I've given up on selling AGM batteries to clients, regardless of the brand. Way too many warranty problems. AGM batteries seem to not like to discharge very far and then be recharged. Perhaps appropriate for cars that are driven everyday, but they all seem to work very poorly in a 928 application, which may sit, slowly discharging. for a week or two.

 

AS an option you can look at lithium... yes more expensive... but built-in WIRELESS Jump Starting, much longer life-cycle and if you let it over-discharge it will go to sleep and protect itself.

 

Which AG battery size would you deem appropriate for a 928 application?

Is the smartphone app required to make use of the battery?

What functionality does a client opting out of the smartphone app forgo?

 

HI Worf,

There is no Bluetooth Option on this battery... it is a WIRELESS KEYFOB that sends a signal to the battery. So you don't need an app. You get two with the battery... just leave one in your glovebox and the other at home for safe keeping... then if ever a dead battery just press the one in your glove box, start the car and drive away.

For sizing our books show the H7 also called a Group 94r. But if it has the same mounting as some of the other Porsches it can accept the H6, H7 or H8.

Last we have a product called the Battery Tracker that has an App and tracks the voltage of your battery at all times, and give you a real time voltage as well as 31 days or previous voltage readings and allows you to see if you alternator is working and sends you warnings if you battery is low on voltage.... and that is an App you use with your Mobile Phone... but its a different product.


Regards,

scott-

 

dr:
I just received my "new" 1984 Porsche 928S on Sunday and checking the battery tray started wondering.
My 1984 928S Owner's Manual calls for a "12 Volts, 88 Ah" battery. I am wondering why this discussion did not mention this?
Most batteries have ample CCA but they seem to top at 80 Ah. My 928 now has (by previous owner) an FVP94R battery with CCA 750 and RC 135. It is a bit smaller than the cradle size but still functional. If I replace it, what with?

 

In my part of the world DIN88 is a recognized battery code. Ask for an equivalent to that where you are. Here they are 340mm long x 175 x 175, and fit early 928 battery cavity. I think DIN85 will also work.
jp 83 Euro S AT 57k

 

84 requires the bigger group 49 battery, the smaller battery can move around. Pepboys have the Bosch brand for around $120 and if you top off the fluid, they last a long time. Mine is 8 years old on 1986 928.

​​​​​​

 

Thanks for the info. The group 49 dimensions seem a bit larger than what there tray is. However, I am going to PepBoys and have them make the decision on the size.
I have another issue that perhaps you may have suggestions to. The Owner's manual calls for the ATF to be changed at 30K miles intervals. The ATF prescribed for this transmission in Lubrizol 3216C. The Porsche dealership here in Albuquerque tells me they cannot change because they no longer service these vehicles (too old).
Any ideas?
Thanks again.

 

I got my Bosch group 49 from Pepboys online with a promo code for $120 about 8 years ago not sure the current price. The 1984 Porsche uses any Dexton 2/3/4 ATF and the transmission is actually built by Mercedes, any shop can do a fluid and filter change. The power steering uses the same Dexton ATF .

 

Which Bosch specifically? I see PepBoys offers Bosch S4571B. Is this the one you mean?
Thanks

 

It's about 14" inches long. Here is a link:

https://www.pepboys.com/bosch-premiu...roduct/9073755

 

Thanks again.
It does not mention its Ah. Is it necessary to have the 88Ah the Owner's Manual calls for my 1984 928, or it is an irrelevant issue?

 

Doesn't matter I've had the same battery on my 1986 for close to 8 years however, I live in San Diego California with an average temperature of 75 all year not too hot not too cold. Extreme temperatures kill batteries.

 

If the previous owner modified the battery box to take the smaller 48 group, then just replace it with S4 battery size but make sure it doesn't move.

 

The rule of thumb for converting CCA to Ah is dividing it by a 7.25 constant. For instance, if your battery is marked with a 1450 CCA, it represents 200 Ah. A battery of this rating should last for 25 hours while producing power of 8 amps.