yes, the big 3 should always be done before the H.O. alt upgrade. I did mine years ago, but redid the alt positive for the alt upgrade.

the purpose is to reduce resistance in the alternator-battery circuit for both power and ground.

the big 3 is an internet forum term. most local shops don't know what it is, and many people don't understand why. if you can explain what you're doing in electrical terms, they usually shut up. i'm an EE working in Acoustics, and I can get as detailed necessary with sales staff. For the most part, I usually end up teaching them something.

 

I don't understand what the ELD is really for. I couldn't get to the link that was posted with the PDF explaining it without signing up for yet another forum. I am interested, from what it sounds like the computer could see that there is such a huge draw and affect fuel mileage? What other problems could it cause. I do have some DC power background (telecom) but I guess I don't understand how the ELD could really negatively affect anything.

 

Did a little research, came across this in another forum, pretty much explains the ELD situation, not sure if I like his fix with the rheostat, you would always have to remember to turn it down.

http://www.civicforums.com/forums/21...-detector.html

From the looks of your drawing, the alternator would always be running at max if the switch is on and the remote wire is providing power to the relay. Wouldn't that cause damage to the alternator in the long run. I know you have two of them now, but not all of us have that luxury! LOL

 

the alternator doesn't run at max with the switch in the on position and the radio on. the PCM simply sees what it thinks is a load on the ignition system, and it decides how to best control the field current in the alternator. i'm not forcing anything into a position that could cause damage. the alternator doesn't provide max output if the load isn't there - that's not how generators/alternators work. as load on the alternator increases, so does current out of the alt, up to a certain point. as current increases so does resistance to turning the pulley - thus the load on the engine increases and fuel economy decreases. this happens in all cars, not just Honda. the only thing unique to Honda is the ELD's approach to save fuel. i compensate for the extra current/load that is on the system that the PCM doesn't know about. i'm simply informing the car not to save gas by turning off the alternator when i'm listening to my system. it's only bypassed if two states are met and it can remain like this indefinitely if necessary - i.e. if the load is there. granted, i'm an EE and i always pay attention to voltage and load, so i can intelligently control the system, hence the extra switch.

the only reason for the ELD is fuel economy.

i've seen that thread also. i have yet to see a solution other than mine that is as safe and that doesn't present an opportunity for damage. the only risk with my method is the person's ability to actually perform the work. once it's wired correctly and properly, it's totally safe.

i have been thinking about a second method that used more parts, incorporated some logic, and sensed current on other wires - but i'm busy enough with other projects.

 

Incorporating a current transformer that covered both the main feed going to the fuseblock and the main power for stereo/misc distribution would cover the entire thing, then you would never get a false reading. Only issue there is the cost of the CT and finding a good place to put it, the main stereo distribution would need to run close to the fusebox for that to happen. I just don't really like the idea of "tricking" the PCU. That has always caused problems in other vehicles I have done it in.

 

Guess I showed my true colors there. I know enough about DC power to be dangerous, but a CT will not work in this situation. The only real way to do it would be to add the power to the shunt in the fuse block, but also upgrade the shunt and main fuse of the vehicle right? Now we are back to where you had it figured out with tricking the PCM with a resistor and a switch. That is why I am a dc power installer, and you are an engineer, I bow to you sir. Funny thing here is the only difference between us is the 6 yrs of schooling you had to "endure", I'm sure there is a lot more than, I just hate electrical engineers for the most part because the ones we have at work are complete morons, and while they have a wealth of knowledge they have no way to apply it to the real world and we always end up correcting them and letting them know that they don't know anything about powering telecom equipment. Sorry for the rant, not directed at you!

 

haha. i understand. a degree means nothing other than a title on a business card. what really matters is what you do with the knowledge you have, however you attained it. DC electronics is a hobby of mine. I design electrical systems for hospitals, colleges, etc. (power distribution, lighting, fire alarm, and coordinate with mechanical systems). I also design acoustical treatments and vibration isolation for buildings, writing computer programs that analyze field recordings for spectral content, construct computer based models for various rooms/spaces to determine acoustical treatments and noise isolation, estimate outdoor noise propagation for noise ordinances, etc. i also solve existing noise and vibration issues, existing power and lighting issues, and help ensure speech intelligibility with spoken and amplified voice. in short - i help make buildings work and make them comfortable for the occupants. but my background in circuit design comes in handy when i want to build a circuit that does something unique. it all comes down to analysis of the individual components and how they behave in the circuit.

