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MG Midget and Sprite Technical - Battery

Time for a new battery before the winter. Its about 6 years since the last replacement and I cannot remember the specification. The Handbook doesn't appear to list details. Haynes lists it as 40 or 50 Amp Hour for the MK 1V Sprite. Other sources I have checked vary from 20 Amp through various steps to 43 Amp.
Any recommendations about battery specification or a supplier (NOT Halfords)

This looks like a good source:

but their search engine doesn't list our cars so one has to know the detailed specification

I believe either of the following are suitable:

063 terminals at the rear as original

Startup Power: 360 Amps
AH Value: 41
Bench Charge: 4.1 Amps
Dimensions (LxDxH): 207x175x175mm

or the more common 038 with terminals at the front

Startup Power: 265 Amps
AH Value: 35
Bench Charge: 3.5 Amps
Dimensions (LxDxH): 238x135x202mm

Doug Plumb

Thanks Doug,

I won't buy from Halfords as I have had "issues" with them refusing to honour their own 3 year guarantee on batteries. (twice, now) It's become a matter if principle for me!

But that gives me the detail I need to buy online from Battery Megastore, else, cheaper too! Is it worth paying a bit more for a calcium battery?


This one looks like the equivalent to the first specification one you listed,

Same physical size, but 380 Amp starting and 44 Amp Hour capacity so marginally better. Also has 4 year guarantee and is 30 cheaper! Its a sealed calcium one. Is this a GOOD THING ?


A traditional, liquid lead-acid battery I will not use in any of my cars. They constantly vent corrosive gasses which will eventually cause rust in the metal work around them, and they occasionally leak, making it worse.

Battery sizes are listed in something called a BCI chart:

If you measure the space that you've got, you can easily find which ones will fit. Note that the BCI chart doesn't show CCA, only outside dimensions. Luckily, our engines are so small, and we drive them so rarely in sub-zero weather (or store them outside in that weather and expect them to start in those conditions) that getting the absolute maximum CCA is less important than it would be for a regular, daily driver.

To avoid the corrosion issue (and to extend battery life), battery makers developed Absorbed Glass Mat (AGM) batteries. But, the typical AGM batteries (developed and sold by Optima and Orbital, and some others now), which are so great because they will not vent or leak, do not fit in the very small space available on the heater tray of a midget. Their construction is by coiling the mat into 6 Fosters can-sized cylinders.

Luckily, Panasonic developed an AGM battery of uniquely small proportions (5" x 7" footprint) for the Mazda Miata/MX5, and it is sold today by a company named, Westco, part number 12V31M. Moss sells this battery, and it is the only one that I will use in my Midget. The last one I owned worked for 15 years (seriously).

Norm Kerr

I can see the point about non- acidic batteries. But those AGM ones are a lot more expensive! The equivalent AGM battery to the 36 Calcium battery I found, is 130 in the UK. Too big a price jump to make it worthwhile for me.

But can anyone tell me, are calcium batteries any good for these cars?


there seems to be an opinion that calcuim have pros and cons (what a surprise)

one example -

see also -

I can't remember what model Sprdget you have and why you think 6 years is the limit for the battery but being in Cumbria you'll certainly want a good battery through your longer winters :)

my car had the battery on when I bought it just over 4 years ago, it looks like a 038 style, I've just looked and it's a Faimm, 42Ah, 330 amp and is maintenance-free (which I've never noticed before as it has two removeable manifold tops) and I've never needed to top it up

the date isn't marked up so I only know it's over 4 years old

I've never had any trouble with this battery or its charge, it's never been on a battery charger, sometimes it's been left for 2 or 3 weeks without starting without any problems and for two years I've had an electric cooling fan that runs for quite a while after the ignition is off even in winter

I've had an uprated alternator for over 3 years and hi-torque starter motor for about 3 years though
Nigel At

Thanks for those links. Some interesting reading there!

My car is a MK lV Sprite - which is why I mentioned that model at the start! Actually its an Austin Sprite. The battery, at 6 years old isn't holding its charge too well and fails the 15 second cranking test.

So for the cost of a new battery I think it is worth renewing in preparation for winter. There are few things more frustrating than a normally well running car that doesn't start on a icy morning just because of a lazy battery!


many aplogises Guy I do (now you've pointed it out) remember and see you've put it in your original post

by the time I've read other replies and started typing mine I've forgotten that - I do type very slooow

as its an Austin Sprite then I think I've already mentioned that you can add your vehicle profile to save having to put it each time (and for those like me, that's if you want to add it)

if I have mentioned it sorry for repeating but twice is better than not at all

as for battery yes change it

and make sure all connections, leads, earths to battery, body/engine and starters are all clean, secure and protected then the battery lasts longer and stronger :)

a pet dislike of mine is a car that wont start
Nigel At

Ha! Nigel. My car almost always starts as it turns past the first compression stroke. But when the battery won't even turn it that much it is relegated to a useless pile of junk! I then have to bump start it which is getting a bit much at my age!

