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MG Midget and Sprite Technical - My midget is eating batteries - help!

Hi there. First post for me - I'm the proud owner of a '75 1500 midget which gave me lots of fun over the summer, but not so much during the winter months.

After replacing the alternator after an afternoon sat by the side of the A64, I've had no end of battery related problems.

Firstly, I bought a new battery charger to see what I could do with the old (now flat) battery - no luck, it just wouldn't hold a charge. So next was a brand new HB015 battery from Halfords. Popped it straight in but again, wouldn't start. Jump starts fine and all the voltages read as they should meaning the alternator is working.

I've tried to charge the new battery but that one won't hold a charge either. Am I just unlucky in buying a dead battery from new, or is the midget eating them for dinner? What's the most powerful battery I can get in the midget?

I've added a battery disconnect switch but any other tips for keeping a battery alive in the cold?

Any help would be much appreciated!

Chris.
C Dalrymple

The charging system should be a simple affair, and not stressful so lets see.

First the standard battery should be fine, therefore the first test is to check the voltage at the battery when the engine is idling, 12.7+ volts, now check the voltage when the engine is running at 2000RPM should read approx 14.5 Volts. If you can check these 2 readings first and report back it will decide what you have to do next.
Bob (Robert) Midget Turbo

Yup, I tried that shortly after jump starting - voltage at idle and higher revs are good (all recheck tomorrow to confirm though). However this was only after jump starting, if I leave it overnight it won't start the next day, and after charging it won't hold a charge.

The strangest bit was despite putting in a brand new battery that didn't help - wouldn't start straight off unless I jump start it. I see to be killing batteries just by putting them in the car!
C Dalrymple

As said do check the charging, then we need to ask is the battery flat or is there a problem with the starter circuit, poor earth or whatever. Finally is the vehicle causing the battery to discharge when engine stopped.
Do you think the battery was flat when it would not start the car? I don't think it was you need to check the connections especially the earth strap from gearbox to body.
Bob (Robert) Midget Turbo

C Dalrymple. Welcome to this BBS.

My thoughts would immediately think a faulty Battery, it's not uncommon, however, before you rush back to Halfords with it, check that your battery connections are CLEAN and tight, your car may be charging and it may be going nowhere, putting jump leads onto it making it start does indicate that the rest of the starting system is OK. Once established that all is OK here, then take the battery back, it will have a date code on it somewhere but if you still have proof of purchase, even better, they will carry out some discharge tests and establish if the battery is OK.
Bill Mohan wrote in the latest (I nearly said 'current', but that would have been too much of a pun...) MASCOT (Midget and Sprite Club magazine) on Batteries and testing them; well worth reading if you have a copy.....

Don't hesitate to get in touch if you need any more advice or assistance. Also Yorkshire meeting held, so it would be nice to meet you.

Mark.
Mark T. Boldry

When you say it won't hold a charge, what do you mean? Does the new charger indicate that the battery is charged, or does it simply not get that far, after several hours charging?

When you jump it, where are you clipping the neg. on?

Nick

You can put a test light "in-line" between the battery post and the + cable (With the key removed). If it lights, then something is draining the battery (like the infamous boot light)
Trevor-Jessie

Seems like he said that he put a brand-new battery,
out of the box, in the car. And the car would not
start. But he could "jump start" the car.

But he never said whether he tested the new battery
for voltage before or after trying to start with
it. That would have been helpful info.

btw - In the UK does "jump start" mean using another
battery and jumper cables, or does it mean pushing, climbing in, and popping the clutch while in gear???
Also helpful info to have.

If a good battery will not start the car, but popping
the clutch while moving will, then I would suspect
connections or bad ground. But If a good battery will
not start the car, and jumping using cables from
another battery will, then I would suspect the "good"
battery ain't so good.

chuck
c c

Wow, lots of responses! Thanks all. I'm going to get under the bonnet tomorrow evening and see what I can find out answers to some questions. Have just given the new battery another charge in preparation. Currently 12.5v and looking stable. I'm assuming the best thing to do would be to check:

1. Check a test light in-line as Trevor states above
2. Check voltage at idle and 2000 RPM as recommended by Bob

Anything else?

Mark, thanks for the warm welcome! I'm afriad I don't have a copy of MASCOT, but hopefully I can sort this through the process of deduction...

Cheers,
Chris.
C Dalrymple

I think there is something drawing alot of power. and not leaving much to start the car

the wrong new battry, maybe to small.

are the idiot light working okay...what about the regulator

the good thing, its a simple system, so wont take alot to track down....Im sure it will be something stupid and small, alwway is.

prop
Prop

Chris
check the boot light

check the battery terminals for corrosion

check the cable to connector condition too

and check for a drain with your ammeter in your multimeter (wot I am assuming from these posts that you have) connect the ammeter to the earth wire and the battery post with the battery disconnected fom the earth cable

any amperage showing indicates a completed circuit somewhere in the wiring

like this

BATTERY --- AMMETER ---EARTH CONNECTION

any flow with the ignition off will show there is a problem

less than half an amp may show a radio keeping its presets alive and shouldnt hurt, more than that you have something to sort out

me?

