (in your application, ANL fuses might be over kill) fuses, they have the least amount of resistance. I only say this for you because you are concerned with the least amount of voltage drop. Have you tried running a negative wire all the way back to the battery? I'm curious if you would get more voltage compared to using the wiring harness negative wire.

 

[Arisley]

I will be running a dedicated ground circuit.

 

[TARM]

Yes you have me pegged perfectly. I am using ANL fuses and do have a ground run back to the battery for each as well as it spliting off to frame ground. Yes I know that is a bit of overkill LOL I just had this goal of wanting to get the most volts from the battery that I could to the pump. I have only lost 0.1 volts. I was happy with that.

 

[QtrHorse]

I am going to run 4G from the batt to the terminal strip. From there, 12G to each relay and from the relay to the pumps. There will be a 30Amp fuse on each pump. I have a couple little sets of vise grips to shut off fuel flow to a pump in case one dies, I will eventually put some ball valves to do the same thing.

This is a phased plan, it started years ago when I Hutched and Harpooned, it will not be finished until I put my sump in, delete the bowl and redo the supply and return lines.

If all you are going to run off that terminal strip is the two relays, 4ga is going to be overkill. You would be fine with 8ga wire. Be sure to fuse the wire from the battery to the terminal strip and then each wire coming from the terminal strip.

Be carefull if that terminal strip will be in the open because it will always be hot/ have power running to it.

 

[Arisley]

Nope, it is boxed.

It will eventually also be running an on board air system and an onboard inverter for A/C supply. I will incrase the size of the supply wires before I put the inverter on there.

 

[QtrHorse]

Tarm,

I'm all about overkill.

Try upgrading the grounds for your batteries, that might net you a little more voltage. It's a simple trick the audio nuts do to get more voltage to their amps.

I upgraded all the wires for my batteries when I installed my new 200A alternator.

Sorry for taking your pump install off topic Arisley.

 

[QtrHorse]

Nope, it is boxed.

It will eventually also be running an on board air system and an onboard inverter for A/C supply. I will incrase the size of the supply wires before I put the inverter on there.

Every decent sized inverter I have seen needs to be connected directly to the battery.

Instead of a terminal buss type bar, maybe use a fused bloack for your relays and other misc. accessories. See the link and picture below.

I like to power my fuse blocks with large capacity relays but that's just a personal preference for me.

Fused Distribution Block

 

[TARM]

OtrHorse,

Good idea I will try that. I am getting ready to relocate my bats to the passenger frame rail and when I build the wire harness I will go up on both but take the ground up. If you have any recommendations or things to watch out for etc on doing this and wouldn't mind taking the time to give me you opinion recommendations could you PM me. I do not want to side track Arisley's thread any more with my stuff as its not pump related. Thanks

 

[Arisley]

Good idea.

 

[Tom S]

I have actually enjoyed reading all the electrical stuff.

 

[Aljay]

So you are saying I should fire a seperate relay for each pump. I am assuming the little cube relays that are used for everything else.

I have dual S/D pumps on my OBS , each pump has its own fused/relayed power supply . Been this way for 5 yrs.
And yes use the little cube relays. Mine came from a big truck supply place with plug.

 

[Arisley]

It is in, each pump has it's own relay. Each power source for each pump is fused. Got it all hooked up. One little bitty, tiny leak. About a drop every ten seconds. Snug up the compression fitting just a touch, leak is gone. With all of the pipe fittings and compression fittings, I am surprised that one is all I had.

Runs much better up top. Amazing how much better the injectors work if they have all the fuel they desire.

 

[Aljay]

Don't run them dry too often you wont like the outcome.
Put a gauge on it and see what happens don't go by seat of the pants ...... Just sayen.

 

[blackbetty13]

looks good andy

 

[Arisley]

Don't run them dry too often you wont like the outcome.
Put a gauge on it and see what happens don't go by seat of the pants ...... Just sayen.

There is a guage. Or was for testing. Adles at 65lbs. WOT, it will slowly drop to 60 and hold steady as a rock.

I am planning on putting a permanant guage on there. I have the parts to hook it to my Scanguage, just have not done it yet.