Odyssey PC680MJT install

FixedWing · 08-24-2005, 03:30 PM

Installed an Odyssey PC680MJT today.

I used a standard battery kit from a local auto parts store consisting of a plastic cross brace with metal J-hooks to hold it down. My original intent was to install it temporarily so that I could see if a PC680 was sufficient for my needs. But actually it worked pretty well! Light too.

On weight savings, I notice that the stock battery sits on a bolt-in platform. This is quite large. This could be removed and a substitute installed in its place. This would save weight and allow the battery to be mounted slightly lower in the car.

Too soon to tell how effective the battery will be but so far it is ok. I do notice though that the voltage of the dry cell battery is slightly below that of the wet cell that came out. Before, the gauge would be pretty stable. Now there is a difference between the charging voltage and the static voltage. I want to run it a little to make sure it is fully charged and then I will put a volt meter on to check it.

It is nice to finally be doing things that improve the car rather than fixing things that break. :-)

Stephen

Odyssey battery install, 24 August 2005

Imolavirus@BuehnEngineering · 08-24-2005, 03:31 PM

davenew · 08-24-2005, 03:58 PM

from earlier post:

The smaller PC680MJ looks darn good at 16lb (see link below.) It has 680 Cranking Amps for 5 Seconds. For reference, I just weighed the oem battery at 44lb.

zhenya · 08-24-2005, 05:03 PM

TwinTurboTerror · 08-24-2005, 05:09 PM

capacity that's causing that.

FixedWing · 08-24-2005, 05:34 PM

I'm in eastern Connecticut. Only way to know is to try it and see.

My feeling is that it should be pretty good. From reading the technical material, the battery can deliver a lot of power for a very short period of time. So the only problem would come if the engine needed to crank and crank. That shouldn't be a problem with these cars. The material isn't that clear but it appears that the dry cell should be less affected by the cold.

Anyway, ask me in March. :-p

Stephen

FixedWing · 08-24-2005, 05:39 PM

I think that the dry cell is designed to have a slightly lower voltage than the wet cell because it needs the voltage difference to charge properly.

I took some measurements this evening. With the alternator running, the car is at 14.1 VDC. With just the dry cell battery the voltage is 12.7 VDC. The wet cell battery that came out was 13.1 VDC disconnected.

So there isn't a lot of difference between the engine on/engine off voltage of the system with the wet cell in place. There is a bigger difference on/off with the dry cell in place. The small difference isn't noticable on the gauge with the wet cell. But it is noticable with the dry cell. The voltage, power off, on the gauge is definately lower than it was before with the wet cell.

Does it matter? I don't think so. Both batteries keep the car within spec.

Stephen

FixedWing · 08-24-2005, 05:44 PM

I think the best way to mount this battery is to remove the lower support bracket and then make a new bracket which goes around the side of the battery mounting between the two bolts on the back firewall where the original bracket was mounted. That bracket would wrap around the front of the battery and squeeze it back against the back firewall. This way it would be possible to mount the battery about two inches lower and the weight of the original bracket would be saved.

Stephen

BlackS4tt (Josh) · 08-24-2005, 06:46 PM

EdyJun · 08-24-2005, 06:50 PM

08-24-2005, 03:30 PM	#1
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	Odyssey PC680MJT install Installed an Odyssey PC680MJT today. I used a standard battery kit from a local auto parts store consisting of a plastic cross brace with metal J-hooks to hold it down. My original intent was to install it temporarily so that I could see if a PC680 was sufficient for my needs. But actually it worked pretty well! Light too. On weight savings, I notice that the stock battery sits on a bolt-in platform. This is quite large. This could be removed and a substitute installed in its place. This would save weight and allow the battery to be mounted slightly lower in the car. Too soon to tell how effective the battery will be but so far it is ok. I do notice though that the voltage of the dry cell battery is slightly below that of the wet cell that came out. Before, the gauge would be pretty stable. Now there is a difference between the charging voltage and the static voltage. I want to run it a little to make sure it is fully charged and then I will put a volt meter on to check it. It is nice to finally be doing things that improve the car rather than fixing things that break. :-) Stephen Odyssey battery install, 24 August 2005 __________________ ================================================== ======================

