Battery Connection Question

[Leon82]

They make anti-flyback diodes for relays. They have plug-in modules for industrial relays I'm not sure if they're suitable for automotive though.

[AndyF]

Thanks Danny, that is the video I was referring to in the first post. His point about connecting all these high amp draw components to one point (a stud I imagine secured to the firewall). That makes sense why it's bad to hook your Sniper power to it. I went and researched some terms he dropped like "transient" and "flyback" voltage. That is where I was reading about "dirty" and "clean" power and curious about a lead from the battery for each type for isolation. For any "dirty" power to make its way to "clean" power, it has to hit the battery first only to be "smoothed" out.

My original question was posed as to when does too many connections to the battery becomes the same thing as a distribution point. Only difference being that there is not a lead between the battery and the "distribution" point.

Yeah nobody ever explains that issue which is why I discount a lot of the various discussions. People are always saying to not connect "dirty" power to the ECU, but if everything is connected to the battery then it's all connected.

Personally I think it's more helpful to focus on known problem areas such as transbrake flyback, bad alternators and powerful cooling fans. The more bad actors you have in your system the more you need to think about how you're going to protect the ECU. If you don't have any bad actors in your system, then the Sniper connections should be fairly easy and painless. Use a late model OEM grade alternator and you should be fine. If you have a monster cooling fan setup then make sure that you use high quality relays (with flyback protection) and that you use heavy gauge wiring. Transbrakes need flyback protection. Ignition wires need to be kept away from any digital lines, etc.

[AndyF]

Watch this video, especially @ 6:53 minutes: https://www.youtube.com/watch?v=M2Rw...9AF17&index=18 (Holley EFI ECU Mounting & Wiring)
• Ensure the ECU main power & ground is wired directly to the battery. Battery acts as a great capacitor/filter. (LINK & LINK)
• Cable from negative battery post to engine block, engine block to frame and #8 AWG wire from body to battery. (LINK)
• Ensure the Switched +12V red/white wire (pink wire - Sniper EFI) remains powered in the "Run" and "Crank" key positions.
• Check the switched (keyed) 12 volt red/white wire connection. 14 AWG 12 volt battery red wire too. Important! (LINK)
http://www.youtube.com/watch?v=MdGXh...C6FEA0BB99AF17 (Holley EFI Tech Video - Grounding)

If lengthening the EFI main power & ground wires to the rear trunk battery, then increase one size larger AWG.
So 10 AWG EFI main power & ground wires: https://www.holley.com/products/fuel.../parts/558-490 (Holley Sniper EFI Main Harness Wire Gauge List)
2 or 4 AWG battery cables. Watch first two minutes: https://www.youtube.com/watch?v=BQdQBesuJCs (Holley EFI Proper Grounding & Wiring Practices)

None of those links really prove anything. They're just recommendations & advice from people with some experience. I haven't hooked up any lab equipment to my own cars yet, but my cars work just fine without the ECU connected to the battery. To prove the issue one would need to hook up a scope to some different points in the wiring harness and sample for noise. I haven't seen anyone do that yet. I'm pretty sure that if the connections are solid and ample wire size is used then it doesn't really matter where things are connected. I understand why Holley recommends hooking to the battery, but I'm pretty sure it isn't really required. Having said that, I always tell people to follow the instructions even though I don't follow them myself.

[jameswagoner]

Thanks Danny, that is the video I was referring to in the first post. His point about connecting all these high amp draw components to one point (a stud I imagine secured to the firewall). That makes sense why it's bad to hook your Sniper power to it. I went and researched some terms he dropped like "transient" and "flyback" voltage. That is where I was reading about "dirty" and "clean" power and curious about a lead from the battery for each type for isolation. For any "dirty" power to make its way to "clean" power, it has to hit the battery first only to be "smoothed" out.

My original question was posed as to when does too many connections to the battery becomes the same thing as a distribution point. Only difference being that there is not a lead between the battery and the "distribution" point.

[Danny Cabral]

Holley says to hook their stuff directly to the battery because they're trying to force people to think about the wiring. The wires don't need to be literally connected to the battery. They just need to have a very good connection to the battery.

Watch this video, especially @ 6:53 minutes: https://www.youtube.com/watch?v=M2RwQoyiFHE&list=PL24C6FEA0BB99AF17&index= 18 (Holley EFI ECU Mounting & Wiring)
Connect the sensitive power & ground components directly to the battery, and the other battery wiring to power & ground distribution studs/blocks nearby. A battery with dual positive & negative posts is advantageous.

