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Posts posted by JFP in PA

  1. 1 hour ago, laalves said:

    There is no way to properly test an alternator in the car, only in a bench, there's no way to cycle it to max load and back in the car.


    I would not bet on that, modern load testing equipment can load test the alternator in the car, and can even test the diodes' with it in there.  Units can be pricey, often $4K (US) or more, but will test the entire system.



  2. 28 minutes ago, laalves said:

    Any recent car has an electrical system designed to not let that happen, if working per spec. The alternator produces enough energy to all the consumers in the car at all regimes. The 996TT has a nominal 150A alternator which provides max current, if needed, already at idle. AFAIR, those Bosch alts max at 1300rpm (alt rpm, not engine). It's just 2.8HP stolen from the engine anyway. If a consumer requests more current, the regulator ensures that it is provided.


    What that behaviour tells is that the alternator and/or regulator were not to spec. From the moment you turn the engine on, the battery is not doing anything other than getting recharged from the starting effort. As one throttles up and down, the battery will serve as a sink that will smooth out voltage peaks, shielding the electronics from those peaks. Other than that, start the engine and take the battery out if you want to, engine will continue to turn happily, lights will remain on, music will continue to sound. Possibly fry the ECU as well since voltage peaks will not be filtered.


    If those cars needed a battery to have basic, stock consumers working properly at idle, the alternator and/or regulator was shot (or there is a severe current transmission issue) and those new batteries became very old very quickly because they wouldn't get properly charged.


    Sorry, but no, voltage and amperage out put of the alternators in question were dead on rated spec for the vehicle involved, and remained so under load; the weak spot was the amperage reserve, not the voltage reserve, in the battery during periods of high demand. 😉

  3. 34 minutes ago, laalves said:

    Let me try to get this thread back to its original intent: I bought a new interesting toy for my car and am sharing my experience with the other members. I have learned a lot in this forum, much more than I have given back and occasionally I try to share a bit of my knowledge and experiences here and in other forums I participate in. For quite a few years, I have been also giving back in financial support to help keeping the place up and running. 


    Let me also make a disclaimer: I don't work for or in any way am affiliated or have any interest in battery manufacturers, resellers, car dealers, workshops, race teams, whatever. I won't also go on to claim high levels of technical knowledge or authority on anything and certainly this is not the place to do so. You can look me up in Linkedin, that's where I believe to be the place to ruffle professional peacock feathers to try and get attention to gain some professional and hopefully, financial advantage. If you find me there, you can have an idea of my level of professional technical knowledge, if any.


    I come to places like this to have fun, proudly showing my toys and enjoying somebody else's as well as looking for help in solving technical problems and giving back when I can.


    I don't understand why this is happening in this thread, an insistence on demeaning a toy, copy/pasting specifications of a different battery to try and make a point against another battery because they look the same? What is this?


    Further, claiming that lithium batteries are no good to start a street car because one race team in one competition starts their cars with off-board AGM batteries and then switch to on-board lithium, thereby lithium are no good for street cars, is laughable. What do racing conditions and hardware have to do with street cars? Guess what, many race teams in many competitions change Michelin tires twice per race, thereby Michelin tires are no good.


    In these few days of use, this battery has been performing beautifully in the car, starting it without hesitation or hiccup and showing no signs of lack of power under any circumstance.


    If you have seen cars with their engines running and having issues with headlights dimming when the stereo or AC was running, then I suggest to check the electrical system in other elements other than the battery since that would be unrelated.


    Let me very clear, again: I'm not claiming any kind of superiority of the battery I bought over any other kind. I don't care.


    I'll be reporting back on this thread on my experience over time, so that others may have an idea on how good or bad this particular battery is for this particular application: Porsche 996 Turbo living in a temperate climate and sleeping every night in a garage where temperature never goes under 18ºC.


    No one here is "demeaning" your postings.  Our intent is to help people with problems, and provide some educational context for all readers to consider when considering potential purchase decisions.


    My comment on headlights dimming was a real world experience that has occurred more than once when customers with light weight Li batteries brought cars into the shop complaining of these problems. Subsequent testing showed their charging systems were performing completely within normal specs, but when the AC clicked on, or a strong base section hit the stereo system, the lights dimmed because the available reserve amperage capacity of the battery was not up to the conditions.  To demonstrate to the customer where the problem actually was, we put a brand new 800 CCA AGM battery in the car at no charge to the customer, with the agreement that they would return in a day or two to tell me what happened. In every case, they came back and said the problems had disappeared immediately and did not reoccur, and most purchased the battery we had installed for them.  Those that did not purchase the replacement battery at least left the shop understanding why the problem happened, and in every case remained a good client with a better understanding of their cars.


