What did you do today to your 3/S?

[2fnloud]

I've already been running an Odyssey 925 in the back, I'm going to keep that there for stereo, fuel pump, other accessories, etc. and run the 680 as the starting battery up front.

OK why that keyed battery switch?

[sketch]

going to run a secondary line between the batteries with that as a cut off - i thought it'd be neat to be able to self jump in a pinch.

as in, that line will always be cut and will only be active for self jumping in an emergency.

[green-lantern]

going to run a secondary line between the batteries with that as a cut off - i thought it'd be neat to be able to self jump in a pinch.

as in, that line will always be cut and will only be active for self jumping in an emergency.

I have to admit I'm interested in what you are saying. I want to see how this is going to be set up.

[CoopKill]

going to run a secondary line between the batteries with that as a cut off - i thought it'd be neat to be able to self jump in a pinch.

as in, that line will always be cut and will only be active for self jumping in an emergency.

How are you connecting to the alt? The cut off is mandatory if you are doing any sort of racing, along with a sealed box...

[Chris@Rvengeperformance]

I'm interested in what you are doing as well, but wouldn't two batteries and all that cable be heavier than one group 51 regular battery? (28 lbs)

[NickS VR4]

Also, don't batteries lose their charge over time? When you need it, it may be dead, unless you are able to charge it while running and disconnect while off.

Sent from my Nexus 7 using Tapatalk 2

[sketch]

I have to admit I'm interested in what you are saying. I want to see how this is going to be set up.

I've drawn out a few wiring diagrams, I'll scan/MS paint a few so everyone can get an idea. I'll probably end up posting it over in my ancient build thread that hasn't been touched in a while

I'm interested in what you are doing as well, but wouldn't two batteries and all that cable be heavier than one group 51 regular battery? (28 lbs)

the 680 weights 15 pounds and the 925 weighs 24 pounds for a grand total of 39 pounds
the Optima blue top I've got in my SVX weighs 38.4 pounds
I can weigh the cable later to get an accurate number

In comparision, an Odyssey 1400 weighs 46 pounds

How are you connecting to the alt? The cut off is mandatory if you are doing any sort of racing, along with a sealed box...

Also, don't batteries lose their charge over time? When you need it, it may be dead, unless you are able to charge it while running and disconnect while off.

Starting battery up front still directly connects to the alternator, the 2nd (accessory) battery will have the battery isolator in front of it. The isolator prevents the batteries from interacting with eachother while the car is off. I've got a couple possible wiring options in mind; I'm still trying to determine which one works best for me/I like best. Odyssey batteries are SLY drycell batteries, I'm not worried about the [vented] box as I'm not planning on racing the car.

tl; dr which may be longer than my above writing:
the general gist of the wiring is that there will be two connections between the starting and accessory batteries - in the main connecting line will be the battery isolator and in the secondary connecting line will be the cutoff switch, which will remain in a disconnected state at all time (less emergencies).
The battery isolator in the main connection line will function as intended - allowing the alternator to charge both batteries while the engine is in a running state and will not allow interaction between the batteries while the engine is not running. It eliminates the push/pull draining that two batteries would normally have on each other if connected (+) to (+) and (-) to (-)

hope this clears things up

[Chris@Rvengeperformance]

so what is the purpose of having 2 batteries that are heavier than one?

[green-lantern]

so what is the purpose of having 2 batteries that are heavier than one?

In case one fails

It's kind of a cool idea but not practical for racing. If you do it I suggest getting a quick disconnect for the extra one so you can yank it quick at the drag strip.

[Blackmount]

I just don't get it seems like alot of work for something that you might not ever have a issue with........very rare I have a battery fail on me.... if it does, just give the car a push and pop the clutch....