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

[fastegg]

Originally Posted by oil pan 4

The electric coolant pumps I use now use 5 and 7 amps.
The pump I plan on putting on the truck is bigger and takes 10 amps. I have a low speed setting that will cut it down to 5 or 6 amps.

What's the story with your electric pumps ? Have you gotten any gains ?
What brand are they ? Can you tell me something about them ?

[Daox]

Originally Posted by fastegg

Hey daox... how do you put your cars in your left hand column under your signature ?

Click the "Garage" link up at the top of the page.

[oil pan 4]

I never did anything like a-b-a testing.
On the car I installed a proform (cheap, should have got a nice one) electric coolant pump, but at the same time I also converted to electric fans and that was about the time the car started having bad transmission slipping problems. So its hard to track any improvements on the car.

On the truck in addtion to the electric coolant pump it was part of a new engine build, installed a new set of tires, moved from sea level to 4300ft and changed my entire intake setup. The plan was to get the truck running 6 to 9 months before moving, that didnt happen, it was more like a week.
With the new elevation (12% less air here), new tires and different intake setup I am down about 5mpg from what I was getting in virginia during summer with the old engine set up and 10 year old 31'' goodyear RT-S tires.
I have a good data showing that on a smaller truck you lose about 2.2mpg highway when going from old goodyear RT-S tires to new yoko AT-S tires.
(its a good data set because my friend gave me his old goodyears and swapped them for the yoko AT-S and about 2 years later I replaced his old goodyears with yoko AT-S tires too).

Just converting to an electric coolant pump in cars is said to be good for up to 15% and up to 10% in a truck.

On the truck I did track a pretty clear 2mpg highway increase when I just converted to electric fans.

I don't normally have time to install just one mod and test it for a few weeks.

[brucepick]

Well I mapped out my plan of action.

Based on notes from California98Civic, it looks like these Gen 6 Civics draw somewhere around 15A without headlights or other major accessories. We don't have very precise information on this so I'd give it an accuracy of +/- 35% or so. Headlights on would add about 12A. In any case, with this setup I do expect to be able to drive an hour+ to work, hopefully even with headlights on as needed in winter, without exceeding the battery capacity.

I'll use a 40AH 12.8V LiFePO4 pack. The one I've selected has a BMS built into the pack that balances the cells, provides charge and discharge rate limits, and gives a few other protections also. I'll charge it overnight from wall current. It weighs only 16 lb so I should be able to remove it and give it a charge at work if needed, when traveling, etc. A full charge will take about 4 hrs. with the planned 10A charger plus 30 min. for the BMS to balance the cells afterwards.

(I extensively researched using a high end AGM lead cell by Odyssey, ~65AH and 60 lb. However you should only discharge it about 20-25% for optimum battery life. The functionally available ~13-16AH isn't a lot, and running several of those packs gets very heavy and also costly.)

At this point I plan to keep the oem battery in the car, connected ONLY to the alt and the starter. I can disable the alt via switching in the field power wires so I have some control over that.

[EDIT] (This calc was way off when originally posted) I calculated that if the starter draws 100A and it runs at most 2 seconds to start the car, that's about .055 AH of battery capacity per start, or about .55 AH/day if I do it ten times. Mostly I bump start the car after EOC but typically I do use the starter 2-3 time on each commute run, for a total of maybe 0.5AH/day, more if doing lots of EOC in heavy traffic. [/EDIT]

I'm not preserving very much of the Li pack's 40 AH capacity by using the lead pack for starting. I'd rather get a 2nd deep cycle of some type into that location to handle starter + headlights or just to supplement the Li pack in parallel. Of course if wired in parallel, it probably should be a matching chemistry Li pack. Or a simple lower cost lead deep cycle.

[cbaber]

I have been following this thread and like the ideas you have. I have the same car and want to do the same things with the alt. cut off switch. I have the same commute as well. 50 miles. Just to get things straight, are you going to add in the 40AH 12.8V LiFePO4 pack to the system seperate from the main battery or in parallel?

When you switch the alt. off everything but the starter is still powered through the Lifepo4, right? So assuming the specs are accurate you could drive on good enough voltage for your whole trip without having to recharge the battery or use the alt. and then charge it overnight at home, right?

I am curious as to whether this method is better than just adding a second car battery in parellel? It seems like you can EOC for as long as you need to with that setup but can it last the entire trip without using the alt?

[brucepick]

Thanks for the good word! I wish you success on this if you go forward with a similar project.

Originally Posted by cbaber

... Just to get things straight, are you going to add in the 40AH 12.8V LiFePO4 pack to the system separate from the main battery or in parallel?

Separate is my plan. Heavy power lead from bat to starter and then to alt will be connected to existing original battery. Smaller lead that goes to fuse box and maybe elsewhere, will go to the LiFePO4 pack. So the whole rest of the car is powered by the Li pack. Both batteries will be grounded to chassis. That way the old lead battery will only be starting the car.

I'm not fully certain that within the alternator, there is no crossover of voltage/current between the two systems but I think/hope it is so. Hopefully the "system" voltage to the field coil windings and the voltage regulator do not cross over into alt's output.

