Iron Sportster battery relocation

[Guest]

I have a bit of a basket case 78 sportster anniversary edition that has the the original battery box and oil tank swapped out for a horseshoe oil bag by the PO. It's going to be a cheap swingarm bobber running just the bare essentials electronically. The problem is I cannot find a good place to mount a battery. I'm looking for advice here on where and how to mount a battery box.

Some specifications:
- I want to use a regular AGM battery, not a lithium. Mostly for cost, but also so I can use regular battery chargers/tenders. I can get an AMG for around $40, so I'm not dropping over $100 on an Antigravity unit.
- It is an electric start only bike, so I'm looking for about 14 amp, 210 CCAs at minimum. What's the least power I can get away with for regular use?
- Dimensions of the battery will be about 5.25L x 3.50W x 6.50H inches. If anyone can offer suggestions for smaller "standard" batteries with good power, I'm all ears.
- I can weld and don't mind cutting things up, but I'd prefer to not hack into the frame too much. I have A harbor freight welder. It's good for making brackets and such, but not for moving frame parts around.

I'll add some pics later, but here's photo of Pigpen.

[Tattooo]

Isn't there room in the oil tank????

[Guest]

No, the cutout in the oil tank goes around 2 frame down tubes. I guess I should have mentioned that. Honestly, Im not entirely sure what is stock and what is 40 years of hack job engineering, but that appears to be stock. It would have originally had the oil on one side and a big battery in the other.

[Tattooo]

No, the cutout in the oil tank goes around 2 frame down tubes. I guess I should have mentioned that. Honestly, Im not entirely sure what is stock and what is 40 years of hack job engineering.

Can you post a pic????

[Guest]

Bad picture, but you can see how the tank wraps around the frame.

[farmall]

I'd shitcan the battery cooking horseshoe abortion (PO was retarded, they don't even look good on a swingarm frame) and run a stock oil bag and battery tray. Those old starters need all the battery they can get.

Buy or download the factory parts book and the exploded views with part numbers make everything fairly clear.

[Guest]

Buy or download the factory parts book and the exploded views with part numbers make everything fairly clear.

I'll just hit up the Jebby Shack - local purveyor of fine used harley junk. I'm cool with the horseshoe, it's free, doesn't look bad, and I'm hiding a bunch of electrics back there (those horrible stock fuses are going) but if it doesn't fit, it doesn't fit.

[Sky]

Might be able to mount an AGM sideways under the swingarm...
Be sure to rubber mount it somehow