Ideas needed for going 36v on a P3

[webertime]

My P3 has a 24v setup currently. Two batteries on a shelf on one side, cranking and oil on the other shelf. The gap between is all the pumps and plumbing. I want to go 36v and would love to see some of you battery/rear compartment setups for ideas. Thanks all
Currently running a 27 cranking and 2 31s for tm so I need to add a 31.

[burrhead]

I believe you will need to add a bridge between your shelves and move oil there and add your battery where oil was.

[webertime]

That seems wisest

[basshole51]

my friend just did this to his p3 I will see if he can't send me some pics to post here

[Boatseller]

When I purchased my P3 2 years ago, the previous owner had a 36v using the cranking battery as the 3rd battery. I have a 2001 Merc 200efi and have never been able to run my batteries down while fishing. I have a 1000 CCA cranking battery and 2-29 series trolling batteries. When I run across a 200 ProXS, I will do away with that type set up.
Good Luck

[shapfromla]

I have been running a 3 battery (one is troller and cranker) 36 volt system for quite some time. I did it on my 2001 Classic with no issues for 14 years and I have it on my 2018 Eyra now. I Currently have 3 31 series AGM's and have yet to have an issue with Cranking my 250 pro xs optimax or any of my electronics. That's fishing long days in the current and the wind. 2 Helix 10's, Ultrex 36 volt trolling motor, stereo system and all the other goodies. Just a thought and It could save you some trouble from having to move everything around to add a 4th battery. Just make sure you get the biggest, baddest cranking/deep cycle you can for the one that is going to be serving dual roles.

[Elwood]

Also if you decide to go with a three battery set up make sure the neg wire for you trolling motor comes off the dual purpose battery or you will run it down quickly. I ran the three battery setup in my Sabre for 9 years with zero problems after the first week and moving the ground wire to the dual purpose battery.

[Ben Danbleume]

There is room for four batteries, without a bridge, might need to move the oil tank over a couple inches. Got two on each side of the gap, they set two on the oil tank side, run the same way as the transom, the other side has them set length wise, still have enough room on that side to store an anchor and rope wrapped in a life jacket.

[OldTimer57]

How does neg vs positive on cranking battery matter? Actual electron flow comes from the - post and goes to the + post. Not sure why one battery would drain before the others...

[Ben Danbleume]

How does neg vs positive on cranking battery matter? Actual electron flow comes from the - post and goes to the + post. Not sure why one battery would drain before the others...

If you don't have the ground correct on a three battery set up, you'll get interference/electrolysis. Don't know about running a battery down other than if one battery starts weaker than the others.

[06 SB]

You can make 4 batteries fit. The bridge is the easiest. I did this on a P2 and used a small coated wire refrigerator tray. It worked great!

Another option that has not been mentioned is to go Lithium. Three 50ah Relions are slightly larger than a single Grp31 battery.