    As for race cars, as another poster mentioned above, they have relatively very low power draw when out on the track, so a light weight battery with enough current output to run the few electronics use is sufficient.  But when the car pulls into the pits and has to shut off for refueling or tires as required by the sanctioning body, the light weight Li battery was not up to spinning over the hot, high compression engine under restart, so they would plug in a high output conventional battery to get it going again. Under those conditions, reserve amperage capacity momentarily become critical, and demonstrates the limitations of lightweight batteries.


    At the end of the day, it is your car and your money.  The battery you installed may serve you needs well in the climate you reside it, but for someone living in northern Montana, where the snow is already on the ground and daytime high temps are in the mid teens Fahrenheit, it might not be such a good idea.  So context becomes important.

  4. The Li battery business is suffering from a similar problem that the light bulb business had when switch from incandescent to LED.  People had long associated bulb wattage with light level output, even thought wattage was actually measure of how much energy the bulb consumed and heat it generates rather than light output levels.  So when consumers saw that an LED replacement for a 7 watt night light bulb only used 1.3 watts of power, their immediate assumption was that the LED would be much dimmer in light output than the incandescent bulb, which was anything but correct; and that stalled acceptance of the LED replacements for a period of time.  Fortunately, there was another widely accepted scientific standard for light output: Lumens  So when comparing replacement bulbs, consumers discovered that a 25 watt incandescent bulb and a 3 watt LED bulb both produced 130 lumen, meaning they were equally as bright, and that a 40 watt incandescent had the same lumens as a 5 watt LED, consumers now had a sound and reproduceable way of relating the product specs to their needs.


    Unfortunately, no such relatable second scientific measure currently exists for comparing conventional batteries to Li based units amperage performance under the same conditions.  As as shown by the comments I quoted above, even within Li battery manufacturers there is no mutually agreed upon "equivalency" standards that either the BCI or SAE could buy into, much less help consumers make purchasing decisions.

  5. He also went on to state that you could use their lightweight Li battery in a daily driver, "..as long as it is not used in cold weather.", without defining how cold that weather really was.


    Li technology for automotive use is a relatively new and evolving technology, and a very interesting one at that.  But like most emerging tech, it still has a bit of the "wild west" in it that will shake out over time, but using "equivalencies" that seem purposely deceptive to sell the products is not helping their case any.

  6. Here is an interesting published statement by a representative of the Antigravity Li battery company about their use of "equivalency ratings" used by Li battery manufacturers:


    "Unfortunately for you consumers....the waters are muddy because none of the lithium battery company put the ACTUAL and REAL Amp Hour of the Capacity ON the Battery itself.... For example most of the battery companies including Antigravity go by a "PB-EQ" (means-"lead-acid equivalent") rating which is essentially stating what size our Lithium Battery is roughly equivalent to the Starting ability of a Lead/Acid Battery. And even this PB-EQ rating is not accurate because a company like Deltran, who makes the Battery Tender lithium battery version will state they offer a battery that they claim is equivalent to a "20 amp hour lead acid battery" yet the size of the lithium battery pack inside their battery is actually only 7 REAL AMP HOURS. At the same time a company like us, Antigravity, will claim we offer a battery that is equivalent to "20 amp hour lead acid battery" yet our lithium cell pack will be 12 REAL AMP HOURS... "


    I particularly like the "roughly equivalent" statement.

  7. 3 minutes ago, Silver_TT said:

    Ya and I see they are using Red Tops as the starter, that makes perfect sense.  Since they are only using the LI battery to supply reserve energy, does that make it a "deep cycle" LI battery?


    I looked into batteries a lot when I did my swap this summer so went from knowing nothing to knowing a little.  Like you are saying, some of these LI batteries can get to dizzying costs.  Like look at #3 on this list -- it's $1,000 cash (and the $300 Optima which you can get for $250 at AAP beats it to take second place).  



    Are you looking for the best deep cycle battery? If so, here is a guide for you. Know what to expect from this battery. Finally, compare the


    In my next life I want to come back as JFP's kid......or at least his next door neighbor.


    If there is one thing all Li batteries do not like, it is being overly discharged (read deep cycled), which really damages them.  This is why many newer Li batteries have a "BMS" or electronic battery management system included in their construction, which will step in and cut off the battery before it gets into an overly high discharge condition.  Most Li battery BMS systems also include thermal protection as Li cells do not like getting very hot either.

