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Battery and battery box

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Andymon Avatar
Andymon Andrew Tillinghast
Medford, OR, USA   USA
1976 MGB. So, I've searched and read many threads on which battery when using a batter box and am still confused. I need to replace my battery and use a battery box. My positive cable barely reached the terminal post as is! any input will be greatly appreciated. I really want a good quality battery. thanks!!

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jjonns74 Avatar
jjonns74 Gold Member John Dailey
Indianapolis, IN, USA   USA
1974 MG MGB "Athena"
1974 MG MGB "Apollo"
Andy

I use the 26R in both my '74s (no box, using original)

see:

https://www.mgexp.com/phorum/read.php?1,717489

John

Be Coming Avatar
Be Coming Kelvin Dodd
So. Calif., USA   USA
Hi Andrew.

The end of the positive cable tends to have corrosion under the insulation, so it is a good idea to replace the end anyway.

What I recommend is to install a battery cut off switch in the rear kick up panel. Cut the positive cable and install a terminal to one side of the switch. Make up a new positive lead from the switch to the battery positive terminal (you can buy these premade at most parts stores). That way you get rid of a likely bad connection, have a cut off switch and get to run a longer cable to the battery which will be easier to run into the plastic battery box.

Your later car has a bigger battery box than the earlier version, so size is not as much of an issue. Interstate lists an MT24 for the application, but there are others that will fit.

Kelvin.


edit: Derp! Thank you Andrew, I forgot you were running the battery box. Type 26 would be it.

I use the little Mazda Miata gel cell in my cars, as they are small and light. Much easier to swap from car to car.



Edited 1 time(s). Last edit at 2018-05-16 12:40 PM by Be Coming.

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Andymon Avatar
Andymon Andrew Tillinghast
Medford, OR, USA   USA
the battery box says a Group 24 won't fit but a Group 26 will. I will replace the positive cable with a longer one. I'll look into a batter kill switch. Not to savvy on those types of things but pretty sure I can figure it out. thanks!!

V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
In reply to # 3737356 by Be Coming

The end of the positive cable tends to have corrosion under the insulation, so it is a good idea to replace the end anyway.


thumbs up

Exactly what I discovered years ago, when troubleshooting my dad's '63 B not spinning the starter. I found it with my Fluke meter. That was a new one for us.

Andymon Avatar
Andymon Andrew Tillinghast
Medford, OR, USA   USA
In reply to # 3737356 by Be Coming Hi Andrew.

The end of the positive cable tends to have corrosion under the insulation, so it is a good idea to replace the end anyway.

What I recommend is to install a battery cut off switch in the rear kick up panel. Cut the positive cable and install a terminal to one side of the switch. Make up a new positive lead from the switch to the battery positive terminal (you can buy these premade at most parts stores). That way you get rid of a likely bad connection, have a cut off switch and get to run a longer cable to the battery which will be easier to run into the plastic battery box.

Your later car has a bigger battery box than the earlier version, so size is not as much of an issue. Interstate lists an MT24 for the application, but there are others that will fit.

Kelvin.


edit: Derp! Thank you Andrew, I forgot you were running the battery box. Type 26 would be it.

I use the little Mazda Miata gel cell in my cars, as they are small and light. Much easier to swap from car to car.

I was looking at those! I think it would be a good fit with a little extra room.

Andymon Avatar
Andymon Andrew Tillinghast
Medford, OR, USA   USA
In reply to # 3737356 by Be Coming Hi Andrew.

The end of the positive cable tends to have corrosion under the insulation, so it is a good idea to replace the end anyway.

What I recommend is to install a battery cut off switch in the rear kick up panel. Cut the positive cable and install a terminal to one side of the switch. Make up a new positive lead from the switch to the battery positive terminal (you can buy these premade at most parts stores). That way you get rid of a likely bad connection, have a cut off switch and get to run a longer cable to the battery which will be easier to run into the plastic battery box.

