Following your phone conversation with Mr. X this morning, I…

[Joj]

Following your phone conversation this morning with Mr. X, I have attached the data sheet of the batteries that you have requested.
If you require any assistance/clarification, do not hesitate to contact me by phone.

 

[emsr2d2]

Following your phone conversation this morning with Mr. X, I have attached the data sheet of for the batteries, that you have as requested.
If you require any assistance/clarification, do not hesitate to contact me by phone/call me.

Note my suggested changes above. I changed "that you have requested" because it wasn't clear whether the thing(s) requested was/were the data sheet or the batteries.

 

[Joj]

it wasn't clear whether the thing(s) requested was/were the data sheet or the batteries.

He requested the data sheets.

 

[Joj]

I have attached the data sheet for the batteries (I can say also) for your reference.

 

[emsr2d2]

I have attached the data sheet for the batteries for your reference.

That sentence is OK. I don't know why you added "I can say also" in the middle of it. That made it ungrammatical.