Simply,..a BIG Battery install,..1989
01-22-2011, 10:19 PM
#16
Rennlist Member
Excellent point! With the appearance of acid damage in the crossmember area underneath, including mine, is the reason I went Optima a few years ago. If acid gets out of the battery, it is almost impossible to completely neutralize it all once it gets in the pan.
+1
Stopped using conventional lead-acid batteries in my classic Porsches years ago.
Why live with risk of an acid spill if you can avoid it entirely? Maybe I'm just being overly cautious in my old age!
Hope the new battery gives you many years of trouble free service dshepp! Good job being pro active and replacing the old battery before it has the chance to ruin your day. Let us know how the disconnect works out for you.
Phil
Stopped using conventional lead-acid batteries in my classic Porsches years ago.
Why live with risk of an acid spill if you can avoid it entirely? Maybe I'm just being overly cautious in my old age!
Hope the new battery gives you many years of trouble free service dshepp! Good job being pro active and replacing the old battery before it has the chance to ruin your day. Let us know how the disconnect works out for you.
Phil
01-23-2011, 01:13 AM
#17
"Decided to go with Wrench's recco, INTERSTATE Battery, MTP 93, big boy."
Actually, use of those large batteries are NOT a good idea for a 911 3.2.
When I initially bought my 3.2, removal of the large capacity battery was one of
my first fixes. To my many Porsche independents and dealers in SoCal, I always
recommend NOT using that type of battery on a 911 3.2.
Here's why. An alternator with its regulator is a constant voltage source as apposed
to a generator-regulator unit which not only regulates voltage but has a current
limiting relay in the regulator. A constant voltage source theoretically will supply
an unlimited amount of current in an attempt to provide the regulator voltage.
The alternator used in the 911 3.2 (and the late 911SC) is a Paris-Rhone internal
voltage regulator type. The regulator voltage is set at about 14.7 volts versus
a 964/993 Bosch alternator which has a regulator set at about 13.8 volts.
So when the 911 3.2 alternator is paired with a high capacity battery, i.e. the
over size type, excess charging currents result which can cause the alternator
to fail especially when the battery is low on charge.
The smaller capacity batteries will not consume large charging currents as their
voltage output rises more to match the 14.7 output voltage of the Paris-Rhone
alternator. The charging currents of the larger batteries can approach 70-80 amps.
With the Paris-Rhone alternator only rated at 90 amps, the margin of safety is
significantly reduced when considering just the fuel pump, ignition, DME alone,
and notwithstanding use of A/C or lights.
Actually, use of those large batteries are NOT a good idea for a 911 3.2.
When I initially bought my 3.2, removal of the large capacity battery was one of
my first fixes. To my many Porsche independents and dealers in SoCal, I always
recommend NOT using that type of battery on a 911 3.2.
Here's why. An alternator with its regulator is a constant voltage source as apposed
to a generator-regulator unit which not only regulates voltage but has a current
limiting relay in the regulator. A constant voltage source theoretically will supply
an unlimited amount of current in an attempt to provide the regulator voltage.
The alternator used in the 911 3.2 (and the late 911SC) is a Paris-Rhone internal
voltage regulator type. The regulator voltage is set at about 14.7 volts versus
a 964/993 Bosch alternator which has a regulator set at about 13.8 volts.
So when the 911 3.2 alternator is paired with a high capacity battery, i.e. the
over size type, excess charging currents result which can cause the alternator
to fail especially when the battery is low on charge.
The smaller capacity batteries will not consume large charging currents as their
voltage output rises more to match the 14.7 output voltage of the Paris-Rhone
alternator. The charging currents of the larger batteries can approach 70-80 amps.
With the Paris-Rhone alternator only rated at 90 amps, the margin of safety is
significantly reduced when considering just the fuel pump, ignition, DME alone,
and notwithstanding use of A/C or lights.
.... (sorry, just trying to be funny like Iceman)
01-23-2011, 08:42 AM
#19
Rennlist Member
Thread Starter
Thanks, Loren. I noted the charge current demands in my post #8. Your points are well-taken.
Although Porsche recco'd this battery size in its day, it won't be the first time where they maybe pushed things to the "rail", if you will.
