I recently added a Humminbird 1199 to my boat. It runs all day in addition to 2 other smaller Lowrance units. Cranking battery seems weak at the end of the day when cranking a Evinrude 150.
Reserve power wasn't an issue until I added the 1199.

24volt Trolling motor runs off of other batteries.

Does the Humminbird unit use that much juice during the day?

Do you route your electronics to a separate (4th) battery?

Thanks for any input you have.

I use a deep cycle trolling battery for a cranking battery and never have a issue.

I haven't noticed a difference with mine on all day!

How's your battery?

I ran a dedicated 10ga wire directly to the unit from my battery to reduce interference and to keep my unit from shutting down when starting the motor!

Spiderman yes, if you are running an 1100 series the draw on that unit is 1.3 amp, which is significant (big Lowrance units draw similar). To give you a sense a 600 or 700 series draws 615 mA's, or less than half as much. So if you are running multiple units your pulling on your crank battery hard. There are several solutions, buy one of the mongo big high $$ Sears batteries, go crazy and buy lithium, or you can do some battery linking. Any of us that run multiple big units have the same issue. One easy fix is to turn off, or at least kill the sonar on the unit you are not looking at which is easy and quick on HBird units.

If you are running three graphs all day plus your live well and don't have a good strong cranking battery......it will definitely pull it down. Especially if you aren't doing some running with the big motor to help keep it charged and your battery has a couple years of use on it.

I run two 1199's for the entire time I'm on the water and, so far, have had zero problems BUT, I didn't install them. Cal in my signature did and great job too.
My setup is like yours, 3 batteries 24V. I start the engine, run the power trim and TM a LOT.
But, that's what an old amateur does...
Sounds like you have another problem in how it's sourced for power.
Wish I could offer more....you should not have the drain your describing
Just IMO
God Bless

Thanks for the input, I'll pick up a 100 amp load tester for the battery at Harbor Freight and go from there.

Thought about running dedicated wires for electronics or running all the electronics off of a smaller separate battery to ease the load on the cranking battery.

Brightness of the screen effects amp draw. Also turning off sonar helps.

I run two 1100s on mine, but I also run an extra optima so I always have a strong 12 for graphs, and starting and livewells. Went to optimas all the way and have no probs what so ever with them or low power

Be careful doing that, You can blow your rectifier.

I bet if you blow your rectifier that will require surgery

Just get a Group31 AGM battery and be done with it; Diehard Platinum series. You'll have enough power to run livewells, bilge, graphs, etc all day. I run 2 HDS 12s, and all pumps all day. Going on 3.5 years now with no issues.

I recently had a similar problem. If I left my graphs on all day and fished a lot, after a several hours it became hard to start my motor. I usually keep an eye on the voltage on the graph and when it gets below a certain level, I run the motor to charge the battery a little but assumed that all my 3-4 mph driving wasn't putting out enough charge. Everything had been working properly the week before. Put the battery on another charger made sure it had a good charge and used a tester to check it under a load and it was bad. A new battery and not another problem. It had become an instant issue, not a gradually worsening one.

Put a full charge on it and take it to a parts store. They have testers and will check it under a load for free.

Replaced my cranking battery with a 29 series trolling battery from Walmart and it resolved my issues.

The load test showed the battery was weak even when fully charged.

It works like a champ. I have several friends doing this with no blown rectumfires