How to store a spare car battery at home?

My maintenance-free car battery was showing its age and the winter cycle of heavy use with all the electrics on, plus short stop and starts gradually took its toll.  To avoid being stranded in the middle of nowhere with a flat battery, I swapped it for a new one and the Honda dealer shrugged (usual reaction) when I asked if I could keep the old one – no need to scrap it when it’s good enough as a spare, for jump-starting or running 12V accessories (notably a 12V impact wrench or 12V lighting). I could also hook a 12V inverter to it, to obtain 230V mains voltage in a power cut.

Car batteries have enough capacity to melt a metal watchstrap and great care is needed not to short them accidentally or this could start a fire or cause serious burns. Old ones are also an explosion risk due to hydrogen gas escaping. Problem is, how to store a car battery in safety?  The answer came from the marine and camping sector, where 12V lead-acid battery storage is a common problem. I found Italian  manufacturer Trem produces a wide range of high quality plastic battery boxes for camping (leisure batteries) or marine use, and I found a tough box with removable lid that was just the job.

Trem Standard battery box [click to see]Trem’s Standard box with a red lid measures 270mm x 190mm x 200(H) mm  excluding the lid dimensions, so once the lid is on there's some clearance for battery posts etc. As my car battery measured 230 x 120 x 200mm(H) it would fit perfectly.  My Trem battery box came from a specialist marine distributor in Scotland but happily they are now also available from Amazon.

I packed the battery inside a little to stop it moving around. The lid is retained with a buckle and nylon strap (cut to length) with fittings to secure it to a flat surface if wanted. The moulded plastic body has two carrying handles and the red lid is shaped to allow heavy duty cables to exit.  Note how the sides appear to be curved inwards, presumably to allow for ventilation. It’s easy to carry and pretty tough, but should be handled with care or it will shatter if dropped onto a hard surface from any height.

Occasionally I top it up with my CTEK MXS5.0 conditioner/ charger. The Trem battery box has proved a very neat and tidy storage solution, and the battery is now safely stored in the garage out of harm’s way and it’s always ready for use.

• http://www.trem.net
• http://www.trem.net/home.php?lan=eng&div=cam&pag=catalogo  Multi-lingual catalogue