The removed battery was a big boy with many, many years on it. I did change out the alt/VR several years back when it displayed a momentary over-voltage condition on more than one occasion. The removed alt was the original factory installed alt!!!!!!!! How's that for performance! What is the Bosch alt rated at? (I'll look). So,..I guess I've been lucky in that I've not had any leaking situation from a +6-7 year old battery and the original alternator lasted +20 years,..both good footnotes, I'd say.
Then, again, I do undertsand your electrical points (concerns) fully. As well, I understand other posters' views on complete avoidance of possible leaks. Guess I could have made a better choice, afterall. She's no garage queen and is driven several times per week. Maybe, for the next few years of usage of this battery, I'll place her on the battery tender should she not be driven for 3 or so days to assist with maintaining max charge and "help" with minimizing the charge current demands. Hell,..now I'd like to measure this charge current (and other load currents) to see how close this can be to the Bosch ratings (Is the Bosche rated a tad higher?) I would assume (also) that the diodes will be the ones to "take the hit" should currents be excessive in your noted scenarios.
I'm sure my Wrench will say that it's not an "overrated" battery but is, in fact, the one that came in it (essentially) and will not know much about the electrical numbers side of the game. I, however, AM interested and thank you for sparking another footnote relating to these large capacity batteries.
Next round, I'll reconsider the battery selection. To be honest, I'm FAR more concerned with the very points you made than I am about leaking batteries or weight. Back when I first heard that audible beep from the detector, notifying me of a momentary overvoltage condition, all I could think of was possible damage to the DME from an extended over-voltage condition. In fact, I recall (way back then) looking into the DME circuit to see if there existed any over-voltage protection circuitry on its incoming DC buss. As I recall, there wasn't any (zeners, etc)/ Since you repair these, Loren, have you ever considered installation of such to further protect the DME components in this condition?
I'd surely like to quantify what's happening electrically, in terms of current.
Oh well,....I think I'll look into this a bit more. Thanks, again, Loren for the information. I didn't really think this to be an issue, but see where it can be (dependent upon the Bosch alt rating).
BTW,..Loren, which battery did you select for your car?
AlfonsoR: Iceman IS funny,..so keep trying! (just kidding with you,..you funny, too). You couldn't be more correct on the Nitro!!!!!
Best,
Doyle
Although Porsche recco'd this battery size in its day, it won't be the first time where they maybe pushed things to the "rail", if you will.
The removed battery was a big boy with many, many years on it. I did change out the alt/VR several years back when it displayed a momentary over-voltage condition on more than one occasion. The removed alt was the original factory installed alt!!!!!!!! How's that for performance! What is the Bosch alt rated at? (I'll look). So,..I guess I've been lucky in that I've not had any leaking situation from a +6-7 year old battery and the original alternator lasted +20 years,..both good footnotes, I'd say.
Then, again, I do undertsand your electrical points (concerns) fully. As well, I understand other posters' views on complete avoidance of possible leaks. Guess I could have made a better choice, afterall. She's no garage queen and is driven several times per week. Maybe, for the next few years of usage of this battery, I'll place her on the battery tender should she not be driven for 3 or so days to assist with maintaining max charge and "help" with minimizing the charge current demands. Hell,..now I'd like to measure this charge current (and other load currents) to see how close this can be to the Bosch ratings (Is the Bosche rated a tad higher?) I would assume (also) that the diodes will be the ones to "take the hit" should currents be excessive in your noted scenarios.
I'm sure my Wrench will say that it's not an "overrated" battery but is, in fact, the one that came in it (essentially) and will not know much about the electrical numbers side of the game. I, however, AM interested and thank you for sparking another footnote relating to these large capacity batteries.
Next round, I'll reconsider the battery selection. To be honest, I'm FAR more concerned with the very points you made than I am about leaking batteries or weight. Back when I first heard that audible beep from the detector, notifying me of a momentary overvoltage condition, all I could think of was possible damage to the DME from an extended over-voltage condition. In fact, I recall (way back then) looking into the DME circuit to see if there existed any over-voltage protection circuitry on its incoming DC buss. As I recall, there wasn't any (zeners, etc)/ Since you repair these, Loren, have you ever considered installation of such to further protect the DME components in this condition?
I'd surely like to quantify what's happening electrically, in terms of current.
Oh well,....I think I'll look into this a bit more. Thanks, again, Loren for the information. I didn't really think this to be an issue, but see where it can be (dependent upon the Bosch alt rating).
