For how long can you leave the car until the battery dies?
Discussion
If you go on vacation and do not start your Caterham for one whole month, do you think the battery would end up empty? Or is this car less prone to that problem because of the lack of electronic devices? The battery cut-off switch would prevent this but it's not a very good solution. If you park your car outside, you have to remember to remove and take with you that bulky key. If you forget to do so and someone steals it, you're in big trouble.
Is it really that big? Seems smaller than the remote on my wife's Cupra Born to me! No idea of the power drain of the current alarm/immob system, but the cut-off is the answer if there's no power for a long period.
If the inconvenience of the master switch key is putting you off, are you sure a Caterham is for you?
If the inconvenience of the master switch key is putting you off, are you sure a Caterham is for you?
I carry a small cut off key on my keychain just in case. It almost came in handy on the weekend when the actual key fell out of my pocket, but I luckily spotted it a few meters away!
If I park the car up, I always cut off them power. I didn't always used to do that, but now that I'm on my 3rd battery, I'm using the cut off whenever possible.
I've never seen the size of the key as an issue, given my steering wheel is a quick release, that's a far larger thing to carry around!
If I park the car up, I always cut off them power. I didn't always used to do that, but now that I'm on my 3rd battery, I'm using the cut off whenever possible.
I've never seen the size of the key as an issue, given my steering wheel is a quick release, that's a far larger thing to carry around!
BertBert said:
Human said:
Best advice is, get your self a LiFePO4 battery from Jack Webb motorsport, apart from weigh nothing you can leave it for months before it even goes flat. Best battery I used on mine.
How does that work if there is a parasitic drain from the immob system?The disadvantage of lithium batteries (IMHO) is the cost and hence they are usually spec'd about 1/3 of the capacity of the lead acid that they are replacing (which gives the same cranking current). That give less battery capacity to play with when the engine is not running.
quote=Entropia]Aren't lithium batteries more prone to catch fire?
[/quote]
Overcharge with too high a current, puncture/damage or short circuit then you’d better have a fire extinguisher handy or run fast! Otherwise in normal use perfectly fine. Been using lithium batteries in RC models for years.
[/quote]
Overcharge with too high a current, puncture/damage or short circuit then you’d better have a fire extinguisher handy or run fast! Otherwise in normal use perfectly fine. Been using lithium batteries in RC models for years.
DCL said:
I'm a bit of a fan of Lithium battery in the Caterham. The main advantage of a lithium battery (as I see it) is that they don't 'self discharge' and can be stored for long periods, even years without needing charged. They also store much better in a partly discharged state. That's the opposite of a lead acid battery which eventually discharge themselves (even if totally disconnected). Lead acid also sulphate and lose capacity if not kept 100% fully charged. Generally lithium is well suited to the typical Caterham occasional use.
The disadvantage of lithium batteries (IMHO) is the cost and hence they are usually spec'd about 1/3 of the capacity of the lead acid that they are replacing (which gives the same cranking current). That give less battery capacity to play with when the engine is not running.
How is being stored for years really all that helpful? I just can't see any advantage other than weight in a road car, even a caterham. Experience of trying to use a lithium battery in a race car to save weight did achieve that but it was hopelessly unreliable.The disadvantage of lithium batteries (IMHO) is the cost and hence they are usually spec'd about 1/3 of the capacity of the lead acid that they are replacing (which gives the same cranking current). That give less battery capacity to play with when the engine is not running.
BertBert said:
How is being stored for years really all that helpful? I just can't see any advantage other than weight in a road car, even a caterham. Experience of trying to use a lithium battery in a race car to save weight did achieve that but it was hopelessly unreliable.
It's an opinion based on 15 years of having the car - by the 6th year I was on my 3rd lead acid battery and then replaced it with a 10AH Super B (which was very expensive at the time) and it's been 100% trouble free since. Non of this trickle charge nonsense every few weeks. The battery is a good as the day I put it away after a winter in storage. More over a 50% charged Lithium battery still provides full cranking current, a lead acid at 50% charge is as good as dead.Parasitic drain is only a small part of the lead acid problem and is often confused with the tendency of the lead acid to discharge themselves through its own internal resistance and internal electrical leaks. So going Lithium does reduce the speed of what we perceive to be 'parasitic' drain. Just do the maths on how long a 30AH battery should take to discharge a with a few milliamps current drawn by an immobiliser.
When I had my k-series caterham I had to experiment with this because it was parked on the street. I was paranoid about increased theft risk with a flat battery. As long as the immobiliser was activated before disconnecting or removing the battery, the car stays immobilised.
So for example with the battery removed (I was charging it at home), it's not possible for someone to just drop in a new battery and drive off. Same for the cut-off switch, right?
With a recharged battery installed it took a few goes to deactivate the immobiliser. Having a cutoff (just a simple one at the battery terminal) seemed to be the best answer when leaving the car for a longish period.
Having a lithium battery pack from Halfords to jump start a low/flat (racing) battery was also really useful and easy to use.
So for example with the battery removed (I was charging it at home), it's not possible for someone to just drop in a new battery and drive off. Same for the cut-off switch, right?
With a recharged battery installed it took a few goes to deactivate the immobiliser. Having a cutoff (just a simple one at the battery terminal) seemed to be the best answer when leaving the car for a longish period.
Having a lithium battery pack from Halfords to jump start a low/flat (racing) battery was also really useful and easy to use.
DCL said:
Just do the maths on how long a 30AH battery should take to discharge a with a few milliamps current drawn by an immobiliser.
Just curious about this a bit more. The parasitic drain (in general) can easily drain batteries in a shortish period. My Evora with its lithium battery wouldn't last 2 weeks in the garage. That makes the drain about 100 mA (roughly). So it depends on the magnitude of the drain surely? Had to keep the Evora on a conditioner.BertBert said:
Just curious about this a bit more. The parasitic drain (in general) can easily drain batteries in a shortish period. My Evora with its lithium battery wouldn't last 2 weeks in the garage. That makes the drain about 100 mA (roughly). So it depends on the magnitude of the drain surely? Had to keep the Evora on a conditioner.
The Sterling immobiliser fitted to most Caterhams draws 17 milliamps when the ignition is turned off which is about is about 75 days for a 30Ah capacity, or 25 days on a 10Ah battery. But a lead acid has really only has about 20% usable capacity for starting, so it is effectively 15 days compared to the Lithium which has probably about 80% usable capacity (for starting) and so about 20 days. But my point was that Lithium ion batteries don't self discharge over typical use timescales, so, if fully isolated, they hold their charge better than lead acid.
Edited by DCL on Wednesday 6th September 15:58
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