• Ensure the ECU main power & ground is wired directly to the battery. Battery acts as a great capacitor/filter. (LINK & LINK)
• Cable from negative battery post to engine block, engine block to frame and 8 AWG wire from body to battery. (LINK)
• Ensure the Switched +12V red/white wire (pink wire - Sniper EFI) remains powered in the "Run" and "Crank" key positions.
• Check the switched (keyed) 12 volt red/white wire connection. 14 AWG 12 volt battery red wire too. Important! (LINK)
http://www.youtube.com/watch?v=MdGXh...C6FEA0BB99AF17 (Holley EFI Tech Video - Grounding)

If lengthening the EFI main power & ground wires to the rear trunk battery, then increase one size larger AWG.
So 10 AWG EFI main power & ground wires: https://www.holley.com/products/fuel.../parts/558-490 (Holley Sniper EFI Main Harness Wire Gauge List)
2 or 4 AWG battery cables. Watch first two minutes: https://www.youtube.com/watch?v=BQdQBesuJCs (Holley EFI Proper Grounding & Wiring Practices)
https://forums.holley.com/forum/holl...953#post330953 (Related Forum Post)

Also, I've never any problem with MSD 8.5mm Super Conductor spark plug wires. Holley EFI users also have great service with FireCore50 spark plug wires. Also, FireCore50 spark plug wire sets are known to transmit far less electrical interference than others (low resistance and impregnated with ferrite molecular compound used to absorb RFI/EMI).

In reference to J1A-A2 "Fuel Pump Relay Out" (10 amp max) Red wire: This controls the Fuel Pump Prime time (default 5 seconds). After the initial five second Fuel Pump Prime Time, the ECU only runs the fuel pump when it detects an RPM signal. It's controlled by the ECU, so the fuel pump only runs when the ECU reads an RPM signal. It's a safety measure.

[jameswagoner]

That is making sense Andy, thanks. I have a worn out 3/4 ton work truck that has been jerry-rigged, I'm sure throughout its life. For Holley to give it's customers the best shot at a successful EFI conversion, I can easily agree running straight to the battery. A purpose built vehicle from the frame up, and knowledge of electrical systems, should have the capability of having clean power at other locations than just the battery. Still, it's very simple to go to the battery.

Which is what I'll still do for the Sniper. I'll wire in the CDI box into my fuse panel and that would leave me with four lugs on the battery terminal (three if I crimp alternator & starter together). That'll let me reinstall the boots over the terminals.

[AndyF]

There are other ways to solve the issue depending on how much work you want to do. I have a Pro Street car with a power distribution panel under the dash. A 10 AWG wire from the battery brings power to the panel which then distributes it to a block of relays and a fuse panel.

Holley says to hook their stuff directly to the battery because they're trying to force people to think about the wiring. The wires don't need to be literally connected to the battery. They just need to have a very good connection to the battery. You can run a distribution block or a power stud or whatever you need as long as it is connected very well to the battery. Sometimes you just have to lay all the parts out on a table and move them around until they all fit together. I just rewired one of my cars this summer and I was able to clean up a ton of wiring by just moving some things around. I put the ignition box under the dash next to the fuse box and some things like that. I put a relay bank at each end of the car rather than run wires back and forth, put the ammeter in the trunk next to the battery, etc.

[Leon82]

I got a marine battery for my car, there's posts on top and then a stud for accessories on top, as well on the positive & negative side.

[jameswagoner]

6 AWG from the alternator to the battery - instructions for the Ford 3G wire harness from Painless says connect to the battery rather than starter solenoid hot side.
2 AWG from the battery to starter solenoid.
These two can be combined to make one.

That is an idea. Assume a 0 AWG or 1/0 AWG lug would fit for combining those.

Add one 4 to 6 gauge for a distribution block.
12 AWG from battery to a fuse/relay panel I did add in preparation for the Sniper install to power the 12V trigger (ground in the fuel pump's case).
Connect this one to the newly added distribution block.

So the 12 AWG is what is feeding the panel. Currently what it is running is +12v trigger for ECU and CDI box, and then powers the fuel pump. 12 AWG looks to be adequate for that amp load. Adding lights (seamed beam, 30amp fuse) I might want to go to 10 AWG? Also the panel wire lead is a foot long at best, I have lots of room near the battery so the only long cable runs will be to the Sniper and CDI box.

The CDI box can go to the distribution block assuming you put the distribution block within 12" of wire from the battery.

I'd like that especially since I did not see a fuse on the power wire for the CDI box. Feel like it should have one. More so if you are wiring it straight to the battery. What is there internal circuit protection? HyperSpark manual does not mention anything.

