Unable to charge flat battery - Dwight Van Driver
Yesterday dear beloved daughter phoned - had left courtesy light on her sports car for two days and now vehicle refused to start.

Obviously flat battery so round to hers with jump leads. Connected up and donor car running.....zonk... nothing when car ignition turned. Neither was there anything from horn or lights.

Connected super duper Airflow battery Condition/Charger (as HJ recommended) and all I got was the 'power'on light and no light at 'compensating'

So couldn't get any charge into battery.

Home Breakdown called out - attended with boost battery pack and got vehicle started.

So, you knowledgeable lot - why couldn't I get juice into battery?

dvd


{slight amendment to header - DD}
unable to charge flat battery - Dynamic Dave
DVD, how flat was the battery?

According the Airflow blurb I found via a google:- "It will charge a battery from a minimum of 9 volts to 13.8 volts and then turn off."

www.airflow-uk.com/shop_accessories_battery-condit...l

That says to me that if the battery has less than 9 volts in it, it won't recharge. I could be wrong though.
unable to charge flat battery - Dynamic Dave
To add further:

"The Airflow charged between 0.35A to 0.4A most of the time, but wouldn't pick up batteries much below 9.5V, so a really flat powerpack would need boosting first."

www.autoexpress.co.uk/products/products/59293/batt...l (deliberately made non clickable)

It appears that your charger is more of a trickle charger for vehicles parked up for long periods of time to stop the battery from going flat, rather than a conventional battery charger.

That aside, I paid £4.99 for a very similar product recently from LIDL to maintain the charge of my motorbike battery over winter.
unable to charge flat battery - John S
DD

Exactly right. I have one of these units. The Airflow instruction specifically state it won't charge completely flat batteries. At least one on the red 'voltage indicating' LEDs on the unit must be illuminated for it to work. It's designed to maintain stored batteries, charging them to 13.8 volts, and then turning off, recharging only when the battery volts drop due to self discharge. This is claimed to be better for the battery than a continuous trickle charge. It's certainly worked for the last 5 years or so on my little used Minor.

JS
unable to charge flat battery - Civic8
>>Obviously flat battery so round to hers with jump leads. Connected up and donor car running

Did you leave it to charge before trying to start say 5-10 minutes
unable to charge flat battery - Screwloose
DVD

If even the lights didn't come on then that's easy; the clips weren't making contact or the leads are faulty.

No matter how poor the jumpleads [and most are laughable] they'll still pass enough current to power the supplementary circuits - even on a car with a totally drained battery.
unable to charge flat battery - Dwight Van Driver
Dankershun peoples.

Didn't appreciate that Airflow wouldn't work under 9v and its main purpose as stated ^^^^ is trickle charge.

Will have to check them jump leads. Did have a good connection.

dvd
unable to charge flat battery - nick
I have a couple of the Lidl battery conditioners. They work just the same as the very over-priced Airflow units. How can they charge so much for a few cheap electronic components?
Unable to charge flat battery - MW
Best policy now is to give it a slow 24 hour charge from a conventional battery charger. Clean up nicely all the connections and it should go.
Unable to charge flat battery - none
Many years ago I came across a heavy duty garage charger that wouldn't charge a totally flat battery. To overcome this, the flat battery was connected to the charger, and a charged battery 'flashed' across the connections. Something used to click inside the charger - and then it started charging. Apparently it was supposed to do this !
Unable to charge flat battery - nick
I had a similar problem with a huge battery off my old tractor. The Lidl charger wouldn't touch it, an 'intelligent' conventional looking charger neither, but an old-fashioned 'bung in lots of amps' type worked ok. After a while on this, the Lidl charger would handle it. As has been suggested, your battery was simply too deeply discharged.
Unable to charge flat battery - cheddar
Connected up and donor car running>>


IMO best not to leave the donor car running these days, should be enough in the donor car's battery so best to have it switched right off because as the recieving car starts it's alternator will start charging so the current through the jump leads will switch from drain to charge and *can* screw the electrics in modern cars.
Unable to charge flat battery - SaabFanatic
These rather neat-sounding Lidl chargers are on-sale again from today (in certain regions), even cheaper than before at £2.99.

www.lidl.co.uk/uk/home.nsf/pages/c.o.20070730.p.Ca...1

I downloaded their instructions from the web, it confirms they'll charge any battery showing at least 7.5volts across the terminals (lower will be rejected, but you can always "zap" it first with a boost charger or jump-leads to get it charging); "pulse" charging mode to revive deep-discharged batteries if necessary, then ~3.6A bulk-charging, followed by indefinite intermittent charging at ~14.4V to keep topped up and prevent sulphation of the plates.