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Expected current draw when ignition off?
I've just replaced a 10 year old battery that tested bad, which would go flat after a few days. In addition to the battery simply just being worn out, the previous owner seemed to think there might be an abnormally high draw on the battery when the ignition was off that was contributing to the old battery's tendency to go flat in a few days.
Upon installing the new battery, I did note that there was a not insignificant arc (not big, not small, just notable) when I connected the final terminal. I haven't put a meter on it yet to measure the amperage between the positive post and battery lead with ignition off, but I plan to measure it in the next day or so. In the meantime, what would be the typical amperage draw with the key off that I should expect to see? . |
I've seen numbers around 0.5A after engine shutdown, then 10-15 minutes later, 0.05A. The computers in our car were state of the art back in the mid to late 80s, but not nearly as intelligent as today's which draw very very little power when inactive. Aftermarket alarms are notorious for high parasitic draw. There was a TSB for pre-1992 cars about parasitic draw and dead batteries. The solution? Install a bigger battery tray and battery... My 1992 had the modification done at the factory. |
Originally Posted by NTL1991
(Post 1914234)
I've seen numbers around 0.5A after engine shutdown, then 10-15 minutes later, 0.05A. The computers in our car were state of the art back in the mid to late 80s, but not nearly as intelligent as today's which draw very very little power when inactive. Aftermarket alarms are notorious for high parasitic draw. There was a TSB for pre-1992 cars about parasitic draw and dead batteries. The solution? Install a bigger battery tray and battery... My 1992 had the modification done at the factory. Well, now that is interesting... the battery that is specified for my 1994 that I just bought, and the old one that I removed, are a bit narrower than the battery tray. A previous owner has actually placed small ~1/2 inch blocks of wood on each side of the battery so that it can't move from side-to-side. The battery that all the automotive shops specified are of the size: Battery Group Size Designation: H5/LN2 Battery Height: 190 mm - 7 1/2 in Battery Length: 246 mm - 9 11/16 in Group 47 battery is used on multiple cars including European, Asian and Domestic. It may also be referred to as Group Size 47, L2 or H5 battery. Group 47 batteries are 9.7" (Length) x 6.9" (Width) x 7.5" (Height). The positive terminal is on the right side of the battery. Terminal type is post. Typical cold cranking amps range between 290A and 650A while reserve capacity ranges between 75 and 110 minutes. Do you have a reference to the TSB that specified a larger battery to see if Jaguar recommended a battery larger than the H5 and to what size, or if they were raising the specification to H5? . |
I know it originally spec'd a DIN55 and was upgraded to a DIN66 after the mod. ALL battery interchanges that I've found for my 1992 have listed the wrong size (DIN55). This was a TSB in 1992 so no mention of a V12. :P I had the same issue with my 1996 XJ16. It uses a bigger, longer battery than the XJ6, but ALL auto parts stores called for the smaller XJ6 battery, even though it was clear larger battery was required by the bracketing in the trunk. I had to have the service manager (this was Sears) come out and visually see the old, larger (correct) battery in my trunk to convince him when I got a replacement. "Oh yeah, I guess the computer is wrong..." Do not trust ANY info on batteriey sizingother than Jaguar's. |
Okay, so some info on this...
The XJ12 1994MY Introduction Guide lists the changes over the 93MY XJ6, nothing about a larger capacity battery is listed. It does list a 120A alternator, however. So opening up the 199MY Sedan Range Guide, I see the battery listed as a 72Ah battery. That would be the same for your XJ12 too. |
Well, the Autozone battery I bought doesn't mention DIN sizing, but it's general specifications exceed the DIN55 specifications I find online, and are in line with DIN66 although the case is about of the battery I bought is about 30mm shorter in length than most of the DIN66 I can find.
https://batterytown.co.nz/products/din55 https://batterytown.co.nz/products/din66 What I bought at Autozone: https://www.autozone.com/batteries-s...0_707394_25698 There is no mention of AH rating for any of these. Are you suggesting the battery I bought is correct, even though a little shorter in length, or not? . |
Well I wouldn't necessarily say that DIN66 is the correct size. It is for my 1992 which has the battey underhood. I would check interchanges to look up Ah ratings for the batteries you're interested in or look up a Group Size Chart to see the biggest battery that'll fit in the space provided |
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Here is a TSB Jaguar recommended battery fitment.