BTW,..Loren, which battery did you select for your car?
AlfonsoR: Iceman IS funny,..so keep trying! (just kidding with you,..you funny, too). You couldn't be more correct on the Nitro!!!!!
Best,
Doyle
01-23-2011, 08:46 AM
#20
Rennlist Member
Thread Starter
My alternator is good for 115 amps, BTW,,..I'll doublecheck this, as I understood it to be a high output version (rated above the 90 amp world).........wasn't cheap, for sure.
I think I'll plan to quantity what's going on in the system next week and post my results. I would imagine an inductive probe (measuring peak) would suffice to give me the TOTAL current at FULL LOAD (in the car)...just to see what's being demanded.
Doyle
I think I'll plan to quantity what's going on in the system next week and post my results. I would imagine an inductive probe (measuring peak) would suffice to give me the TOTAL current at FULL LOAD (in the car)...just to see what's being demanded.
Doyle
Last edited by dshepp806; 01-23-2011 at 09:05 AM.
01-23-2011, 12:43 PM
#21
Pro
Join Date: Jun 2006
Posts: 633
Likes: 0
Received 0 Likes
on
0 Posts
[QUOTE=Lorenfb;8235290]"Decided to go with Wrench's recco, INTERSTATE Battery, MTP 93, big boy."
Actually, use of those large batteries are NOT a good idea for a 911 3.2.
When I initially bought my 3.2, removal of the large capacity battery was one of
my first fixes. To my many Porsche independents and dealers in SoCal, I always
recommend NOT using that type of battery on a 911 3.2.
------------
Here's an example using downsized DEKA 690MF and 520 CCA. Oversized Interstate about 47 pounds. This DEKA about 32. Simple modification of standard battery hold down clip required.
Porsche put that huge battery in to add weight to the front end. It's overcapacity has nothing to do with starting a small six cylinder engine with moderate compression ratio. Frankly, the Interstate is a pain in the *** to work around. Glad I made the decision with the smaller DEKA.
DEKA (East Penn Mfg) makes a number of batteries for Porsche replacement, AGM included.
Actually, use of those large batteries are NOT a good idea for a 911 3.2.
When I initially bought my 3.2, removal of the large capacity battery was one of
my first fixes. To my many Porsche independents and dealers in SoCal, I always
recommend NOT using that type of battery on a 911 3.2.
------------
Here's an example using downsized DEKA 690MF and 520 CCA. Oversized Interstate about 47 pounds. This DEKA about 32. Simple modification of standard battery hold down clip required.
Porsche put that huge battery in to add weight to the front end. It's overcapacity has nothing to do with starting a small six cylinder engine with moderate compression ratio. Frankly, the Interstate is a pain in the *** to work around. Glad I made the decision with the smaller DEKA.
DEKA (East Penn Mfg) makes a number of batteries for Porsche replacement, AGM included.
Last edited by sig_a; 05-29-2014 at 06:43 PM.
01-23-2011, 01:37 PM
#22
"What is the Bosch alt rated at?"
Bosch never made an alternator for the 911 3.2 nor the late 911SC, both of which
are problematic with the wrong battery. The rebuilt Paris-Rhone (only 3.2 alt) will sometimes
come in a Bosch rebuilt box. Bosch only contracts with rebuilders to have the Paris-Rhone
alt rebuilt and supplies Bosch shipping boxes. And, the alternator is only rated at 90 amps!
Whoever indicated otherwise is providing mis-information about its rating.
"I understood it to be a high output version (rated above the 90 amp world).........wasn't cheap, for sure."
Total hyperbole used to sell it at a higher price! Take a look at the old unit (if you had it)
and compare them. There're identical.
"I would imagine an inductive probe (measuring peak) would suffice to give me the TOTAL current at FULL LOAD (in the car)...just to see what's being demanded."
Yes, but that's only part of the total alt load. One must consider what a discharged battery
will demand plus the total electrical usage load is.
"I'm sure my Wrench will say that it's not an "overrated" battery"
Maybe time for a new 'wrench'.
As to what battery I use, in all my cars I use Diehards.
