a.k.a Numax Automotive Batteries
a.k.a Numax Automotive Batteries
Was 'tricked' into buying two units from this company's range of sealed lead acid (SLA) 12v automotive batteries. One was for a motorbike, the other for a car. Very glossy website, praising themselves very highly, and making claims to be "market leaders" in the UK. I should have smelled a rat at the time, as I'd never heard of them before in all my years buying these types of products.
Both vehicles are cold stored during the winter. Both batteries were brand new and came with a 1 year warranty (motorcycle battery), and 3 year warranty (car). However, neither battery made it to the spring with any charge left in them.
When I removed them to test for voltage readings, neither battery gave a reading. As they were a few months old and had worked out of the box, I assumed they could be reconditioned with my 8 stage smart battery charger.
For the motorcycle battery, absolutely nothing happened after an attempted reconditioning. For the car battery however, at first things seemed positive, with the smart charger showing it had automatically selected reconditioning mode. So, I left it and went about my usual business.
Returning to the charging battery some 4 hours later, I noticed the smart charger had gone from reconditioning to the maximum 12 amp charge mode. Also, there was liquid on the floor beside the battery, a bad smell of rotten eggs in my garage (sulfur dioxide), and I could tell that the battery itself was giving off a lot of heat.
After a quick inspection, and seeing that the smart charger was only operating at 12.2v (normally 14.4v), and pointing my infrared heat gun at the battery, I realised the battery had released its fluids and was boiling itself dry. I switched the charger off immediately, but the battery had already reached 90C on the outside casing.
I've charged literally hundreds of batteries before using this same technique, but this is the first ever time it's ever resulted in this dangerous situation.
For both batteries to fail under warranty would be rare. Statistics show 1 in 100 fail under warranty. For 2 to fail would be a 1 in 10,000 chance. But the most unforgivable result is for a battery to fail, then allow an attempted reconditioning. This could have been catastrophic.
In my opinion, and based on buying, using, and recharging automotive batteries from any number of other manufacturers, these Numax batteries have to be the worst purchase I've ever made considering the potential damage they could have caused had I not caught this situation just in time before my house went up in fire.
Needless to say, I won't be buying Numax batteries ever again. Maybe you have used these batteries yourself and have positive things to say about them, but is it worth putting the safety of your home and family at risk?
I'll be writing to this company forthwith, and I'll be sending these batteries to Trading Standards for further testing. If I hear anything of note arising from this, I'll be sure to post back here.
In the meantime, I cannot and will not recommended to anyone this company's products. 1 star is too generous, but this review is not a scoring exercise, but more of a public awareness notice.








