Smiths battery gauge

Post by **yellowpinky** » Wed Dec 07, 2005 9:55 pm

Hello
I recently purchased a smiths battery condition gauge off ebay. All is well with it as it is in good nick and looks simple to fit. However, a part is missing from the back of the gauge...namely...the shaft which holds the bulb holder in place. Am i right in thinking that this metal sleeve should be part of the gauge? Is it common for these to be missing? and does anyone have one ? If so will it just slot in with a gentle tap of the hammer?
Or.. have I purchased a humdinger?

Post by **Shawn** » Thu Dec 08, 2005 4:50 am

If it looks like this one, I'd just find a generic bulb and holder to fit.

Post by **Multiphonikks** » Thu Dec 08, 2005 7:55 am

Generic bulb holders are quite easy to get hold of

I shouldn't worry - Like Shawn says - if that's what you're missing then you can get it to work

Post by **lowedb** » Thu Dec 08, 2005 7:56 am

There are two sorts IIRC. One as in the pictures above, where the bulb holder has a spring clip around the rim. The other type has a tube on the guage, with a split in it. The bulb holder slides in and is retained by friction.

Either type is quite common so try the back of instrumnets in scrappies.

Post by **Dave1979** » Thu Dec 08, 2005 7:58 am

hi

looks like you have a minssing bulb holder on some guages these are seperate and some thay thay are fixed but you should have no probs geting one most motor factor sell them try halfords

Post by **yellowpinky** » Thu Dec 08, 2005 10:58 am

It is the sleeve part that is missing (with the 4 slits around the edge), that fits to the back of the gauge. The bulb holder itself is indeed seperate. What worries me slightly is that I have a spare oil gauge which i tried to remove the sleeve from, but it wont budge.

Post by **lowedb** » Thu Dec 08, 2005 1:33 pm

But not all gauges have the sleeve with the slits. Some have a hole and no sleeve, like the one you have. These take a spring clip bulb holder.

Post by **bmcecosse** » Sat Dec 17, 2005 10:23 pm

Why would you want this anyway ? You can see from the headlights if the battery is being charged , or not!

Post by **Chris Morley** » Sun Dec 18, 2005 12:26 am

Why would you want this anyway ? You can see from the headlights if the battery is being charged , or not!

Yes, that's true.

Anyway, if the charging circuit fails then Morris / BMC have already provided a reliable warning system - the ignition light in the speedo clock will shine bright red with the engine running.

Post by **Pyoor_Kate** » Sun Dec 18, 2005 12:31 am

Anyway, if the charging circuit fails then Morris / BMC have already provided a reliable warning system - the ignition light in the speedo clock will shine bright red with the engine running.

That's not always true, if the charging system's a bit marginal (as it was on Rebecca before the alternator was fitted) then it can just glow very dimly as the battery discharges nice and slowly. This glow is only-just-visible; so particularly in winter with low sun you may not notice it until you suddenly find your car won't start...

Post by **Chris Morley** » Sun Dec 18, 2005 1:15 am

Agreed that the light glows dimly if the engine revs are too low - it was designed that way and it's clearly stated in the Minor handbook (and yes, it can be hard to see with sunlight behind you). However it doesn't mean that the charging system has failed. The dynamo needs at least 1500 rpm before it starts charging the battery and probably 2000 rpm plus to start recharging properly. The same thing happens to a dynamo driven bike light or elderly MK1 railway carriages of the type hauled by steam engines on preserved railways (the dynamo only produces power when 25mph is reached).

Kate, I bet your recharging system was working more or less as it was designed to - as I mentioned in a post ages ago you were simply asking too much of basic 1960s technology because of the added gadgets you had. If you keep the lights, wipers, heater and radio on with a dynamo then it simply can't keep up if the car is caught in slow moving traffic - unless you rev the engine quite hard. Yellowpinkey's gauge would show the battery discharging in these circumstances but it would also be plainly obvious to the driver as the lights dimmed and the wipers slowed down. The maximum a dynamo in good nick can produce is 22 amps -if the electrical items draw 22 amps it can't recharge the battery and if they draw more amps then the battery will slowly discharge.

If my battery is very badly run down then my indicators can stop flashing - however press the accelerator and they immediately come back to life. When the charging system fails outright (a totally different situation) the red light WILL come on and it's very bright.

If anyone suffer from a slowly discharging battery they should pull over, switch off every electrical item (including lights) and rev the engine gently for 3-5 minutes. I've found that a flat battery which can't even turn the starter motor before starting can be adequately recharged on a 3.5 mile/10 minute run - as long as it's daylight and you don't need the heater, wipers etc.