Originally Posted by cbaber

... When you switch the alt. off everything but the starter is still powered through the Lifepo4, right? So assuming the specs are accurate you could drive on good enough voltage for your whole trip without having to recharge the battery or use the alt. and then charge it overnight at home, right?

Exactly, that's the plan. Except it's not switching off the alt that causes the car to be powered by the Li pack. It will be because the Li pack will be wired to the main system, and only the starter + alt will be connected to the lead acid battery.

Originally Posted by cbaber

... I am curious as to whether this method is better than just adding a second car battery in parallel? It seems like you can EOC for as long as you need to with that setup but can it last the entire trip without using the alt?

Should be better. The 2nd battery in parallel does solve the problem of EOC running down the main battery voltage. But the alt does still have to ultimately recharge the batts, one way or another it is still providing the current I'm using, and that energy comes from my gasoline.

By hopefully running the whole car off the Li pack (except the starter), I can disable the alt electrically. That way the alt will present almost no mechanical load to the engine, and that's where I expect to gain some mpg. California98Civic has done it with a smaller single battery but he has a much shorter commute. Regardless of the size of the battery, you'd need to charge it when not driving, unless you can get a satellite to beam power down to you while under way. Yes there is solar recharging but from what I've read you won't get power as fast as you'd need it to keep things charged up.

[3dplane]

Originally Posted by brucepick

Separate is my plan. Heavy power lead from bat to starter and then to alt will be connected to existing original battery. Smaller lead that goes to fuse box and maybe elsewhere, will go to the LiFePO4 pack. So the whole rest of the car is powered by the Li pack. Both batteries will be grounded to chassis. That way the old lead battery will only be starting the car.

I'm not fully certain that within the alternator, there is no crossover of voltage/current between the two systems but I think/hope it is so. Hopefully the "system" voltage to the field coil windings and the voltage regulator do not cross over into alt's output.



Exactly, that's the plan. Except it's not switching off the alt that causes the car to be powered by the Li pack. It will be because the Li pack will be wired to the main system, and only the starter + alt will be connected to the lead acid battery.

I think as long as you keep the original battery,starter and the alternator's heavy positive circuit in their own separate loop and not allow a lead to go to your fuse box where it can share the positive with the lithium you should be good.

I'm thinking from the three phase windings out through the rectifier diodes,main output stud it SHOULD be really self isolating.( However who knows if they made some monitoring circuit within the regulator that ties in to one or more of the diodes etc.)
Now the voltage regulator might be sampling from the "fuse box" circuit and will try to control the alt based on that voltage (Li-pack) but other than that it should not be able to interfere in my opinion.
It will be interesting to see how things turn out!
Barna

[GeneralAnarchy]

Originally Posted by brucepick

Regardless of the size of the battery, you'd need to charge it when not driving, unless you can get a satellite to beam power down to you while under way. Yes there is solar recharging but from what I've read you won't get power as fast as you'd need it to keep things charged up.

Perhaps not if it charges while decelerating and coasting downhills faster than you'd like. A mercury switch controlling a relay should capture "free" energy to some extent. Or more conservatively, a brake pedal circuit. Better the drivetrain forces the engine to spin and alternator to charge as much as possible, than all the kinetic energy turns to brake dust.

[brucepick]

Originally Posted by GeneralAnarchy

Perhaps not if it charges while decelerating and coasting downhills faster than you'd like. A mercury switch controlling a relay should capture "free" energy to some extent. Or more conservatively, a brake pedal circuit. Better the drivetrain forces the engine to spin and alternator to charge as much as possible, than all the kinetic energy turns to brake dust.

I've kind of tried this, manually. Leave car in gear for a downhill coast to charge the battery. Unless the hill is very steep, you lose too much speed if in gear with the clutch engaged. On my somewhat hilly commute on "limited access" roads (pretty much like an interstate), I more or less maintain speed on the steeper downhill coasts, with tranny in neutral. If in top gear, the coast ends pretty soon and I need fuel to complete the downhill.

Another concern is that my engine still has some issues with fuel cut coasts in gear. Every now and then that type situation will throw a CEL with code P0401: Exhaust Gas Recirculation Flow Insufficient Detected. I know there are fixes for this but haven't been able to get to it yet.

[California98Civic]

Originally Posted by GeneralAnarchy

Perhaps not if it charges while decelerating and coasting downhills faster than you'd like. A mercury switch controlling a relay should capture "free" energy to some extent. Or more conservatively, a brake pedal circuit. Better the drivetrain forces the engine to spin and alternator to charge as much as possible, than all the kinetic energy turns to brake dust.

This is part of how I do it. I live in a foothills area. I scale and descend 200-500 foot hills repeatedly in my 11 mile commute. One is 500 feet over the course of about a mile to 1.5 miles. Hills like that become a spot for me to throw some energy back into the battery by turning on the alt for DFCO. I do this even when my battery is still close to full charge from the previous night's grid charging. Eventually, I will also have some sort of solar assist. It is working really well right now. I really couldn't be more happy with it. My battery charge stayed at 12.2 or over (when running) all day yesterday, which means my deep clycle never went below half-spent. That will help me preserve the battery long term.