Hello, as a new owner of a Jaguar s-type 2003, I have learnt from internet forums that not driving (or driving little) the car can cause battery drainage due to the highly sophisticated and extensive electronics. If so, and provided there are no spurious sources of drainage (spurious contacts, leakages, etc), and with a new battery, how often/how much should one drive to avoid battery drainage? Many thanks in advance for a reply.
Hi, welcome to JA, Your Jag will drain approximately 50mA - 75 mA (milliamps) at a given time with the igniton off and all doors closed. This is normal draw for computer operation. When the computers are awake and running or testing systems the drain can be higher. In the event the vehicle is stored, thee drains will cause a good battery to discharge enough to prevent starting of the engine in about 10-14 days, also dependant on temperature. If the vehicle is rarely used, I recommend keeping it on a trickle charger once a week. Or, you can purchase a solar trickle charger which will keep the charge up, if the solar panel can be in direct sunlight. I don't recommend starting the engine for short periords of time to charge the battery,as this does a number on the engine and charging systems, not being able to reach operating temperature. In cases where the vehicle is stored, installing a battery disconnect on the negative battery terminal will aid in discharging and is better fo the battey longetivity. The minor downside to this is that, without the vehicle's computers being powered, they loose memory and when the engine is started, subtle abnormalities in performance can be noticed for the first few miles until the computers learn the strategy again. In most cases, the driver never feels these changes. Hope thi can shed some light on the subject.
Hello thanks to Rip for his answer and very good advise. However, my question is slightly different.
How many kilometers/week should I cover to keep the battery for draining?
Approximatley 3.2 km a day, or every two days. Not much, the engine needs to reach operating temperature to assure a good charge on the battery. If te battery is now new this applies, once a battery has begun to weaken, it needs more driving and sooner intervals to keep it stable. Short trips, where the coolant temp cannot reach normal, is where the problem begins so every few days give it a good drive and you'll be fine, but don't just let the engine idle, as this does no good.
Ok, that's really great info. One last detail. Instead of 3.5Km a day, as Rip suggests, can one go only once/week
for, say , 50-70 km?
Yes, however,daily driving is much better, in a 6-7 day period the battery will only have depleted 10%, if you drive once a week you will be fine as far as the battery not completely discharged; but you may see battery life decrease. So a new battery that typically lasts 3 years, may last half it's life. As a lead-acid battery sits unused, it can become sulfated, where the lead plates have a coating. This decreases it's enery retention. Another option for you to avoid any hassles, may be to upgrade to an AGM (glass material) battery, which has better energy retention, release and storage and more suitable for longer periods between driving. Although the cost of these battery's can be double the price of a standard lead-acid.
Many thanks to Rip. Very exhaustive answer
No problem, hope that can help you better understand the affects on the life of the battery for your vehicle, and hopefully this will prevent yo from premature faiure or jump starts; please feel free to direct any concerns to me anytime :)