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MG Midget and Sprite Technical - flat battery?

Hi guys! been using the mg nearly every day and has been starting great, yesterday it wouldn't start; very slow turn over and ignition light wasnt on so think its a flat battery! Got a starter pack from work and it fired right up. So today i have bought a smartcharge unit to charge my battery and condition it. Anyway i've attached it and the light thats says fully charged is on and charging light is out? does this mean it it actually charged and something else is wrong?

thanks steve.

oh its a 12v charger with 0.8A charge setting rate!
s j knox

LOL Steve - have you tried to start it and it hasn't started since putting the smartcharge on - coz I think you've perhaps missed out a few words!!!!!!

However, if not, then, if the light says fully charged, and the charging light is out, then yes, it is fully charged :)
rachmacb

chargers can also say that when the battery is faulty - ie down a cell or 2
Mick struggling with the wiring

Right, get a mirror-on-a-stick and check the electrolyte levels.

-:G:-
Gryf Ketcherside

by what you've put it seems like the battery is now fully charged

if you've got a good battery and alternator (and all connections) then the battery should not have gone flat so the fact that it has suggest a fault of some kind

did you check the fluid level on all the cells in the battery before and after charging?

did you need to top up with distilled water?

did you charge the battery off the car?

are all battery connections, leads, lugs, earths clean, secured and protected?

unless you lay up the car or fit an immobiliser then the charger/conditioner should only be used by friends and neighbours

apart from starting the car and running the electric items it's best to have a good battery and all connections for problems solving as a battery going flat can slow up or stop problem solving
N Atkins

hi again guys! took battery out and down to work and they tested it at 12.1v, it still wouldnt start! so charged it back at work and it was 13.2v and car started!

so now im even more confused! how can a 12v batt charge to to over 13v and does that mean my charger will never put enough charge in to crank the car? Am going to check alternator tomorrow to see if its working.
s j knox

I can't do the technical bit but if at work they got a booster or commercial type charger then I'd be thinking of perhaps replacing the battery as they cost so little compared to the hassle they cause when low or save when good

again,
did you check the fluid level on all the cells in the battery before and after charging?

did you need to top up with distilled water?

you could get/borrow a hydrometer to test your battery

or if the battery is furred up inside (can't remember the correct term at the moment) you can give it some alca-salca type tables to clear it up

techie type link - http://www.topbuzz.co.uk/info/car_battery/car_battery.htm

N Atkins

hey nigel, i didnt do any of the above as i aint got a clue! think im going to buy a new sealed unit as i think acid and myself or car will come into contact at some point? do you know if my new sport coil would effect battery power at start up?
s j knox

found it - sulphated, that the word

link below also warns of over charging (perhaps at work, though it might not have been)

http://www.carbatteryshop.co.uk/carbatteryinformation.php
N Atkins

car batteries aren't difficult to look after even an idiot like me can manage

personally I'd say to you get a new good quality battery and then you know for certain (well almost someone bound to say you can get duff new batteries) that is covered

clean all battery connectors and leads and when securely refitted protect the connections

if you fit a battery and leads and connectors well and use the car regularly then other than regular checks in normal circumstances even with non-maintainence-free batteries there is rarely anything to do

the engine earth strap is very important for good engine starting personally I don't like the braided type but if it's in good condition, clean, secure and protected then it can stay

plenty of threads about this subject

the new sports coil will may no real difference to starting other than it being in good condition so helping in that way
N Atkins

Hi Steve just skippe through this thread so please forgive me if I repeat something already said or miss something obvious

Firstly I notice you state that your ignition light was NOT ON when you tried to start the car. If this was the case then the Alternater is probably kaput!

It also explains why your battery is at a low voltage 12.1V this is typical of a low battery and then you state after charging to 13V the car starts.

To get current/power into a battery the charging voltage must be higher than the battery voltage. When the 2 balance hen the battery is fully charged. So effectively and I know you will not fully understand it the battery voltage changes slightly when charging and indicating state of charge.

When running the output of the alternater needs to be higher than the battery an is generally aound 14.5 volts. This can be meaured very easily by connecting your voltmeter across the battery terminals. With engine off expect to see a reaing in the region of 12.5 to 13 volts with the engine running expect to see a reading of 14 to 14.5 volts
Robert (Bob) Midget Turbo

Steve,

Bob as always has a good point but I read what you put differently allowing for posting typing – if with the battery full charged and installed the red ignition light is still not on or is dim then ignore it possibly being, or only being, the battery

I’ve just remember you done your rear dampers so if a battery is needed it’ll be easy

Always having the battery and connections in good condition will obviously help with starting the car and running the electrical items but also it will help with problem solving many items whereas a battery and/or connections in poor condition will create problems or not help with other problems

Also have all battery leads and connections, other earth leads and all connections - clean, secure and protected - as this will help with starting of the engine and all electric circuits, same applies to all electrical wiring and connections too

On another note it’s great that you’re using your car so much and it will help you and the car by doing this but it will also turn up the niggles and wrinkles with the car that much sooner

As I remember your car was serviced by a classic garage but there are services and services, I would be very surprised if they done a full 36,000 mile service which would help find existing issue and prevent future issues with the whole car