08-24-2005, 03:31 PM	#2
Imolavirus@BuehnEngineering Elder Member Account #: 33927 Join Date: Mar 2002 Posts: 17,986	what was the weight savings of the actual battery? __________________ -Jacob ^^^CLICK SIG FOR BUEHN ENGINEERING WEBSITE^^^ <big><big>Website Here!!!</big></big> <big>Items For Sale</big>

08-24-2005, 03:58 PM	#3
davenew AudiWorld Super User Account #: 70028 Join Date: Feb 2004 Posts: 7,828	44 -16 = 28lb from earlier post: The smaller PC680MJ looks darn good at 16lb (see link below.) It has 680 Cranking Amps for 5 Seconds. For reference, I just weighed the oem battery at 44lb. __________________ '00 S4 EPL Stg 3 (March'04-May'08) '08 BMW 135i Dinan Stg 2 (May'08-Present) '00 S4 Imola widebody AWE Stg 3 (Bought Nov'08. AWE stg 3 kit is sold.. I'm switching over to ASP GT soon)

08-24-2005, 05:03 PM	#4
zhenya Junior Member Account #: 70550 Join Date: Feb 2004 Posts: 1,122	Nice! What's the word with these in cold climates?

08-24-2005, 05:09 PM	#5
TwinTurboTerror AudiWorld Super User Account #: 3779 Join Date: Apr 2000 Posts: 13,279	I did the same thing with my 925. The voltage on mine doesn't jump around. Must be the 680's smaller capacity that's causing that. __________________

08-24-2005, 05:34 PM	#6
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	I think I'm about to find out... I'm in eastern Connecticut. Only way to know is to try it and see. My feeling is that it should be pretty good. From reading the technical material, the battery can deliver a lot of power for a very short period of time. So the only problem would come if the engine needed to crank and crank. That shouldn't be a problem with these cars. The material isn't that clear but it appears that the dry cell should be less affected by the cold. Anyway, ask me in March. :-p Stephen __________________ ================================================== ======================

08-24-2005, 05:39 PM	#7
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	I don't think so... I think that the dry cell is designed to have a slightly lower voltage than the wet cell because it needs the voltage difference to charge properly. I took some measurements this evening. With the alternator running, the car is at 14.1 VDC. With just the dry cell battery the voltage is 12.7 VDC. The wet cell battery that came out was 13.1 VDC disconnected. So there isn't a lot of difference between the engine on/engine off voltage of the system with the wet cell in place. There is a bigger difference on/off with the dry cell in place. The small difference isn't noticable on the gauge with the wet cell. But it is noticable with the dry cell. The voltage, power off, on the gauge is definately lower than it was before with the wet cell. Does it matter? I don't think so. Both batteries keep the car within spec. Stephen __________________ ================================================== ======================

08-24-2005, 05:44 PM	#8
FixedWing Senior Member Account #: 66531 Join Date: Dec 2003 Posts: 7,155	Thinking about this some more... I think the best way to mount this battery is to remove the lower support bracket and then make a new bracket which goes around the side of the battery mounting between the two bolts on the back firewall where the original bracket was mounted. That bracket would wrap around the front of the battery and squeeze it back against the back firewall. This way it would be possible to mount the battery about two inches lower and the weight of the original bracket would be saved. Stephen __________________ ================================================== ======================

08-24-2005, 06:46 PM	#9
BlackS4tt (Josh) AudiWorld Super User Account #: 68919 Join Date: Jan 2004 Posts: 8,882	is your Y-pipe abnormally close to the firewall or is it me? __________________ ================================================== ============= Email: blacks4tt AT yahoo.com VAST Tuned Stage III, Blouch 997 KO4s, Custom FMIC, Stoptech, OZ

08-24-2005, 06:50 PM	#10
EdyJun Member Account #: 48484 Join Date: Dec 2002 Posts: 2,849	it does look a bit too close. __________________ 2000 Audi S4 STG 3 FATS = 3.66 w/ 91 oct AIM: EdyJun 11 September 2001 In their honor. In their memory. <font color="red">---------------------------------------------------------- <u><big> <a href="http://homepage.mac.com/edyjun1/S4/index.htm">EdyJun's S4 Directory (FAQ, DIY, Info, Tips and Help) </a> </big> </u>---------------------------------------------------------- </font>

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