Thread: Dual battery box for D2 and D2a coming up...

Originally Posted by Jazzman

If the theory works... the two options will be. 2X D34 [II II] or 1X N70ZZ type battery [=]. The limitation will be approx. 170mm width for the STD battery to fit, but there will be extra space on one long edge for other things.

Hopefully works ... but I'm thinking the major obstacle is going to be the height(ie. the height of the 70ZZ).

My personal preference would be 2 x 55Ah batteries as opposed to 1x 110Ah batteries.
The major selling point is that batteries die. It's a fact of life and we just have to live with it.

if you have 1x 110Ah battery and it dies, well that 110Ah is pretty much useless.
If you have 2x 55Ah and one battery dies, at least you have 55Ah from the usable battery, instead of the situation above.
The likely hood that two batteries will die at the same time is much less likely, than it is for a single battery going dead.

And when I say dead battery, I'm referring to dropped cell, manufacturing defects, etc, not dead due to misuse/absent mindedness, which is another issue again.

That second battery may also die .. undoubtedly!! That's not an issue, but it's extremely unlikely to die at the same time as the other one.
And when the one battery in the dual setup does die, there is a greater chance that when it's replaced, the working battery will be tested to be confirmed to be OK .. ie. preventative maintenance!
In the 15 years I had dual batteries in my RRC, I never had both batteries end up unusable at the same time. Changed plenty of batteries during that time for sure, but they were usually many months or years apart.

Originally Posted by Jazzman

I had not heard of a Traxide isolator until tonight. I can see it's benefits, but to crack from a second faulty battery configured in parallel, can be a worry. But assuming you don't have a dropped cell in either battery this would work well. And really, how often does one have a dropped cell?

Good piece of kit by the looks of things.

If the second battery was faulty it wouldn’t crank from it.

Originally Posted by Jazzman

.... But assuming you don't have a dropped cell in either battery this would work well. And really, how often does one have a dropped cell? ....

Maybe it's just me! ..

basically a brand new Exide .. started having troubles with mine just before it's 1 year anniversary .. slow cranking sometimes ... and I thought it was something I did/doing wrong.
Then one day after a while sounding fine(ie. sound of the speed of the starter), it just cranked like it had about 8 volts! .
I hardly gets 'used' as my aux battery takes the brunt of any accessories running. And this was in Jan(warm) so wasn't due to cold weather.
I gave it a couple of shots with the charger too, to help it a bit and a week or so later it started dying again. Took it into the store to get a replacement but they 'tested it' and found it perfect!
Stupid me tho I drove there with the battery connected, so it got a surface charge(about 20mins) .. so of course it showed pretty good volts.
Then at the end of Jan, the day kids back to school .. dead as a dodo. I tested it, it showed high 8 volts. Took it out swapped the aux to get there, Exide rep was at the store when I got there .. ripper!
He confirmed dead cell. Store operators didn't have their usual spring in their step when they brought me the replacement tho.

I have a Redarc isolator and I think their 12.7v setting for cutoff is a waste. I like Traxide's idea of keeping them connected to lower voltages.
I reckon 12v would be about ideal.

CAD drawings are starting to come together. It is looking like either 2X D34's or 1X standard battery with extra space along one long side will be the design. At least this way it is backwards compatible if anyone changes their mind for any reason.

Hi all. Sorry it has been a while but here are some pictures of the 1st prototype. The idea is that there will be a tray and box, if one should decided they wanted to go back to the single large battery it can be done. In total it weighs just under 4kg, folded from 1.6mm stainless sheet with a 3mm stainless support brace. This brace is for the factory battery clamp to pull against if using a single battery arrangement.

Keep in mind this is a prototype, the nuts that are welded on will be Nutserts. The screws holding the top to the bottom will likely be changed for something with a shallower head. The plan is to have finished the prototype stage by the end of this month.

IMG_20180718_182450.jpgIMG_20180718_182638.jpgIMG_20180718_182706.jpgIMG_20180718_182745.jpg

Looking good mate ,

Oh and it looks so similar to something i`ve seen before

Oh do you remember the brace we spoke about on the bottom

Originally Posted by rangieman

Looking good mate ,

Oh and it looks so similar to something i`ve seen before

Oh do you remember the brace we spoke about on the bottom

Yep, this unit is made from the next size up sheet to the others. This will brace it much better, however due to the current design the 3mm piece across the centre will also provide some support. I'm thinking the lateral support will not be an issue. However if it is, the plan is to fold the bottom legs on both planes.

Depending on how this prototype goes and feedback received, I'll likely remove the screw together option and make it 1 piece.
As it is currently there is a tray the std battery could be mounted to. OR
The box screws to the top of the tray and can fit the std battery with much space behind it. OR
Fit 2X D34 optima batteries.

If we decided to lose the first option it will probably result in a stronger assembly, and a flat metal surface for the battery to sit on. But at this stage I don't believe the brace will be required.

PROGRESS:
The prototype came back with some modifications required to improve fitment, it will be modified to a one piece design. We're also adding an extra bolt option so the side bolt can be utilized for lateral support if required. I believe the space has been utilised well, there will be room to mount things under the battery box, but we couldn't utilise it for the ECU, so the ECU will be mounted in more or less the factory position.