Car battery light on… New battery and alternator but keeps dying

ANSWER : This may be a sign of a failing voltage regulator or potentially a bad grounding problem causing a draw on the system. The voltage regulator is a unit that regulates the charging of the battery by the alternator. Often times this will result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. In either case, I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.

ANSWER : The problem is not the battery, but the charging system is not keeping the battery recharged. The alternator is the most common cause of this, though failing battery cables can also be a cause. I would recommend having the battery cables and alternator tested and checked by a mechanic, like one from YourMechanic, who will come to you and diagnose the problem for you. Do not try and drive it or it will leave you stranded from the battery going dead again. The cables to the battery from the alternator may be bad or the alternator is not charging. Only the testing and diagnosis will reveal the problem.

ANSWER : Hello. If your charge indicator is on, this indicates a problem in the system. The charge indicator will have a resistor that is about 390 ohms when tested and if it is bad then may cause light to come on. You are having a possible charge problem with alternator. A junk yard alternator may be bad and you would not know it until it is installed. You should have the complete charging system diagnosed by a qualified mechanic that will be able to go over the entire circuit.

ANSWER : The problem sounds like the alternator has failed and stopped charging. Your alternator should be tested to see if it is putting out any voltage and amperes to recharge the battery. You should also make sure the main cable off of the alternator is not shorted out between main fuse panel and alternator. Replace the alternator and retest the system after recharging the battery.

ANSWER : As you may yourself have seen, there are many reports of this fault with the Civic, that is a battery or alternator is replaced only to have the warning light fail to extinguish despite checking every conceivable electrical possibility. Your only recourse is to have a certified mechanic go through that exercise with your car and that involves first attempting to "re-set" the light. If the warning light returns, the alternator output has to be carefully measured both loaded and unloaded. All terminal connections have to be verified including all grounds. Fuses have to be checked for integrity (continuity) and the possibility of shorts, in for example dash wiring, has to be checked. To request this repair, simply request an electrical components diagnostic and the responding certified mechanic will seek a resolution to this.

ANSWER : The battery should be load tested. Simply charging the battery or measuring voltage is not adequate. Measure charging output, too. You want to confirm that the ignition system, including for instance the ignition coil and ignition switch, are not intermittently cutting out. Coils can fail as temperature rises (resistance increases with temperature) so if you run the car for a while and all of a sudden it quits, measure the resistance of the coil windings to see if that provides a clue. Apart from that, the ENTIRE primary side ignition circuit has to be checked, using voltage drop testing (and testing of the hall effect sensor in the distributor), to rule the primary side in or out. If you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a stalling diagnostic and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : The initial failure was likely caused by a sudden fuel system (e.g., failed fuel pump) or electrical (including ignition) faiure. Prior to performing diagnostics be sure you have a fully charged battery that passes a load test. Then, confirm that the engine immobilizer system (security system) is not activated thus preventing the car from starting. If the starter motor is not functioning, check for power to the starter motor when the key is held in the "start" position. If there a large voltage drop at the starter motor or no power at all, you may have a faulty ignition switch but you do have to check out the entire starter circuit, which includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch and terminations. On the other hand, if the starter motor is getting power but the starter doesn’t work, then the starter is condemned and replaced. If you desire that a certified mechanic resolve this, please simply request a no start diagnostic and the responding certified mechanic will get the problem diagnosed and repaired for you. Please let us know if you have further concerns or questions as we are always here to help you.

ANSWER : Hi there. The best way to diagnose why a battery would constantly drain is to review it’s job and how it is recharged. The battery is responsible for powering all electrical systems until the vehicle is started. At this point, the alternator takes over and also continually charges the battery while the vehicle is in use. A battery will drain when one of two things occurs. First, a battery will drain if it is constantly in use; supplying power to an electrical component even if the key is not in the ignition. Second, the battery will eventually die if the battery is not being charged frequently. However, since this is happening every two days, my initial thought would be that some electrical component on your 86 Olds is continuing to draw power from the battery. This is known as a parasitic drain. The best way to determine the source of this battery issue is to have one of our professional mobile mechanics come to your location and complete a battery will not hold a charge inspection.