How long should a 6V 1.2 Ah Rechargeable battery last

stephenliverpool1

My 6V 1.2Ahr rechargeable battery, which I bought from Maplins and I use for my WIFI Solar House Alarm, has lasted less that 18 months.

I have been advised that this battery should last for between 3-to-5 years. Is this correct and, if so, what should I do next ?

fwor

It depends how it has been used. If it has regularly been allowed to discharge deeply or fully then that will shorten its life. If the only thing charging it is a small solar panel then it would not be surprising if it was getting inadequate charge during short dull winter days.

The other thing (from personal experience) is that bad design of the charging circuit can ruin a lead-acid battery quite quickly. In my case, the charger's voltage was too high - probably to make the battery recharge quickly after a power cut.

I solved that by adding a zener diode into the circuit to drop the voltage, and I was then getting at least 5 years with good quality Yuasa batteries.

However, if your battery is only charged from the solar panel, it's unlikely that overcharging will have been a problem.

RobTang

It depends on the battery type and the use its getting.

for Li ion and NiMh my rule of thumb is 1000 days where it has been charged. I dont really expect more than 2-3 years useable service out of these battery and maybe a year and half for nicads

You should also check that the solar charging circuit is compatiable with the battery type you are using, if not it can shorten the life of the battery.

stephenliverpool1

Thanks for the replies.

I have had the solar alarm for over 12 years. I have replaced the battery three times. The first two replacement batteries lasted for approximately 4 years each. The last one just lasted for 18 months as advised in my previous post.

The replacements have all been Yuasa NP1.2-6 6V, 1.2Ah batteries, which I am advised by the solar alarm supplier is the only battery compatible with the alarm.

kwikbreaks

As Maplin is presumably local why not take it back and try complaining. They probably won't replace it but you'll have lost nothing by trying - especially if you intend to buy a replacement there anyway.

It may be the charging circuit that isn't working well too - make sure the solar cells are clean.