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MG TD TF 1500 - What's the physically smallest battery?

Since we're on the subject of batteries:

I'm going to mount my coolant recovery tank on the short end/right-hand side of the battery box [see picture] so I'm going to need a small battery. Now there are a bunch of motorcycle batteries that would slide in there, and I'm sure a few garden tractor and maybe a few Miata batteries as well, but I'd like to keep the traditional battery posts, and it's got to be big enough to handle a 60 amp alternator.

Aside from the cool looking battery cover that I must have just missed on eBay, what's the experience in the group for small/potent batteries?

Give me a battery size, and I'll work from there. NAPA and Sears have Canadian stores as well. Gord - any Canadian Tire stuff that might fit?

Thanks,
Dave


Dave Jorgensen

Not sure Dave... I chose their '$62.00' size!!!!!
gblawson(gordon)

Dave ,
I have a NAPA version of an Optima battery. Center universal style posts and side mount screw type. Will give you 3 1/2" of room from the battery to the battery tray side. Can't see it in the photo but the space is on the passanger side. Labeled Orbital 06, NAPA # 9934/78, BCI # 34/78.
Perfect place for me to pack around a spare quart of oil. Looks like a midget overflow tank you have there.
Not sure about smaller sizes.

LaVerne


LED DOWNEY

26 series batteries will give you plenty o room to mount a coolant recovery tank. Cheers - Dave
David DuBois

Hi Dave, I have what I consider a small battery that measures 9" in length, 5 3/8" in width, and 8" in height. I got it from Canadian Tire and has served me very well over the years. It has a "Product Number" of 10-4503-6. It leaves a lot of space in the battery box, and may have enough for your tank.
George Raham
TD4224
G. L. Raham

How about this one I use in my vintage racer? It's the Odyssey PC680T - I have the normal terminals on it but prefer the bolt on cables.

http://www.odysseybatteries.com/battery/pc680t.htm


Gene Gillam

Dave,

A battery should be sized according to the device that has the highest inrush current. In our small cars, the starter is by far the most demanding, with the (dual) horns next.

A continuously-rated device like headlights, doesn't enter into this, because the generator should be able to handle this.

The WSM states that the locked torque current of the starter, is in the validity of 350 to 400 amps. That's a lot of current.

Your generator is rated continuously at between 14 and 17 amps. So with a jammed starter, even your battery and generator together, wouldn't be able to operate for more than a few seconds before they would blow up.

The WSM doesn't state the cranking amps for the T-Series starter, but I am going to guess that its likely in the 50 to 60 amp range.

So it would seem that you need a battery that will crank 50 to 60 amps, and be able to hold it for a few seconds. The larger the car, the likelihood of a larger motor, calling for a larger starter which begs larger batteries. But our Ts have low demands when compared to big-engined cars with A/C. A snowmobile battery is much too small, but the smallest available car battery will probably be quite adequate.

The new technology batteries with spiral-wound cells, like the Optima, offer high cranking power capacities, and for longer periods as compared to the standard flat plate type. Furthermore, they operate better in adverse conditions and have longer life. LaVerne Downey has it right.

IMHO, the duty cycle of the Optima Red Top model is perfect for a T. They're not cheap (about $140) but they will give yeoman service for many years. I don't have one (yet) but when I do buy a new battery, it will be an Optima Red top. Have a look at http://www.1st-optima-batteries.com/red_top_battery.asp, and make a selection.

Gord Clark
Rockburn, Qué.





Gordon A. Clark

Dave - I have been looking into battery size lately and the Group 21 or Group 26 batteries are only about 8 1/4 inches by 6 3/4 inches. They are plenty strong enough to start our engines and with an alternator, you shouldn't have to worry about draining the battery down. I found a good article about replacing the 2 MGA 6 volt batteries with one 12 volt. A good read. Good Luck - Lou
http://mgaguru.com/mgtech/electric/et203.htm
Lou Van Koningsveld

Running a single group 26 in place of the two original six-volt batteries is pretty common practice among MGB owners. I run a single group 26 battery in my B/GT with a 96-amp Saturn alternator, an aftermarket high-torque starter, and A/C. No problems. I bought the highest-output group 26 I could find. ' Think it's something like 660 cold cranking amps. Certainly it should serve well in a TD.

FWIW,
Allen
Allen Bachelder

Running a single group 26 in place of the two original six-volt batteries is pretty common practice among MGB owners. I run a single group 26 battery in my B/GT with a 96-amp Saturn alternator, an aftermarket high-torque starter, and A/C. No problems. I bought the highest-output group 26 I could find. ' Think it's something like 660 cold cranking amps. Certainly it should serve well in a TD.

FWIW,
Allen
Allen Bachelder

I use Westco batteries as found in Miatas in two of my MGs. They have plenty of power for my cars, which isn't surprising since they power all the Miata's electronics, stereo, lighting, etc. They are very small, no maintenance required and will not leak battery acid. If you shop around you can find them for about $90.
Steve Simmons


Coolant recovery tank my ar*e!! That's a flask with a two piece liquid delivery system for the driver!! LOL

Jim
Jim Rice

I'm reactivating this thread with a question: first, Gene Gillam, can you email me at geoffreybaker@cox.net? I'd like to talk more about your battery choice for your vintage race car.
Otherwise, I'm thinking its time to get a new battery; cleary my starter motor woes suggest my battery is getting weak.
I'm still interested in finding the smallest possible battery that will do the job, as I have a project in mind (using a tartopper case) for it.
Technology is constantly improving... any new choices out there for smaller batteries?
Geoffrey M Baker

Actually, the answer to Dave's question is - a Hydrogen atom. But it's tough to hook a cable onto it. Bud
Bud Krueger

Dave, If your looking for small auto battery look at the listings for the Mazda MX5 2006. battery is very small with 650 CCA.

If you require a smaller battery, look at your local Toyota dealer for the 12V battery for the Prius "V" Hybrid.

Do yourself a favour and stay away from Canadian tire batteries... they simply are junk. If you want a low cost battery ... go to TSC and look at there home brand tractor batteries.... much better quality than CTC, and less money.

... CR
C.R. Tyrell

CR, I doubt if Dave's still hunting. The original thread was from 2008. I was just being facetious. Bud
Bud Krueger

For what it's worth, I once borrowed a clamp on over the cable device to test for starter draw. Cranking amps was about 105-120 as I recall and was pretty uniform on my two Morris Minors, TD, and Austin America which all use essentially the same starter motor. Did not take a locked torque figure.
John Quilter

John, will a standard clamp on ammeter made for AC current measuring work to measure DC current? Jud
J. K. Chapin

Geoff,

Soooooo,,, are you going to tell us what your special project is ???

Steve
Steve Wincze

Jud, AC clamp-ons will not work with DC. Last I knew, Sears sold an AC/DC unit at a reasonable price. I use on the car quite often. Bud
Bud Krueger

Lol Steve, it's months out... I'll provide details when I get around to doing it and have pictures & video.
Geoffrey M Baker

Thanks Bud
J. K. Chapin

This thread was discussed between 18/06/2008 and 18/12/2015

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