Bosch never made an alternator for the 911 3.2 nor the late 911SC, both of which
are problematic with the wrong battery. The rebuilt Paris-Rhone (only 3.2 alt) will sometimes
come in a Bosch rebuilt box. Bosch only contracts with rebuilders to have the Paris-Rhone
alt rebuilt and supplies Bosch shipping boxes. And, the alternator is only rated at 90 amps!
Whoever indicated otherwise is providing mis-information about its rating.
"I understood it to be a high output version (rated above the 90 amp world).........wasn't cheap, for sure."
Total hyperbole used to sell it at a higher price! Take a look at the old unit (if you had it)
and compare them. There're identical.
"I would imagine an inductive probe (measuring peak) would suffice to give me the TOTAL current at FULL LOAD (in the car)...just to see what's being demanded."
Yes, but that's only part of the total alt load. One must consider what a discharged battery
will demand plus the total electrical usage load is.
"I'm sure my Wrench will say that it's not an "overrated" battery"
Maybe time for a new 'wrench'.
As to what battery I use, in all my cars I use Diehards.
01-23-2011, 02:43 PM
#23
Rennlist Member
Thread Starter
Thanks, sig_a...that's a much "neater" arrangement for sure.
Doyle
[QUOTE=sig_a;8236062]
Doyle
[QUOTE=sig_a;8236062]
"Decided to go with Wrench's recco, INTERSTATE Battery, MTP 93, big boy."
Actually, use of those large batteries are NOT a good idea for a 911 3.2.
When I initially bought my 3.2, removal of the large capacity battery was one of
my first fixes. To my many Porsche independents and dealers in SoCal, I always
recommend NOT using that type of battery on a 911 3.2.
------------
Here's an example using downsized DEKA 690MF and 520 CCA. Oversized Interstate about 47 pounds. This DEKA about 32. Simple modification of standard battery hold down clip required.
Porsche put that huge battery in to add weight to the front end. It's overcapacity has nothing to do with starting a small six cylinder engine with moderate compression ratio. Frankly, the Interstate is a pain in the *** to work around. Glad I made the decision with the smaller DEKA.
DEKA (East Penn Mfg) makes a number of batteries for Porsche replacement, AGM included.
Actually, use of those large batteries are NOT a good idea for a 911 3.2.
When I initially bought my 3.2, removal of the large capacity battery was one of
my first fixes. To my many Porsche independents and dealers in SoCal, I always
recommend NOT using that type of battery on a 911 3.2.
------------
Here's an example using downsized DEKA 690MF and 520 CCA. Oversized Interstate about 47 pounds. This DEKA about 32. Simple modification of standard battery hold down clip required.
Porsche put that huge battery in to add weight to the front end. It's overcapacity has nothing to do with starting a small six cylinder engine with moderate compression ratio. Frankly, the Interstate is a pain in the *** to work around. Glad I made the decision with the smaller DEKA.
DEKA (East Penn Mfg) makes a number of batteries for Porsche replacement, AGM included.
01-23-2011, 03:17 PM
#24
Rennlist Member
Thread Starter
Thanks for the reply, Loren
I meant to ask "what the factory-provided alt ratings" were..Yes, I have understood this to be at 90 amps but wanted to verify. Thanks.
Loren, I'm not quite sure I fully understand your comment as to higher rated alts being "hyperbole". There are several selections out there to provide ratings higher than 90 amps, right? BTW, forget my comment as to high output on my 911 alt install,...was thinking of 944 -NOT 911, this one providing 115 Amp rating. I was mistaken (there). I guess I would ask that, should a certain alt/reg selection FITS, couldn't one get a higher output rated capable alt? ,...something north of 115 amps? Wouldn't this rating (alone) be considered a "high output" unit? Just asking for hyperbole definition, I guess. I don't have the removed original '89 alt/VR but will doublecheck what WAS installed (specs),..as you suggested, probably another Bosch 90 amp unit ..
As to the cranking specs (CA/CCA), what is considered the "adequate" spec to turn our engine? I notice that as one goes down in size (not Optimas, BTW?), so does this cranking spec (capability).
Noted: the CA (charge amp) requirement can greatly impact the alt (as you stated, there needs to be a proper "marriage" B/T alt/Reg and battery selection). Yes,..a BIG variable as to magnitude of demand (as you stated=a discharged battery would provide a worst-case scenario).
