2 Battery problems?

I just had some stereo work done and the shop installed a small audio battery behind the kick panel for the amps and what not..Well i went to start it up to go out after the install and it wouldnt start? Took it to the dealer and he said my computer went out on the motor. The installer said he was running the small battery inline with the regular battery. Could this have caused my computer to go out?..I just dont see the computer going out on its own while being stored?

Depends what he means by inline. If he wired it wrong it would make the system 24 volts. Frys everything. Computer first. Waas it a reputable shop, familiar with boat installs.

if it helps any i didnt have a battery in the boat during and after the install and i couldnt start the boat with the little battery but could run the stereo with it. I installed the regular battery and thats when it wouldnt start.

Any help appreciated

If the installer shorted out the electrical system (when installing or testing) it can blow your computer. If the batteries are inline, it will blow your computer. If the system isn't grounded properly, it can blow your computer. Also, if you are pulling to much power from under charged system you can cause some of these problems as well. All of these can cause you problems that can/will return if not set up properly. Your dealer should be able to check the power supply, wiring and grounding to ensure it is ok.