12 volt charging question

[JumbleDuck]

...indeed it is often the only way to 'revive' and get a bit more life out of an otherwise dud battery which a modern (intelligent?) charger won't touch.

I keep an old basic charger for just that very purpose. Of course everybody will tell you that a flat battery will never hold a charge a again, but as long as they don't tell the battery it doesn't seem to know.

 

[ripvan1]

Ok, at present all I want to do is check what voltage the batteries have - I'm sure there's some power there because of spark and heat.

So far I've plugged correct cables into the correct plugholes on the m/meter turned dial to 20 on the dcv side and put the steel pointers to respective terminals on battery.

As stated small spark from contact with terminal and wires becoming hot instantly with 0.0 remaining on digital readout.

What am I doing wrong

 

[elton]

Ok, at present all I want to do is check what voltage the batteries have - I'm sure there's some power there because of spark and heat.

So far I've plugged correct cables into the correct plugholes on the m/meter turned dial to 20 on the dcv side and put the steel pointers to respective terminals on battery.

As stated small spark from contact with terminal and wires becoming hot instantly with 0.0 remaining on digital readout.

What am I doing wrong

You've got the meter set to an Amp or Ohms range? You're looking at the wrong end of the meter range selector switch?

 

[William_H]

Ok, at present all I want to do is check what voltage the batteries have - I'm sure there's some power there because of spark and heat.

So far I've plugged correct cables into the correct plugholes on the m/meter turned dial to 20 on the dcv side and put the steel pointers to respective terminals on battery.

As stated small spark from contact with terminal and wires becoming hot instantly with 0.0 remaining on digital readout.

What am I doing wrong

There are only 2 choices here. 1) You have got the settings on the meter and plugs incorrect or 2) the meter has a peculiar internal fault that causes it to draw a lot of current form the test circuit. Only choice for you is to get another meter and compare/ check.

Vic Mallows. I love the type of charge you have. The peaks of waveform ensure that current goes in even at high battery terminal voltage so you can get a full charge. You do need an analogue amp meter to measure the average current becaue a digital goes haywire. And of course you have to tur the charger off if you don't you cna cook the battery. I remain sceptical of these all singing and dancing set and forget chargers. They may save you from battery damage but may not give a full charge. good luck olewill

 

[charles_reed]

What were you trying to measure with the multimeter? For the leads to get hot you must have been pulling quite a few amps and that should only happen if the meter is in current (amps) mode. If you were trying to measure volts, were the leads plugged into the right holes on the meter?

If you were trying to measure current then make sure the leads are in series with the load. Never put the probes directly across the battery in current mode. All you will do is heat up the leads and blow the internal fuse in the multimeter. If the fuse doesn't blow immediately you will probably damage the meter.

Did your meter come with a manual or leaflet. If so, read it carefully and try again (if the meter still works!).

It's a good idea to read the instructions before using anything novel.

However, in most masculine opinions, it shows a singular lack of machismo - hence the contsnt stream of male DIYers in the average A&E department.

 

[VicS]

Ok, at present all I want to do is check what voltage the batteries have - I'm sure there's some power there because of spark and heat.

So far I've plugged correct cables into the correct plugholes on the m/meter turned dial to 20 on the dcv side and put the steel pointers to respective terminals on battery.

As stated small spark from contact with terminal and wires becoming hot instantly with 0.0 remaining on digital readout.

What am I doing wrong

I would guess that most likely you have the red lead plugged into the 10A socket

But what meter do yuo have. If we know it may be possible to look at it on line in order to make a more educated guess.

.

 

[ripvan1]

oh deep embarrassment and apologies - i had plugged red lead into ac socket - now showing 12.7 volts on 1st battery and 13.4 on the one still charging

 

[VicS]

oh deep embarrassment and apologies - i had plugged red lead into ac socket - now showing 12.7 volts on 1st battery and 13.4 on the one still charging

Unusual to have an ac socket .

The 10A socket I referred to above is for use when measuring current up to 10amps (DC only as a rule) .
It connects directly to the internal shunt so that large currents don't have to pass through the selector switch.
( if you ever use it be sure to return the plug to the normal socket as soon as you have finished .... recipe for disaster if you don't!)


The 12.7 volts reading is good assuming that is after standing for 12 hours or more. Check it daily for as long as possible. It will fall quickly at first but then more slowly. It should take several weeks to fall below 12.5.

Keep the other one cahrging until you get up to 14.4. Keep going for a few hours longer unless the reading suddenly rockets. Then let it stand for 12 hours and check it.

 

[ripvan1]

Thanks Vic et al