External battery charging while still on car

I should think that picking a battery up and shaking it would do the same job as pulsing it.

Reply to
Doctor Crippen
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Try that with my Renault Master battery.

Reply to
newshound

I put on one of those recently, the big one, 110 AH iirc. 150 quid in GSF, 75 in Costco, same type of Bosch.

Reply to
MrCheerful

With an output of about 1 amp, not really a car battery charger. Would takes days to charge the average car battery. The one MrCheerful probably means is the Lidl one - on sale now. Will charge most car batteries overnight - and can safely be left for as long as needed. And it provides a tiny charge current when the battery is full to maintain full charge.

BTW, that one on Ebay isn't legal to sell in the UK. It doesn't have a fitted 13 amp plug.

Reply to
Dave Plowman (News)

I think the point is that any battery with too low an off-load terminal voltage to trigger the output of an 'automatic' charger is probably a lost cause in any case?

That said, there are some (chemistry) car batteries that seem to be more tolerant of being over discharged, like the 'Calcium' battery I happened to have in my kitcar (that was so flat it only just lit the ignition light and may have been like that for a while) that seems to have made a good recovery after a good bench charge (and since removing the faulty alarm).

As others have mentioned you can often 'bump start' such batteries on auto-chargers by putting them in parallel with a good battery ... or, keep one of the older basic chargers on hand. ;-)

I just use a variable / constant current / voltage bench PSU and could never understand how anyone could live without one! ;-) [1]

Cheers, T i m

[1] A mate gave me his old CCTV unit the other day that he replaced because it stopped working and was 'clicking'. Upon investigation the 'clicking' was the fan trying to start up and failing. The brick style PSU seemed to be outputting 12V off load but was failing on load. Now, the issue there was 'is the unit drawing too much load or was the psu faulty'? I set the bench PSU to 12V and 4A max (the rating of the stock PSU) and made a temporarily connection to the power input and the CCTV unit fired up fine and was only drawing about 2A (as displayed on the bench PSU) . Once I knew it wasn't drawing excessive current I cut the output lead off the old PSU and made a better connection to my bench PSU and ran the unit up longer .. and then ordered a replacement off eBay. Whilst this was nothing to do with a car, having such a bench PSU is not only very handy as a temporary battery charger, you can also use it to test / power many other car related items (like car radios) whilst testing / checking them, or just (safely, safer than using a spare battery say) proving that they work before trying them in the car itself.

And *no* household, especially one with a car (or motorbike, caravan) should be without a DMM, especially when you can get them so cheaply! ;-)

Reply to
T i m

That was something I wondered. Steve hasn't mentioned that they have and it didn't. ;-)

A young lad, getting his first car, used a 12V cleaner to give it a good once over, flattening the car battery in the process. He took it out and indoors and borrowed one of my chargers. A neighbour volunteered to help him put it back on (no idea why) but couldn't understand why he had to open the small post battery terminal right up to get it on and the other would only clamp when you trapped some screws in the gap ....... (where was Darwin when you want him)? ;-(

*Luckily* he only blew the fuse to the radio and killed the alternator and 'of course' the neighbour didn't offer any money to fix it ...

Cheers, T i m

Reply to
T i m

was the psu one of those tiny ones like they put in blade computer units? about 6 inch long by 2 x 3. I have had two of those fail in my cctv unit and have decided to just replace it with an external conventional computer psu with extended leads (several lying about) I found that the little one just overheats, even with a new fan and an extra fan blowing into the side, despite the actually low power consumption .

Reply to
MrCheerful

With a mesh case? If so, no, it was a std laptop type 'brick' MrC.

I think heat can be the (premature) deathnell of much of this electronic stuff and / as most of the stuff I've had that runs cold / cool seems to have run the longest.

That's why I think it was stupid of Vauxhall to put the ECU in the Meriva on the end of the block! ;-(

Ok, it has the advantage of keeping all the engine wiring in the same movement plane (so sensor and injector wires short) but it doesn't seem to have worked if that was an idea.

Cheers, T i m

Reply to
T i m

That's when you go look in the shed for the 30 year old charger that is just a transformer, a diode pack, an ammeter and maybe a switch for 6V.

Trickle charging needs only a few mV in excess of battery voltage. But some chargers switch to "pulse" mode.

"Pulse" charging is used by newer chargers for batteries that are flat. The Lidl ones and similar use this for 12V batteries that output between

7.5V and 10.5V +/-0.5V. Pulse charging puts about 20V on the battery. It pulses 20V for a short time, then waits, re-tests the battery voltage. If it's over 10.5V switches to normal charging. If it's still under 10.%v it gets a another 20V pulse.
Reply to
Peter Hill

Steve pretended :

Just to put this to bed for you guys:

First, I have to say that Tempus doesn't half Fugit - turns out it's been *5* *months* since my neighbour first injured her arm! It only seems like a few weeks, but that explains why this year seems to be zipping by. Anyway, I digress.