I strongly expect that on a Midget it will be boot light wire fallen off the switch and shorting to earth or switch not switching off when the bootlid is closed.

Test by pushing the little plastic button in and seeing whether it turns off the lamp and making sure the bracket allows the light to switch off

good luck

fingers crossed for the cheap option, always the best.
Bill

WOW BILL,

You nailed that dead on, that is exactly what I was personally thinking, but didnt know how to decribe it...I didnt think of the boot light draining, as I replaced mine with a manual turn on light from a pick up truck that looks similar in size and shape....good call...but I certianly agree with ALL the usaual suspects you pointed out....that leads me to thinking its going to be something easy and stupid when he finds it

prop
Prop

Fit a battery isolator switch, you know the battery won't drain then.
Also check your starter solenoid, with the main feed disconnected put a DVM across the battery / starter motor terminals & check for continuity when the solenoid is engaged. Your need long arms, a helper or a 12v feed to the solenoid to do this.
It may also be a dodgy starter motor, next time the car won't start, try turning the square nut on the end of the motor.
cheers
Brad
Brad (Sprite IV 1380)

I had the same problem last year. Original battery 'died' whilst driving, but car runs fine from dynamo/alternator until you switch the engine off and try to start it again, when nothing happens and you need to jump start it to get it going. Replaced the battery with a brand new one, but problem was still there. Measuring the voltage across the new battery terminals with a multimeter showed about 12.5 to 12.7 volts. Borrowed a dedicated car battery tester from someone that actually puts a load on the battery, and it registered only about 7 to 8 volts under load. Took the duff new battery back and exchanged it for another new one (tested using the car battery tester under load - read 12+ volts), fitted it to the car - problem solved.
Adrian Jones

Chris Dalrymple, If you care to mail me 'off board' with you postal address, I will endevour to get a copy of the current MASCOT sent to you.

Cheers,
Mark.
Mark T. Boldry

there is another way Mark

goto:

http://ssnbmasc.freezoka.com/

open Techy Stuff

open "battery testing.pdf" after ticking disclaimer

But if you send the mag Chris gets a read of a good mag...
Bill

Good article Bill, maybe rather excessive but contains all that spridget owners need who are not competent with batteries. Rather too much than not enough! keep it up.
Bob (Robert) Midget Turbo

For c.c.
Jump start is using another car's battery connected in parallel to dead car's battery with "jump" leads.
Push starting is often called Bump starting.
Graham.
Graham P 1330 Frogeye

Reading this I noticed one thing.

"After replacing the alternator after an afternoon sat by the side of the A64, I've had no end of battery related problems."

Since it started with the alternator replacement, are you sure the alternator is not faulty? Just because it is new or recently rebuilt does not mean it is not defective. An internal short could cause the problem you describe.

Mike
Michael Hirsch

Well spotted Mike, a very valid point.... The A64 is not a nice place to be stuck on, I drive a long section of it most days.....

Mark.
Mark T. Boldry

when changing alternators make sure the plug terminals aren't corroded or distorted by heat

poor connections happen here often

Many suppliers will be reluctant to honour guarantees if the plug isn't changed when the alternator is, because the overheated plug often causes alt failure... and they overheat because the resistance builds up in the copper connectors inside the plug

check for simple corrosion, green or black copper tells the story
Bill

I think everyone might be on the wrong track here.

If it starts from a jump start (I assume you are clipping the negative jump lead to the engine) but not from a seemingly good battery, it means the engine has a bad earth.

Try clipping a jump lead between the engine and the negative side of your battery as a temporary solution and see if the problem is fixed. If so you should replace/reattach the engine earthing strap. which usually goes to near the steering rack.
chris claydon

Chris

Spridget earths run from underneath the floor near the gearbox to the bell housing bolts ISTR

Bob specified at the start of the thread to check the connections, earth and such

" is there a problem with the starter circuit, poor earth or whatever."

as did c.c later

seems reasonable to assume t'other Chris has looked at this to me.

(which doesn't mean you are wrong :-) )
Bill

Yes - where are you, Chris? You were supposed to address this 6 days ago.

We don't expect this kind of slacking.
Nick

Hi Bill, on the 1500 IIRC it runs to a bolt by the steering rack, maybe earlier models are different.
chris claydon

serves me right for being the owner of an old fashioned Midget

but the rest is still valid I hope

No doubt Chris #1 would have checked last week...
Bill

Well,

It looks like chris just used us, abused us, left, and didnt bother to make us breakfast on the way out the door......I feel so dirty, and I never even touched a wrench....lol

prop
Prop

This thread was discussed between 08/12/2008 and 17/12/2008

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