  8. Li technology is very interesting, but also quickly evolving. One way to look at light weight LI batteries to to watch what happens with race teams at the track; most serious race cars run Li lightweight batteries with one major caveat: they  don't use them to start the car, only to supply energy reserve while the car is running. For starting in the pits they hook up a conventional AGM battery:




    There are Li batteries that are fine for daily drivers, with high CCA ratings, but they are also not super lightweight and expensive because they are relatively low production item.  Even Porsche released an Li battery for street use, but it was over $1700 at retail.

  9. 5 hours ago, laalves said:

    Now I noticed where you picked that, it’s the wrong battery: 


    The perfect battery for your EV, PHEV or HYBRID vehicle. Delivering reliable, environmentally friendly and safe power to start PHEV and...

    that one is for EVs, PHEVs and the like.




    They both appear from their dimensions and other specs to be the same battery ("Starter Battery - 68Ah EqPb lead-acid/AGM/GEL equivalent", etc.), but with different terminals.

  10. 3 hours ago, laalves said:

    Right, so out of curiosity, just emailed the manufacturer in Australia and they replied in about 30 seconds:


    "The RESTART9 is nominal 24Ah and 800CCA."


    Not toooooooo different from my guestimation.


    If it truly was, it would be purely luck.  Interestingly the battery manufacturer's website says, and I quote, "up to 400CCA for ICE engines in HYBRID models with 900CA available at the press of the button" (notice we are jumping from CCA @ 0 F to CA ratings @ 68 F in that statement), apparently referring to its reserve cell capacity when a button is manually depressed, but at 68 F, not 0 F; and goes on to state, "Specifications: 68Ah PbEq, 400CCA with Push Button Reserve", so at 400 CCA (without the manual reserve button depressed) it has about 1/2 the cold cranking power of a conventional or AGM lead/acid battery of 800 CCA.  


    As with most lightweight Li based batteries we have seen in the shop, it is low on amperage capacity.  Every one we ever saw suffered from low capacity problems (headlights dimming when the stereo or AC was running, poor starting in cool/cold weather, etc.).  There is no such thing as a free lunch.


    Have a nice holiday week end.

  11. 5 minutes ago, laalves said:


    I was comparing the small lithium battery values in my bike its mfg published (real Ah vs "PbEq" Ah; CA and CCA) with the bigger lithium battery in my car, for which the mfg only published "PbEq" Ah and CA and since it's more or less apples to apples (LiFePO4 to LiFePO4) I was making an approximation to come up with possible missing values for the bigger battery. Given there's a relatively hight probability that the same Chinese manufacturer made the LiFePO4 cells in both (BYD, CATL, AVIC, etc), it's not too bad an assumption.


    Actually, it is not.  You simply cannot take values for a smaller battery and extrapolate them to a larger unit, or visa versa.  There are many other factors (internal conductivity, heat retention, cell pack, conductor resistance differences, etc.) that complicates such a mathematical solution attempt to the point of being unreliable. This is why battery manufacturers continually test their batteries to see how they rate rather than attempt calculated performance projections.  If it was simply a matter of extrapolation, life would be a lot simpler in the battery business, they could save a whole bunch of money by not testing or having large test facilities, plus the technical consortiums (BCI/SAE) who's standards they have agreed to adhere to require actual repeatable test data rather than extrapolations.

  12. As someone that spent a significant part of his career in the battery business, your use of "assuming the proportions are the same" is more than seriously flawed.  The CCA test used by the BCI (Battery Council International, the international technical consortium that sets standards for battery ratings and testing procedures used by battery manufacturers world wide) is very similar to the one used by the SAE (Society of Automotive Engineers); which requires storing the finished and fully charged battery a 0F (-17.8 C) for a period of 24 hours, then load testing it to determine its CCA rating.  There is no known "proportioning" formula for determining this value, only hard testing data.


    Lightweight battery manufacturers have been "inventing" unique rating values and "equivalencies" without a basis in technical facts, and that are really totally meaningless, simply because they know what the outcome of publishing the more widely accepted testing data would be: Their batteries would appear weak compared to conventional SLI (starting, lighting, ignition) batteries.

    • Like 1
  13. I would also like to know the unit's cold cranking amperage (CCA run at 0F after 24 hours), not the cranking amperage (CA which is done a 68 F) in the specs.  A lot of these small, lightweight units are fine for race cars, but fall flat on their faces (literally) trying to spin over an engine at 20 F. 

