mounting batteries mid frame

[TigerToothBikes.com]

i want to convert an old pannier rack to a "mount" of sorts. thought i'd ask you fine fellows whether you;d tried this and what the verdict was. I envisage better weight distribution and handling.
Of course i'd LIKE to go LiFePO4 however i have a feeling it'll have to be SLA.

 

[POPS]

IMHO..Too high Tiger
Bottom of the frame...Low as you can go...POPS

 

[deacon]

My kit came with a couple of baskets that mount to the bike's axle. I didn't use them but they mount low.