Elise battery life: green knob & ECU

sunmax said:

Dear Lotus enthusiasts,

I just joined your wonderful community and I already have some questions,
(I split them according to the forums), here come the ones about the battery.

The original battery kicked the bucket after I did no drive (alas!) my
sweet Elise (a laser blue Fed 06) for a couple of weeks. It's possible
that the weather (hot and humid here in Miami) could be a factor too...,
so I replaced it with a heavy, but long lasting Optima Yellow Top D35.
High temperatures do shorten a battery's life due to sulphation

Building up some basic knowledge reading through your forums I decided
to install a "green knob" too.

Now, considering that I normally can enjoy the Elise only once or twice
a week for ~20 miles, I'm trying to maximize the longevity of the battery.

a) when the Green Knob is unscrewed (i.e. going through the fused path)
is the battery drainage lower than through the normal path (when the
knob is closed)? Battery drain is exactly the same, you need to remove the fuse to stop it.

b) I read that there are 3 major factors discharging the battery:
ECU, alarm/immobilizer, radio.

My car is in a secured gated parking, alas outside (but well wrapped
in a Weathershield cover ;-), if I don't insert the alarm using the
Cobra, is the battery going to last much longer? Yes

Anyway, between the gated parking, the locked car cover and the green
knob, I think I can sleep safe even without the alarm... ;-)

c) I know the green-knob is meant as an anti-theft device, but what would
happen to the Elise if I used it to completely cut off power removing
the fuse, before unscrewing the knob (I would of course disarm the
alarm first!) ? No parasitic battery drain

I don't care that much about radio stations, but what about the ECU ?
No power to the ECU is no problem

Is the car going to start ok if, let's say after a couple of weeks,
I come back and screw the knob back in? Yes


Looking forward to your expert suggestions!

Thanks!
-Max

P.S: I'm pretty new around here, and even if I did some homework it's possible
that I missed something in one of the previous threads. If this is the case just
point me to them, and I'd be glad to read them ;-)

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ojars said:

Consider a battery tender -- I took the advice found in these fora and purchased a Battery Tender Plus a few years ago. I am still running the stock battery.

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TimMullen said:

The a good choice is the Solar powered Battery MINDer (or the other solar powered battery maintainers) : BatteryMINDer 12 Volt 15 Watt Solar Battery Charger: BatteryMart.com

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sunmax said:

I remember that last year a Lotus dealer had to upgrade some sw (forgive my imprecise lingo!) in the ECU - is the update going to get lost if I cut the power off for 2 weeks ?

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