Early 1978 battery recommendation/ and what is this connection?
08-27-2016, 12:40 PM
#16
Burning Brakes
Thread Starter
Did you look at the H8 battery? That's the size you really need to fill the well and such. The factory-fitted cables are long enough for the bigger battery, but may be too short to reach the terminals on the shorter battery.
As far as the hold-downs, they are critical. The battery will literally rattle/bounce around in the well. With no hold-down, the real (and well-documented...) risk is that the positive post and connection will contact the lid, and weld itself there in a fraction of a second. A hard short-circuit like that will cause the car to immediately stop running as ignition and fuel pump power are shunted to ground through the lid. There's a very real risk of battery explosion, typically contained within the battery case fortunately. Now the lid is welded to the battery and there's no easy way to disconnect it, not that you'd really want to mess with it immediately. With the cables helping maintain the battery position fore-and-aft as well as vertically, battery movement will loosen the connections or break the cables, sooner or later.
You can make spacer blocks out of wood to limit fore-and-aft movement in the box. Adding a clamp and/or a rubber mat on top of the battery can help with the short-circuit risk, but only the clamp will hold the battery in place.
As far as the hold-downs, they are critical. The battery will literally rattle/bounce around in the well. With no hold-down, the real (and well-documented...) risk is that the positive post and connection will contact the lid, and weld itself there in a fraction of a second. A hard short-circuit like that will cause the car to immediately stop running as ignition and fuel pump power are shunted to ground through the lid. There's a very real risk of battery explosion, typically contained within the battery case fortunately. Now the lid is welded to the battery and there's no easy way to disconnect it, not that you'd really want to mess with it immediately. With the cables helping maintain the battery position fore-and-aft as well as vertically, battery movement will loosen the connections or break the cables, sooner or later.
You can make spacer blocks out of wood to limit fore-and-aft movement in the box. Adding a clamp and/or a rubber mat on top of the battery can help with the short-circuit risk, but only the clamp will hold the battery in place.
08-27-2016, 12:44 PM
#17
Burning Brakes
Thread Starter
CCA is pretty meaningless unless you are AK or Canada eh. The battery you got will have a lower amp-hour rating than the group 49. This is important for older cars where there is a longer crank time, as you've noticed with hot start issues. The smaller battery will heat up faster, and not dissipate the cranking load as fast as the big group 49 battery. I think the 49 batt is rated at 92Ah, and a 41 is prolly more like 60Ah. So, don't crank your starter a long time, as it will tend to over heat the battery in summer, and maybe boil off some of the electrolyte, or warp a plate. When that happens, the battery is basically dead.
A V8 engine about 5L or so, with a high C/R requires a pretty decent battery, which is why the 928 came with that big dude we have in there. Also, 928s are harsh on batteries anyway, and the newer the car, the harder they are on batteries. I'm sure you'll get away with the smaller battery for a time, but it's not going to last very long if you continue to have hot start problems. I would take it back, and find the group 49 or H8, or whatever it is, and let the larger mass of the plates and electrolyte dissipate the cranking power needed.
If you doubt me, touch the side of the batt after having run the starter for 30 seconds. It'll be plenty warm.
A V8 engine about 5L or so, with a high C/R requires a pretty decent battery, which is why the 928 came with that big dude we have in there. Also, 928s are harsh on batteries anyway, and the newer the car, the harder they are on batteries. I'm sure you'll get away with the smaller battery for a time, but it's not going to last very long if you continue to have hot start problems. I would take it back, and find the group 49 or H8, or whatever it is, and let the larger mass of the plates and electrolyte dissipate the cranking power needed.
If you doubt me, touch the side of the batt after having run the starter for 30 seconds. It'll be plenty warm.
08-27-2016, 01:23 PM
#18
Burning Brakes
Thread Starter
Wal Mart did carry the group 49 batteries? I have a 79 - 928- ROW ---I got mine from Autozone -Platinum Series- $174.98 - it has a guarantee. Has held up well - again, I highly recommend an alternator upgrade - it has made a world of difference in performance of all of the electrical components on the car.
08-27-2016, 03:00 PM
#19
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Warranty is one reason for going with Walmart - their warranty is good at any store. The Advance system means that the store in BF Egypt doesn't know you or have a record of your purchase. The store of original purchase should still have the record, or if you buy it online (by far the best way) you will have your own record. Whether you will have it with you is another question.
The maxx battery at W-M is exactly the same case as the Advanced Auto gold, and weighs exactly the same. So this isn't a cheaper version with fewer plates. Better, the local Wal-Mart store has a no-questions-asked warranty policy on batteries. No hassle at all. Plus there are Wal-Mart stores in more places than there are Advance Auto stores, if you happen to be away from home when something takes a dump.
Then, remember that annual electrical maintenance obn the car includes cleaning the connections and grounds, and also includes testing (and recording...) the specific gravity of the battery electrolyte in your maintenance log. Gravity is a telltale of failures to come. With the no-hassle warranty and some predictive testing, you can replace the battery -before- it strands you someplace. Even if that someplace is in your own garage, it's easier to take care of this early and at your own convenience, rather than when you are ready to go somewhere. I hate getting stranded by stooopid stuff.
08-28-2016, 04:48 AM
#20
Rennlist Member
My 83 Euro has the big battery, and both here in Oz and in Saudi it is known as a 'DIN88' model - height seems to be unusually lower than average battery here. The plastic pole covers are vital to help protect against shorts caused by coming into contact with the lid.
jp 83 Euro S AT 56k
jp 83 Euro S AT 56k
07-23-2017, 08:50 AM
#21
Rennlist Member
From what I understand the 78 had H8 or H9 as an option. Is this correct? I called Walmart and although I knew this car needed an H8 or H9. They didn't have one and the "Battery selector for your car" option on their website said the group 41-4 battery was correct. I was in a pinch and needed a battery so I got that one one which they listed as correct fitment for my car. I just called them and they said batteries are NOT returnable, after telling them their website said it was the right one even though it's not, the manager agreed to allow me to return this one and get the bigger H8. Am I correct in stating that their early OB"s could use an H8? and that an H9 was an option?
Here's my thread on it, with good discussion there too. These should be combined?
Linky: https://rennlist.com/forums/928-foru...8-battery.html