Here's a couple of pictures of my voltage regulator mod. I dont think 14 volts is enough to proporly charge a battery especially when it's cold so I decided to use a ford regulator in place of the factory bosch.
It charges at 15.2 volts at idle.

Attached Thumbnails

   

I would like to see a pic of them side by side if you have them handy.....

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Would this modification have the same benefit of upgrading to a higher amp alternator?

__________________
Pictures of the MB: http://s230.photobucket.com/albums/ee41/EricandRobyn/1981%20Mercedes/

1981 300 SD with a Goldenrod water block and Injetor line heaters. EGR is missing

1999 F-350 with HP X-over, Dahl 100 Fuel Filter, Coolant by-pass filter, CCV mod, Tymar intake.

Both on single tank WVO blend

Actually, it is current that charges the battery not the voltage. Unless you are doing a lot of short trips when it's cold, the original regulator shouldn't be giving you a problem. I've seen more of a problem with bad connections causing poor recharging than anything else.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Negative! The 12 volt battery in your car has 6 cells that hold 2.2 volts per cell for a total of 13.2 volts per cell. In order to charge that 13.2 volt battery you need to exceed that voltage. On a cold day you need a lot more than 14v to charge a battery than you do on a hot day. If you have a modern car put a voltmeter on the battery with it running on a cold day. It was a little below freezing yesterday and my explorer was charging at almost 16 volts. Most if not all modern alternators have a temp sensor somewhere in that charging circuit for exactly this reason.
Remember the old wives tale about charging a battery on a concrete floor? It's hard to get a battery up to temp on a giant heat sink.
If it's only current that charges a battery try charging a 12v battery on a 6 volt setting. Those of you with old battery chargers will even have a high amp 6v setting.
It's not hard to exceed the current output of our alternators and this mod is never going to change that. But when your driving with only a few accessories on the battery has a much better chance of getting fully charged.

I believe it is due to the higher amp rating of newer alternators. It would not be a good idea to install a 24 volt regulator on these cars to speed up the charging.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Here are a couple of pics to show my ****ty wiring job.

There are three wires at the old voltage reg. 1 wire goes to each brush and the 3rd goes to ground. All you need the old regulator for is the brushes.

The new regulator (from an old ford pickup maybe) has 4 wires labeled I A F S. A goes to battery pos. F goes to one of the brushes. S goes to power from the key. I goes to nothing.

At this point you will have 2 wires remaining coming from the alternator. Combine these and attach to the case of the new voltage regulator. One of them is from one of the brushes and the other is from ground.

Attached Thumbnails

   

At 24 volts your past the point of diminishing returns. In fact you would blow up your battery and probably fry everthing in your car.
Even if the alternator in our cars could put out 150 amps and the max voltage output was regulated to 14v you would not fully charge that battery in cold weather. But you could run more accessories and not drop below 14v which would be nice.

Omegaman is correct. Even my '89 Nissan PU alternator puts out more voltage when it is cold outside vs hot. Typically, anything over 16 volts will boil your battery, and less that 14v will not charge it completely. Amps allows more accesories to run while still applying charging current to the battery.

Run your accesories and rear defogger and see what happens to the headlights, ventilation fan, etc. The less accessories running, gives higher fan speed, brighter lights, etc. IF MB gave us 110 amp alternators, we would not see the drop in power as accessories are turned on.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Sorry I didn't think to take before and after pic. I should mention that this will make your charging light work in reverse. When I get some time I'll fix this all I have to do is reroute one of the wires from the alternator. This problem doesnt affect it's performance.

"rear ended harder that elton john" LMAO!

Thanks, I'll be here all week........

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Just use this. the voltage is adjustable. Works fine (I've used several), but I recommend a little silicone seal over the adjustment screw as water ingress was a problem in early attempt.

http://www.transpo.de/Catalog/E_Cat.htm

Go to >browse catalog>regulator>bosch>IB372A or IB373A

Direct link will not work on the site, so you have to get there by "hand".

FWIW

The Volvo guys use this or a diode soldered in the regulator, as a resistor, to increase voltage output from the alt.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Here's the diode trick from the Pantera guys:

http://www.detomaso.nu/~thomast/alternator/

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Power formulas don't lie and have been proved over and over again........ as long as I have been in electronics (35yrs)............

P = I X E or P = I (squared) X R

According to formula, which gives you the most power?....... raising the voltage by 2 volts? or the amperage by 10, 20 or 50?

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

You want to really make sure the battery is maintained correctly? Install one of these: http://www.xantrex.com/web/id/107/p/1/pt/7/product.asp Thats a fairly basic marine unit but it is way better than any internal regulator. Of course you would have to be a bit nuts to want one of these on your MB. Or have more electronics installed than mission control..... RT

__________________
When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K