MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - parasitic draw...

'evening Chaps....has anyone suffered from this situation? Still wrestling with problems of sluggish starting after a period of non-use. [I know....get out and use it more often...] and PD could be the cause of the battery going down.. Just a thought...comments invited, with thanks as usual
Dave
David Cox

I thought the post was about when your friend kept wanting to have a smoke on your cigarette! :)

On a serious note, I had this with an XJ Cherokee Jeep all I could do was to fit a battery isolator on the earth side.
Peter Burgess Tuning

David
See the thread below alternator/ battery issues.

On my Midget I use a ‘disconnect’ on the battery and it acts as a safety device when parked up in the garage.
richard b

thanks both..looks like an isolator switch will be the order of the day....either that or I smack my friend in the face, Peter!
David Cox

Peter and Richard are spot on. A battery isolator is the way ahead. Mine is on the nearside inner wing (1500) and is the Big Red Key type which is accessible from the passenger "glovebox" area.
They are not expensive.
Greybeard

Get one with a removable key and they provide an additional ant-theft deterrent.
GuyW

Quite right Guy - the Big Red Key is removable.
I had three of them in my campervan. One for each battery and a third to link the batteries if it needed a "virtual jump-start".
Greybeard

Sorry David - didn't really address the original question.
PD might be the cause as you said, but with a simple car like a Spridget there aren't too many things that can be at the root of the problem (unlike in a modern, which is is a whole other minefield).
The top contenders would most likely be the radio, even if its switched off, and the starter solenoid which has a permanent live connection to the battery.
After those, various hidden things like the light in the boot, but on a Spridget it's easy to isolate the culprit. Again, unlike a modern.
It's at least as likely to be the battery self-discharging and an isolator switch won't make any difference to that, although I still think they're a good idea.
If the car is not used enough a small mains battery maintainer is a cost effective option. The one I have was about 20 quid and can be connected either with croc clips or with permanent connection to the battery, which has an ISO connector (which is in the kit) somewhere in the car of your choice. Edit:I meant in the position of your choice, eg: under the bonnet or under the dash. Park, plug in, switch on, done.
Actually I have two - I got one for the garden tractor as well - just need to get around to installing them!
Greybeard

thanks for all your comments....all much appreciated.

wasn't there a song about a big red key...or is my memory hampered by rampant decrepitude?
David Cox

Thanks for input..

I couldn't find much evidence at all of PD..and as you say Mr G in a simple contraption like a Midget there is not much opportunity for current to leak away...no boot light/interior lights/glove box light [or glove box come to that!]. It seems like a trickle charger/isolator switch combo is the way to go.

Dear Santa...
David Cox

I, many years ago, had a 1965 Healey Sprite that would sound it's horn for a few seconds in the middle of the night for no apparent reason. This happened very occasionally when it was cold and damp. After a lot of investigation it turned out to be an intermittent short to earth on one of the horn terminals. The one that went to the wire that went to the horn button. There seemed to be some sort of organic grey furry growth on the terminal which would eventually contact the body of the horn causing it to sound then due to current flow blow like a fuse and stopped the horn sounding. For a time I thought it was possessed until I found out the cause. I have also seen similar growths around the battery terminals which necessitated thorough cleaning to stop it coming back.

I'm not sure if this applies to your problem but it is something to consider.

Rob
MG Moneypit

...that's an interesting one, Rob...no mysterious horns overnight [snigger] but there could be some other intermittent shorting going on...nothing surprises me with these cars..
Dave
David Cox

Just having gung/gunge/growth on or across the battery on on the battery posts and/or post clamps can have a big effect on the battery holding, putting out and getting back in. Best to have all wires, connectors, connections clean, secure and protected.

I've seen a few cars with battery clamps loose (even loose batteries) with the owner complaining of starting problems. Once a battery post with a tiny spot of gung/gunge/growth which prevented the vehicle from starting (well it was a then new 1990 Land Rover V8 Disco).

Batteries are one of the most oversold items on a car but eventually, especially if they've not been maintained fully by charging system and/or owner, they are best replaced with a suitable good quality new one. Recharging, trickle or conditioning can sometimes help to hide how worn a battery has got.

I'd expect a standard Spridget to have it's battery connected and car not unused for say a couple of months and readily start in cold weather.

Leaving the battery connected in the car, and even without charger/conditioner, means the car is easily ready to take advantage of the many dry and even sunny driving opportunities over winter.
Nigel Atkins


"charging system and/or owner, they are best replaced with a suitable good quality new one."

Good point Nigel. And where do you suggest getting the new good quality owner from?

;-)
GuyW

Amazon?

They have everything else. And you can get next day delivery.
Martin

Well, uhmm, freudian slip? :)

No slur intended on David and excluding the other good folk on here of course but many cars do need a good quality new owner though.

Guy with lines like yours you could do well in journalism or shaming me on Facebook, or more so if I already feature with previous remarks, I'm sure there's at least one (hundred? / million?) FB group I wouldn't be allowed to join.

I'm thinking of taking up English as a second language but can't complete the application forms.

ETA: just noticed >>on on the battery posts<< should also be - or on the battery posts, I need better eyes or bigger screen.


Nigel Atkins

no offence taken, Nigel..all jolly banter along with some sound advice, as usual! Dave
David Cox

David, is the song "Brand new key" by Melanie, turned into "Combine Harvester" by the Wurzels? Both have a vehicular reference!
Bill Bretherton

There is absolutely no need for a new owner. Follow the 36000 mile new owner service schedule in the good book.

Or at the minimum, perform the weekly service schedule:
1. Bath, apply suitable de-greaser for those heavily oil stained areas.
2. Shave (wet shave for a more authentic owner)
3. Check hydration level and replenish with suitable real ale.
4. Grease all moving parts with a full English Breakfast (sorry Cedric, a cup of coffee and a croissant simply wont do for a Spridget owner)

Old owners benefit from regular use. Sat still for too long and they have trouble moving again. Snoring can become an issue too without regular use.
Chris Madge

Bill: That's the one...how did a thread starting on parasitic draw end up with the Wurzels??!
Chris: maybe you have found the problem..I've not had a shave [wet or dry] since 1975. [Coincided with the purchase of my Midget]. I don't intend to start any time soon...
Dave
David Cox

Dave, I wouldn't worry about changing the owner. The old ones were often better made in the first place and better to keep than switching to a new one of unknown provenance. Old ones do have their problems. They are a bit more likely to blow a fuse, or even let out smoke. They can overheat and smell a bit after a long run. Worth checking for damp in their boots which can lead to mold around the rear end.
Generally though, old owners were well made and can be cleaned up with a little alcohol and reused for many years.
GuyW

Weekly bath! Are you fiddling the water meter?

I have to schedule my seasonal baths with Anglia Water (and Dyno Rod) so that leave can be cancelled and overtime allowed for.

I had a bath the other month and I didn't even need one!

Any dermatologist will tell you too much washing will dry your skin out and make you oily, but I like the rehydration technique.
Nigel Atkins

This thread was discussed between 03/12/2019 and 06/12/2019

MG Midget and Sprite Technical index

This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now