So, I would further ask: Are you running the 90 amp alt? If not, what do you run for alt/VR? And, which DieHard model? Also,.what are your rules for this marriage? (ALT-VR to battery)...It would seem to me that a higher charge current battery would warrant a higher output alt (increased current rating)--simply?
Thanks for the dialogue.
Doyle
I meant to ask "what the factory-provided alt ratings" were..Yes, I have understood this to be at 90 amps but wanted to verify. Thanks.
Loren, I'm not quite sure I fully understand your comment as to higher rated alts being "hyperbole". There are several selections out there to provide ratings higher than 90 amps, right? BTW, forget my comment as to high output on my 911 alt install,...was thinking of 944 -NOT 911, this one providing 115 Amp rating. I was mistaken (there). I guess I would ask that, should a certain alt/reg selection FITS, couldn't one get a higher output rated capable alt? ,...something north of 115 amps? Wouldn't this rating (alone) be considered a "high output" unit? Just asking for hyperbole definition, I guess. I don't have the removed original '89 alt/VR but will doublecheck what WAS installed (specs),..as you suggested, probably another Bosch 90 amp unit ..
As to the cranking specs (CA/CCA), what is considered the "adequate" spec to turn our engine? I notice that as one goes down in size (not Optimas, BTW?), so does this cranking spec (capability).
Noted: the CA (charge amp) requirement can greatly impact the alt (as you stated, there needs to be a proper "marriage" B/T alt/Reg and battery selection). Yes,..a BIG variable as to magnitude of demand (as you stated=a discharged battery would provide a worst-case scenario).
So, I would further ask: Are you running the 90 amp alt? If not, what do you run for alt/VR? And, which DieHard model? Also,.what are your rules for this marriage? (ALT-VR to battery)...It would seem to me that a higher charge current battery would warrant a higher output alt (increased current rating)--simply?
Thanks for the dialogue.
Doyle
"What is the Bosch alt rated at?"
Bosch never made an alternator for the 911 3.2 nor the late 911SC, both of which
are problematic with the wrong battery. The rebuilt Paris-Rhone (only 3.2 alt) will sometimes
come in a Bosch rebuilt box. Bosch only contracts with rebuilders to have the Paris-Rhone
alt rebuilt and supplies Bosch shipping boxes. And, the alternator is only rated at 90 amps!
Whoever indicated otherwise is providing mis-information about its rating.
"I understood it to be a high output version (rated above the 90 amp world).........wasn't cheap, for sure."
Total hyperbole used to sell it at a higher price! Take a look at the old unit (if you had it)
and compare them. There're identical.
"I would imagine an inductive probe (measuring peak) would suffice to give me the TOTAL current at FULL LOAD (in the car)...just to see what's being demanded."
Yes, but that's only part of the total alt load. One must consider what a discharged battery
will demand plus the total electrical usage load is.
"I'm sure my Wrench will say that it's not an "overrated" battery"
Maybe time for a new 'wrench'.
As to what battery I use, in all my cars I use Diehards.
Bosch never made an alternator for the 911 3.2 nor the late 911SC, both of which
are problematic with the wrong battery. The rebuilt Paris-Rhone (only 3.2 alt) will sometimes
come in a Bosch rebuilt box. Bosch only contracts with rebuilders to have the Paris-Rhone
alt rebuilt and supplies Bosch shipping boxes. And, the alternator is only rated at 90 amps!
Whoever indicated otherwise is providing mis-information about its rating.
"I understood it to be a high output version (rated above the 90 amp world).........wasn't cheap, for sure."
Total hyperbole used to sell it at a higher price! Take a look at the old unit (if you had it)
and compare them. There're identical.
"I would imagine an inductive probe (measuring peak) would suffice to give me the TOTAL current at FULL LOAD (in the car)...just to see what's being demanded."
Yes, but that's only part of the total alt load. One must consider what a discharged battery
will demand plus the total electrical usage load is.
"I'm sure my Wrench will say that it's not an "overrated" battery"
Maybe time for a new 'wrench'.
As to what battery I use, in all my cars I use Diehards.
01-23-2011, 03:23 PM
#25
Rennlist Member
Thread Starter
BTW (and for the record), I don't think I'll kick my P-Wrench to the curb over this....I would think that he considered this to be the same specs as the factory installed battery (maybe).....maintaining originality?
