Size 34 Optima Battery w/positive ground

[SideShifter Tri-Carb]

Getting ready to replace the battery in my BT7, which still has + ground, and I see everyone that gets the optima is getting the 34 group size battery. My concern with this is that the terminals appear to be situated such that the posts are tucked under the fender <(+) towards tail> and create a challenge to get a wrench on the bolts without arching on the metal. One could pull the battery out, but this is not ideal in my book. Also getting a "jump" on a dead battery seems difficult with jumper cables.

So, for those that have this setup, are these concerns of yours? Or, did you point the (+) end toward the front and extend the (+) cable. Maybe they aren't as tucked away as I am concerned.

I see they make a 34R with the terminals reversed, but my local store did not stock them. This was the way my group 27 interstate was, but it leaked.

Olin

 

[Keoke]

You might Google: First optima Battery and see if they have the "R" version they ship free.-Fwiw-Keoke

 

[Robert560]

I got an Odyssey battery instead of Optima... but regardless, I think you want a group 25 battery instead of group 35. It's the same physical size, but with the terminals on the opposite sides. That way, the orientation is same as original for positive ground.

Here's the Odyssey page showing the terminal differences...

https://www.odysseybatteries.com/battery/pc1400series.htm

Optima's website isn't quite as intuitive, but I'm sure they have the same options.

FYI... I got my Odyssey brand new from a company selling on eBay... super great price, super awesome battery! If Optima is what you wanna stick with... just guessing here, but I think this is the one you'd want...

https://www.summitracing.com/parts/ULT-9025-160/

~Robert

 

[SideShifter Tri-Carb]

Robert,

From the link you gave me, the group 35 has the terminals situated for a (+) ground car. I did find another store in the area with 34R optima. I also found one at another store, but it had a 7/07 date, which is almost 3 yrs. The last one I found was 11/09. So, I am going to pick it up this afternoon.

The odyssey seems like a comparable battery, but seems to be much more expensive. Tax and all for the Optima was 161 after a 15% disc. at advance auto. Shipping was free, but I wanted to pick mine up to make sure I didn't get one of the old stocks.

 

[Robert560]

...errr sorry... you said 34, not 35. Well, everything I said above is still correct, but if you want to stick with size (group) 34, then the version you need with the terminals on the opposite side would be 34R.

https://www.odysseybatteries.com/battery/pc1500series.htm

...or you will find 34R in the battery selector on Optima's page.
https://www.optimabatteries.com/battery_selector/
(just click the "view all parts" button to get the whole list)

The sizes I talk about above... 25/35... are actually a bit smaller than 34, and in drycell form still has way more power than a Healey needs. So I recommend checking into the size in my original post. I was looking for anything I could do to gain a few more inches of trunk space.

I've got a pic on my website if you want to see what size 25/35 looks like in the trunk (link in sig).

~Robert

 

[Robert560]

$161 is a steal for that battery... good buy!

~Robert

 

[SideShifter Tri-Carb]

15% off is good through the 19th. Complete order online and pick up at store. I agree, good deal.

 

[andybj8]

Cannot remember if i got the 34 or 34r, optima's are difficult to get in the uk. The terminals are the wrong way round (couldnt get the right one at the time), but I thought whatever battery I got would be wrong (negative earth). I did get a tar topper from the US to hide it a bit, and with a lucas sticker and the bj8 vinyl cover should look period?

 

[andybj8]

just need to buy the vinyl cover and sticker
I take it the bt7 still has the wood block to keep the battery from the wing, your positive earth shouldnt be a problem, your terminals will be on the other side about where the yellow caps are

 

[Keoke]

OLIN
Just turn the battery around like Andy says. Access to the terminals for servicing is no problem.--Keoke

 

[SideShifter Tri-Carb]

Andy, looks like you have the right setup. 34 if it is a (-) ground and 34R if it is (+) ground. I picked mine up and it is the 34R and will be positioned like Andy's after I install it on my (+) ground car.

