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

[steffen707]

Yeah that optima charger is like $200 I thought. Crazy. I'll have to calculate how many amp hours you get from an optima and from this lifep04 thing. I also have to calculate if its worth all the hassle for me.

[brucepick]

Yeah, it's not a quick project, and not inexpensive either.

The battery and charger are only part of the cost - you also need to add in about 60' of heavy cable (I used all 4 ga except one run is 6 ga) and three switches plus a couple fuses. A friend sold me about 20' of 4 ga he didn't need any more; saved me a small bundle of $$ but that didn't make it a low cost project by any means.

[steffen707]

Yeah and stereo wire isn't as cheap as it was when i was into car stereo's in high school. Think then it was like $1 per foot. Can't imagine what it is now since copper is so damn expensive.

[steffen707]

Originally Posted by brucepick

I'm trying to avoid that degree of home-brew. I found a nice 14V AGM battery but found only one on the market. XS Power D1400. Rated 50 AH. Cost with dedicated charger would be about the same as the ~12V Odyssey I described above. I hope to test for lean burn at 12V this week or maybe next weekend. Hard to get time for real world stuff; much easier to type on a keyboard :-)

I know you went with a different battery, but do you know if their 50AH rating is for 1amp draw for 50 hours? Do they all just assume its a 1amp draw? This is kinda a sweet setup as you don't have to use a DC-DC converter which would have an efficiency loss every time you use it.

I also am concerned about this charger for your pack, http://www.batteryspace.com/Smart-Ch...de-use-CE.aspx doesn't mention if its a 3 stage charger or not. It says "smart" charger, but what does that really mean?

[steffen707]

Originally Posted by brucepick

In my case, I'm pretty sure the Civic water pump is gear driven of an engine shaft. Not related to the alt drive belt at all. I do like having a/c and power steering. True that I could drive the car without either.

Hmmm... removing the belts would be a long lasting decision for me - I'm not handy at installing + tightening them. I'd probably cut 'em off and that would be the end of them.

The civic water pump is driven off the engine timing belt. There are water pump delete kits you can buy that just have an idler pulley there to run the same timing belt, but then you have to plumb in your electric water pump somewhere. I know some honda racing people do this, but that's mostly with b16 and k series engines. The d series economy ones might not even have these kits, but you could just as easily cut off all the blades on the water pump so you make an idler pulley; however, it might not be balanced then.

I wonder what the gains would be. Kinda seems like a PITA, but if its 5-10% MPG gain, then......

[brucepick]

Originally Posted by steffen707

I know you went with a different battery, but do you know if their 50AH rating is for 1amp draw for 50 hours? Do they all just assume its a 1amp draw? This is kinda a sweet setup as you don't have to use a DC-DC converter which would have an efficiency loss every time you use it.

I don't know. But I THINK if you search on the XS Power D1400 you might find the info. I wasn't happy at the charger's price; made it an expensive proposition. And I didn't find any other chargers for 14V lead acid batteries around. Plenty of them for hand held power tools but those batteries are a fraction of the size of the 14V Stinger and mostly now have lithium packs; these are completely different beasts.

Originally Posted by steffen707

I also am concerned about this charger for your pack, Smart Charger (10 A) for 12.8V LiFePO4 Battery Pack, Worldwide use, CE listed doesn't mention if its a 3 stage charger or not. It says "smart" charger, but what does that really mean?

No it's not a 3-stage, it's one stage. However I believe that's what you want for a lithium pack. With lithium cells, the important thing is management of the voltage and charge level of the individual cells. My pack has a passive circuit that kicks in after charging completes, to balance the cells.

The Wipedia page on LiFePO4's says:
"Charge: Up to C/1 rate up to 3.6 V, then constant voltage at 3.6 V until I < C/24" C/1 translates to 40 amps charge rate for a 40 AH battery, 10A rate for a 10AH battery, etc. The "C" reference also applies for discharge rates which aren't necessarily the same as the charge rates. The "until I < C/24" translates to "until Amps drops to [capacity in amps] / 24".

The charger's spec sheet includes:
"Cut-Off voltage = 14.6 +/- 0.3VDC (3.65 +/- 0.08VDC per cell) "

So my charger runs at 10A until charging voltage rises to 3.65V/cell which is 14.6V overall. Not exactly the same as what Wikipedia's page indicates but I think in actual use, the volts and amps from this charger are within a very small delta from what the Wikipedia page would suggest.

[brucepick]

Originally Posted by steffen707

The civic water pump is driven off the engine timing belt. There are water pump delete kits you can buy that just have an idler pulley there to run the same timing belt, but then you have to plumb in your electric water pump somewhere. I know some honda racing people do this, but that's mostly with b16 and k series engines. The d series economy ones might not even have these kits, but you could just as easily cut off all the blades on the water pump so you make an idler pulley; however, it might not be balanced then.

I wonder what the gains would be. Kinda seems like a PITA, but if its 5-10% MPG gain, then......

I suppose there's potential there. I'm more comfortable working the electrical projects than I am with the mechanical ones, but that's just me.

You still need to pump the water through the system; you can't do without like you can get by without a/c or power steering. I'm sure the oem electric water pump systems are computer controlled. I think for a DIY version you'd have to be pretty good about ensuring there's appropriate circulation, or you'd be paying the consequences later with a blown head gasket. Or pushing a lot more coolant through than you need, if you mis-estimate in the other direction.

[steffen707]

Originally Posted by brucepick

No it's not a 3-stage, it's one stage. However I believe that's what you want for a lithium pack. With lithium cells, the important thing is management of the voltage and charge level of the individual cells. My pack has a passive circuit that kicks in after charging completes, to balance the cells.

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.

[steffen707]

Originally Posted by brucepick

I'm sure the oem electric water pump systems are computer controlled.

While this may be true, the mechanical pump is always pumping, and i'm sure you always want some flow as there could be "hot spots" in the head or block. So with a little electrical work, you could control the pump to always run on low, and then run on high setting when you read a certain coolant temp, head temp, ect. The radiator fan and thermostat will operate like they normally would.

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.

EDIT*** From the quick reading I did for a race b16 engine making 250 horse they saw a 4hp gain, or only 1.6%, however, this is 1.6% on an already highly efficient HP engine when squeezing any kind of power out is tough to do. So for an economy car the % could be a ton. I also read from http://www.vetteweb.com/tech/vemp_08...s/viewall.html they saw a 10.5hp gain or 2.17% of the ending 482horse vette engine.

[steffen707]

Originally Posted by brucepick

The old oem wire from starter to alt is disconnected at the alt and taped over.

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.