New battery choice

Yup, that might do it. Could probably camouflage my Interstate AGM with that.

 

My Interstate is now more than 5 years old and the LEDs on the CTEK started flickering recently. Not a good sign. I think an AGM is in order and I may go with the NAPA 9834 at $180. Made by East Penn in the good 'ol US of A. Anyone have experience with this one?

NAPA The Legend Premium AGM Battery BCI No. 34R 750 A Glass Mat

 

Likely an Interstate or Johnson Control manufactured battery, so if she fits, should be fine. May need longer J-hooks since the OEM ones are kind of short.

 

I will look for my J-hook stretcher! In the meantime, is there a source for longer J-hooks? I have seen reference to these being "too short" a number of times for otherwise acceptable battery fitments over the years...

BTW - the NAPA AGM is manufactured by East Penn - another large battery manufacturer similar to Johnson Controls. They supply to many brands, including NAPA, DEKA, Duracell, Everstart, Diehard, OEM batteries and many others. They also make the well regarded OEM Harley AGMs. Interstate is actually made by Johnson. In the end, most batteries in the US come from Johnson, East Penn or Exide and are made to a number of specifications. I don't think you can go wrong with any of them.

 

Gracias!

 

Those will complement my GM alarm horn nicely!

 

I see no evidence of any form of battery heat shield on my 97 550. Thoughts on adding something? Or not a big concern with the AGM?

 

Johnny,

Your 1997 550 didn't come with a battery shield. The shield made its appearance with MY1999. My 1999 550 came with one, but it went missing with a battery change made by a previous owner. I added one several years ago when they were still available...


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I had a Braille AGM battery at the time. It's been replaced with an Interstate AGM. The AGMs are very heat-resilient and were used during Desert Storm for that reason.

I'm not sure how effective that stainless steel plate is in protecting the battery but it's there nonetheless.

More important is the battery connection cover for the positive terminal. That also went missing years ago. I recently replaced it on recommendation by Dave (Ferraridriver).

Barry

 

Thanks you for the feedback, sir! I will then skip worrying about a heat shield - given the AGMs thermal robustness. And, the existing Interstate MTP-91 predates my ownership, so it has lasted greater than 5 years with no shield. It is completely dead now. Seems to have gone high impedance internally - and it did give me a few "weak starts" before storing it for the summer as fair warning. I did find a substantial "sleeve" covering the front of the positive terminal and planned on reusing that. I can't say if it's original fitment or not; however, it looks to be effective enough.

 

MTP-91s were great batteries. My last one was in there for 7-8 years. Just needed to make sure the vent tube was installed.

 

I have one in my 2002 456M GT. Fires up every time. Highly recommended.

 

No vent tube apparent anywhere on mine. No real evidence of acid damage. Surprising for it's age. I did not have any issue lifting it out of the car, as some have suggested can be a strain...

 

Johnny- You got lucky. Interstate sold a matching vent tube for the MTP-91 for ~$5, which dealers usually threw in for free.

 

As the battery went totally flat before I could get a 12V supply or charger on the system, can someone kindly refresh me on all the "relearning" procedures needs for the various ECUs? And, for future reference, can the system be conveniently backfed through the cigar lighter receptacle?

 

Here is a nice shortcut procedure gleaned from several WSMs.

Run Cycle



Run cycle.

Turn battery disconnect switch off and turn off all accessories (stereo, A/C, etc).
Let engine get completely cold or wait at least 30 minutes.

Reconnect disconnect switch.

Disarm immobilizer with the fob.
Insert key in ignition and leave for 30 seconds.
Turn ignition to on and leave for 30 seconds.
Turn ignition off and leave for 30 seconds.
Turn ignition on, wait for Check OK, and start. May have to push fob again if 120 seconds have elapsed since last fob actuation.
Let idle with no input whatsoever for 10 minutes.
Turn accessories back on and drive gently for 10-15 minutes at least.
You will have to insert stereo code, if required.

 

Funny I went through the same thing. Previous owner tossed the heat shield, positive terminal cap. Was a pain to find the stainless heat guard. I ended up buying the Braille battery last year... see how it holds up. Cranking power is awesome. I've had terrible luck with Interstate in all my vehicles but could just be me, one thing though is they replace them under warranty with zero hassles sometimes even after the warranty period

 

Update. The NAPA 34R AGM is a nondescript gray lump with a black top (the label ends up facing the firewall). The carry handle was convenient for hoisting it in to place - and it fit perfectly! No need for longer J-bolts. Works great so far. Early rating - 5 stars. And, at $179.95 - a great value. My indie Ferrari Shop owner's opinion is that all batteries have a finite service life, so why overpay for replacements. I will say, I was tempted to get the red and black Odyssey just because it would look so "right" in the car and they probably are marginally more well made. The "relearn" cycle went without a hitch. Ready to rock with the 550 again!

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Anybody tried one of these Antigravity LI/Ion batteries in a Maranello? Seems like an easy, if pricey (for a car battery), way of shedding 25-30 lbs of weight.
https://antigravitybatteries.com/products/starter-batteries/automotive/ag-t6-rs/

 

Coming down in price, but still and awful expensive way to save weight. A few years ago, equivalent Li batteries were around $1500.

 

I peeled all the NAPA stickers off too

 

I looked at Lithium but kept reading they get killed with heat. Not sure how true it is but didnt want to take the risk.