Battery confusion again...... Second Battery?

[HDavies]

Hey,

Recently bought a split charger for my vauxhall combo (1.7 diesel) to run a second battery for ICE system.

Question is does the second battery (that i need to buy) got to be the same as that which the van uses in the engine compartment?

Reason i ask is that the equivilant battery to that of the existing one is a lot more than i have to spend. Due to the fact its a diesel.

Thanks x

 

[Spark123]

I don't think it has to be, however if you have something like a silver calcium battery there may issues.