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battery size

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Westampton, NJ, USA   USA
Hi again,

I'm a little confused about the battery size for my BJ7. I went thru a bunch of posts and thought I came up with the correct info on battery size. I bought a group 27 battery. It's huge! The battery terminals are outboard on the right side of the battery towards the fender wall. I have a 3/4 inch wood block mounted on the fender wall which is specified for the BJ7. I don't see how you are supposed to attach the positive (ground) terminal when installed. There is no way to get a wrench on the terminal. There is about an inch of clearance between the terminal and the tail light mounting. I have a short (12 inch) ground cable to the battery switch. Do I need to get a much longer ground cable? allowing me to slide the battery out in the open, attach the ground and then slide it into place? Is this the recommended way to install? I've been working on cars for over 50 yrs and have never attached cables first and THEN installed the battery. I have seen pics of the battery installed where the posts are on the inboard side of the battery towards the center of the trunk. That would require a 27F battery. I have also seen BJ8 installs where the wood block is 3 inches, pushing the ground terminal more towards the center of the trunk allowing more access to the ground terminal. I have also seen negative ground conversions where the battery is flipped around putting the posts on the inboard side of the battery which makes the posts accessible after install. I could also just find a battery of much shorter height (going against the specified type). However, that probably reduces CCA. What do you guys recommend? What am I missing?



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Westampton, NJ, USA   USA
Never mind I figured it out.....

Bill F BJ7 Avatar
Bill F BJ7 Silver Member Bill Fulcher
Dorking, Surrey, UK   GBR
Although you've said not to bother I'll throw in my two penn'orth. For interest: the workshop manual specifies a type BT9A (whatever that is) with a capacity, 20 hour rate: 58 However what you fit may well depend on what you intend to do. I imagine it can get pretty cold in January in NJ, but if you don't need the car to start after standing overnight kerbside at 6 am mid winter, and you aren't going for concourse spec, then you can use a much smaller battery. I've used a smaller battery, I think rated for an MGB, for years and I haven't had any trouble firing up to keep the engine turned over mid winter at 0 deg C. In fact for a while, decades ago, I used a battery off one of my early (1970s ) Minis. I don't think there are any incompatible charging rate issues with this. You shouldn't have any trouble with the earth cable. My earth cable, which is original, is more like 13 - 14 inches, quite difficult to measure accurately in situ! It is a pain connecting to the battery post when the posts are close to the inner wing, but shouldn't be impossible. I've converted to negative earth. To do this I turned the battery round to connect the negative post to earth. As a result, as you mention, the terminals are now inboard and accessible. However you do need to keep the live (now positive) terminal shrouded against earthing mishaps in its more exposed position. Stating the very obvious: it is vital to have the earth isolated when putting a spanner to the live terminal, and the more so when the terminal is close to the inner wing, because of the danger of grounding. Glad you sorted the problem but hope the observation is helpful. Bill

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petnatcar Avatar
petnatcar Silver Member Peter Carbone
Watertown, NY, USA   USA
Hi Steve,

I'm not consumed so much with authenticity as some guys are and
that goes for the battery.

With today's electronic cars you need more power to operate all those modules, LED's,
relays and giant stereo systems, I think that's why they invented the AGM batteries.
I don't completely understand the engineering theory behind them but they are more powerful.

AGM batteries are in all the vehicles and after experiencing 24 degrees below zero for the past few days
it was a relief to have the Trailblazer fire right up.

Although the Healey is low tech I'd still rather have the best battery I can get.

In regards to the battery posts being on the wrong side I just live with it but back in the day I was
able to get a Die-Hard Marine type battery that had the posts on the outside so you may have to look for one of them.

Good luck,

Edited 2 time(s). Last edit at 2019-01-21 06:24 PM by petnatcar.

IMG_6077.jpg    56.2 KB

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