Your later car has a bigger battery box than the earlier version, so size is not as much of an issue. Interstate lists an MT24 for the application, but there are others that will fit.

Kelvin.


edit: Derp! Thank you Andrew, I forgot you were running the battery box. Type 26 would be it.

I use the little Mazda Miata gel cell in my cars, as they are small and light. Much easier to swap from car to car.

Kelvin, thanks for the replies! this is for a Miata and the size is perfect. Is this a good battery? https://www.batteriesplus.com/battery/car-and-truck/mazda/mx=5-miata/2007/l4-2.0l-410cca/sli51r

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mgbtf Avatar
mgbtf Silver Member Dave Kalp
Fort Wayne, IN, USA   USA
1969 MG MGC GT
1980 MG MGB
For years I have used the Interstate MT24.

Andymon Avatar
Andymon Andrew Tillinghast
Medford, OR, USA   USA
Does that fit in a batterybox?

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Diver648 Gold Member Warren Siringer
Tucson, AZ, USA   USA
1967 MG MGB
1967 MG MGB GT
1971 MG MGB GT
1974 MG MGB
Is there any advantage or disadvantage in using the battery disconnect on the positive side rather than the negative?

Fogliner Avatar
Fogliner Mark Vanherd
Port Clements, BC, Canada   CAN
1974 MG MGB
I have mine on the negative side and mounted close to it on the front passenger side of the rear kick.

I used this kind because of its ease of use.

https://www.amazon.ca/Allstar-Performance-ALL80156-Battery-Disconnect/dp/B003C01FHW

mark


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lgorg Avatar
lgorg Larry Gorg
Renton, WA, USA   USA
1966 MG MGB "Robbie"
[

In reply to a post by Driver648
Is there any advantage or disadvantage in using the battery disconnect on the positive side rather than the negative?

It depends on a few variables. Per Astley in his book "MGB Electrical Systems" prefers that the switch go into the earth circuit. The benefit of this arrangement is that you can work on the hot side of the battery terminal, and if you touch any metal part with a spanner, you will get no reaction. He also states that the end of the earth circuit has an eyelet. Some switches come with instructions to do the opposite, and install in the positive side.

As for me, my 67 which really is a 66, it was positive earth but I installed my cutoff at the time I switched to negative earth. It was easier for me to simply use the old positive circuit because the ground had an eyelet. I simply used the old black cable to the starter and removed the battery connection on the cable, which I found corroded, and put an eyelet on that cable. I deliberately did it this way because I have a modern radio in my car, and I have heard of horror stories about a cutoff switch in the earth line, but the radio having its own line to the earth. In this scenario, with the cutoff in the off position, and you forget and hit the starter, the starter will use the radio and its ground. You just fried your radio.

Since I have the engine out, I may just remove the old black cable and reinstall it with a red one. Time will tell if I get that part done. Too much sunny weather, and NOAA says we will have a hot and dry summer here in Seattle. I want to get out on the road and try out my black label OD. My black cable has red tape around both ends to warn anyone that cable is the hot one.

Whichever way you choose, think things through and decide which way you want to go. There are many pros and cons doing it either way.

BumbleB74 Avatar
BumbleB74 William Milholen
Tidewater, Tidewater VA, USA   USA
Replacing the positive cable is pretty easy, just dirty job. I pulled mine off, and stretched it out along an old 2x4 to measure length....then added a couple more inches just because.

Went to NAPA and bought cable by the foot, was very reasonable. They crimped on the eye for the starter, but I went ahead and soldered it on as well using a small propane torch, then covered with 2 layers of heat shrink. Most excellent results.

Good news is now my pos batter cable IS red, so future owners if there are any will have a little more clue.



1974-1/2 Roadster, "Bumble Bee", Corvette Yellow - in shambles, wire wheels
1976 Roadster, "Virus", Sandglow - "driver" condition (stock + 32/36 Weber DGEV, cast iron header, 25D distributor), bolt on wheels, ON the road!

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