yes, a shunt will set up a voltage drop (i.e. 75mV @ 100A) which can be monitored by a circuit. you can characterize at what current you want the bypass to engage by setting the threshold for the circuit to trigger. even a 555 timer could work, throw in a couple of NPN transistors, a regulated supply, a delay, and then just add that to my circuit above for the bypass. the goal is to have a circuit that automatically senses when you have enough current. of course, music is dynamic, so you'd also need a delay on the circuit so that it wasn't constantly triggering the relay during song pauses and quiet passages. You also may need logic to compare the ELD voltage with the additional shunt circuit voltage and allow either system to engage the PCM bypass (this might be inherent in the design).
In the end, i think it's making the problem more complicated than it needs to be. All i really want to do is bypass the fuel economy mode at will - when my stereo is on. I keep a volt meter in the dash so i can see when the ELD engages, and then decide if i want to bypass. The switch is really for when my kids are in the car and i'm playing kids songs at low volumes (sub off). For my needs, and the needs of most people, the above circuit will work with very low cost and very little modification to the vehicle.

i have a 75mV 100A shunt that i was going to use for a DC Ammeter. Just never got around to installing it. I figured i'd may use that to play around with someday.

the real issue i see is that some Honda's don't give you easy access to the ELD wires like my Accord - for some it's below the fuse box and replacing the ELD usually means buying a new fuse box! now that means you need to access the wiring at the PCM - and there are a lot of wires there. i haven't seen a pin-out for that harness that i'd trust.

thanks for the discussion.

 

you can't upgrade the fuse box shunt - the fuse box isn't designed for any more current then there is now. you don't want to add any load to the factory fuse box, more than 10A anyway. while you can upgrade the fusing, you can't change the current rating of the connectors and OEM wiring without totally changing the fuse box. i've seen fuse boxes melt from added car stereo load and up-sized fuses - it's ugly and very difficult to fix.

I believe (and practice) that a sound system should not compromise any of the OEM wiring or ratings. when adding load to a vehicle, go to the battery with properly sized and fused wire. if you must interface with the OEM wiring (for an ignition wire) then use a relay.

 

the main problem with designing electrical distribution and branch circuiting for telecom equipment is getting anyone to make a decision on equipment to be used is near impossible during design (usually 2 years before it's installed) and if they do decide, they change their mind when it comes time to install it anyway. change orders are inevitable with technology equipment as the equipment is constantly improving. i hate sizing wire and circuits for telecom racks - that should be performance spec'd and coordinated between the E.C. and T.C. with an EE approving the final installation for NEC compliance. But we are forced to put something in the construction documents, and use CYA notes like "coordinate with field conditions" which is a weak way of saying "i have no idea what you will encounter".

it also bugs me that these wonderfully designed telecom racks are perfect for wire routing but offer shyt for receptacle mounting. You're usually needing normal power, critical power, and UPS power - all in the same area but in different raceways. we usually end up designing some custom conduit and back box configuration - relying on the technology designer to tell us the location of all power supplies, the expected load, the expected voltage, the power system (normal or emergency), and if UPS power is required. All of the EE's decisions are based on information from other people (owner's, users, maintenance, Code, AHJ's, designers, engineers, etc.). then we rely on the other designers to actually put what they told us in the documents. we're constantly checking and re-checking other trade's documents in order to gain confidence... and of course, we are the last one's to finish since everyone else needs to finish before we finalize wire and circuit loads. that puts a huge push on us to work 90 hr weeks for large project deadlines - and mistakes are inevitable. When I moved away from the EE department and into Acoustics and i removed a lot of stress.

All that said, not all EE's are good at real world problem solving. there is a big difference between a typo and design flaw. I personally think that any engineering degree should require a few years in the field - like an internship or apprenticeship. when an engineer asks for something that isn't possible or feasible - they look stupid.

 

Amen to the time in the field. I have asked every single engineer I have ever dealt with to come out to the field with us for the first week on a couple of big jobs, only had one ever do it. After he came out our working relationship with him was a lot different, instead of him telling us what we needed to do and then arguing about how his records were inconsistent, he started having us do walkthroughs and I couldn't tell you how many offices I ended up having him trash the records and we started over with complete new diagrams of the entire office, on every level from grounding, floor plan, power, cabling, racking, etc, etc etc. Extremely time consuming, but in the end it saves money, couldn't get the company to understand that though so they put an end to it, they would rather keep slamming in equipment and not knowing what they really had, even if it meant an office burned to the ground, idiots. Anyways, things were great with him for a long time, then he lost his fiancee to a pretty bad car accident(off a cliff in Colorado) and he went deep in a hole and ended up getting fired.

Now we are way off base!