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

[3dplane]

Look at dc to dc converters for EVs. Yes it should output 13.5-14V. The input voltage is rather high because they are designed to be fed by EV pack voltage.
Making a high voltage small capacity pack is easy but for charging it back up you would have to find an acceptable method. ( tapping into the pack by charging leads and use multiple chargers, or get the appropriate high voltage charger etc.)

Here is the first one I found on an ebay search EV DC to DC Converter Electric Car Voltage Reduce 144V volt to 13.8V 35 Amp 480W | eBay

There was also talk about diy converters on this forum too but I did not search for that.

Barna

[California98Civic]

Originally Posted by brucepick

I'm interested in LEDs for the tail lights and front corner lights. I looked into LED headlights but my take was they're not yet ready for prime time.

I looked for LEDs for our Civics [EDIT: I meant LED headlights, sorry, I found the others just fine and have been running them for months]. I did not find them (now watch someone post-up a quick link). I did find LEDs [headlamp] in the old-style round form, but those don't fit the car! I am running HID headlights. I paid extra to get the hi-beam ability. Total was $70. The regular beam wattage is 70w for the pair. It was 110w with the stock bulbs, IIRC. The HIDs work differently: they do not dim at lower voltage but they will cut-out entirely twice if you run the battery down under 11.2volts.

[brucepick]

Originally Posted by California98Civic

I looked for LEDs for our Civics. I did not find them (now watch someone post-up a quick link). I did find LEDs in the old-style round form, but those don't fit the car!...

This might help - I didn't take the full amount of time needed to investigate fully.
LED Vehicle Bulb Finder

The site offers various bulbs for any given car. You can see pics and dimensions of the bulbs. I think from what you wrote, it would make sense to get a good look at the bulb housing and try estimate whether the LED assembly would fit the available space.

I'm not going to try look into the HID option; I've read negative reports on beam pattern results with HID conversions. But if you're happy with yours, that's a good thing.

[brucepick]

Any other words of wisdom on finding DC-DC voltage regulators?? I'd likely have a battery pack somewhere between 13-18V and would want it to put out a steady 13.5 or so, to mimic a running alternator.

OTOH,
I'm still leaning towards a 4S (four cells in series) LiFePO4 pack that will give a nominal 13.2V. Several of those in parallel. Have them just run the headlights and maybe the heater fan if I can wire that up. Switch the small battery pack in manually when needed or with a clever relay circuit as discussed earlier.

The benefits: I'm making no headway on finding a proper DC-DC converter for this application. And, this method would avoid any losses from the DC-DC regulator that would modify the higher voltage battery pack. I'd be able to start using the battery pack with the number of cells I can afford to get, and add more in parallel later for increased AH. When it gets big enough to power the whole car for 3-2 hours, add battery disconnect switches to switch between the Li Fe Phos pack and the oem starting battery.

[brucepick]

Did a proof-of-concept test today. Worked very well. 51 mpg going to work, and 48+ coming home.

No fancy LiFePO4, just a big old second battery (575 CCA rating) on the floor in front of the passenger seat, connected via a couple fat cables snaked out the door frame and under the hood's rear edge to the main battery connections.

Driving in rain, with headlights and wipers and even the fan running on low, I found I could coast with engine off (EOC) for even the longest distances I usually can go - about a mile - and voltage generally didn't drop below 11.5V, once I got past the warmup period.

That's the result I was looking for. With headlights on, EOC is very problematic because the battery voltage drops pretty quickly. With the additional battery capacity, voltage drop was not a problem, so I could EOC as much as the road would allow without needing to spin the engine just to keep the battery happy.

I've looked into building a 10AH pack of LiFePO4 cells, but building a charger for the pack would be pretty serious business.

I'm leaning towards a big Odyssey battery, maybe their PC1500. It's an AGM, about 66AH. Mount it in the trunk and run a fat cable up to the engine bay, like audio guys use to power their amps. I probably could ditch the regular battery that's in the engine bay.

It can be charged via the alternator. Or for a next step, I can build a switch to cutout the alt, and charge the battery off wall current. The battery will use up my budget so I'll have to get creative about funding the charger.




Hose clamps hold the bare copper strands to the battery posts, plus an assist from Vise-Grips.

[California98Civic]

Nicely improved numbers. Congratulations! When you compare recent fuel log entries, this certainly seems to prove your concept. The longer EOC is a benefit.

[deathtrain]

ok confused a little. Bruce what you did (if i read this right) was to add a battery and you got a plus in MPG because the alternator was not working as hard.

Or adding the battery is just allowing you to EOC longer than you where. And thats how you got the gain in MPG?

