I have a small battery (similar to an odyssey 680) under the hood. Works well,but the parasite discharge of some of the car components make the battery not '100percent' and given the fact that I don't use it all the time also doesn't help the matter.

I'm thinking of putting an extra optima battery in the trunk in a parallel fashion, so that I would have two batteries (under hood and in the trunk) so I won't need to worry about discharge and any other issues related to a powersport battery / small battery.

If I were to track the car, I could remove the battery in the trunk to save weight and in the winter I could remove the lithium battery (bring it indoors) and just trickle charge the optima. That way I could start the car once in a while in the winter time.

Has anyone done this?

I saw one post on the forum, but the guy just had an extra battery for backup with no intention of removing it. I would like to be able to remove one of the batteries if my needs change either for weight or winter storage.

Does this sound like a dumbass idea?

 

You could but it is reccomended to use the same battery in the trunk as you are using up front. You could use different batteries but that would complicate the situation. What I would do is keep the current battery in the car on trickle charge.

 

Surely a trickle charger is the better solution or even a solar powered trickle charger if there is no power close.

As long as your alternator is charging it properly it shouldn't draw alot of power if just left for a while

 

I cringe when I hear people say this. It's so bad for the car...

 

I would just get a optima redtop and call it day... It will be able to handle any type of slow discharge and still have the cranking power to turn over everytime.

 

Did you read "why" he want's a 2nd battery?

 

for traditional batteries i would do this, but for lithium poly batteries you will wreck the battery with normal trickle charging. and it only has about a few days before the parasite draw weakens the battery.

 

i haven't started the s2k all winter..hahaha

 

i hear you, but it weighs about 5-7x a lithium battery and wont fit in the oem location.

 

Option 1)
Buy a proper lithium charger with balancer and dont worry about a second battery and start the car in the winter.

Option 2)
Remove the Battery in the winter and don't start the car at all (the best solution since there is absolutely no need to start the car until your ready to use it in the spring)

Option 3)
Do with a traditional battery and use a trickle charger periodically

Side note: How much parasitic loss are you experiencing?
You're alternator will have to charge two batteries, not sure what the repercussions will be.