Unfortunately TSB 86-119 is a PAPER document that was not converted to .pdf when I worked at the dealer. We stopped getting PAPER TSBs sometime in the early 2000s and were directed to use the online USERNAME/PASSWORD site to logon and read/download TSB and Service Actions/Recalls. I probably have it in a 3 ring binder in a plastic tub with all my old manuals. H6 is the recommended battery if the larger battery tray was retrofitted. bob |
Originally Posted by motorcarman
(Post 1915310)
Here is a TSB Jaguar recommended battery fitment.
Unfortunately TSB 86-119 is a PAPER document that was not converted to .pdf when I worked at the dealer. We stopped getting PAPER TSBs sometime in the early 2000s and were directed to use the online USERNAME/PASSWORD site to logon and read/download TSB and Service Actions/Recalls. I probably have it in a 3 ring binder in a plastic tub with all my old manuals. H6 is the recommended battery if the larger battery tray was retrofitted. bob Thanks Bob, that is very helpful. I'm sure a lot of owners are unaware and continue to fit the H5 because the parts store computers specify the H5. However, the H6/65 batteries cited in the document appear to be about 10-15mm longer than the battery tray fitted in my car, even though the H5 battery is also about 30mm shorter than the tray. So it appears I have the original pre-TSB tray and an H5 seems too small and H6/65 will not quite fit. But I see all of you discussed much of this in the following thread, so maybe I need to do a bit more research and precise measuring before heading back to Autozone to perhaps exchange the battery: https://www.jaguarforums.com/forum/x...40-usa-143554/ . |
Length of the battery tray currently in my trunk: 11 1/16 inch (281mm)
H5 battery length: 9 11/16 inch (246mm) According to the thread I linked above, and a link below, the part number for the new battery tray associated with TSB 86-119 is DBC10489 and it pertains to XJ40's with VINs 594576 - 653469. Here is the other reference link: https://workshop-manuals.com/jaguar/...ort_discharge/ Some searching for part DBC10489 specifications only turned up one link: https://www.sngbarratt.com/uk/#!/Eng...3-b25a3eed62d1 depth: 29cm height: 5cm width: 21cm But as Don points out in the "under the hood battery" thread, his 93 with the H5/Group-47 battery takes a toll on batteries. So I guess I'll have to do some research to see which DIN/Hx/Group-x battery meets the DIN66 power capacity spec called for in the TSB but will fit the later VIN trunk mounted battery tray. DIN66 battery size specs: Length (mm): 275mm Width (mm): 175mm Height (mm): 190mm Looking at US suppliers, cross referencing a DIN66 isn't proving too successful, but as pointed out before it does come close to an H6 Group 48 for some models. I've seen some H6 such as the Autozone Duralast Gold H6 with a length of 306mm which is too long, but the Autozone Duralast Platinum H6 would be a good fit as it is 278mm. The Autozone Duralast Platinum H6 has about 100CCA over the H5, and 20 more minutes of reserve, so that may be a good option that both fits the tray and offers some additional capacity. . |
Whatever battery you get, always disconnect it if you're going away or not using the car for a couple of weeks or so.
Larry |
OK, have exchanged the battery. The Autozone Duralast Platinum H6-AGM is a perfect fit for the battery tray.
https://www.autozone.com/ignition-tu...0_609415_25698 . |
Al,
Sorry to join so late but for future readers, on our '93 XJ6 I think I recall measuring 30-35 milliamps of quiescent current with all the doors closed, the interior lights off, and after all systems including the security system had gone to sleep, which can take 60 minutes or more. I know you're aware of this, but for other readers an important consideration on Jags that can make you suspect a parasitic drain is that corrosion on the battery power connections and grounds can lead to low charging voltage at the battery and premature battery failure. It's laborious to go through and clean all those connections, especially at the fuse boxes and the firewall connection on the passenger compartment side, so at the very least do the ones that are easier to access. I'd start with the alternator, the jump-start terminal on the firewall, the engine ground strap and the battery ground, then do the others whenever you're working in those areas. Cheers, Don |
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P.S. I found the attached document in my files which contains quiescent current data for several Jaguar models.
Cheers, Don |
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