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[barryfoote]

Hi guys,

Well a little problem has just occurred. I decided to charge up my 12 volt 7amp battery on my Lady T. I use a Model Flight mullticharger, which has a red mains led and a green charge led. After connection, the green charge light failed to illuminate, so I tried it on 6 volt 4amp battery and the green light lit up.

Back to the 12 volt battery but could not get the green charge light to illuminate, even after cleaning the terminals. The battery is in good order and still powers the model so I know that it is okay.  Any ideas as to why?

Using my newly aquired multimeter, I checked the battery's voltage and got 11.2. After connecting the charger to it the voltage went up to 14 so I am guessing that it is charging the battery??Am I right??

When I first bought the battery the green charge light did operate on it.....My brain hurts now.... :'( :'(

[sheerline]

Hi Footski, well it sounds as though your meter knowledge is expanding and finally paying off. The fact that your battery voltage has increased after connection to your charger is definately an indication that your charger is putting something in. I am not familiar with your particular charger and ther is always the possibility it could be faulty. It could be that the charger is able to supply current but at a very low level, insufficient to cause the lamp to light but just enough to bring the battery voltage up. This is where a current reading from your charger to your battery may help you see how much the battery is drawing. If you set your meter up to read current (Amps) and fit one meter lead to one of the charger wires and the other lead to the battery terminal you should get an indication of how much current is being drawn by the battery. This coupled with the stated battery voltage and capacity (amps) will tell us how long it will take to charge up.


 

[Sandy Calder]

Hi Footski,
Confirm your voltmeter battery is OK.If the meter instructions don't mention a "low-batt" indicator then you need a gold standard battery to be sure of readings.

11.2 is not good at all.If the voltage jumps to 14 on a trickle then that is a bad omen.

Even without the original instructions,the green light issue could be diagnosed if you try a large capacity battery or add a couple of wheat grain bulbs to increase the load current on the charger.
Your meter,on current, would show if the green light needs a minimum current draw to work or if a bimetallic circuit breaker has opened.

Regards,
Sandy Calder

[barryfoote]

Sheerline,

Oh dear here we go again...Did as you say and got a reading of 0. I put the black meter wire to the black charger wire and the rd meter wire to the positive battery terminal.....Nothing except 0. I ried various configs but could only get 0......I know it is down to me being a thicky, but the battery voltage reading after a couple of hours charging reads 12.2 so I am happy with that.....I think.

Hi Sandy and thatnks for the response. My voltmeter is new and the battery seems okay.......As for the rst of your post I am afraid it may as well be written in Chinese.....Electronics are not my thing as many on the forum will vouch for...

[Sandy Calder]

Anyone care to provide a diagram instead?
And by that I mean photoshop the picture of the voltmeter with the dial at the correct point and the probes in the correct sockets? 
Sandy

[andygh]

Sounds like battery is duff. You could try leaving it on for a full charge and see what you have at the end of that, it might give a clue as to it's state

[Sandy Calder]

I put the black meter wire to the black charger wire and the rd meter wire to the positive battery terminal.....Nothing except 0. I ried various configs but could only get 0......

Hi Footski,
After doing that,you'ld be well advised to check the multimeter fuse!

I can't help you on a Chinese translation but another thing springs to mind....
If your forum profile picture taken is nearly five years old then there's your solution! 
Regards
Sandy

[sheerline]

Hi again footskie, try your meter probes in the VA ohms socket instead of the 10A socket, this way it will read a lower current. Set your meter to read 200mA and try again and see what you get this time. It is possible that the 10A socket on your meter will not show much of anything if the battery is drawing an extremely low current. The fact that your battery appears to run your boat ok with what remaining charge it has does not suggest it is stuffed. I think your charger is not delivering sufficient charge current for your 12 volt battery.
One thing you could try at this point is measuring the battery voltage  whilst running up the boat. Remember to rotate the meter switch to read 20V dc (left hand side scale on your dial) Make a note of it and after leaving the battery on charge for a few hours, repeat the process and note the voltage again. If whilst running the boat up the voltage tends to hold up, it would suggest your charger is indeed poking some current in but of course it may only be a trickle.
 As you say, leave it on for a while and see what you get out of it before condemning your battery or charger.

[sheerline]

Just a quickie Footskie, I assume when you did your initial current readings that you plugged your meter leads into the com and 10A sockets when you measured the current. If you did, remember to rotate your meter switch to the 10A position (around the 4 o'clock mark on the dial) then take a reading but DO remember to remove your leads from this 10A socket before measuring any voltages... especially the battery or it will blow the internal meter fuse as had been mentioned already. If the fuse has blown, you can still use the meter for voltage readings and low current readings up to 2Amps using the VmAohms socket but you wont be able to use the high current 10A socket.
Sorry, don't mean to give you too much tech nonsense at your stage of the game so trying to keep it as light as possible.
Hope it helps.

[Sandy Calder]

Footski,
I haven't looked at my cheap yellow meter today ,but it requires removing the cover to replace battery and the fuse.That meter has no low battery indicator and gives spurious readings a partially used alkaline PP3.The other meter will happily use the same battery for many hours and give accurate readings showing "low-batt"
It's just a thing to remember when you've clocked up a few hours or if your supplied battery has an old date code.
Be extremely careful when the dial is on the unfused Amps range.

