Anyone out ther having problems with their battery being dead, I have not driven my MCS for 4 days and the battery was dead and it's about a 3 week old Sears Battery, I have ask around and I was told that if the car is not driven longer than 20 mins (drive time) that the battery is not sufficiently charge. Is this true? Does the Alarm system draw that much power from the source? Guess that I have to spend a day troubleshooting or taking it to someone that knows what's up.

 

What was your driving like before those 4 days. A bunch of starts and stops with the car only running for a few minutes would drain it a bit.

It could also be that the Sears battery isn't holding its own. Could be faulty, not powerful enough, or doesn't handle slow drains (as from your alarm system) very well.

You could also have an electrical "leak" which is slowly draining power away.

I wouldn't say 20 minutes to sufficiently charge if all you did was start your car. The MCS alternator, while being smaller then the MC, is still powerful enough to have lots of left over charging capabilities.

Like you said, it's going to take a bit of troubleshooting, and unfortunately troubleshooting electrical problems in a mini are a pain.

 

Some cars seem to be afflicted with additional current draw when shut off than normal. When shutting off and leaving the car, there is a minite or so period where all the subsystems in the car are still active before going to 'sleep'. unlocking the car with the keyless entry feature is one of the ways that the car's electronics 'wake up' once again yet mostly appear dormant (save for the interior lights, for example). Unless you get in and drive the car or otherwise make use of it, the car's systems shut back down normally. Some cars seem to have a glitch that keeps the systems in a sort of 'standby' mode rather than going fully dormant. This increases the drain on the battery. If the car is not driven enough, this draw, though not huge, will have a cumulative effect of draining the battery more than the alternator can keep it charged. Remember, if you drain a battery with a rather low current over time, you cannot fully charge the battery with a high current for a short time and bring it to a fully charged state. Likewise, if you drain a battery trying to crank the car to the point where it will no longer turn over, a quick charge of high current in a relatively short time brings the battery back to nearly a full charge. In other words, yuo have to charge a (lead-acid) car battery the same way you discharge it.

All this being said, however, there is no excuse for a car to drain it's battery in a week's time of non-use. MINI often denies battery replacement for cars that are not driven often, nor concedes there is a problem other than the owner's not using the car enough. This is bullcrap. A car should be able to sit for a month unused and still fire right up. If it cant, then there is a problem with the electrical system, be it a fault, or designed in.

My car would originally take well to sitting for a week or two with no problems. Recently, though, the original battery, which to be honest is vastly undersized for the car, began to give out. I replaced it with an Optima yellow top deep-cycle battery with double the capacity of the original. No problems so far, and my current draw testing shows the systems drawing less than 10 milliamps once the systems finally shut down.

 

Thanks for the input I will check with Sears, I took a Volt Meter to it today and found out that by checking the battery it give a 12.5 reading and when the engine is on it reads 14.6 so I know that the alternator still does what it suppose to, this is with the lights on and the stereo blasting. Considering that the battery only reads 12.35 after the engine is turn off, lets me know that the battery might not be taking the charge. I was told it should read at least 13.2 when the engine gets turned off.

 

I cleaned a ton of corrosion off my contacts this weekend, caus eI was taking 2-3 tries to get enough current to start and the OEM batt has been reading insuffecent charge for a few months even though it gets 2 hours a day everyday of driving.

I'm next checking my grounding as I haven't seen a sufficent charge since the dealer changed my leaky motor mount and reinstalled the grounding wire differently than t was from the factory.

 

The voltage per cell in a lead-acid battery is about 2.1 - 2.15 volts, so a fully-charged battery may only show an open-circuit voltage of 12.6-12.9V.

An open-circuit voltage of 12.35V indicates a battery that's about 70% charged.

One note, though. When measuring open-circuit voltage to determine state-of-charge, you have to wait for a few hours after the car's been turned off to give the voltages a chance to settle out. After a battery has been charging for a while (either on a charger or from the car's alternator), the voltages can be artifically high for a while after being removed from the charger.

 

im still running the original battery on my 03. i charge the battery every
2 weeks during the winter time (storage). has plenty of power to start
the car.

i too have a yellow top sitting in the garage standing-by to be swapped
when the original gives out.