So, the car has been stood for 5 months. I connected my Ring 6A RCB206 charger and the amber 'Charging' LED lit up. Just been into her garage now to find the green 'Fully Charged' LED lit so I disconnected the charger, turned the key and it fired up like a good 'un :D

Thanks all.

Reply to
Steve

Being as it's in a garage and near power ... would it be a good idea to either get a suitable charger that you could leave on all the time for her or ... put one on a timeswitch so that it comes on for a day a week or (assuming it will self start) or if you want something different and have the space / opportunity, connect up a small solar panel (outside the garage of course ) for her?

Whilst a small panel might not charge the battery as such, it might prevent / slow it discharging as fast (even in the winter)? ;-)

Cheers, T i m

Reply to
T i m
[...]

This one has decent reviews:

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Chris

Reply to
Chris Whelan

My local Lidl has their superb little one on offer at the moment. Costs about 13 quid. About 4.5 amps output, so will charge most batteries overnight. It then reverts automatically to a maintenance charge, so can be left on indefinitely. Excellent value. Other makes are available - as they say - at often three times the price.

Reply to
Dave Plowman (News)

Yeah, that's the sort of thing I was thinking of and Maplin often have something similar on offer.

I don't think there is any issue connecting such low power panels directly (via their built-in diodes etc) but I had two 5W panels charging a LA battery in the garage to give me 12V lighting but via a small charge controller and I feel the controller was discharging the battery faster than the panels could charge it up! ;-(

I'll bypass it and try it again (although it provided over discharge protection in the even of me leaving the lights on etc).

Cheers, T i m

Reply to
T i m

Does it have a 'Push to start' button on it though Dave? If so It (and I have a few that do) are no good if you run them from a timeswitch (although you would say why would you need to if they are designed to be left on 24/7). ;-)

It's just that 'some people' (often older) don't like the idea of leaving stuff on (or even plugged in, even if switched off) unattended and so I've found the timeswitch solution is often 1) a compromise they will go far and 2) often actually more than sufficient to do the same job and possibly at less overall power consumption?

Noted.

I built a 4 way charge switcher that will move a charger around 4 (max) 12V batteries over a preset period (6 / 12 / 24 hours etc). If a battery isn't present it will simply jump over that outlet and move onto the next etc. So, that means I can't use those chargers that require you to press the 'Start' button so have to use the Optimate instead (or the old Halfords auto charger).

Handy for maintaining 4x (disconnected) LA batteries over the winter. ;-)

Cheers, T i m

Reply to
T i m

Yes. Push for on.

Well, the timeswitch has to be left plugged in and switched on to work, hasn't it? ;-)

The snag is most modern chargers have a relay in them to prevent reverse connection. Leave it connected to the battery (but switched off) and that relay will take some current - thus discharging the battery more quickly.

Reply to
Dave Plowman (News)

Check.

Quite ... and the fridge, freezer, cordless telephones, the CH ...

We were helping one old dear re-locate her mobility scooter from the shed at the bottom of the garden (where she couldn't get it out on her own) to up on the patio (via a ramp I built) and under a small semi-rigid cover. The idea was to then take a low voltage (~24V) extension cable out though the wall in the lounge and then keep the charger in the lounge so that when you come back you plug the 'charger (cable)' in, cover the scooter then when indoors (in the dry) power up the charger and turn it off either at night or when it shows charged. So she gets a rele to put a waterproof socket on the outside meaning she's now got to take the charger out there (nice trip hazard with long wires and she now only has one hand free to steady herself), plug it in to the mains and the buggy and put it somewhere where the wind can't blow the rain ... and go out there again to switch it off and / or bring it in (possibly in the dark and the rain). The good thing about this is that I've had less to do with it, should something happen.

Even worse then. So, a solar panel or an 'automatic start' charger like the Optimates.

Cheers, T i m

Reply to
T i m

Wouldn't it be easier to fit a battery disconnect, and disconnect the battery when fully charged? If the battery is good, it will start the car several months down the line. Easier than messing about with a charger to keep the battery topped up while connected.

Reply to
Dave Plowman (News)
[...]

The ECU would revert to base settings, and would have to 're-learn'. Some cars require a specific procedure for that(1), and until that has completed there would be some performance anomalies. As the vehicle is owned by an elderly person, that might present problems.

The radio code would also require re-entering each time, although that is less significant.

(1) As an example, some Fords need to be allowed to idle through two fan start cycles, then driven at a variety of speeds. Depending on how far from optimum specification an individual car is, it may not idle correctly until that process is complete.

Chris

Reply to
Chris Whelan

Oh for the good old days...

Reply to
Davey

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