Why a flat battery?

Preamble
The Electrical Systems of present day cars are a far cry from the Amby’s and Fiat’s of yore, where WW-II vintage ‘Dynamo’s had a max carrying capacity of 20 Amps/12 Volts and that too at a road speed eqvt of 50+ kph and regrettably, none at idling.

The advent of ‘Alternators’ by the mid ‘80s in India with the Maruti800 changed all these limitations for the better and presently, the average continuous rating of a mid-size sedan is around 60 Amps, and suitably higher for more luxurious ones.

Nowadays, the whole electrical system of a car is so designed that the Alternator has battery charging capacity to spare under ‘all’ operating conditions, right from idling to b2b traffic with ‘all’ the designed continuously usable electrical loads on, such as the music system, air-conditioning, wipers, fog lamps/headlamps etc. And yet people have problems, invariably of their own making…

Problem:
I have a 1997 model Esteem and have problems with Car Battery. I travel to my office from Malad to Bandra and back in peak hours. While going home, around half way, half of my car’s lights, tape, AC stops working. I travel about 40KM everyday in b2b traffic One way it takes me around 1.30 hours to 2 hours. When I put off AC, music system, all the lights work fine. The moment I start either AC or the MS, lights get low. I have to keep AC and MS off for some time and when I re-start them, everything works fine together. I got my battery checked from a Maruti Authorised Service Station and also from local battery dealer. Both said battery is fine and need not be replaced. The MASS checked the Alternator also and confirmed it is working fine. This is one and half year old battery with one-year warranty, which is over. I don’t understand what to do now. Should I replace the battery or is there some other problem.

Diagnosis:
Prima-facie, it appears to me that either - a) your OE wiring harness has been tampered with by the crude auto-accessories people for installing some non-OE approved electrical accessories or, b) you have installed a high-powered music system having sub-woofers/amplifiers etc. or, c) you have higher than OE wattage headlamps, such as 100/100W instead of 65/65W ones or lastly, d) have some electrical leakage in your AC/Music System that plays up when they’re in use.

But for these, there’s no reason why your battery should keep running down in b2b traffic, when a MASS has declared your Alternator as ok. I’ve come across such a problem in an Esteem earlier on also and most of (a) to (d) above existed over there. They had to be removed to OE specs and the tampered front-end wiring harness of the car had to be replaced with an ‘MGP’ set to cure the problem, once and for all.

Music/Central Locking Systems for MPFi Cars
Given the human spinal cord like sensitivity of the MPFi Cars’ Main Wiring Harness, it’s advisable NOT to cut/splice/tape/twist-joint it anywhere, for installing any electrical accessory. In fact this is stated so in the Car’s Warranty Policy, given in the Owner’s Hand Book.

Consequently, practically all such Cars have an OE/Dealer Option of Music Systems specially produced in India for them by renowned players including 12-months warranty and assured after sales service. These are ‘model specific’ by way of ‘mating’ wiring harness couplers, which slip in straight away w/o having to tamper with the OE/WH.

Likewise, for the present day fad of Central Locking, vis-a-vis MPFi Cars. Take the Dealers’ advice on this/get him to install it too. However, it’s been established internationally that a ‘visible’ deterrent such as a Steering/pedal Lock is far more effective and reliable - more so when a good one costs under Rs:1k. One can also go in for the more fancy ‘imported’ one - ‘Mul-T-Lock’ - which is purely a mechanical device that gets installed near the Gear Lever and locks it in IV gear, costing about Rs: 3k.

Higher Wattage Headlamps
The main Wiring Harness of an MPFi Car is sacrosanct and as such, it should never be mutilated to install various Relays etc. necessitated for using higher than OE Wattage Headlamps or additional ones. If you do, you’ll end-up having insurmountable problems later on, such as flat batteries for no apparent reason, as in the case above. Besides, this will closely be followed by burnt out headlamp couplers built-into the main wiring harness and distortion of their all-plastic reflectors.