My Brother in Law has owned a 1.8 litre Mazda MX-5 since new, first reg 2005 but the original Panasonic Gel Battery has become so deeply discharged that none of the usual battery revival techniques seem to be effective. The car is left for weeks at a time unused with the alarm armed and as a result the battery becomes deeply discharged. He bought a set of new tyres for it last August and had to get a push start from a pasing Rugby Player when it stalled on the way home and would not restart due to severe chronic battery capacity/output depletion. Since then the car has only been started and driven once (by using jumper leads from a good battery) for about 20 miles, just a few weeks ago after many months of neglect and then more recently trickle charging for more than three weeks (at about half an amp) alternating with normal charging at about 3 to 4 amps. The 'settled open circuit voltage' is always a healthy 12.6 to 12.8 volts but as soon as you apply a load to it, even just sidelights, the voltage falls to below 12 volts and attempting to engage the starter motor/solenoid just results in a rapid clicking noise, at the best, and battery volts falling to below 8 volts, even just on full beam headlamps with the engine not running. Everything else electrics wise seems to be ok and once 'started on the jump leads' the engine ran smoothly and battery volts stabilised at around 14.8 volts with the alternator keeping things all hunky dory!

Does anyone know how to 'disolve or disperse' the heavy sulphation in the honeycomb lead matrix inside this relatively young battery (Owners say that used daily, these batteries can last for over 15 years) to release the full surface area and the associated 200 amps or so necessary to turn the starter motor over?

The local Mazda Dealer has quoted £190 for a replacement battery - which he declined saying that he would like to persevere with trying to 'revive' the original battery. We know that suitable conventional wet plate maintenance free (sealed) batteries can be purchased from LION, VARTA and Yuasa at between £70 to £90 but would like to give the Panasonic one more chance of coming good.