Partly in theory, yes. You're definitely onto something here. Look at new cars/trucks, they do have multiple distribution points. One of the reasons (among many other) is the same problem you're having. Remember this, as you add wire length and connections, you add impedance and several other possible degenerative issues (the antenna effect). Even so called "clean" loads have transient voltage spikes, although much less than a standard mechanically controlled circuit, they're still there. When you start to stack them on the same distribution point, they can add up to unwanted behaviors.

You would call a distribution point just a single stud, correct? Would a fused / relay panel with a single +12v buss fall into that same definition? I know that fuses and relays don't offer any suppression, but it certainly looks proper.

@jameswagoner: If you look at all of your components you can probable arrange them in a way that makes it simple. For example, if the starter relay is next to the battery you can often use the hot side of that relay as a post for multiple connections, since the relay posts are usually fairly long. A battery with double terminals also helps. You can also use the OEM trick where they crimp multiple wires together in the battery connection.

I cleaned up quite a bit of janky-ness from the previous owner that wired things to the hot side of the solenoid. The terminals I upgraded to a mil-spec style where you have either side of a 3/8" bolt to attach leads to. It has a good inch on either side of the terminal, just starts to look ridiculous with all these leads coming off of it.

Dual post battery is something I'm thinking of. Only hang up is that my battery being on the RH side is dual posts have the terminals on the wrong side for my truck. Are there any issues if the positive and negative cables cross over each other?

[AndyF]

@jameswagoner: If you look at all of your components you can probable arrange them in a way that makes it simple. For example, if the starter relay is next to the battery you can often use the hot side of that relay as a post for multiple connections, since the relay posts are usually fairly long. A battery with double terminals also helps. You can also use the OEM trick where they crimp multiple wires together in the battery connection.

[a b c]

6 AWG from the alternator to the battery - instructions for the Ford 3G wire harness from Painless says connect to the battery rather than starter solenoid hot side. 2 AWG from the battery to starter solenoid.

These two can be combined to make one. Add one 4 to 6 gauge for a distribution block.

12 AWG from battery to a fuse/relay panel I did add in preparation for the Sniper install to power the 12V trigger (ground in the fuel pump's case).

Connect this one to the newly added distribution block.

14 AWG from battery to a headlight relay powered harness.

This one also goes to the distribution block. Then you'll have the additional +12V for the Sniper. The CDI box can go to the distribution block assuming you put the distribution block within 12" of wire from the battery.

Couldn't isolation also come from a lead from the battery powering those "dirty" components, and another lead from the battery for the "clean" sensitive power components?

Partly in theory, yes. You're definitely onto something here. Look at new cars/trucks, they do have multiple distribution points. One of the reasons (among many other) is the same problem you're having. Remember this, as you add wire length and connections, you add impedance and several other possible degenerative issues (the antenna effect). Even so called "clean" loads have transient voltage spikes, although much less than a standard mechanically controlled circuit, they're still there. When you start to stack them on the same distribution point, they can add up to unwanted behaviors.

[jameswagoner]

Well that's the thing, what I have connected to the terminals each had their own instructions on connecting the battery. Here's what's connected.

6 AWG from the alternator to the battery - instructions for the Ford 3G wire harness from Painless says connect to the battery rather than starter solenoid hot side.

2 AWG from the battery to starter solenoid.

12 AWG from battery to a fuse/relay panel I did add in preparation for the Sniper install to power the 12V trigger (ground in the fuel pump's case).

14 AWG from battery to a headlight relay powered harness.

Now I do have space in my relay panel for the lights so that relocates one ring terminal. Still going to end up with 5 connections with the Sniper and HyperSpark.

I did manage to read some articles on transient and flyback voltages as main reason to wire to the battery to isolate them. Those issues being caused be high amp draw components and labeled "dirty".

Couldn't isolation also come from a lead from the battery powering those "dirty" components, and another lead from the battery for the "clean" sensitive power components?

[Danny Cabral]

Connect the sensitive power & ground components directly to the battery, and the other battery wiring to power & ground distribution studs/blocks nearby. A battery with dual positive & negative posts is advantageous.

[jameswagoner]

How many connections to battery terminal before it turns into a distribution block?

After watching Holley's video on wiring directly to the battery, the example they show as "dirty" is all these high amp components connecting to one stud. Now before this gets lengthy, I accept the fact that things should be connected at the battery and will follow that instruction.

I already have four other things wired to the battery and will need to add the Sniper and the HyperSpark making it six. This leads me to my question above. Starts to look ridiculous that I would have a nearly 3/4" thick stack of ring terminals connected to the stud of the battery connector. I can't compare my 35 year old truck with a modern vehicle but I'm really jealous at their nice fuse and relay power distribution panels.

The video Holley did dropped some electrical theory terminology, and I'm going to read up on those to see if I can gain enough understanding.