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Stern Heavy - Lithium Ion Battery or Relocate AGM to Console
So I'm in the middle of rewiring my cranking battery. As I pulled everything out, it got me to thinking. My boat is stern heavy to begin with. I have a big 300HP Suzuki 4 stroke outboard on an Atlas jack plate, a 9.9 kicker with power start/trim/tilt, and a Minn Kota Vantage all hanging off the transom. I've recently added Lenco trim tabs, but still have to figure out a good four blade stern lift prop for my setup. Before the trim tabs were added, I actually had a couple of instances where I couldn't get the boat to plane...yes, it's that bad. So as I looked at the current AGM sitting on my deck to be rewired, I thought maybe now would be the time to get a little weigh out of the stern.
My first choice is to relocate the battery under the starboard console. I already have a similar battery under the port console for my electronics system. This would probably be the most effective means of maintaining good battery capacity while moving the weight out of the stern. My issue with this option is I am not quite sure how to accomplish it. I thought about mounting a piece of starboard with a couple of Blue Sea Systems 600A Bus Bars, one for the power and one for the ground from the battery. The rest of the fuse blocks and other wiring components from my stern rewiring project could also be neatly mounted on the board. It seems perfect in theory. But I am not sure how to determine how big the wires need to be running from the battery twelve or so feet to the bus bars. Heck I am not sure this is even feasible to do safely.
The other option is to replace the AGM battery with a Lithium Ion battery. This is less effective at dealing with the problem because there is still a battery in the back, albeit much lighter. Issues I have with this project are finding a lithium ion battery to replace the very high capacity AGM battery I am currently using. It looks like a Relion RB100 would likely do the trick though. I'm not sure how to figure out what the cranking capacity is with the Relions though. Also, I have a brand new Minn Kota MK230PC charger for this battery. I'm not sure if it will work with the Relion, and I really don't want to go to Dual Pro chargers just to be able to charge a lithium ion battery.
So, my main question is if the relocation to the console is feasible is a safe and effective manner. If not, I'll need to look into the lithium ion setup more closely. Thanks.
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Like Chief Brody said "We are gonna need a bigger Boat!". Even with the Lithium it will still weigh almost half what the AGM does. The cables to that midship starter bat will need to be large. Remember it works out to be a 24 feet! Must size the cable for the total wire length Positive to Negative. That will also require some kind of circuit interrupter. As far as the correct Relion battery I would call them. There is an HD(heavy duty) version and also there is an LT model of the 100.(low Temp) It has a heater for charging below 0c. I know you guys like it cool up there. Bob
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I found this document on Blue Sea Systems' website, which seems to be helpful. What would the highest current be in the system? Starting the battery I would think. Where can I find that info? I have the shop manual for my Suzuki DF300, but it's at the lake at the moment. Also, would starting the outboard be a non-critical circuit, where 10% voltage drop is ok? I came across this info last week, but can't find it now.
I'm still favoring relocating the AGM to the console if I can figure out how to do it properly.
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What else will be on the starter battery? Anything electronic I would think you would want to keep 12.0 on it while starting. The initial current flow will be much higher than what the starter would draw once the motor starts spinning. I would make a swag of either 1 or 1/0 wire. with a big fuse(maybe 200?) Please get someone that knows the numbers and exactly what to do with them. Good luck Bob
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I think I would maybe go with an LI battery and then find the right prop to get all that weight up on plane. That is the best solution,IMO.
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After giving it more thought and doing more research, I think I will just replace the current battery with a smaller Group 24 AGM I have and put the downrigger leads on the trolling motor bank. I won't have any significant draw on the cranking battery except the trim tabs and the jack plate, which should only be used when the outboard is running. The Relion is just an expensive pain to get up here and won't work with my new Minn Kota charger...and the weight savings aren't huge. The battery relocate has the potential for some logistical and perhaps safety issues. I'll put the smaller AGM in and work on prop selection this season and see where I am in the Fall. Thanks for the input.
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You have done a great job using all the information you received! A testament to the great service BBC and all its members and sponsors provide. Good fishing and boating. Bob
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