Keoke, I did turn the original around at first, but the terminal were in an inconvenient place. I like to have access to put a wrench on it or jump-start without concerns of grounding the hot side against the fender.

 

[Robert560]

Still sorry for my misleading information earlier... I forgot that I deliberately picked a battery that would put the posts towards the outside on a negative ground setup. So I guess I did pick the post location that would be correct for a conventional positive installation. I was trying to maximize every bit of trunk space I could. I even shaved down that wood block a bit as well to push the battery further over. It still seems like I could get to the posts safely if I need to jump someone, and it's an AGM battery, so don't need to worry about servicing. Putting the posts towards the outside really didn't help with the space any, but I just wanted them out of the way... looked cleaner, and less chance of anything in the trunk accidentally striking them.

~Robert

 

[Keoke]

Good call Robert, I did all those things to my cars too and had no problem getting access to the battery terminals for repair ,charging or the occasional boost. I thought you had a neg ground set up
judging by the battery terminal size and location.--Keoke

 

[Johnny]

Good day Olin, and all. Not to throw a wrench into things(sorry, no pun intended)but you have to be careful not to buy too large a battery. Unless you've changed out the generator to an alternator you may no longer have the capacity to keep the larger battery fully charged and it will eventually run down. Think of it as a water faucet filling a bucket vs filling a lake.

 

[Keoke]

Well Johnny. Lets look at it from another perspective.If the battery is larger, but the car is still consuming it's original amount of energy, the generator should be capable of replacing that amount.---Keoke

 

[Robert560]

That's a good point though, Johnny... I was worried about that as well. This is especially true if you're moving to a drycell type of battery (AGM or the like), as most of them have monster power. The one I got seemed pretty average, and has 740 CCA at 0°F! Plus, with the deep cycling and reserve time most of these batteries have, I could accidentally leave my parking lights on... for like 2 weeks... and still have more than enough juice to start the car. I even considered going with one of those super tiny AGM batteries to really free up some trunk space, as even they have enough power to start a Healey.

As Keoke said though... if you're only using a little juice, you'd only need a little recharge... so in theory it wouldn't take much to recharge from a normal start. But still... if there's ever an instance where you really draw off the battery for some reason - leave the lights on by accident, or do a lot of engine turning while working on it or something - if you don't have enough generator to get it back to full charge, you could potentially create a cascading draw problem that will eventually affect battery performance.

I wouldn't have put such a big battery in the car if I didn't combine it with a 100 amp alternator conversion.

~Robert

 

[Keoke]

if you don't have enough generator to get it back to full charge, you could potentially create a cascading draw problem that will eventually affect battery performance.

No I do not think so Robert, regardless of the generators charging capacity it will just take you "X" hours to recharge the battery- For example, if your battery has a capacity of say 60 Ampere Hours and your generator will only develope a 5 ampere charging current then assuming 100% charging efficency,not usually the case, it will recharge the battery in 12 hours.-Fwiw--Keoke

 

[Robert560]

Keoke, I agree with what you're saying, but that's assuming there is no additional drain within that 12 hour charging period. If there is additional drain, then the charge time becomes even longer... and if there is additional drain that exceeds charging capacity within the allowed duration (lots of starter activity due to short drives, or leaving the radio on for a while, etc.), then this will result in a continuous decrease in overall battery charge. Ultimately, that would lead to a dead battery after some period of time (a week... a month... depends on severity of this cycling), and continual battery draining can often lead to shortened battery life overall.

~Robert

 

[RonMacPherson]

Keoke, is telling you basic automotive electric 101

The output of the alternator/generator needed to recharge the battery is just marginally over the draw used by the system....
You can run 88 batteries (the big humongous military truck ones) with a 30 amp system, if the vehicle only draws 25 amps... I know, we did it "in country" on a whole slew of vehicles...

 

[Keoke]

I was just going tell Robert that the example I provided provided a chargng rate in exces of the systems consumption.-Keoke- :thumbsup: