Thread: Battery charging problems

Originally Posted by drivesafe

Hi Hawc, there have been quite a few similar problems reported over the years, and one fix it to do a HARD RESET.

You do this by first removing the negative cable clamp from the Optima's Negative ( - ) battery terminal.

Then remove both the negative ( - ) and positive ( + ) cable clamps from your cranking battery.

I usually let it sit like that for 20 minutes or so.

Then get a single jumper lead and connect one end the negative battery clamp ( NOT TO THE BATTERY'S NEGATIVE TERMINAL )

Then touch the other end of the jumper lead to the positive battery clamp ( AGAIN, NOT TO THE BATTERY'S POSITIVE TERMINAL )



Once this is done, refit the cranking battery's positive ( + ) clamp.

Then refit the cranking battery's negative ( - ) clamp.

And lastly refit the Optima's battery's negative ( - ) clamp.

Then try turning on your ignition and see if you are still getting the message.

Tim, thanks for this and all of your other excellent advice.

Hi Alan and not sure if you understand why you need to make the earth connection away from the battery.

In certain situations, if a battery is worked hard, it can be caused to gas. An example of such a situation is if you have been cranking your motor for a fair while but not succeeding to start it.

This type of use can produce hydrogen gas in the battery and it will expel from the battery over a period of time.

When connecting leads to a battery, such as jumper leads, the last lead connected completes the circuit and this final connection can cause a spark

By making the last connection the one to the negative side of the battery, because the battery's negative is earthed to the body/chassis, you can actually make the last connection somewhere other than the battery's terminal.

This moves the spark potential away for the POSSIBLY gassing battery, and thus demonically reduces the potential of an explosion happening.

If you use the plug with the two eye terminals and connect it to the battery without having the charger connected, then you are safe, because the plug moves the spark potential away from the actual battery.


These vehicles keep a chronological map of battery events, and while you may charge the battery separately from the alternator, the vehicles memory "remembers" that the last time it checked the battery it was low, and as you have not driven the vehicle since the last battery check, it must still be low.

By you leaving your battery disconnected for a few hours or what ever, achieves the same thing as the Hard Reset does.

The reason for the hard reset is that many of the electronic devices in your vehicle, that collect and manipulate data, use two basic types of memory to store that data.

One is non-volatile memory, where the data is maintained when the power is removed.

The other is volatile ( or RAM ) memory, where the data is lost if power is removed, and this is what we are trying to delete when we do a hard reset.

Data for your Trip meter and some radio channel info and some of the chronologic battery data is stored in Volatile memory.

But unfortunately it is not just a simple case of disconnecting one of the battery terminals and then reconnecting it to clear/delete this volatile memory.

All your electronic devices have large suppression capacitors in the power supply circuits.

These large suppression capacitors are there to FLATTEN OUT any voltage spike that may occur.

But when power is removed, the same suppression capacitors now act like small batteries, and keep many of the circuits powered up, circuits like those containing the Volatile memory chips.

The suppression capacitors will progressively self-discharge over time, or by removing the cranking battery terminal clamps and bridging them together, you literally short circuit the suppression capacitors. Thus deleting any volatile memory.

Or as you did, by leave the battery disconnected for an hour or so, you allowed the suppression capacitors to self-discharge, achieving the same results.

PS, sorry Alan I was typing at the same time you were.

I have personal experience of detonating a car battery as a kid - a deafening experience to say the least. I don’t recommend you do it

It blew into tiny fragments, the explosion deafened me for over 5 minutes, covered me in battery acid ams ruined my clothes lol. I guess it’s fair to say I was lucky that no shrapnel killed me.

I learnt a lesson that day about gassing batteries.

We we kids and enjoyed putting hacksaw blades across the terminals and making them glow red. We did this until the battery was flat. We then put it on charge and the following morning had another go. Boom!!!!!!
Battery acid also all over my friend’s fathers new Nissan Maxima! Thankfully a swift wash down prevented damage.