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Battery Connections???

Discussion in 'Boats and Motors' started by sws4bass, Feb 12, 2017.

  1. I have a Minn Kota Ulterra trolling motor connected to 2 deep cycle batteries for 24 volts.
    I have a deck and console Humminbird Fish Finder with the console, i-pilot linked with lake master to the trolling motor. That is hooked up along with the lights, bulge and live well to the cranking battery.
    I have low voltage and trouble firing up motor after long periods of use.
    Anyone have any suggestions or experiences to share? Would appreciate it.
    Steve Schrock
  2. You need a separate battery to power your big motor, lights, and graphs. The two trolling motor batteries should only be for your trolling motor.
    fastwater likes this.

  3. X2
  4. I have a 9.9 Johnson motor
  5. Let me get this straight first as there is some confusion with your first post. You have 2 deep cycles that are for the trolling motor only and 1 cranking battery that powers everything else?
  6. Yes, 2 deep cycle hooked together for TM only and everything else on the cranking battery = 3 batteries total
  7. Ok, big boat, small boat doesn't matter. You have the same problem as everyone. You are at slight disadvantage because you are not going to get a lot of charging from your 9.9. You have two options bigger battery or another battery. A good group 31 AGM will more than likely handle your needs. I run a 31 AGM but with multiple fish finders, live well, marine radio and other things for hours on end and I find that my big motor is close to not turning over. I run two two cranking batteries, just in case, but if your running a 9.9 I'll assume it's a smaller boat and 4 batteries is out of the question. Worst case scenario for you would be keeping a set of jumper cables on board and jumping off your trolling motor batteries if you had too.
  8. I do have a smaller cranking battery which I use to have hooked up to run everything before getting a deep cycle for trolling only. I may have weakened it, as, deep cycling a cranking battery isn't good!
    When I purchased the new TM I got another deep cycle designated just for that.
  9. So larger cranking would be the ticket as I go long periods of time fishing and like you said the 9.9 would have to be run for a long time to recharge.
  10. An AGM battery is good for cranking and running accessories. Very rarely will I run my cranking battery down enough to have too switch over to the other battery. Keep your two deep cycle batteries for running just your trolling motor and get a good group 31 AGM to run everything else and I bet you'll be fine. You could more than likely get away with a group 27 AGM but if your buying a new one, and have room, just go with a group 31.
    fastwater and crappiedude like this.
  11. your 9.9 charging system can,t keep up, or your battery has issue,s.
  12. Not to take over your post but i have a question around the same lines .I am new to owninga boat . i and looking to change it from 12voltto 24 volt system.How do i do this i know i need to buy a 3rd battery but other than that i have no clue
  13. don,t do this till you have a diaghram of how it goes, batteries are nothing to second guess. they can explode.
    fastwater and williamonica0214 like this.
  14. why do you want to do this? If you run two batteries in parallel (Positive to positive and negative to negative) you would only need to purchase a 12/24 plug setup and you could still use the batteries for 12-volt services (lights/graph/accessory outlet) while still running a 24-volt trolling motor. I don't mean your trolling battery and starting battery. You should still use three batteries.
  15. Yep!
    ...and as bountyhunter posted, your 9.9 charging system(if it even has one) most likely will not keep up with the batteries charging needs running the things you listed as having connected to the starting battery regardless of size of battery. The output rating of the 9.9 (again, if there is one) just won't be enough to recharge the battery.
    What going to a larger series battery does is obviously gives you more running time before it goes dead. Just keep in mind that it is an 'absolute' must that after a day of fishing that the battery is put on a charger at day's end and charged to max as it will be low.
    You don't want to be surprised the next day on the water.
  16. ...and if you've ever had one explode, you won't soon forget it.
    It's a fairly violent explosion.
    And, just a reminder, if you happen to be standing over the battery when it explodes with any exposed skin make sure and rinse any exposed skin repeatedly with large amounts of water. Even if the skin is not wet to the touch from the explosion. The force of the explosion can be violent enough to blow acid into the pores of your skin and the skin won't feel wet.
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