Replacement Vehicle Battery

Many of us will soon be looking for a replacement vehicle battery, and John M. has been doing a lot of research to find the ideal replacement.   The Mopar battery (BB0H5500AB) identified in both my Specs section and my battery articles written a few years ago, has apparently been discontinued, and superseded by one or two others, and like most Fiat parts, seems to be overpriced. As Stefan reminds us in the first comment, Fiat has simply selected an existing Jeep battery that is a little smaller, so that it fits in the battery tray.

So what ended up being John’s best solution?  The exact Q85* replacement battery obtained from a Mazda dealership.  He writes:

I found an actual original factory battery source for our Spiders. Once again, it’s as simple as Mazda dealers.  The Q85 battery in our Fiats is the same factory battery as used in recent year Mazda 3’s equipped with something called “i-ELOOP”  (start-stop).

And apparently there is no substitute that will work for those cars, so Mazda dealers stock them – but in very small numbers. My closest Mazda store stocks just one and doesn’t order another until it sells (which they do regularly).  Local price here is $425.  Also online for about $320 not including what must be very expensive shipping.

The Mazda part number for the battery is PE1T-18-520-9U.  It is a Group 35 size battery.  The batteries that Mopar lists are in larger size groups and I don’t see how they could fit into the Spider battery tray.

[UPDATE 3/12/2022] John sent me this today:

My battery research of a while back is now out of date.  Then local Mazda dealers said they sold the factory Panasonic battery.  Because my original 6 year old factory died suddenly last week, I found that Mazda dealers near me now only sell Interstate batteries (but with the original part number and very high price).  Because of good past experiences with Duralast batteries from Autozone, I bought the one shown below.  Perfect fit including sleeve, much less expensive, and plenty of power.

Panasonic developed a Q85 battery exclusively for Mazda’s i-ELOOP vehicles, to be used with a non-standard alternator and a capacitor, as explained in this article that John found.

The i-ELOOP system uses a unique variable voltage alternator that can produce up to 25 volts during deceleration. The electricity that is generated during deceleration is not sent directly to the vehicle’s battery, because the battery cannot store more than 12 volts. Instead, the capacitor stores the electricity, up to the 25 volts produced by the alternator.

The Q85 battery that Mazda has installed in our cars is more generic, is only designated as Stop-Start, and is a flooded cell lead-acid battery apparently produced by a few companies, one example of which is shown in the top photo. If the price is right (and you can find one), that battery, made by Bosch @ 620 CCA would fit perfectly!

Replacement Battery: As an alternative to the spec battery, FIAT has recommended that U.S. dealers install their stocked H5 battery (currently MOPAR # BB0H5500AB), which fits OK, although slightly smaller in height and capacity (500 CCA). 

See my battery article for other BETTER alternatives, which include good-value and readily available Group 35 (and Group 51R) batteries, unlike the Q85, at least here in the U.S.

*  Q85 Specs


19 thoughts on “Replacement Vehicle Battery

  1. This should be an easy check for compatibility.

    Fiat replacement(ish) Mopar BB0H5500AB:
    Group D23 or D23L or H6 [correction by ameridan: H5] is the battery size and post (pos/neg) location. Just make sure the size is similar/smaller than OEM, and the negative/positive posts are lined up the same and not reversed.
    This has 500 CCA (cold cranking amps), mandatory buy anything >500 CCA
    Also has 60Ah (amp hour, how much energy it stores), recommended buy anything >60Ah [photo added by ameridan]

    The original Mazda Q85 is Group 35 at 65Ah and 520 CCA, so those should be your minimums.
    Optima Yellowtop seems to be a common replacement for Mazdas.

    Liked by 1 person

    • Thanks for the reminder Stefan. I reworded the article to reflect that Fiat is selecting an existing Jeep battery that is a little smaller, so that it fits in the battery tray.


      • The Q85 Bosch looks like it may be a good alternate choice and available in many countries but I’m not finding a USA supplier. Is there one I’m missing?


      • The Bosch battery, like the Panasonic, seems to not be readily stocked/available, because people are making do with lower- price alternatives, that aren’t necessarily designated for start-stop.


      • When the time comes, I plan to go with the OEM Panasonic from a Mazda dealer. In part because my original has already outlasted the factory batteries in every other car or truck i’ve bought new in the last 15 years (Examples: Volvo and Ram both well within vehicle factory warranties)..

