I just purchased a Motorguide xi3 pinpoint kayak trolling motor that i'm installing on a fourteen foot flat bottom jon boat with a single twelve volt battery. I run an old trolling motor, Lowrance Elite-4 HDI graph, bilge pump and navagation lights off this battery (pull start engine). The installation instructions say not to run this trolling motor on the same battery as a graph and to run the wiring on the opposite side off the boat from other electronics. The only experience i have with kayaks is what i've seen on YouTube but you guys that run a graph and a GPS trolling motor do not run two batteries right? Or do you? And with the limited room of a kayak do you seperate the wiring on opposite sides? Any advice, suggestions and comments are greatly appreciated.

I cannot speak to running a trolling motor on a kayak (I'm running with human power). However, most of us use a small lead acid or lithium battery to power our graphics. Perhaps you can use something like this for your graphics and run everything else on the large battery.

https://www.amazon.com/gp/product/B00K8V2Y8W/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 (this is what my son uses for his Lowance Elite 4)

https://dakotalithium.com/product/d...gLNU19Gm4J7efkQaruq1o2rqOsRoCPtAQAvD_BwE

I run a Lowrance HDS 7 with TotalScan transducer. This setup pulls a lot of power (1.3 ah). Because of this, I use a 17.5 ah battery. It's pricy, but its a very good battery. I think it's actually slightly smaller than my son's 9ah lead acid battery... if not smaller, it's certainly no larger.

https://www.amazon.com/FPV-Power-Lithium-Ion-17500mah-Fishing-Battery/dp/B07YNWWSBX

Jerry knows a lot more about batteries than I do. Maybe he will see this and offer you some guidance.

Thanks for the info Mike. I hate to put another battery in my boat but i sure want everything to work like its supposed to.

I think the issue is one of interference, not positive though. But a small deer feeder type battery will run that FF for a long time, I have that setup on my slayer.

I believe they are stating that because many sonars are sensitive to voltage drops. Due to the varying amperage a trolling motor draws during the course of a fishing trip I can see why the would say that. I believe it is more for the protection of the sonar unit than anything. If you can run a small battery for your lights and FF. The fuse in your sonar should prevent anything from being damaged but best to have separate batteries if you can.

I use this little guy to run my 5" Garmin Echomap. It will last at least 2 full days.

Since you have a bilge pump I would recommend this one.

I believe you are correct that its just an interference issue. I'm leaning towards getting a small, 17ah battery that will be dedicated to my graph. Then run the trolling motor, bilge pump and nav lights off my existing battery. I very seldom use my nav lights and bilge pump so it would pretty much be dedicated to the trolling motor. Thanks for the advice!

I like the 16ah battery you posted the link to. I may run with that one and just dedicate it to my graph. Thanks for the info!

You can use one battery but anytime you turn the trolling motor on you'll get interference on the graph. Only way around it is a separate battery.

Second tmd11111 - from personal testing as well!

If you run the trolling motor off the same battery as the finder you will see interference (fairly significant) on your graph. If you get fancy you could put a filter/rectifier on the line but that causes more draw and is almost as expensive (if done right) as picking up a cheap second battery for your finder.

Ok, you guys have talked me into a second battery for the graph. Now, how about running the wiring for the trolling motor on the opposite side of the boat from the rest of the wiring? is this necessary?

So first off - my past career involved audio engineering - which is very cross talk sensitive when dealing with analogue - not so much when digital.

That recommendation depends on a number of factors - how long is your cable run, how shielded are your cables - so on. From my own personal experience - the only reason i see them giving this advice is to prevent the trolling motor from "inducing" noise on the finder power supply/line. This is not usually a huge problem on DC lines - but is not unheard of.

From personal testing experience - since i move my finder and trolling motor between 2 kayaks and my porteboat i've gotten to play around with this a bit.

1) run your transducer cable separate from your power cables when possible (4-6 feet max) - if not possible keep it as short as possible or introduce some shielding (various ways of doing this). Your transduce cable is the most sensitive to induction and will introduce the most noise from cross talk.

2) Personally - i feel it is not super required - but the more space you can separate them (trolling/finder power/lines) the better your graphing experience will be.

My recommendation - if you are going with a separate battery - just place that battery in a different location. This is usually fairly easy because it is smaller. My battery is in a fully sealed case with SAE connectors - i usually strap it into my crate or under my seat - right near where i mount my fishfinder. Where the trolling battery is wherever it needs to be for weight distribution. Because of this my lines usually are at least 4-6 inches apart at their closest and only for 2 feet max (in any of my setups).