Biggest Battery for Factory E250 Battery Box

[jso5000]

Hello -
I have a factory metal with plastic top battery box installed on my E250. Its installed on passenger side frame rail.
I have done some searching but my findings are not conclusive.

What is the largest (size) battery that I can fit in the box without any box modifications?
From an Amp/hour perspective any recommendations for the battery?

Thanks

John

[jso5000]

What I have found is that a group 65 battery is what is recommended by Ford.
If anyone has another size that works that would be good info or if someone has a recommendation on a good group 65 battery that would be great too.

[mikracer]

I think theres a battery size that fits the width and length of the box, but its too tall for the top to close. But I would imagine that the Ah for that battery would be similar to the group 65 that would normally fit in there.

Some people add a second battery box and run two Group 65's which would be a pretty simple add on to get some more juice.

[jso5000]

MIKRACER: Yes, good point. Might end up doing that.
I see in your signature you have a CTS-V wagon - for the baby - very cool.

[dhally]

A group 27 will fit in the box at 90 amp hours, but the lid won't go on and I think it has to mount lower.

[wander]

I have a 1998 Econoline E250 EB50. I have 2 Group 27 Batteries (1 on each side) and they fit fine. I don't know if it was modified to fit, though.

[1der]

This is probably the best thread on adding batteries on the E Series frame rail. LOTS of info! My post#40 has the way I did it. Ramsey (RIP) mentions Agile has a dual battery setup that can be purchased. I am not sure if John is still offering it.

https://www.sportsmobileforum.com/fo...up-1707-2.html

If you are going to to the trouble of working with two boxes to add Ah then go to two Grp 31 AGM batteries. you can use the mounting ears from your box and have a battery tray fabbed up to securely hold the two batteries. They will fit laid on their side and will tuck up well. if you are not worried about ground clearance then they can be mounted in the up right position.

If you decide to go w two grp 65's in the stock boxes, you will likely have to reposition the current box to make room for the second box. This will require drilling some new mounting holes in the frame. Pep Boys carries a Bosch Platinum Grp 65 AGM that is around $180 when on sale. It has 65 Ah capacity. A Grp 31 has around 100 to 110 Ah.