Anyway, a shiny brand new battery at half of Halfords rip-off prices will be winging its way to me tomorrow!

Hi Guy,

Running a Frogeye 1430cc.

Purchased from Battery Megastore last year, (next day delivery).
Alphaline 55457 @ 49.95

54ah @ 20 hour rate
540 Cold Start (CCA)
243 x 175 x 175
May be a bit OTT but works a treat!


That's a good chunky battery!

Just bought one at £47.95 incl vat next day delivery.
Should help with my cold starting 11:1 compression
Gary & Gaps

Just a response to the advice from Doug Plumb. I just bought a 063 battery today and it would NOT fit in the battery tray. It might just have squeezed in if it were not for some additional 'ridges' (measuring about 1/4 inch around the bottom edge - for clamping in some applications I guess). I had to change it for the more usual 038 which did fit.
Chris H (1970 Midget 1275)


Thanks for the update.

ISTR the info came from a well known forum but my database of potentially useful info for the future has been suitably amended.
Doug Plumb

very useful, on Battery Megastore you can search for batteries of maximum and minimum sizes

Nigel At

I think I fitted a 068 battery to my '66 sprite in March this year. Fitted with plenty of room.

Lenco Motor spares. 49.99. Its listed as a 015n in their part list. I'll look at it later and double check.
Lawrence Slater


I don't know about a 068 (I bought an 063) but consulting the reference book on batteries the 038 was listed as one choice for a 1275 Midget with 015 listed as an alternative 'heavy duty battery'. I would have liked an 015 but needed a battery in a hurry and could not find one locally.

Chris H (1970 Midget 1275)

I don't understand the numbering system - 038, 063, 068 etc. Do the numbers actually mean anything or are they just Halfords random number codes?

I ordered a battery from Battery Megastore on Saturday. 36.95 inc VAT and delivery. This for a calcium battery at less than half the price of the Halfords equivalent! I thought it might have arrived today but no; should be here tomorrow though. I will then find out if it fits!


Sorry, my mistake.

The batery I bought is indeed a heavy duty battery, type 015, but it is a 42 amp hour job. I don't know where I got the 068 from. Dreaming I think.
Lawrence Slater

I think this may depend on what heater box you have fitted to the car. A mate years ago bought a AC Delco maintenance free battery at a car boot sale for his Austin Sprite and it wouldn't fit so we did a swap and it fitted my frogeye no problem at all and gave many years of service.

I noticed Norm's comment earlier about lead acid batteries always venting but this AC Delco was a sealed maintenance free battery and about late 1980s vintage so not sure what they did to do that, I assumed it had a small platinum catalyst to recombine any hydrogen and oxygen produced in the battery back to water but don't know that for sure. Would be interesting to know.
David Billington

Some batteries come with a little vent nozzle that you connect up to a length of plastic windscreen washer hose and lead it away to the outside. Presumably cuts down on the risk of explosion and disperses the acid- laden fumes to where they can do no harm

Mine arrived today. Won't be fitted till the weekend.
Just out of interest can a sealed battery be charged up on a trickle charger if it goes flat. Is there some kind of vent?
Gary & Gaps

Hooray, my battery arrived.

And l can now confirm that an 063 size doesn't fit a Mk lV car ! Boo !

It's about 3/8" too deep, front to back. Sod !

I'd have thought the battery can be charged on a trickle charger provided you don't leave it on too long, a battery conditioner would be better once the battery is up from totally flat as it's self adjusting

you could contact the supplier to check

as said I think it's a case of how close the heater blower motor is to the battery
Nigel At

So how do all these confusing numbers corelate?

015 = What in terms of 038, 063, 068, etc.?
Lawrence Slater

From Auto Express - the physical dimensions expressed as a three-digit code

Read more:
Nigel At

I thought that link was going to explain how to interpret the "dimension expressed as a three digit code" ! Not much help there.

Clearly the heater box position limits the battery tray size. But I am pretty sure the heater box position is not adjustable so the available space will only differ on the earlier cars with the different heater. From when they introduced that later style heater (around 1969?) onwards the space must be the same right through to the end of the 1500 production.

Anyway, I now have to decide what to do with this slightly oversized 063 battery that won't fit!

