Thread: Discovery 2 Battery Charge to 70%

Just so we are clear on definition...

What constitutes a long drive to you?

An hour (I am a pommy)

Originally Posted by Shakey

An hour (I am a pommy)

From 70% to full would take several hours above idle. Idle doesn't really help much!

Originally Posted by Shakey

Just measured it again overnight and it's down to 12.28v

Hi again Jake and that voltage reading is quite common.

Here is a bit of background and then you can see where I am coming from.

Voltage readings are an indication of the state of charge of the capacity in a battery that can actually be charged.

The problem is that this is no indication of how much of the battery’s total original capacity is actually still available and there is no quick and easy way to work out how much of a battery’s capacity is still available.

With a battery in a good state of charge and at it’s full original capacity, a battery can be discharged down to 40% SoC ( 11.9v ) and still maintain it’s CCA rating.

When a battery’s SoC is below 40%, it no longer has the capacity to maintain it’s CCA “RATING”, but this does not mean you can not start the motor.

I have tested many new vehicles over the last 10 or so years and I have not found a single new vehicle that I could not start using a battery with an SoC of 20% ( 11.58v ).

There is a catch, the batteries were always in good condition. In other words, they were at their maximum capacity.

Now back to your battery.

Through continual short drive use, and a 1 hour drive is not long enough to charge a battery that is in a low state of charge, your battery, like most cranking batteries, is in a poor condition, but it will probably still make it’s CCA rate.

Your battery can actually remain at that level of charge and it will continue to start your motor.

The drawback is that it will probably have a much shorter operating life.

So the only way around this common problem is to give your battery a periodical charge with a battery charger or fit a small solar panel.

While personally prefer a small solar panel, this is in most people's case, not a viable option.

So a battery charger is the way to go, to recondition and maintain your battery at it’s best.

SPECIAL NOTE, to get the best results from battery charger reconditioning, use a SMALL current capacity battery charger, and any cheap, 3 stage battery charger is all you need to get your battery back to a good condition and to increase it’s available capacity.

High current battery chargers do not charge lead acid batteries properly, they just charge them quickly.