Civic EPES: Alternator Delete Project (with additional lithium battery...)

[brucepick]

Originally Posted by steffen707

I think something may be wrong here.

My car has a power cable from the battery positive to the main fuse box, it also has a power cable that goes straight to the starter.

The alternator wire however, only goes the main fuse box and is not directly connected to the battery. This is at least the factory setup. You might have another setup, but I don't think they ever put a wire directly from the starter to the alternator.

Hmmm. You might be right on that. I'd read that most cars have the alternator's + wire connected to the starter where it joins the battery + cable - just a low cost way to connect them both to the battery + terminal. I assumed our Civics were that way.

Yes there are 2 heavy wires at the under-hood fuse box. One is visibly traceable to the battery. If the other is white then that could be the one that goes to alt +. I had guessed that 2nd wire at front fuse box goes to the under-dash fuse box. But I was just guessing.

At any rate, the alt has only one oem heavy cable and I disconnected it. I'll be looking at my front fuse box to see the color of that second wire.

[brucepick]

Originally Posted by steffen707

... So there could be some gains, but i'm wondering how much. I'll try to read up on some racing sites to see if they do a back to back dyno comparison. You want me to post that back here, or start a new thread? I don't want to muddy your EPES project info. ...

A topic definitely worthy of its own thread, in my humble opinion. Kinda related though, as are all things ultimately.

If you run an electric water pump on an EPES car, you'll need additional battery capacity. You'll certainly want to know approx how much amperage it will draw under various load conditions so you can keep it turning.

[brucepick]

Originally Posted by steffen707

So if you just plug the charger in to the wall, once its fully charged, does the charger shut off, or does the lithium cell pack passive circuit just stop the charger from overcharging?

Reason i'm asking specifics, is I wonder if you need to run the charger on a timer, so that it will shut off after 5 hours, to let the passive circuit run for 30 minutes and balance the cells. I read on that site batteryspace.com that after charging up the lithium pack, you need to allow that 30 min to balance...

For now i'm just playing around with my regular old lead/acid starting battery, but want to make sure all my research is right before I go dumping a bunch of cash on this. My main concerns are how long can i drive, which correlates with the available AH, max discharge allowed, and amount amps my car pulls with load and without.

I do usually run my LiFePO4 charger on a timer, but only because the fan will keep going after charging is completed - in the middle of the night when I'm sleeping. I prefer to shut of the unit entirely via timer, though it would not overcharge the LiFePO4 pack if not shut off.

Once the battery is charged the charger goes into "not charging" mode. Its LED changes from red to green to let you know. Sends no more current to the battery, so far as I know. At that point the "PCM" (protection circuit module) goes to work balancing the cells. The PCM is built into the battery pack. Follow the batteryspace.com link to the charger; you can see pretty good detail there.

On the batteryspace.com site the packs with PCM have a link to it (PCM is available for purchase individually). You can read the specifics for the PCM there. FYI John at batteryspace told me that for my (largish) 40AH pack, I should allow more like an hour for the PCM to do its job.

[brucepick]

After driving several tanks with the EPES which runs mostly around 12.5V instead of the alternator's approx 14V, I found my MPGuino consistently reporting somewhat more fuel usage than the car actually consumed.

I expect that the fuel pump is running at somewhat reduced pressure at the lower voltage. So for any given injector pulse length, less fuel is being injected. The MPGuino reads pulse length, so needed an adjustment for use with the EPES.

Anyway, the correction I needed was right around 3%.
FYI. YMMV.

[steffen707]

Originally Posted by brucepick

After driving several tanks with the EPES which runs mostly around 12.5V instead of the alternator's approx 14V, I found my MPGuino consistently reporting somewhat more fuel usage than the car actually consumed.

I expect that the fuel pump is running at somewhat reduced pressure at the lower voltage. So for any given injector pulse length, less fuel is being injected. The MPGuino reads pulse length, so needed an adjustment for use with the EPES.

Anyway, the correction I needed was right around 3%.
FYI. YMMV.

WOW!, I suppose you could hook up a fuel pressure gauge to the fuel line to test this, although if the 3% directly compares to 3% less fuel pressure, then it will be hard to tell unless you have a really acurate gauge.

I'm wondering if the same thing is happening to me, because monitoring my voltage while driving with the alternator on, it will go for miles without going above 12 volts, then it shoots up for some reason. On the highway today I noticed that it almost always stayed at 13-14 volts even with a low accessory load. I don't know if that's because the injectors and ignition were using a lot more electricity on highway use, or if it figures at higher speed you can charge faster?

[brucepick]

Originally Posted by steffen707

WOW!, I suppose you could hook up a fuel pressure gauge to the fuel line to test this, although if the 3% directly compares to 3% less fuel pressure, then it will be hard to tell unless you have a really acurate gauge.

I'm wondering if the same thing is happening to me, because monitoring my voltage while driving with the alternator on, it will go for miles without going above 12 volts, then it shoots up for some reason. On the highway today I noticed that it almost always stayed at 13-14 volts even with a low accessory load. I don't know if that's because the injectors and ignition were using a lot more electricity on highway use, or if it figures at higher speed you can charge faster?

That's the ELD circuit. Electrical Load Detection. Search for it here on ecomodder; we've had some discussions over the past year. You'll find it in the threads on Civic alt cut via switches. The ELD circuit reduces (or eliminates) alternator output when it determines that [primarily]: the battery is topped up and demand for electrical power is low. It does NOT disable the alt if coasting in gear, or if speed is over 50 mph.

[steffen707]

Oh gotcha. I know the ELD is hooked up to the ecu, and then the ecu calculates when to shut down the alternator.

Wonder how many amps its pushing when above 50mph if the battery is already topped up.

[WD40]

I wonder if there is a way to fake this on a Canadian VX as they do not have ELD, so they don't go down to the 12.5 volts.
I would prefer this to a total alt kill, at least this way if you do forget it won't kill the battery.

[steffen707]

Originally Posted by WD40

I wonder if there is a way to fake this on a Canadian VX as they do not have ELD, so they don't go down to the 12.5 volts.
I would prefer this to a total alt kill, at least this way if you do forget it won't kill the battery.

My guess is that you would have to fully convert your car to a cali spec or 49state federal and add in the ELD and the right ECU, and the proper oxygen sensor.

I don't know much about Canada Vx's.

[MetroMPG]

Bruce - FYI, there's now an EcoModder blog post about this project:

Alternator delete with lithium and lead acid battery