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MG TD TF 1500 - A different kind of charge light

A little off topic but applicable for those who like me, think a volt meter gives more information.

I changed the single phase alternator in my Commando for a higher output 3 phase. That meant the charge warning light wouldn't work.

Casting about for some sort of mini volt meter along with a voltage sensitive relay to run the light I stumbled upon these:

It seems perfect for me and maybe some here for a LBC.

From their propaganda:

Below are our recommended voltage thresholds for lead-acid battery systems including an alternator or other charger. Completely bespoke thresholds and output patterns can be created for you during production (e.g. for custom or ultra-low power applications):

Voltage: Output:
>15.20 Green/ Red alternating (over-voltage)
>13.20 Green (charging/charged)
>12.45 Amber (75%+)
>12.25 Red slow flashing (50%+)
>12.00 Red 2 fashes, repeating (25%+)
>11.80 Red 3 flashes, repeating (low charge)
<11.80 Red 4 flashes, repeating (very low)

After a little searching on MC forums I found nothing but complete satisfaction. They have a 5mm light on the price list. I've written to find the bezel size.
JE Carroll

I finally finished the bike and am returning my focus to the TF.

The Spark Bright LED that I substituted for the original charge light works better that I could have imagined. The TF will get one as well.

When I turn the ignition on with a fully charged battery it shows amber. After start as the battery recovers it turns green. Sitting at a light with the headlight on it turns amber again and if I shut it off with the headlight on, as the voltage drops it starts to flash red.

The old warning light only told me if the alternator was putting out, not if it wasn't putting out enough.
JE Carroll

That looks perfect. I've been wanting a very small volt meter just to monitor the generator performance and battery condition. Did you order directly from the company? Was shipping to the US any problem. Thanks. Jud
J K Chapin

The light says integrated "circuit board". So is the whole thing just look like an LED with long pigtails on it? Or is there a separate control unit. If it is just an LED with long pigtails on it , it would be perfect both for the TD and the MGA.

Let us know, please.
C.R. Tyrell

CR, I believe it's all built into the LED housing. You can get one as small as 5mm (w/8mm hole). As the voltage meter does use a small amount of current all the time (8ma) you might consider a small switch to turn it off.
Geoffrey M Baker

Geoff, I don't think that would be a problem as I use a battery disconnect when the car is not in use. I use the "Green knob" type that opens the neg. circuit. Sounds like a very unobtrusive method tho keep an eye on voltage.
C.R. Tyrell

Just keep in mind that you will have a bright green LED staring/glaring at you under normal driving conditions. I wouldn't replace the existing lamp with it, but I might consider mounting one on a little panel below the dash. Bud
Bud Krueger

CR, The circuit board is tiny, covered by shrink tubing, and attached to the LED by a pigtail. It just gets tied to the wires.

I bought the smallest as I was away from home and guessed the size of the hole. I could have gone one size up. I just secured it with a dab of RTV on the back and yes, you deal directly with the company and they send it in the mail quite quickly.

Bud, The LED is self-dimming. In full sun on an open motorcycle it's just bright enough to be seen. In a darkened garage it's not objectionable at all. It's a very small LED.

Geoff, I just wired it to the ignition switch. There's no need for it to be on all the time. Turn the key on and there's your voltage. It goes through a quick self test then settles to the color that represents the present voltage.

I dealt with Andrew Ferguson; below is a copy of his correspondence, the website has been improved as he says:

Hi Jim,

Thanks for your email. The 5mm versions have a bezel that fits an 8mm hole
(although you could mount the LED directly into a 4.9 or 5.0mm hole and secure it from the back with a dab of silicone or similar).

My website is being overhauled just now, and the new version should be live perhaps tomorrow or certainly early next week. There will be a bit more
technical information for customers and copies of the fitting instructions and datasheets available.

Many thanks,

JE Carroll

That is pretty cool. I have been thinking of ways to re-utilize the lights... one thing I want is a Oil pressure low warning light (i.e. Red flashing for oil, so I can actually check the oil pressure) need to work out the details. I was thinking of integrating it to the fuel light.

Being a man of the 2000's.. I do like having more detail about what is happening in my car... but I also don't want to replace everything and make it look gadgety... I want to keep the traditional look

D Engel

Another alternative: there are neat little voltmeters available that fit into a cigarette lighter. If you search the bay with "cigarette lighter voltmeter", you will find a nice selection. Some have a USB port for charging phones included (which I think is a great idea), some show temperature as well (questionable function for our cars, though..). Just a few bucks and simple plug and play.
Since my nsdpo had fitted a lighter in the dash, for me that was the obvious choice. The lighter socket (or the whole car) needs to be wired for neg. ground, obviously.
They show similar "diagnosis" tables as above in their adverts, just linked to voltage values

Best rgds
Mike Fritsch

Early 59-60 VW's used an oil pressure switch that had an adjustment screw in the center. The oil pressure was set to turn the light off at 4-5 lbs. so if you had more than that the light would be off. I do not know the total range of that adjustment.
ss sanders

You can buy pressure switches with various set points. I would think a 15PSI would probably be a good one.
JE Carroll

This thread was discussed between 01/05/2014 and 05/08/2014

MG TD TF 1500 index

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