[brucepick]

Originally Posted by deathtrain

ok confused a little. Bruce what you did (if i read this right) was to add a battery and you got a plus in MPG because the alternator was not working as hard.

Or adding the battery is just allowing you to EOC longer than you where. And thats how you got the gain in MPG?

The second one is what's happening. The two batteries wired in parallel - just like when jump starting - have approximately double the capacity of the single battery. So with no support from the alternator when coasting, they last longer before voltage drops to "too low for comfort". Yesterday I was able to coast whenever I wanted, as long as I wanted, never needing to spin the engine to keep the battery voltage up. Voltage readout is on the dash, of course.

The alternator has to work just as hard because the car's needs for current haven't changed. Lights, fuel pump, ignition, computer, etc. etc. all the same. The batteries are just a "storage bucket" of sorts.

I have to say that not all the gain is from the increased battery system. Something has changed in the engine and/or computer that's allowing it to be in lean burn mode (an original factory feature of the Civic HX) at lower speeds for longer amount of time. This changed just over the last couple days. I don't know if some EGR piping finally got cleaned out or what. Maybe some rings got degunked and aren't sticking. Maybe the upped battery capacity has something to do with this improvement but I doubt it. In any case, I can do a much higher percentage of my commute in lean burn now, and at lower speeds. I just hope it lasts, because it's a real benefit.

[ps2fixer]

I support the LED idea for ALL lights. I have been researching this for a while starting with night lighting in the house for very little power draw, then starting to target the car lol. In simple terms, Incondesent lights are my base point, fluorescent lights use about 1/4th the power to create the same amount of light, and LEDs use about 1/10th the power. So LEDs are nearly twice as efficent as fluorescent lights. The downside (or upside) of LEDs are that they are effected hugely on angle of light.

Check this out just to get an idea, there are tons of videos like this

http://youtube.com/watch?v=y1yqWTU71DM

One thing to point out, when you are hitting 1w+ LEDs you MUST keep them cool, under 160C. I have read the figure of 12 square inches per 3w led running at FULL power.

Another thin to point out, LEDs are most efficent at less power draw compaired to their max. Example is, my 3w LEDs i'm working with are rated 700ma @ 3.2-4vdc (forward voltage), but I'm planning to run mine around 350ma which will probably only loose about 25% brightness.

One final note on useing "raw" LEDs (DIY setups), you must have a curent limiting device, resisters make heat at higher powered LEDs, so a DC to DC converter is ideal since they are 85-90+% efficent.

The LED method should be a LOT cheaper than trying to add a second battery, probably somewhere in the ball park of $30 or so for the headlight conversion, the rest of the lights you could buy from the linke above me for plug and play (built in resisters).


To give a real world example, I'm running 4 small led lights in my bed room as a night light (on 24/7) at 7ma with 13.8v across the series (around 100mw draw + how inefficent the power supply is). It provides as much or slightly more than a typical 7w night light, but the light is spread out over the entire room instead of just by the wall. Remember, 7w lights are a warm light, and LEDs are a cold light, which skews perception of brightness and color.

Good luck in either way you go about your task!

[brucepick]

Remember - one feature (as yet unmentioned) of having a second or much larger battery is that I should be able to have it power the car with alternator disabled when headlights aren't needed.

I estimate that a battery of about 50-66 AH capacity should be good for 2-3 hours drive time or more, which would get me through a day's commute. Would also get me through a run in the FE competitions I've been in. In those situations my lights would be off anyway, so converting them to a more efficient light source wouldn't reduce current draw.

Re. LEDs,
I did a due diligence web search for LED headlights.
I've found replacements for most smaller bulbs but not for the headlights. Nice that they can be had for the Harleys.

I'm interested in replacing smaller bulbs with LEDs but it's the 55W x 2 headlights that draw down battery voltage. Four or even six corner bulbs at 5-8W each is a relatively smaller load on the system. I believe I won't escape the need to run the 110W of headlights any time soon. Yes I could run a pair of HIDs for 70W total but it's significant $$ for a savings of 40W.

LED headlights would require a complete reflector/lens/bulb holder assembly to replace the existing one. The YouTube above shows exactly that on the Harley. This is because halogen bulbs are built with a very small filament(s) located at the focal point of the optical system. No LED of that brightness will be as small as the short filament of a halogen bulb. So the optical assembly would have to be built to deal with the particular shape of the LED sources, focusing the light appropriately. It could happen but I haven't found them available - and any set of headlight assemblies is going to cost at least $100 or more. BTDT with a regular halogen-fit assembly for this car about 2-3 years ago.