discovery 2 ecu's

Ever since i submerged my D2 in water and blew the ecu, i have had never ending problems with it, since then ive had another two ecu's as the negative on the battery keeps "spiking".

Does anyone know what else might be causing this as from i can see the battery terminals are pretty solid and its a brand new battery?

its due in tuesday to go on a land rover specialist tool for 2hours? not sure what it is exactly but apparently my mechanic says that he wants to check the whole car electronics before he puts another ecu on.


thanks
mpower