Flat battery ... Again

[Meken]

Well our 2008 hse has sat for a few days and the battery is flat again - I did say to my wife last weekend I think i need to put the battery on the charger as it was starting to labour a little to crank it over... So a few days sitting & a very cold morning means we are driving in my car...

I've had the battery tested and it's still has about 90% of its cca capacity - the battery guy said nowhere near stuffed! These things are just hard on the batteries (especially with lots of short 5-15min trips)

I'm thinking of getting an Andersen wired in to plug the charger in once a month BUT not sure about charging the batter whilst the terminals are atill both fully connected (I currently disconnect both +ve & -ve before charging)

[Spudlynicholas]

As long as the charger doesn't raise the battery voltage above 14.6 v you should be right. Just don't use a big charger to boost the battery right up in a short time. A small 'battery fighter' style or cheapy 5 amp jobbie will be fine.

Your battery is charged at 14.5 v ish when the engine is running, so I figure this is a safe voltage for all your on board computers, ecu's etc.

[discovery39]

I would be disconnecting the Battery.
Especially if your are running a cheapy charger.
You don't want to take the risk of a Voltage Spike from the charger.
Might be spending some of your hard earned on some ECU's then..........

[Meken]

So far I always have disconnected both terminals but it's a pita to do monthly and I think with all the short trips we do we really need to give the battery a good top up monthly.

[101RRS]

I am nor sure why your are disconnecting the battery - just is not necessary - just charge like you would like any other car.

My RRS was hit by lightning a few years back - not issues with the cars electrics and computers but sis blow up the Scan gauge plugged into the OBD2 port.

Follow standard charging protocals - that is power off when connecting and disconnecting.

Garry

[inside]

Just for comparison and I'm also in Brisbane I left mine sitting for a month and started first go. Battery is 12 months old.

I think your battery is stuffed.

[Meken]

Nope I had the battery tested last time it went flat - it's at about 90% of the cca. It's not due to the sitting but rather lots of short trips. The battery bloke said you need to drive for about 15kms before you replace the charge used to start the vehicle. It's only a 10k drive to work for the wife so the poor battery never gets "recharged" fully most of the time - even worse when it's a couple of short trips to the shops in a day. The battery bloke suggested giving it an overnight trickle charge once every couple of months (to help preserve the battery life )

[iver]

Get your self a good quality charger like the ctek units which are automatic and suit AGM batterys. Leave the terminals connected when charging

[Meken]

Get your self a good quality charger like the ctek units which are automatic and suit AGM batterys. Leave the terminals connected when charging


But it's not a deep cycle agm it's a cranking lead acid??

[drivesafe]

Hi Meken and first off, unless a battery is a Lithium battery, all other batteries used in vehicles are lead acid batteries.

Your cranking battery is a Calcium/Calcium ( Ca/Ca ) battery, which is a lead acid battery and AGM batteries are lead acid batteries as well.

That out of the way. Your battery test unfortunately is not conclusive because Ca/Ca cranking batteries can be go flat over night and you can not start your motor next morning, so you get a jump start, drive 5 minutes to a auto electrician, who does a load test on the battery, and that 5 minute drive is enough to put enough charge in to a Ca/Ca that it now shows up as being OK.

Next morning, flat again.

You can try and recover the battery by using a battery charger, every night, and all night, for at least a week.

You do not need an expensive or high current charge, just one that is multi stage.

Put the charger on in the evening and leave it on all night. The charger will go from charge to float. It is this FLOAT cycle that actually reconditions the battery and you need to have the battery on a float cycle for around 8 to 10 hours at a time, to get the best benefit.

This is known as SOAK charging.

The battery should be off the charger for at least 12 hours before starting the next charge cycle.

If your battery does not improve after a week of charging, time for a new battery.

If you get a new battery, with the driving habits you have, as suggested, a once a month charge SOAK charge will keep it in good condition.

One more point, your Ca/Ca cranking battery will safely tolerate 15.5v boost charging voltages and your vehicle’s electronics will safely tolerate 18+v, so no need to disconnect the battery while charging and you can not cause spike damage in a vehicle, unless you are using something like an electric welder on the vehicle.

Spike damage in a vehicle is an urban myth.

[Meken]

Thanks mate for the clarification. I didn't charge the battery before test - I removed it and took it with in my car. I have a ctek charger in the van so I might connect it up. I have been using a cheapie trickle charger (nom 2.5amps)

[scarry]

I have to put the D4 battery on charge regularly as well.
It often sits around or does short trips.
Even reasonably long trips of say two hours does not seem to bring the battery up to full charge if i haven't had the charger on recently.

i have the cteck charger short leads permanently wired into the main battery,so all i do is pop the bonnet and plug it into the short leads.

[Meken]

I have to put the D4 battery on charge regularly as well.

It often sits around or does short trips.

Even reasonably long trips of say two hours does not seem to bring the battery up to full charge if i haven't had the charger on recently.



i have the cteck charger short leads permanently wired into the main battery,so all i do is pop the bonnet and plug it into the short leads.


That's what I was thinking of but was unsure of the charging while terminals connected but I'm confident now after drivesafe chimed in :) thanks