        Liked by 1 person

  2. I’ve also been doing some research on sourcing replacement batteries. A lot of Mazda owners seem to have been replacing their Q85 EFB units with AGMs. Since our cars have neither i-Eloop nor start/stop, I wonder whether what luck folks have been having with AGM replacements (CCA similar, size and terminal layout matching, of course). Seems the AGMs I’ve seen are costing quite a bit less than the Q85 EFB units,whether they are Panasonic/Mazda at USD $320-$475, or the Bosch, which I haven’t been able to find a US supplier for. I do have a list of Texas Bosch deaers that I’ve yet to go through. I did see that Hankook/Atlas BX makes a Q85 model, and they are now producing batteries in the US, but I haven’t tried to locate one in the US yet. So even though my OEM battery is holding up for now, I’m trying to be proactive in figuring out what to do when it fails.

    Liked by 1 person

    • An AGM battery can be a good alternative. I have them in other vehicles. In general, AGM batteries can hold voltage longer without charging than traditional batteries which is great for vehicles not driven daily. But (there’s always a “but”), when an AGM sits long enough to drop below about 10 volts, traditional older chargers can declare the battery to be defective. Often not true, but then chargers not designed for AGM won’t work without some trickery involving the use of a fully charged battery in parallel plus a volt meter and stop watch. So if your car gets stored off season, or is started just often enough to keep oil in its “brick”, an AGM capable battery maintainer will be a good idea. And be sure it has manual voltage selection rather than automatic 6V/12V. I let an AGM degrade below 10V once and my automatic charger thought it was a 6V battery! I had to buy one that could be manually set to 12V and that worked fine. Or just get an AGM and drive your 124 Spider a lot all year. That will be fine too!

      Liked by 1 person

      • Thanks for that summary John. AGM is not something I have experience with, and technology advancements all seem to have their own set of pros and cons.

        [off topic]
        I just bought a Jackery Explorer 300 solar generator, and got educated on MPPT vs. PWM charge controllers (only manages the internal Lithium-ion battery charging), 60W PD USB-C (I had no idea USB will handle 60 watts now!), pure sine wave AC inverter, and why 12-volt devices like refrigerators require regulated 13.8 volts from the 12-volt port.

        A solar panel might be a good power source for charging the Spider’s battery, for those storing the vehicle where no other power source is available. It could be placed in the windshield, if the car is exposed to sunlight, but make sure there is a charge controller (MPPT is the most efficient) in between the panels and the battery for overcharge protection.


  3. Yes, I miss the simpler times (a little bit) when there was only one kind of car battery and you just bought another one the same size maybe with higher electrical capacity. New tech is great but comes at a price.


  4. Well, I now get a flashing start button when I fire up the Spider, and I’ve replaced the fob battery so I’m leaning towards it being the 5+ year old OEM battery beginning to die on me. I’ve got it hooked up the NOCO Genius 10 doing a full charge (it showed as 75% when it got hooked up), and when that’s complete, I’m going to run a full conditioning/repair cycle on it.

    I know this is a bit of a Zombie follow up question, but are there any folks here who have purchased the Optima Yellowtop personally, and are able to share their opinion of the battery’s reliability and warranty claim processing? I’ve been proactively researching Group 35 batteries, and see a few decent options. But I sort of like the Optima aesthetically. BUT, they get a huge amount of negative reviews on Amazon. I typically take those negative reviews with a grain of salt since it’s usually people who have bad experiences with products who make the effort to review. So human nature being what it is, the reviews typically tend to bias towards negativity. That all said and done, I do very much respect the opinions of other Spider owners as we’re sort of like family and a lot of us know each other so some degree.

    So, anyone have experience with the Optima (yellow or red top) that they can share? TIA


  5. Mark, I don’t know if the recessed terminal posts will accommodate the wiring harness, especially the negative terminal with the (fragile) current sensor attached (similar to H5 below).


    • Aha, yes, good point, thanks for the heads up.
      Apologies if I sent multiple posts, I kept getting a request to login to WordPress at which point my post disappeared with no confirmation. I now think it may have been the approval process.


  6. Group 35 doesn’t appear to mean much in the UK. Here’s a branded battery without terminal recess. Dimensions look as though the cover should fit and it’s only £60 at with a 4 year warranty.
    D47 Varta Blue Dynamic Car Battery 12V 60Ah (560410054) (005L)


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