I didn't look up the CCA/CA on the removed battery so I don't know if THIS would be the spec he's referring to,..OR, if it were to do with current rating increase.
Hell,..he met me today at his shop to give me a fuel filter so I can finish this fuel repair /rework today. He's a good fellow,..and I'll certainly share this information with him...!!!
Doyle
I didn't look up the CCA/CA on the removed battery so I don't know if THIS would be the spec he's referring to,..OR, if it were to do with current rating increase.
Hell,..he met me today at his shop to give me a fuel filter so I can finish this fuel repair /rework today. He's a good fellow,..and I'll certainly share this information with him...!!!
Doyle
01-23-2011, 03:49 PM
#27
Rennlist Member
Thread Starter
So, it looks like Porsche kicked it up in Late 89 production (C4) with a 115 Amp alternator,..all previously were 90 ampers....? Correct? I would guess this 115 A alt doesn't fit within earlier '89's?
Doyle
Doyle
01-23-2011, 03:49 PM
#28
"I meant to ask "what the factory-provided alt ratings" were"
The standard alt in ALL 911 3.2s were rated at 90 amps.
"I guess I would ask that, should a certain alt/reg selection FITS, couldn't one get a higher output rated capable alt? ,...something north of 115 amps?"
I have yet to see ANY 911 3.2 alt with higher than 90 amps. Again, the only
alt available is the Paris-Rhone 90 amp. If someone is supplying it and
claiming a higher rating for that alt then they are saying hyperbole (B.S.
or smoking the funny stuff).
"Are you running the 90 amp alt?"
Yes, and it's fine as long as one uses the correct battery and doesn't rev
the engine to quickly charge a weak (fully discharged) battery.
The standard alt in ALL 911 3.2s were rated at 90 amps.
"I guess I would ask that, should a certain alt/reg selection FITS, couldn't one get a higher output rated capable alt? ,...something north of 115 amps?"
I have yet to see ANY 911 3.2 alt with higher than 90 amps. Again, the only
alt available is the Paris-Rhone 90 amp. If someone is supplying it and
claiming a higher rating for that alt then they are saying hyperbole (B.S.
or smoking the funny stuff).
"Are you running the 90 amp alt?"
Yes, and it's fine as long as one uses the correct battery and doesn't rev
the engine to quickly charge a weak (fully discharged) battery.
01-23-2011, 03:52 PM
#29
'So, it looks like Porsche kicked it up in Late 89 production (C4) with a 115 Amp alternator,..all previously were 90 ampers....? Correct?'
So, you really have a 964 Porsche (1989) and not a 911 3.2, as the '89 964 had the Bosch 115
alt which was used in the 993 also thru 1998. Again, no 911 3.2 ('84 thru '89) had any alt with a
rating greater than 90 amps.
Or maybe someone modified a 911 3.2 fan housing to use the 964/993 alt with the double
belt system and extended the engine compartment lid because of the double length shaft
on the 115 amp 964/993 alt versus the 911 3.2 alt shaft.
"A look into my Owners Manual shows (only) the following information:
Battery: 12 volts, 88Ah
Alternator: 1260 watts, 90 Amp.AC"
That's correct!
So, you really have a 964 Porsche (1989) and not a 911 3.2, as the '89 964 had the Bosch 115
alt which was used in the 993 also thru 1998. Again, no 911 3.2 ('84 thru '89) had any alt with a
rating greater than 90 amps.
Or maybe someone modified a 911 3.2 fan housing to use the 964/993 alt with the double
belt system and extended the engine compartment lid because of the double length shaft
on the 115 amp 964/993 alt versus the 911 3.2 alt shaft.
"A look into my Owners Manual shows (only) the following information:
Battery: 12 volts, 88Ah
Alternator: 1260 watts, 90 Amp.AC"
That's correct!
01-23-2011, 03:59 PM
#30
Rennlist Member
Thread Starter
I noticed that one of our common "vendors" offers a new "high output" alt,..units produce 95 amps, features high load bearings, an internal voltage regulator, and are designed and manufactured in Australia. Featured in Issue #105 of 911 & Porsche World. 12 month manufacturer's warranty.
Costing something NORTH of $700...!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! WTF?
Doyle
Costing something NORTH of $700...!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! WTF?
Doyle