I am thinking about dropping some money in to my boat. i want to get a couple of Lowrance HDS. one for bow and at the dash also a new trolling motor with 80 lb thrust. My question is how much more battery do they use. i have 3 batteries with an inboard 3 bank charger. Do you think that i would need to get a 4th battery and upgrade to a 4 bank?

you dont need an extra battery. I have the exact set up you describe and easily make it through 8 hours of fishing with no problems. I have 1 starting and 2 trolling.

I'm using 3 optima blue tops: 2 in 24 volt for trolling motor and the other as a starter. 2 HDSs and a hydrowave hooked up to my starter battery and it runs all day.

Unless you have crappy batteries, you should be fine.

It seems impossible for anyone on a forum to give you an intelligent answer without knowing a bit about how you use your boat and your electronics.

For some angler's boats, that are similar to your envisioned setup, it is absolutely necessary to use a dedicated house electronics battery setup to prevent over discharging a cranking battery. I am such a boater. Other boater's demands are often much less.

If you fish on small waters, with numerous motor starts with only short runs, the alternator may not always keep even the largest starting battery safely charged also being loaded with the tasks of running live-well and other pumps and the boat electronics. This can be further complicated if you fish long days or remote area and perhaps camp without electricity being unable to recharge your batteries at the lake every night.

You could even need to go with 5.....3 batteries switching your boat to a 36 v TM to troll longer than a typical 24volt setup, one cranking battery on the motor and also a dedicated deep cycle battery solely on the boat electronics.

Tell us how you use your boat and its length, is your new tm a digital model and how often are you able to charge your batteries after use.

finders use very little power, they should not be a problem with good batteries, livewells, lights, other electrical is what would be my concern.


0.7A at 13 vDC with backlight on, 0.4A with backlight off - See more at: http://www.lowrance.com/en-US/Products/Fishfinder-Chartplotter/HDS10-en-us.aspx#sthash.u56jyk5m.dpuf

Just put a deep cycle on the cranking side and you will be good to go.

If your boat can easily fit it and you can afford it I would invest in a 4th until you know for sure how well everything will work with the existing 3. Nothin wrong with being overly prepared on the water.

I had the same problem. I was advised to run everything on my starting battery, leaving my two trolling batteries for the trolling motor. I was told I did not need a 4th battery just for lights and electronics.

I use my trolling motor more than I do my boat motor. I do a lot of dock and slip fishing.

In the summer I fish mainly at night as it is too hot during the day. As it cools off I will move to more daytime fishing.

So my boat motor was unable to keep the starting battery charged when everything was hooked to it. It might have had I only fished during the day instead of mainly at night.

As a result the starting battery did not hold up.

I take a Power Station with me when I'm on the boat so I was not stranded when the starting battery would not crank the engine. However over discharging the starting battery killed it after two months of use.

It was replaced without charge but I added a separate battery for my live wells, my LED lights, my electric winch and courtesy lights.

I have a two bank charger at the console for the trolling batteries, another two bank charger at the stern for the starting and fourth battery. I preferred that over running two fifteen foot extensions on a four bank charger from the console to the rear of the boat.

I now only have my fish finders and nav lights on the starter battery.

So as stated, it depends on how and when you fish. I didn't want the extra weight of the fourth battery but that was the best solution for how I fish.

I have 3 FF/batteries on my boat. I fish for 8-10 hours at at time and I have a set of jumper cables just in case I need them. You should be fine with 3, but have some cables with you just in case.

Start here and if you notice your power draining too fast, then upgrade to the extra battery.