Lithium Batteries in P2

I've got a 2008 P2 that I'm thinking of swapping trolling AGM's for Lithium. I currently am running the group 31 Duracell AGM's (105 AH I think) you can get at Sams for a 36 volt 112 minn kota. Those suckers weigh over 80lbs a piece, so you can imagine my P2 is butt heavy with three of those plus a starting battery, plus two pro-series power poles. There's a third fat guy on back of boat every trip! It's time (again) to replace these and I want to swap out the three trolling batteries for three of the Relion 100AH (about $930 each right now). Mostly for weight but also seems to make sense from a long-term cost perspective. Those weigh in at about 30 lbs each, so I could shed 150lbs+. My question is...do you think the 100AH batteries are way overkill? I could cut another 15lbs out of each battery if I went with the 50AH. I fish alot of current (which is why I have the 36 volt in first place) so my gut tells me to go with the 100AH, but I have read posts that say the 50AH are more than enough. Also, what kind of charger? I gave up on onboard chargers awhile ago but thinking of just getting a dual pro and not mounting in boat. Can't really find a good alternative charger that I could just keep at house. Also, thoughts/experience here with brands, etc. appreciated. For those wondering my boat has 2008 200 HPDI (stock yamaha three blade prop) and currently runs about 69 MPH with this setup and two 200lb guys and gear. When I got the boat, no power poles, motorguide 24 volt TM, three group 27 batteries (including starter) it would run about 74-75ish.

This topic has 6 replies, 6 voices, and was last updated 5 years, 5 months ago by catdude28.

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December 16, 2019 at 2:02 pm #680453

basscathash1
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I run Relion Lithium batteries in my 2009 Sabre. I went with 2 RB-50AH for my 24V trolling motor and a RB100-HP for the starting and accessory battery. I have yet to run out of power on the trolling motor or the starting battery. I run 4 graphs that are on all the time and livewell pumps on timers running all day with no issues. They also re-charge in a couple hours. I feel 3 RB-50’s would be fine but the RB-100’s would assure you would never run out of power for a day of fishing. To my surprise I did not gain any speed due to the weight loss switching from lead acid batteries but the hole shot was much improved. For the battery charger I went with the Dual Pro with a lithium charging profile. Other than the original cost I have no regrets.

December 16, 2019 at 6:32 pm #680464

Ricochet15
Participant

Basscathash1 what kind of conditions do you fish in? Windy, current, etc. Also how long of days do you put in? I was debating 2 of the same size and just making sure it will cover what I’m needing.

December 16, 2019 at 8:27 pm #680467

himmelrr
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I had a 2010 P2 and I put in 3 x 50ah Relions for my MK 101 Fortrex. I fished two whole days of fun fishing and did not kill them. The biggest test for me was when my son was in a college tournament on Guntersville. The wind was howling and he likes to fish out in it and is always on the pedal. It was a long day as they had the last check in. It lasted just fine. I did not worry about it after that. I moved those same batteries to my Cougar and its 112 Fortrex. No problems there either. I used a MK 460PC charger in the P2 and went with a DualPro with the lithium profile in the Cougar. I have fished long tournament days in wind or current without failure. My gut tells me that if you fish wind and heavy current at the same time the 50ah might get taxed.

BTW, Roy at Wackyriggers sells Relion AND battery trays for the odd sizes of most lithiums (the 100ah is standard grp 31).

December 17, 2019 at 6:40 am #680470

Bassaction
Participant

I run Relions on my Cougar. I went with the 75s just to save a little money and even more weight. Pretty sure I could fish two full days without a charge. Also run the 100hp for cranking and everything else. Been using Minnkota 440pc and has been flawless,I have read alot more issues with Dual pros and lithiums.

Not sure what happened with the text there.

December 17, 2019 at 7:28 am #680471

basscathash1
Participant

I usually fish 8 hour days crappie fishing. I don’t fish current or real windy days. It takes less than 2 hours to charge when I get home so I know there is plenty of battery life left. Never have tried to see how many trips I could fish before charging.

December 17, 2019 at 9:13 am #680479

catdude28
Participant

There are a lot of fellows on BBC running the Ionic Lithium batteries now. You may want to have look at those.
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