I could keep it for my frog, but that is a good long way from being ready for a battery! How long would the shelf life of a new, sealed and unused battery be?

Guy, please look at the link that I posted several days ago to this thread, the BCI list shows what the dimensions are for each one.

It doesn't explain where the crazy numbers came from, only lists them though.

Norm Kerr

sorry Guy,
that was all I could find at the time but you can enter the minimum and maximum size you have available in that search link in my other post

here - very useful, on Battery Megastore you can search for batteries of maximum and minimum sizes -

those tables don't seem to cover our British numbers of 015, 038, 063 and 068
N Atkins

I had looked at your link but as far as I can tell those numbers don't relate to the 3 - digit codes being commonly used here (015, 038, 063 etc) In fact the size combination of the one I now have - an 063 doesn't appear on that BCI list. I assumed it was a UK / USA difference in terminology.

Nigel - I bought the battery from Battery Megastore. They are a god company and I have used them a couple of times before, but sized the battery by using their search engine. However it doesn't include Spridgets so you have to know the sizes needed.

They are very good prices on there - but not quite so good if the battery turns out to be a few mm too big to fit! A couple of responses on here had said that the 063 one was correct for these cars. (which it may be for the earlier models with the less bulky heater box) Shouldn't believe everything you read on the internet! My own fault - I did a quick measurement and it seemed ok but I wasn't being accurate enough.

Megastore are also good in doing free delivery and have a 7 day returns policy (UK legal requirement) The problem is most carriers exclude batteries from their list of what they will take so returning it isn't that easy and could cost half of the cost of the original. So, if the battery will store I may just keep it for the frog currently undergoing reconstructive surgery


If the excess size of battery casing, is the clamping lugs around the bottom, could you trim this off?

Of course it would screw the warranty, but if it's going to sit around unused otherwise, it won't make much difference to you.
Lawrence Slater

Guy - my 1981 Unipart Battery catalogue states: 'premium maintenance-free batteries are supplied ready-charged with a wet shelf life of up to one year'.
Not sure how that relates to the one you have bought but would expect with 30 years of development current stuff should exceed that?
David Smith

A couple of points. . .

Type 063 is normnally fitted to Honda Civic & Rover 200/400.
It is a popular fitment in the MGB when converting from twin 6v batteries, although it is a tight fit, apparently.
The numbering systems differ between UK & US. A type 063 is a 026 in the US.
Dave O'Neill 2

Options seem to be:
1 send it back, but delivery cost is 15 on a 35 battery so doesn't appeal.
2 make it fit, butcher - Lawrence style. Maybe.
3 use it as an incentive to get on with the frog restoring. Bit realistically for me that means storing it for 2 years.
4 buy a car to fit the battery, which may not be as silly as it sounds!




What we need now is for someone to find a link to a UK battery sizing table (or, more likely, a European battery sizing table.

Sorry about that guys, I live on the wrong side and as a result, find myself confused by things and wonder why the whole world doesn't use inches and ounces!

"My goodness, France is such a lovely country, but why ever don't they speak to me in English?!"

Norm Kerr

that's the way I meant to use the Battery Megastore search by entering the measured space you have available rather than your car make and model

with caution I agree with Lawremce if it's just the plastic locationing/securing rails that prevent the battery fitting then remove them as surely they're just an addition to the battery casing
N Atkins

I have a battery from a BMW E36 318ti in my car. No idea of the battery model or whatever else, but fits easily (early heater box in my car) and plenty of juice. Discovered as I had a spare from the wifes car, and the new battery I bought for the Midget (right according to the catalogue) had the terminals incorrect. The BMW battery has the terminals set well back from the side, near the middle, so no danger of shorting out on the hold down bracket, and it has a fold up handle for easy removal. Works great!
Andrew Fraser

Just fitted the Alphaline 55457 on the frogeye and it fits nicely with just under 1 inch spare space between the bulkhead and the back of the heater matrix, however I can't vouch for my battery box being similar to any other in known universe, as some of you will know that remember who built it!
Gary & Gaps

Well I did get my battery (063) to fit. But I wouldn't say it was meant to fit a car with the later style heater box - it needed modification. Interestingly this battery is the same depth (front to back) as Gary's which he says fits with an inch to spare. On mine it was 6mm, sorry 1/4", too big.
I cut off the bottom clamp flange as Lawrence had suggested. That helped, but not enough because the top of the battery is also as wide. So I removed the heater box, slotted the 6 fixing down bolt holes and that got it sorted. But it is still a very tight fit - so much so that it wedges in and doesn't need a clamp.

