Knowing your battery

[Overdose]

I've seen a few posts on here and its seems that alot of people dont understand how their battery charges/discharges.

The basic battery terminology.
Cycles - when a battery has say 2000cycles written on it, that means that the battery can fully discharge from full to empty and recharge again 2000 times before it dies.

C.C.R or cold crank start - most cars will have this type of battery and this is how many amps of current can be delivered for a 30 second period in -18'C conditions. eg. my car has a 550 C.C.R battery, meaning it can deliver 550amps for 30seconds on start up.

Precautions.

The perfect temp for a battery is 25'C. When you increase it to around 33'C this will either take 25% or 50% of the life of the battery(have it written down here somewhere, if anyone is that interested). also leaving a battery on cold concrete is bad because it causes the electrolyte(fluid in the battery) to condense at the bottom and causes the plates inside to corrode.


A battery should not drop below around 9-10v on start up and a full charged car battery will show around 13.5v on a multi-meter.

To test a sealed battery, check it is fully charged then without starting the engine put the headlights on for around 3mins then check the voltage of the battery again and if it has dropped then your battery is on the way out, if it doesnt change its fine.

Any other tips are more than welcome.

 

[andyman]

just so people know cycles is generally used on 'deep cycle batteries' as desciprition says above,
they have a rating of cycles to determine their most effective life,

these batterys are mainly used as a second battery in a dual battery setup for running fridges, lights, radios etc, you generally dont use winches or real high amp drawing component


when topping up battery electrolyte levels, you fill the cell up to where plastic shield ends, when you see the water hit the shield it will 'cat eye' as such, ie the water will curve up at the edges, this is the high mark

ive always used ordinary tap water out of a clean container and never had an issue or come back, no other workshop i know use distilled water either

 

[jetspin_vn]

And beware thermal runaway!

 

[Overdose]

and also I forgot to write about Amp-Hours.

Amp hours are how many amps your battery can supply in one hour without the engine running before becoming flat. eg. 40ah = 40 amps for 1 hour then its flat.

 

[VS Omega]

Regarding the temperature, does that mean the ideal place to store a battery would be in the boot of the car away from the motor?

 

[Overdose]

yep thats it. the boot is a steady temperature instead of cold to hot then slow cool down again.

 

[jetspin_vn]

Just be sure it has a bit of ventilation. Charging causes hydrogen gas to be produced, which as you might imagine is a little hazardous.