relocating batteries to engine compartment

[NJT5047]

It's not all that hot in the engine compartment of an MC9 (or other MCI varients with squirrel cage blowers).   As Stan says, the proof is in when considering the number of under the hood, non-shielded automotive batteries that last for 5 or 6 years.   
Jack Conrad has temp measuring devices in his engine compartment and I cannot give absolutes, but it isn't at all what one would think...I believe on the order of 180* ?  Maybe Jack can help us out here?   
Other brand coaches may be different, but MCIs essentially flood the engine compartment with 180 degree air from above.   Heat isn't going to be any where as hot as an automoble underhood. 
On shutdown, the engine compartment "stovepipes" the heat upward thru the blowers and radiators...really cools the engine room since all the heat makers are on the drivers side and on top of the engine....turbo, muffler.   Batteries sitting on old AC mount are in the Pax rear corner.  Just really cozy you know!   
I'm going into my 4th season with the same batteries...never let them drop below 12V without charging.  Works for me!
My dos centavos, JR