Battery Tender
05-08-2013, 09:27 PM
#16
Electron Wrangler
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Yes a fuse is a very good idea. My charger port is actually a power outlet that is always connected to the battery (regardless of the battery switch) located in the hatch area. I have a plug in flat pigtail that loops out of the hatch between the seals for use. It has other uses obviously and is 10A fused in the battery box
Alan
Alan
05-08-2013, 09:28 PM
#17
Vegas, Baby!
Rennlist Member
Rennlist Member
Thread Starter
I've got 5 cars to do, so I'll do as Wally, Alan, and Maine Porsche. I travel so much that I just want to be able to uncover one of them and fire up, and go for a drive. Having to break out the charger, is a real PITA.
05-08-2013, 11:36 PM
#18
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Alan--
Is there a write-up someplace on how you atached and connected that isolation switch?
To the current subject--
I have standardized on some two-pin MOLEX connnectors for power accessories, mostly so all the jumpers, extensions, chargers and maintainers can talk to any of the cars, boats, toys, etc., and to the box of cables that have charging clamps on them. I started this habit well before the 928 showed up, BTW.
So on the 928 there's a quick-access connector in the front, forward of the jump post and barely sticking out from under the the fender lip where the fan final-stages cable comes out. The cables are 'dressed' together so the maintainer plug looks factory. There's a 10A fuse in the positive side of the harness, connected to the jump post with a ring terminal. It's 14ga wire, in shrink-wrap, and only an expert could tell it wasn't installed by Hans and Fritz in 1988. Accessing requires that the hood be popped slightly for the cable to pass through. The car sits under a cover most of its storage time, but if by chance it's backed out without disconnecting the harness, the Molex will likely pull apart.
In the rear, there's a dedicated harness that's run from battery to tool panel right next to the ground strap. The strap is a 2ga Waytek replacement that's shrink-tube wrapped twice, with the outer layer holding the charge harness at the edge of the strap as it passes through under the edge of the battery compartment door and up past the spare. That harness is 10ga, but still has a 10A fuse at the battery end. In the tool panel, the harness has ~12" of available pigtail to route out under the panel if needed. The ground side of that harness connects directly to the battery, so I can plug in a charger or maintainer as needed, even with the ground strap isolated from the chassis connection. The battery itself is properly vented with a plastic tube that exits under the battery box so no serious worries about corrosive or explosive buildup in the battery well while charging the battery in that closed space.
Some observations:
When storing the car for any extended period, I used to just plug the maintainer into the front connector and leave the ground strap connected. Even with the low (<20mA) static drain on the battery, the maintainer would cycle regularly between the 13V low turn-on and the 14V high turn-off point. Schumacher maintainer, same one Alan shows in his picture. I suspect that the constant cycling was stealing life from the battery. So for the last few years I've been disconnecting the ground strap at the frame end. I sometimes put the maintainer on the battery via the rear harness connector while the ground strap is still disconnected, generally overnight from when I get back from the airport to the next morning when it's time to drive. I've only done this when the car has been idle for more than a month, and don't know if it really needed it or not. Now three years into the current battery, and maybe two years into the replacement ground strap, all seems fine. The car definitely starts/spins more quickly after sitting, really the only 'test' result I can claim.
Now if I can rig a disconnect like Alan has, it should be a tad easier to isolate the car for its irregular hibernations.
Is there a write-up someplace on how you atached and connected that isolation switch?
To the current subject--
I have standardized on some two-pin MOLEX connnectors for power accessories, mostly so all the jumpers, extensions, chargers and maintainers can talk to any of the cars, boats, toys, etc., and to the box of cables that have charging clamps on them. I started this habit well before the 928 showed up, BTW.
So on the 928 there's a quick-access connector in the front, forward of the jump post and barely sticking out from under the the fender lip where the fan final-stages cable comes out. The cables are 'dressed' together so the maintainer plug looks factory. There's a 10A fuse in the positive side of the harness, connected to the jump post with a ring terminal. It's 14ga wire, in shrink-wrap, and only an expert could tell it wasn't installed by Hans and Fritz in 1988. Accessing requires that the hood be popped slightly for the cable to pass through. The car sits under a cover most of its storage time, but if by chance it's backed out without disconnecting the harness, the Molex will likely pull apart.
In the rear, there's a dedicated harness that's run from battery to tool panel right next to the ground strap. The strap is a 2ga Waytek replacement that's shrink-tube wrapped twice, with the outer layer holding the charge harness at the edge of the strap as it passes through under the edge of the battery compartment door and up past the spare. That harness is 10ga, but still has a 10A fuse at the battery end. In the tool panel, the harness has ~12" of available pigtail to route out under the panel if needed. The ground side of that harness connects directly to the battery, so I can plug in a charger or maintainer as needed, even with the ground strap isolated from the chassis connection. The battery itself is properly vented with a plastic tube that exits under the battery box so no serious worries about corrosive or explosive buildup in the battery well while charging the battery in that closed space.
Some observations:
When storing the car for any extended period, I used to just plug the maintainer into the front connector and leave the ground strap connected. Even with the low (<20mA) static drain on the battery, the maintainer would cycle regularly between the 13V low turn-on and the 14V high turn-off point. Schumacher maintainer, same one Alan shows in his picture. I suspect that the constant cycling was stealing life from the battery. So for the last few years I've been disconnecting the ground strap at the frame end. I sometimes put the maintainer on the battery via the rear harness connector while the ground strap is still disconnected, generally overnight from when I get back from the airport to the next morning when it's time to drive. I've only done this when the car has been idle for more than a month, and don't know if it really needed it or not. Now three years into the current battery, and maybe two years into the replacement ground strap, all seems fine. The car definitely starts/spins more quickly after sitting, really the only 'test' result I can claim.
Now if I can rig a disconnect like Alan has, it should be a tad easier to isolate the car for its irregular hibernations.
05-09-2013, 02:15 AM
#19
Electron Wrangler
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Dr Bob - Here you go - original post was even earlier - real blast from the past.
https://rennlist.com/forums/928-foru...like-this.html
Alan
https://rennlist.com/forums/928-foru...like-this.html
Alan
05-09-2013, 03:07 AM
#20
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
My other 'option' includes a 60A circuit breaker I plan to mount near the CE panel. Wire from the jump post to one side, feeder to the CE bus bar on the other. Still power to the LH fule pump relay and the fans via dedicated feeders from battery +. I'll find out if the tiny drains are through the CE panel feeders I guess.
