Looks good. Grn/red from PCM to pole. Throw1 to grn/red. Throw2 to resistor that is grounded at the ELD blk wire.

Thanks for adding to the thread!

 

Thanks for posting this for everyone to see. This will be a fun project if or when I install a after market radio.

 

Great Thread...excellent detail and depth of knowledge! I'm contemplating making some different modifications (I'll report back based on your responses), but need to pick your brain first

1) Is the alternator response from the ELD binary? For example, does feeding the alternator 1V produce the exact same result as 1.7V? Or is there some sort of linear relationship to alternator on or rest time related to this input?

2) In all your testing, did you characterize the voltage change to the load current? If it's linear...IE 100mV per Amp or something?

3) I seem to recall (maybe not in this thread) that you had a pretty good idea about the load demands of your vehicle which allowed you to better size the alternator, etc. Did you measure this? Or just add up fuse limits?

Thanks for your efforts!

 

i believe this document will answer most of your questions:
https://skydrive.live.com/redir.aspx...232&parid=root


here is what i observed in my testing:
the voltage across the ELD appears to be simply resistive - i.e. linear. but the control of the alternator field current is on or off. there is a point at which the voltage across the ELD drops low enough that the PCM ensures the alternator field current remains on.

I did not find the exact point at which this was triggered because I only had step loads available to me, and my real interest was a voltage across the ELD that keeps the alternator on. That value drove the resistor choice.

i've been living with my mod for 2 years now. i still use the switch on a regular basis do tell the car what my intentions are.
i have thoughts of automating the process, but here are a few obstacles:
1. it does you little good to monitor the draw of your system because it is constantly changing. music is dynamic and a musical peak can occur at any time. the auto circuit would need to have a long delay, like a latching comparator that turns on the bypass once you reach a certain current draw. so you are either going to listen to music loudly or not.
2. the PCM considers other factors when controlling the alternator field current. the ELD is just one input to that system. By using the bypass you are not directly controlling the alternator, nor do you want to. I let the PCM do it's job and I manually tell it when i want to listen loudly.

 

Thanks for your reply..those downloads were helpful.

I'm contemplating using a current transformer with a built in adjustable threshold and output switch. As you mentioned, there is the hysteresis issue as you wouldn't want the output switching frequently. I was thinking I could feed that into a 30 second timer where anytime a low to high transition is seen, it would reset the 30 second timer. When the timer is active, a relay would control the pull-down.

I think my next step is to do some load analysis on my car. I'd like to see if my "loud" is loud enough that I'd benefit. I have ~950W of amplifier in the car, but frankly I don't listen very loud. I'd like to get a good understanding of my alternator capability before I work on any big3\ELD needs. A few measurements will probably help.

 

Here is the issue: by the time the circuit senses the load increase and reacts, it is way too late. The draw has already been a hit to the battery. Now the alt has to recharge and keep up with demand. Even with a 30 sec delay it will be switching often and after it is needed.

A latching output makes sense, and maybe a 10 minute delay to reset. If the output for 10 minutes is low, then your listening habit has changed and the alt can turn off, provided the ignition load is also low. That would make more sense to me.

 

ok so here is what is wrong right and none of the above with this post. Everyone in this post so far is right.(Great circuit design Keep_Hope_Alive) keep_hope_alives circuit is well designed and thought out. he uses a relay to switch a load that could in theory be switch alot over the coarse of a year. a relay is made to have a much longer switch life over a toggle switch of any sort rated at the same votlage and ampreage. anyways that a whole neither argument the idea behind it is use a component thats made to do alot of switching and controling a load ie relay. this is smart being it makes componet replacement easy and quick and easy to do a diog on. second by useing the radio and relay with a switch to make the circuit havign a fail safe so its not possibly triped and burn up or short anythings life span. great idea by my thinking better safe than sorry. second yes running a alternator in a charging state 24/7 does shorten its potential i say again POTENTIAL life span of the alternator as for the battery it will only be damaged if over charged ie going over its votage rating in this case 14 volts. The battery is damaged when its is over charged this will happen by the alternators voltage regulator failing and the battery recieving both or one of two things ac current or excessivly high voltage. The eld is intended to help gain a .5 or .8 mpg in the big picture its honda's way of helping them claim a 26 mpg over its competitors 25. and help your pocket book too. with all that being said their are a ton of a ton of ways for you to test in a short term time period if a idea is going to fix something ie just wireing in a toggle switch or or a set of resistors those are great ideas to trying something to fix your problem but it all boils down to the thought when something goes bad, and it alwas will eventually how big of a hassle do you want for fixing it the second time like in Keep_hope_alive design you simple sheck your relay it is what is doing the big work of hte design and will be the most likly thing to fail by his design that remedy is simply unplug one relay and replace. Are you guys getting where this all goes anywho great thread i think should be a sticky if its not already. common problem people would run into and a simple fix. again great post will be pming some people with questions on module names to my current problem

 

thanks for the input. yes, the relay was chosen based on its life cycle, low cost, simplicity, and availability. i also wanted to keep it simple so anyone could do it regardless of their education/background.

 

Great info on the ELD! Just wondering if anybody knows the where to bypass the eld on the 7th gen accords (2003-2007)? I understand that it is integrated into the fuse/relay box under the hood, but the fuse diagram on the box cover doesnt list it anywhere.

I wanna bypass with a 820 resistor to run unrestricted full time for my audio system.

Any ideas?

 

yes this
under hood fuse box on passenger side