  14. We always did it on a lift with an engine support bar under it before we undid the mounts.  You only need to drop it a couple of inches to make getting at it much easier, not out of the car.  Usually, the nut on the ground is not in bad shape, and a quick spray with a good penetrating oil always helps. Just be sure to wipe it off before putting it back together again, and put a small dab of anti seize inside the nut.

    • Like 1
  15. 13 hours ago, laalves said:

    Hi all,


    As I’m changing the battery, I’m checking the whole charging system as well. I measured the battery to ground cable: 0,5 Ohm and the battery to distributor: 1 Ohm. Would these be normal values?
    I’m going to remove them and clean the contact areas to see if those values go down as they seem excessive, with so short and thick cables.

    Also tempted to simply buy new ones, the ground is just 15€, the other is more, 47€.

    I‘m getting 13.6V engine running with no loads and 13.2V all loads on. It’s not bad but I wouldn’t mind having closer to 14V.


    The correct test for the primary cables is voltage drop rather than resistance.  No primary cable should show a drop of 0.5 V, if they do, they should be replaced regardless of what resistance testing shows.

    • Upvote 1
  16. 1 hour ago, JE 17 said:

    The situation: Bought this 2002 S with a bad engine. Replaced it, now getting the P0336 for bad crank sensor. Per past posts here, have checked out the sensor from the new engine and the old one and both are fine at about 880 ohms between pins 1 and 2 and infinity to pin 3. 

    My question: is there something simple I should examine before hauling it somewhere to get the wiring tests done? Yes, I've checked fuses and relays but as you know, the DME won't allow the fuel pump to run without a crank sensor reading.


    Your next step would be to see if the DME is actually seeing any signal from the CPS, which requires a PST II, PIWIS, or similar oscilloscope diagnostic tool.  You could also check the wiring harness for continuity to the DME; pin 1 on the sensor should lead to terminal 78 on the DME, pin 2 to terminal 20, and pin 3 to terminal 28.  If any of those circuits shows a lack of continuity, you have a wiring issue.

  17. 1 hour ago, greg0078 said:

    Recently I heard a knocking noise on the right hand side of the engine.  After idling for a few mins it goes away.  It appears when i do not start w/ the heat/ac controls turned on I do not hear the noise.  2001 carrera cab 64k miles

    I saw another thread which ppl though it could be tensioners, piston/camshaft.  


    Anyone seen this issue and resolved?


    Unidentified sounds like this can be something small, like a loose part, or they could be something much more serious.  Unless you can isolate the sound source, I would recommend not driving the car and flat bedding it to someone that can do more intensive diagnostics for you.

  18. I think the biggest obstacle you face is the leveling system, as even though you fit the mechanical parts, your DME does not have the programming to make it work, and even Porsche has proven to be reluctant to reflash the computer for this purpose.  And without that, the car will fail inspection anywhere in the EU.


    The washer stalk does have a distinct cap which indicates the action required to activate the washers.


    This is a file done by someone that tried this, but it does not address how to get the DME functional: 



    This may also prove useful: http://www.skylersrants.com/Porsche/Litronics/Instructions/Litronic11-02.pdf

  19. 2 hours ago, SLAM said:

    Your lawyer is referring to tire professionals in a shop. They should not tell people to disable it or help them do it.
    if they do, then some slimeball lawyer from the insurance company might try to press a BS case against the shop if they think they can get money from the shop. 

    in any case, I wouldn’t take any legal advice from Renntech postings.


    I am a "professional" that has run his own shop for many years, and my lawyer was advising me as a business owner, based upon multiple legal actions brought against similar businesses, and it two cases, individuals who did it for former buddies that later sued them for damages, and won big $.


    The potential consequences simply are not worth the risk.  And no one here is offering legal advice, only our experience.........


    • Upvote 1
  20. 1 hour ago, SLAM said:

    the regulation requiring TPMS is for manufacturers, not for owners.  


    According to all the related industry literature I've read, and what my shop's legal consul has told me personally, it is a Federally mandated safety system, meaning that if you disable it, or show someone how to disable it, and the vehicle is subsequently involved in an accident, whomever did it (or showed someone how to do it) can be held both criminally and financially liable.  And in many states, the vehicle is considered "unsafe" and would not pass local inspection standards.  The same thing would apply to removing seat belts or disabling or removing the air bags.


    Proceed at your own risk..............................................

    • Upvote 1
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