Thread: How long should a battery last?

Originally Posted by crl

I have a brand new 55AH deep cycle battery which I used last night to cool the fridge (40L) in my Disco. It ran all night at 8-10 Deg C and it was left on into the morning. I checked it mid morning and the temp had gone right up to 19 deg C. The night air temp was about 27 Deg C and the fridge would have run for about 19 hours from switching it on till I discovered it nice and warm in the morning. There were also two 15 min drives in there as well which should have boosted the battery a bit. The battery is only new and the altenator has been tested and works OK.

Is this about normal for 55AH batt or is it not up to par?

Thanks in advance,

crl



2000 Discovery II Auto TD5

Definately something wrong, I have a 60AH second battery that I run the fridge off (40ltr Waeco)in the Disco, along with a camp light and even charging camper, camera and laptop batteries, I have done this for 2 full days (48hrs)and never had a problem, the camper battery was charged through an invertor(it was overcast and usually have a solar panel doing the camper battery)

My dual battery monitor generally looks after things (Traxide), I normally give the car a run for at least 30mins each day, which means I can usually stay anywhere indefinately.

Baz.

Folks, a lot of ppl miss some of the basic principles of lead acid and variants and is always a hot topic. Think of it this way, a glass of milk with cream on top and the battery should always discharge / charge in the cream area and not dip into the lower voltages of milk with cycling otherwise you just reduce the cycle life and whether deep cycle or not, the lower you go the less overall cycles and a battery can fail within say 30 cycles of abuse or hard use.

You can do some basic checks to understand and determine life before you start as you need to know what voltage the car is actually set at to provide the charge as car manufactures are now different to the old guess of say 14.2v I think Prado's are in the high 13.V spec now.

Deep cycles have both float voltage and max voltates and sometimes they are higher than the car can produce so you never really achieve full charge into the cream area. At the other end, as in my van set up, I have 5 deep cycles all with 13.5 float and 14.1 max. I took an educated guess and set the low cycle cut out at 12.25 and I am at the 12 year mark and still going with close to the discharge times (maybe not) with regular use.

I just wanted to make this point given it is just one of the variables of many to so increase the knowledge of matching the load specs to battery type that is often overlooked. A couple of years ago a mate of mine bought an expensive deep cycle for fitout in a hilux but the stated charge rate of the bat (max) at 15.1v to which was never going to happen in most vehicles.

And all the advice in this forum thread is all good information for anyone prior to considering when opening the wallet

Cheers