Can anyone recommend a cheap basic battery charger, ie, the old style non-smart type.
The type that will have a go at charging your battery from near enough 0 volts, rather than the 7 or so volts that smart chargers so often need before they’ll start working ?
Not a good idea.
Why?
The temptation is to leave it on a bit too long, and that will boil a ‘dead’ car battery because it reaches “full” (but no charge) very quickly. Bad news.
However, if a car battery is rescue-able there is a neat trick one can try, and it is safer, no boiling.
Dig out an ordinary 12V 1Amp (or more) plug-top supply from the box of ‘spares’ (or another good 12V car battery).
Next, obtain a 100 Ohm 3watt (or slightly higher wattage) resistor.
Connect together negatives on battery and power.
Link positives via the resistor and leave it for half an hour. Hopefully, the resistor will get warm showing some current is flowing.
If the car battery is any good this will wake it up enough to put the Smart charger on instead.
The value of the resistor doesn’t really matter, so long as the current is not too high for the wattage, anything between 50 and 200 Ohms will work - if the car battery is viable.
Odd scraps of wire twisted together will do for the hooking up.
Of course, be careful not to short anything.
Aldi smart charger Around £14, cannot go wrong with one.
M-m
Only ever use the Ctek from Halfords and safely leave on for months if necessary
They recently had similar in Lidl, £15, I’m using one atm.
OP…get yourself one of these below but i reckon it’ll tell you your battery is knackered anyway.
Hi MM
I have a Lidl charger. As with the Lidl one, I’m fairly certain that the Aldi charger needs the battery to be at least 7.3 Volts before it can operate.
Thanks Mick
I already have one of these, in Topdon guise.
The battery that I needed the charger for was in a neighbour’s Toyota MR2. He’d left an interior light on, and hadn’t been near the car for the last 3 days, which was plenty of time for the battery to go flat. We tried his Jumper cables. They didn’t work, possibly due to difficulty in identifying a workable earth point for the negative. I had a powerbank jump starter, which I didn’t have much faith in. That managed to turn the MR2 over about once, then went dead.
So, at that point I offered my Lidl charger to charge up his battery, but it’s meter showed 0.0 Volts in the battery, and my own multimeter showed about 1 volt…, so the Lidl wouldn’t work.
At which point, we were down to a tow start, but he decided that he would just buy a new battery, and headed off down the road in his daily. So I never got the chance to offer to test his battery with my load tester to confirm whether it was actually ruined or just flat.
I had an old style Bradex charger for many years before going down the smart-charger route. Never had any problems with it. It would charge the battery, and then its meter would show a gradually reducing charge rate. When it got down to almost zero, the charge was done, time to unhook. Never boiled, or ruined a battery.
When I bought the smart-charger, I ttought I’d never need the Bradex any more, so I slung it…
I have an old Bradex charger I bought from Maplin (remember them?) many years ago which still does the job for me.
A while ago I had a phantom parasitic drain problem with my NB which I tracked down to the number plate/boot light which occasionally stayed on when I shut the boot. The first I was aware of it, it drained a brand new Panasonic battery down to 2.5v when I didn’t drive the car for a week.
I trickle charged the battery up on the low setting with the Bradex and the car has been fine ever since including sitting unused outside covered in frost for a week during that very cold spell we had in January.
If your mate’s battery drained to zero in three days I would suggest it’s probably beyond saving.
Can’t you just connect the powerbank cables to it " off the car" and let that put some juice in it to reach the voltage threshold?
Never reached that point…, he was seized with the urge to throw money at the problem.
He’s just got back, from Eurocarparts, with a Lion battery. I resisted the urge to mutter… "Oh…, ffs ".
He’s tried to fit it, and the -ve terminal is rather larger than that on the Yuasa that was flat. I told him they sold him the wrong battery. Yet, it was what was listed when he typed in his reg…
Not my problem any more.
His difficulties only reminded me that it would be quite handy to have a traditional charger around, like my old Bradex, which is why I asked the question.
They pop up on ebay regularly if you’re feeling nostalgic 