SEE TABLE AT BOTTOM FOR CHOICES
DEAD BATTERY IN THE ELISE / EXIGE
If the battery is dead and the Remote Fob was used to lock the doors and arm the alarm system, the doors can't be unlocked using either the Remote Fob or the key. The method used, is to open the Engine/Trunk cover on the Elise and Exige and gain access to the battery, the alarm may not sound due to low battery voltage. Now apply a 12V power source to the battery, using either "jumper cables", "power pack" or a "battery charger", and then use the Remote Fob to turn off the alarm and open the doors. On the Exige the front "power post" can be accessed as an alternative. If the battery is disconnected before disarming the alarm, the system will switch over the the back-up battery and sound the siren.
LOTUS RELATED INFORMATION
Due to the risk of battery leakage in the trunk, replace the existing OEM wet (flooded) cell with an AGM battery, which can't leak, spill, & emits no flammable hydrogen gas under normal circumstances.
2) The choice between "weight" & "capacity" (Amp Hour)
If you track, then you may consider the battery weight
to be the most important.
If you don't drive the car often, (especially in colder climates) and don't have access to a "battery maintainer", a greater amp hour (AH)
capacity is desirable.
The Elise/Exige uses a "BCI group 26R" size battery, however a "35" will also fit. Batteries of other physical size will need a custom support.
The OEM "Exide X-tra" is European only model
The "Black" OEM has the reputation for leaking.
Wet cell batteries typically loose 1% of their energy per day, without any load applied.
AGM batteries will typically loose 1 to 3% per month, without any load applied.
Parasitic load on the battery is;
Alarm/Immobilizer OFF + Radio + ECU = 20.5ma
Alarm/Immobilizer ON + Radio + ECU = 42.5.5ma
SULFATION - THE DEATH OF A BATTERY
The first thing you notice is that the battery is either not accepting a full charge or not lasting as long as it used to. The main reason is that the battery is dying due to sulfation. During it's life, sulfate forms on the plates and can solidify, insulating them, and inhibiting the chemical reaction. The more a battery is neglected the quicker the sulfate forms, but eventually it is inevitable that it will kill the battery.
Batteries sulfate because;
Sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.
Battery is stored without some type of energy input.
"Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.
Undercharging of a battery, to charge a battery (lets say) to 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by the incomplete charging cycle.
Heat of 100 plus F., increases internal discharge. As temperatures increase so does internal discharge. A new fully charged battery left sitting 24 hours a day at 110 degrees F for 30 days would most likely not start an engine.
Low electrolyte level - battery plates exposed to air will immediately sulfate.
Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good.
Cold weather is also hard on the battery. The chemistry does not make the same amount of energy as a warm battery. A deeply discharged battery can freeze solid in sub zero weather.
Parasitic drain is a load put on a battery with the key off.
Battery voltage falls below 12.4V
Simply keep the battery fully charged by either regular driving or keeping it on a "maintainer". Do not use a "trickle charger" which charges constantly, irrespective of the battery condition, and can overcharge. A "maintainer" monitors the battery condition and when a full charge is detected it automatically goes into "float" mode, meaning it will charge upon demand only.
De-sulfating (conditioning) the battery is possible if you have a charger, or "maintainer" with that function. It is recommended to de-sulfate regularly and though a number of cycles in order to keep the plates clean and prolong the battery life. If the sulfation has progressed too far, it may not be possible to rectify. One such maintainer/conditioner is the BatteryMINDer Plus
and from the same company is the conditioning only BatteryMINDer On Board Restorer-Conditioner
The best method is "load testing" (many places that sell batteries will do this test), but without suitable equipment the following voltage measurement method can be used;
Measure the battery voltage across the two battery terminals.
Although a vehicle battery is called a 12 volt battery, 12 volts is considered discharged
Before measuring, the "surface charge" has to be removed. The surface charge, which results from recent charging, will make a deficient battery seem good. The best way to remove the surface charge is to leave the battery for 6 to 12 hours in a warm area. Alternatively, with the engine off, the high beam headlights should be left on for 5 minutes, turned off and then left for 5 to 10 minutes.
100% charged & healthy battery will measure 12.66V.
75% charged will measure 12.45V
50% charged will measure 12.24V
25% charged will measure 12.06V
Below 12V a battery is considered discharged
A shorted or dead cell will read 10.5V
Check the battery cable connections for a secure fit or signs of corrosion.
Typically, an alternator will not bring an AGM battery to a full charge condition.
BASIC ALTERNATOR TEST
At idle the voltage across the battery terminals should be between 13.5 & 14.5V
At 1500rpm the voltage should not exceed 14.8V
ALTERNATOR WARNING LIGHT
Check that the alternator belt is not broken or slipping.
Check that all battery & alternator connections are secure and clean.
The red ALT light, basically, means that either the alternator output voltage is lower than the battery voltage, or the battery voltage is lower than the alternator output voltage. If the light gets dimmer as you rev up the engine, then you most likely have a problem with the alternator. If it gets brighter, then the battery is most likely bad.
Many times one or more diodes in the alternator rectifier assembly will have failed, causing a drop in the unit's output. The alternator will still produce current, but not enough to keep the battery fully charged.
JUMP STARTING FROM ANOTHER VEHICLE
The Elise/Exige does not start easily when being jump started. Frequently, a series of clicks will be heard from the starter solenoid, but the starter motor will not operate. I have had success with the following method;
Connect the cables, making sure you have good connections on both ends.
Start the other "donor" vehicle and let it run for 5 minutes at high idle, about 1500 - 2500 rpm, this will give your battery a boost. Now with the other car still running try to start your car.