Post by **bmcecosse** » Sun Dec 18, 2005 4:55 pm

Exactly ! I guess you are a preserved railway man then Chris ? I do Guard Duty at Bo'ness - and yes our lights are dim because the speed limit is 20mph! If you do go ahead with this thing pinky - be sure to connect it to an ignition controlled circuit - it draws a current all the time to make the gauge work. Perhaps better to just fit it with croc clips - and use it as a diagnostic tool from time to time.

Post by **Pyoor_Kate** » Sun Dec 18, 2005 7:52 pm

Kate, I bet your recharging system was working more or less as it was designed to - as I mentioned in a post ages ago you were simply asking too much of basic 1960s technology because of the added gadgets you had.

Well, back then I only had the radio as an extra, and even with it off just heater / lights was enough to make it struggle and heater / lights / wipers was enough that the battery was too flat to start the car the next day.

So I suspect it was a bit marginal...

Post by **bmcecosse** » Mon Dec 19, 2005 1:40 pm

Would depend on the driving - if stop and go in traffic then the dynamo is no use - but if motoring along happily then there should have been plenty of charge to match that lot! An alternator solves the problem.

Post by **Chris Morley** » Mon Dec 19, 2005 2:57 pm

I guess that severe traffic jams were quite rare things back in the 1960s? I doubt that many Minors got caught up in them on wet Winter nights and so the dynamo's limited performance wasn't so important then? Clearly an alternator is the solution to coping with modern day traffic but it also brings reliability problems.

I've previously quoted the 18amp output/22 amp recharging figure but that was for brand new equipment. It's easy to see that an old dynamo might have worn brushes and copper contacts, carbon dust everywhere and weaker magnets. In which case an output of anything like 22 amps might be impossible to achieve. Similarly wiper & heater motors lose their effectiveness and lack of lubrication could increase the amps drawn, as could earthing problems in the light circuit.

Even if we conclude that the input & output is the same (say 18 amps) this means that the battery will slowly discharge because you can't keep the engine revs above 2000 rpm all the time you are driving (except on long motorway runs). In this respect even a perfect dynamo can be marginal and the driver has to actively compensate for it's limitations.

If I'm caught in a traffic jam I'll switch the headlights and wipers off whenever possible and rev the engine. I'm afraid that's one of the downsides of driving such an old car. The upside of course is that my dynamo has never left me stranded at the roadside!

I guess you are a preserved railway man then Chris ?

Well, I do have a liking for old fashioned trains (steam & diesel). I haven't been to Bo'ness for some years but the D49 and Caley Tank might tempt me soon.

Post by **bmcecosse** » Tue Dec 20, 2005 11:11 pm

Dynamo has field coils - so the magnets don't get weaker - but yes all the other failings will reduce the possible output. Years back I used to fit a by-pass switch connected to the control box - when switched ON this put full voltage to the field windings and boosted the output very considerably! Brush life was seriously reduced - and it was easy to boil the battery if forgotten about.
As for Bo'ness - Morayshire 246 is now on the rails and the track has been upgraded to carry it's weight! Magnificent machine. I have 'fired' the Caley Tank 419 - as a one-off when they were stuck for a Fireman! Great fun but very tiring - mainly because also expected to do all the coupling and un-coupling! The Driver has it easy.

Post by **Alec** » Wed Dec 21, 2005 6:51 am

Hello all,

there is a point to having a gauge, and it is not to tell you when the system fails, the ignition light does that very well, but by then it's too late. With a gauge you can monitor and notice the onset of a possible problem before it becomes terminal.

Alec

Post by **Pyoor_Kate** » Thu Dec 22, 2005 2:52 pm

With a gauge you can monitor and notice the onset of a possible problem before it becomes terminal.

Which is how I noticed my Dynamo biting the dust; it probably just needed new brushes but I wanted an alternator and it dying was 'the perfect excuse'. Of course, the meter then informed me that alternator was happily killing all my electrical equipment. So all in all, I like my meter

Post by **MikeNash** » Thu Dec 22, 2005 3:27 pm

I've just checked my gauge (it's identical to Yellowpinky's) and just in case you wanted to know it consumes 100 milliamp to function and a further 185 milliamp to be illuminated (12v 2.2w nominal), takes 30 sec to begin to move the needle and 75 to get the full reading.
Not a lot of people know that. MikeN.

Post by **bmcecosse** » Fri Dec 23, 2005 8:35 pm

Cars of this age should have an ammeter - not battery gauge ! My ammeter tells me exactly what's going on - without drawing any current.