The clamp would still be a useful (belts and braces) addition, easpecially if the car were to invert as it would stop it shorting on the bonnet as it dropped. I know that I couldn't get passed most scrutineers without a clamp and insulation over the terminals for exactly that reason.
Gary & Gaps

Lawrence will be proud of you :)

any chance of a photo

be interesting with the battery bar and clamp as mine is fairly close to the back of the heater fan motor with the 038 battery
N Atkins

Guy beware MOT men

I had an MOT refused simply because I didn't have a clamp on my battery on (I think) a Cavalier

I swiftly made a tie down with bungie straps and a promise to do a "proper job" when I got home

Because I had a reasonable working relationship with him at the time he stood for it and issued the piece of paper

But I did sort it out at once, risk of electrical fires in a crash was his reason to refuse. He would have been right not to pass the car. (I'm told)

Glad slotting the holes worked though
Bill 1

Ho, Ho !
I knew l would get that reaction.
I did fit a clamp, l merely said that it wedged so tightly that it wasn't needed. I expected to reel one or two. In !
Sorry !!

Good for you Guy,
You said it wedges in and doesn't need a clamp. I just pointed out that it does.
Gary & Gaps


you'll have to make the clamp fit now :)
N Atkins

Great, I love mods.

I haven't clamped mine in for years, never questioned by the MOT. Don't think he can bend his neck enough to look. LOL.

As for car inverting and battery shorting, I'm not sure how much I would worry about that if I were sitting 180 in the sprite.

I guess sparks would be a problem, but my broken neck would probably result in cremation anyway, so it would just speed things up a tad lol.

Lawrence Slater

Haven't you seen a battery clamp before - or perhaps you don't believe me? It is there, and just for you I will photograph it in the morning, hopefully it won't still be blowing a gale and torrenting rain by then!

Annoyingly this evening my nearside indicators suddenly stopped working. Not the usual high speed flashing; just nothing at all, not even the tell-tale either. Offside works fine so I suspect the column switch. Fix one thing and another fault pops up! - that Spridgety things for you!

I was thinking about the oversized battery and off set heater case

but as you've put off photoing it until tomorrow I now has suspicionso about that clamp being on before :)

indicator probably just a clean and/or reconnect job

I can tell you that you don't always break your neck from you and your car being upside down so you should think about these things :)

and before you ask, yes from personal experience, details in a previous thread about roll bars
N Atkins

Hi Nigel.

I did used to have a clamp. In fact it's probably in my garage somewhere. I got fed up using the thing, and it was discarded. I used to have a rubber cover on the top of the bat too when I first got the car, but don't know where that went either.

I'm not esp' opposed to clamping my bat, just got out of habit because it was a pain in the rear to use it as I recall. I always meant to devise one that was just a clip om job, but never got round to it.

OK I thought about it, and off to bed now. :)

Lawrence Slater

Just for you - a photo!



Is that pos' or neg' earth? I ask becuase my terminals are at the front, I'm neg' earth.
Lawrence Slater

Guy, I always wondered what that hole was for in the isolator battery clamp on the negative terminal. I've got my original neg clamp attached via the isolator clamp.! (does that make any sense?)
Now I've seen yours I will change the way mine is set up.
Gary & Gaps

that might be photoshopped!

nice battery with magic colour thingy to show condition of battery very useful considering the battery's position

is that a dis-connect on the neg terminal, do you have remove the knob completely or how does it work?

that looks neg earth just battery has posts other way round
N Atkins

You just unscrew it a bit, you don't have to take it out, although when it is unscrewed completely you can pull the connector apart very quickly. It has a nylon (or similar) insulation so that the circuit is complete only when the turn screw is fully tightened. I like mine but I have heard that there have been quality issues with the cheper ones.
Gary & Gaps

right thanks, I wasn't sure as that looks slightly different to others I've seen but that might just be my poor memory

if you've got a cheaper one do you have to carry a spare in the boot :)
N Atkins

Negative earth, its just that this particular battery has the posts at the back. They appear quite close to the firewall in the photo, but there is actually about 1" clearance.
The neg terminal connector just needs a half turn of the black knob to disconnect. And if leaving the car for any length of time one can fully remove the knob which is quite effective as an immobiliser!

Oh and Nigel, yes I might have photoshopped the clamp in except with my computer skills it was a lot quicker to fit a real clamp!

Guy what a b*gger

I was hoping you'd have feral wiring too :(

Nice disconnector too

Bill 1

That battery looks like the one in my car. I've found it brilliant.
Andrew Fraser

This thread was discussed between 08/10/2011 and 19/10/2011

MG Midget and Sprite Technical index

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