My son recently invested in upgrading our crappie/ catfish boat with Garmin Livescoe and a compatible Garmin Sonar Unit.
Was intalled at BPS Grapevine. First time out it drained starting battery in 30 min. Went to move to another spot and battery was dead.
I'm sure this is a redundent question and I'm sorry but what is the best battery or set up for this to not be a problem going forward?
There's really only room for one battery in the back of the boat. Trolling motor battery is up front.

I had two Echomap Ultra 122svs plus livescope installed this past May. I bought and had it installed by Jones Trolling Motor. They ran a dedicated wiring system back to the engine battery. I also run a hydraulic jack plate and two power poles off the same engine battery. 8 total ground wires are hooked up. So I run a Northstar group 27 dual purpose AGM. No problems fishing all day. The Northstar is a highly rated battery but expensive. Bass Pro's XP series is the Northstar. BatteryBulbs Plus X2 is also a Northstar. Buy from them and there is a 4 year full replacement warranty. Buy direct from Northstar and its a 3 year full replacement. Buy from Bass Pro its a 12 month full replacement and 36 month prorated. The battery is a beast. Weighs almost 70 lbs. The group 31 is even heavier.

That thing must really suck some juice if it killed a battery in 30 minutes, i run my trolling motor, and use spot lock all day, my live well pump, and my Humminbird Helix, all of my trolling motor battery and can run them for 8-10 hours with no problem at all

If it drained it on 30 minutes then something is wrong. It does draw quite a bit, but not that much. I installed a dedicated battery for Livescope and my two front units.

Retired grass grower

This. On my previous boat, I installed a wheelchair battery to run my Helix 10.

I run livescope, 3 93 sv graphs and all the other stuff we have on a deka grp 27 and have not come close to running it down.

what battery do you have now?
how old is it?
need to do a load test on it to be sure it is good, parts house or wal mart will have load testers for about 35.00, worth having.

where did they tie the new stuff to?
you need a dedicated circuit for the graphs, straight from the battery with a fuse at battery.

sounds to me like you have a bad cell in your battery, it can show full charge but will only last a few mins. when any load is put to it.