"programmed battery charging"
 

Can someone tell me where to read more about this? I tried to search this site an online but mainly finding info on how to charge (at home) the battery, but I presume this is something that regulates (takes load off) the alternator when not needed.

Found the term here:

VW Passat Goes 2456 Km On One Tank

"Programmed battery charging" in this case means that the alternator's field is disabled by the car's computer when the battery is charged, reducing engine load. The field is powered up when engine braking, or when the battery's voltage drops.
This is becoming common (Škoda, BMW, and many more), not only in "green" models.

It's pretty much an alternator kill switch, which hypermilers/ecomodders have been using for years, only automated so the driver doesn't worry about it.

OK that's what I thought exactly now where/how could I find more info on it? In a DIY fashion? Hey now something hit me, why not have an AC clutch like setup?? :) That'd be nice thereby not even spinning the alternator when not needed, I presume what you explained happens at the "other end" of the alternator meaning it would still spin just not have any "load" right?

Correct. If your alt has a field wire then putting it on a relay will allow you to manually (de)activate it. On the other hand, if your alternator's field is self-exciting, then it won't be easy. In that case you can either re-do the internal circuits (AXMonster tried, but didn't get it working, iirc), or you can try A/C clutch pulley, which I don't recall anyone actually doing.

There's quite a bit about alternator killing here, but you can start here and then search for more:
Deceleration Alternator

I've got one of these alternator (not my thread or pics) from a Suzuki Samurai:
VWVortex.com - Lightweight Alternator installation on fat Wabbit............

Plan on copying that setup since my TDI block has the same attachments and waterpump

If you install a lower powered alt then it'll take longer to charge your battery once its voltage drops. The load on the engine will be smaller, but it'll stay on for a longer time. Similarly, installing an underpulley on the alternator to reduce its rpms, and therefore load on the engine, also takes longer to charge the battery. Take that into account if you decide to use a clutch pulley of a different/larger diameter.

What would be ideal is an alternator with a power output close to the max safe level that your battery can be charged, that way you'll get the most out of it when engine braking.

BTW:
Groar isn't much worse - he's done 1900km on a single tank in his '97 Megane:cool:

A smaller pulley would increase RPM (not decrease) the alternator would be spinning at and increase the load just as when you put a smaller pulley on the rear of a bicycle / MC, pretty familiar with all that ;)

As for battery I have this one:
Deka ETX14 Power Sports AGM Battery

I am aware that most AC clutches are larger in diameter but here in Calif there's plenty of junked cars with them so I wouldn't be surprised to find a smaller one.

My ultimate goal is to get as close to 3L/100km (80MPG) as possible it's been done with a Mk1 Golf (Rabbit) see my thread here for more info on that http://forums.tdiclub.com/showthread.php?t=305898

Also I've used the 3L VW Lupo as inspiration and a MK5 a university did in Germany.

That depends on where they mounted: whether on the drive or on the recieving end of the accessory belt. Anyway, what I had in mind was such a pulley combo that the alternator spins slower.

BTW: I started reading through your TDI Club thread and you mentioned a 5th gear swap. If you are going all out on this project, then maybe swap for a 6 speed gearbox, as dremd did. He appears to be quite pleased with it.

Yes naturally but we were only talking about the alternator end here :) as were you:

Why would I spend more money (5th gear brand new retails only for around $350 Advanced Automotion , I paid less directly from Germany) on a different transmission that has lower gearing ratios than what I will have!?

My 5th gear combo is from a TDI T4 VW and has a ratio of 0.622 and my R&P is 60/19 (=3.15) so I will have the final gear ratio of 1.95 compare this to the 6 speed transmission you mention:

http://i1219.photobucket.com/albums/...GearRatios.jpg

6th speed doesn't always give you a taller gearing but only more gears to chose from, in fact my factory CTN transmission from the 1998 TDI has a factory 5th gear of 34/45 (=0.7555) which is even in itself better than the 6th gear in that transmission (though not in reality with my R&P (3.15 * 0.7555 = 2.37) hence why I am swapping the 5th gear while retaining 100% original 1-4th gear ratios for my engine/transmission). The reason for this can be found in the original article I linked to at TDIclub here: Project Sipster part 3: Optimism Meets Realism > MotoIQ > Magazine Articles where it is revealed that the older (1998) transmissions have a taller gearing than the newer ones.

Now I will need to get my torque of my engine close to doubled, which will be achieved with the following: VE TDI | Malone Tuning Ltd. I was considering going with what they call in the TDI realms for hybrid turbo but I didn't I stuck to a factory one, so I will be doing the custom chip there which will give me around 100ft lbs of TQ more and will be most likely adding an SDI intake (here's one thread on that http://forums.tdiclub.com/showthread.php?t=196931 there's plenty more) which it appears will help LOW end TQ =(torque) since I am looking at doing 100km (65MPH) at around 1700-1800RPMS, still not final due to not having decided on 165/65-14 or 175/65-14 tires :)

Anyway all this (non alt topic) belongs in my initial thread:
http://ecomodder.com/forum/showthrea...2-12384-8.html

So to get THIS thread back to on topic I'd like to have input on alternator DIY disconnecting options that is anyone tried to get an automated on/off toggle for the charging of the alternator?