Chris,
My posh ,ultra long-battery-life,meter is unfused at 20 amp and measures current by the voltage across an inch of tinned copper wire. It has a 2 amp fuse to protect the precision 0 to 2 amp ranges.
I presume,from that, Footski's meter is likely to have a fuse in the 0-200mA RANGE meter is in the V/OHM/A socket.

Regards
Sandy

[barryfoote]

Sandy and Sheerline,

Thanks guys.    Fuse in multimeter has gone......It could not possibly have been anything I did ::) ::) ::) ::)

I will pick one up and whilst I am at it wil change the battery in it, next time I get close to a shop that sells them.....Probably next week. I will keep you posted..

Meanwhile I have tested the voltage of the 2 6 volt batteries that run my springer and at first it read 6.2 but after a couple of hours charging it went up to just under 7, so at least I know the charger is putting some juice in.
Barry

[Sandy Calder]

The meter below has got a low battery indication and the 250mA fuse protects the 0 - 200 mA range
http://www.p-mastech.com/products/04_dm/m830b_600v_hys004369.pdf

[barryfoote]

Sandy,
Apart from the black grip that could be my meter....I think the battery is fine as it is all new but I will change it anyway.....Oh and I will buy several fuses for it too.......I will probably need them... ???

[sheerline]

 Good morning Footskie, if you want to double check the fuse, take the back off, remove fuse, set your meter knob to 6:oo o'clock position (ohms 200), and with your leads in com and VAohms sockets first touch them together to ensure your meter is doing something... the display will go to zero. Now put the leads across your fuse, the scale will go to zero if your fuse is intact but if not, the scale won't change and will just show the figure 1.
As I said in my first post, blowing the fuse... nothing to be ashamed of.. we've all done it ...and still do!
Off to the fuse shop with you!!
Regards. Chris

[nick_75au]

I would try the battery check with a car tail light bulb lit by the questionable battery. light up bulb with battery and measure volts like you have been, If its reading lower than say 11.5 - 12 volts then the battery is probably unhealthy.
Regards
Nick

[barryfoote]

Chris,

Cheers and yes the fuse is no more....as you say off to the shops with me but as it is chucking down lots and lots of wet stuff over here at the moment it will have to wait...

Nick,

A good idea...like it.

Barry

[Sandy Calder]

Hi Footski,
Your meter fuse is not life critical.....If anyone is up a creek without a paddle you could solder a single strand of 10/0.1 or 7/0.2 cable across a burst fuse of similar rating.

For reference,the Maplin catalogue listed the fuse rating of each size of tinned copper wire. That's what your ironmonger sold on strips of card before you got your electrician to fit circuit breakers and residual breaker.

Don't try that on a 13Amp plug and double don't use a paperclip.

Regards
Sandy Calder

Nick,
it's the way you word it that counts!

[Seaspray]

Hi all   

DON'T SOLDER A WIRE OR USE SILVER PAPER  OR ANYTHING  ACROSS A FUSE   

GET IT REPLACED WITH A CORRECT FUSE. THEY COST PENNIES.

Buy a couple or a pack of fuses. may blow again.

Some of those early Quickblow fuses you just had to look at them at they blew


Martin

[sheerline]

Footskie, the fuse you need to ask for is:    250mA ,20mm glass, and get a few for future use as you WILL blow it again one day.

A few years ago, I travelled down to Farnborough to find an obscure fault which was causing a 5 Amp fuse to blow on our engine test bed equipment . There was nowhere local to get anything and as one of our drivers was going back to the avionics workshops in Croydon I suggested he pick some up whilst I spent the rest of the day repairing the rest of the gear. Hours later and at the end of the day he returned....... with one fuse!!  Guess what happened when I switched on?
As the weather is bad there and you are stuck , may I suggest you crack open another bottle of wine by way of celebrating your new proficiency at fault finding with your new meter because you have moved on quite a bit since your first post.
Chris

[barryfoote]

Chris,

What is this blow it again one day........I reckon most days so had better buy a bucket load....Thanks for all your help on this multimeter thingy....I am determined to learn.

meanwhile......Where is that corkscrew???

barry

[Sandy Calder]

Hi all   

DON'T SOLDER A WIRE OR USE SILVER PAPER  OR ANYTHING  ACROSS A FUSE   

GET IT REPLACED WITH A CORRECT FUSE. THEY COST PENNIES.

Buy a couple or a pack of fuses. may blow again.

Some of those early Quickblow fuses you just had to look at them at they blew


Martin

to that from www.theiet.org/
When you are up a creek without a paddle who b.l.o.o.d.y. cares if your v.h.f. says to fit!
Like I said,for some folk,tinned copper wire in a fusebox is all that stands between your family and and an early grave.

[Seaspray]

Fuse it ............or don't use it   


Martin

[barry park]

Hi Footski,
Your meter fuse is not life critical.....If anyone is up a creek without a paddle you could solder a single strand of 10/0.1 or 7/0.2 cable across a burst fuse of similar rating.

For reference,the Maplin catalogue listed the fuse rating of each size of tinned copper wire. That's what your ironmonger sold on strips of card before you got your electrician to fit circuit breakers and residual breaker.

What the guy is saying is replace a fuse with a fuse.
No graph,no table just where to get it if you don't know where to look... (a strand of servo cable or braided copper).
Here's the table by the way http://www.gxk.org.uk/info/wire.htm
Barry Park