A lot of people with their servicing concentrate on servicing the engine rather than the whole car and deal with other issues as they arise rather than full and proper serving of the whole car

As soon as possible after purchase do a full and proper 36,000 miles service only miss out items that you have 100% proof have already been done very recently, including;
g/box and back axle oils
brake and clutch fluids
coolant
dissy cap, rotor arm and leads (buy good quality ones) - http://www.distributordoctor.com/rotor_arms.html
fan belt

On that, a loose fan belt will not help the alternator to charge and if very loose it wont help the water pump either
N Atkins

thanks guys! this is a big learning curve for me as im pretty much clueless on everything! well not everything, im good with rear springs now and i can even take off the petrol cap!lol. Anyway i will check alternator today, how much play on a fan belt mine seems very tight; although im using car every day im mostly doing short travel of 3 miles to work and im thinking this is not giving batt enough time to recharge.

thanks for the help!

oh and the guys at work told me they had never heard of my batt make and that it is very old.
s j knox

Steve,
With an alternator a 3 mile journey to work should keep a decent battery topped up, at least at this time of the year. If it were a dynamo it probably wouldn't be enough.

You should do a proper cranking test on the battery. Fully charge the battery first. Then measure the voltage across the battery terminals whilst you crank the engine over for a full 15 seconds. The voltage should start at around 12.6 and will drop away, but should not go below 9.8v (10v is better) Anything more than that and you would certainly need a new battery. But you must do it for 15 seconds and of course you need to do something to prevent the engine from actually starting up during the test. ( removing LT coil connection is the safest to avoid stray sparks which could cause a fire)

If it passes this test then the problem lies elsewhere, but you have saved yourself from spending £60 on replacing a perfectly good battery!

Guy
Acknowledgement to Bill M - I thought he would have stepped in with this advice by now but maybe he is away.
Guy

Nigel, do you have an encyclopedic memory for links to useful docs on the web?

This one you posted earlier on ( http://www.topbuzz.co.uk/info/car_battery/car_battery.htm ), is a very good one.



Lawrence Slater

yeah that topbuzz one is very good! all these little things are great to print off for my ever expanding fact file!

Thanks for that guy! will do just as you say today and see what happens.
s j knox

>>Nigel, do you have an encyclopedic memory for links to useful docs on the web?<< I've very little memory of anything, that link wasn't the one I really wanted but I couldn't remember or find the better link so that one had to do, there was a better link for looking after the battery but obviously I must have typed in different words in the search engine last time

Steve,
a journey of just 3 miles isn't good for the car or battery(?), I'm probably wrong and Guy will have the figures but I didn't think 3 miles would be enough to top the battery up from it starting the car

15 seconds should be a good test certainly warm some things up

I'm with Guy on not changing a good battery but if it is suspect it will catch you out first or second cold snap of winter if not before and when you're problem solving and have to use the battery heavily and a good quality battery could be got for less than £60

Fan belt - as with most things look in the Handbook, in this case (red cover) Handbook page 46
N Atkins

well have had car at local lucas workshop testing battery and alternator! battery is fine but alternator isnt charging the battery, so fitting new one tomorrow! i can tell this is going to be a love/hate relationship!!
s j knox

par for the course

fit a moderen uprated alternator and that will help battery and future added electrics

this and dampers, now you see why I put
>>Do not do any cosmetic or improvement work for at least 12 months of regular use, unless you need to replace parts or components, as you may need to use the money elsewhere on the car<<

another one to Guy, well done, proves the need to ask questions and get answers before moving on

ETA page 46 again helps with fitting alternator and belt - DO NOT overtighten belt - would be good time to fit new belt if required
N Atkins

With the engine running you should see between 13-14.2 volts on your meter. Switching on various electrical items should see a slight drop but not too much. No ignition light usually ponts to the alternator. Perhaps one of the diode packs has expired. Also check you have good clean earths, from the battery to the body and engine block. You can test the earths by attaching a jump lead from the neg on the battery to the clean metal of the engine. See if charging improves with the meter still attached.
S Langston

When did I change my name to Guy then Nige?

LOL

Robert (Bob) Midget Turbo

>> When did I change my name to Guy then Nige? LOL<<
ever since I went by memory instead of scrolling back :)
sorry about that – now Guy will be upset, sorry Guy

yet my wife calls someone Bob if she can’t remember their name, so we Mary Bob, Bob Bob, Pete Bob, ect.

Steve,
obviously now you want to get your new alternator fitted and check but based on –
>>oh and the guys at work told me they had never heard of my batt make and that it is very old<<
I would still think about changing the battery for a new one a lot sooner than winter
N Atkins

Nigel,
There's no need for me to be upset. Helping others on this BBS isn't a competitive sport is it?
I only described a battery test and suggested that Steve do this first before spending £60 non a new battery. And the battery testing instructions I learnt from Bill anyway.
Guy

Isn't it?

Damn I have been playing this game for 10 years now on this particular site and last year I promote myself to division 2!

Now I am really upset, think I will throw my clip board at someone like a spoilt child!!

Robert (Bob) Midget Turbo

no point Bob - can never compete with the 'Guru'
;-)
David Smith

This thread was discussed between 25/07/2011 and 27/07/2011

MG Midget and Sprite Technical index

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