Wiring Overhaul

[mitch184]

Wanted to tap into the wealth of knowledge here on my complete rewire for my Osprey rebuild. (i'll post recent updates on that thread too) Ripped out a 50 gallon bin of wiring, most went nowhere. Not sure how that's possible but it seemed that way. Gutted everything and starting from ground up. Done a bit of home work and this is the basic wiring scheme I've thought up. Seeing if I could get any tips or advice.

Suzuki 350 (55 amp) and Merc 25 (16amp)
Major Loads: Simrad NAC2 autopilot, Seastar Power Assist/Autopilot pump, 4 downriggers, pot puller, radar, 3 fishfinders, stereo, bait pump, bilge, lights, etc.

Dedicated AGM starting battery. 200+ aH LiFePO4 house battery. Orion TR Smart DC DC charger, SmartShunt Battery Monitor.

Starting circuit....Main Engine positive engine lead to a Blue Seas Dual Circuit On/Off switch and then directly to the starting battery. Negative directly to negative battery terminal.

House circuit.... Kicker positive engine lead to other side of Blue Seas Dual Circuit On/off, then directly to house battery. Negative directly to negative battery terminal.

Ground Buss with leads from negative side of both batteries and to the Orion DC DC. All grounds will go to buss bar.

Positive Wire from + of starting battery to input + on DC DC. Positive wire from + of house battery to output + on DC DC.

The one place I'm not extremely clear on is how to connect my house loads to the house battery. I'm almost thinking about running a 2nd On/Off switch from the house battery to a positive buss bar. From that bus bar, have 1 heavy wire going to a fuse/break block for all my electronics a 2nd heavy wire going to a circuit block for all my downriggers & pot puller, then a 3rd heavy wire going to a fuse/break block for everything else.

My main concern is I really don't want there to be any voltage issues with my fishfinders and radar whenever the downriggers are cycling. Before deciding to go LiFePO4, i was going to run a 3rd battery dedicated to just electronics. However, it seems like a 200 aH house battery should never really have voltage drop issues.

After I typed this, i realized its pretty hard to visualize. I'll try and make a sketch. But any obvious glaring issues anyone sees? Thanks

 

[sly_karma]

Rough it out on paper, separating loads that need to be always powered (eg, auto bilge pump, anchor light), powered when ignition is on, powered through house battery switch but not key-on only.

 

[wolf]

JUST did all this this fall when my tech could do it and we went big and better took out the 10 and 8 guage and went with 2 for alot of the main as he said bigger is better and use "closed end terminals" and heat shrink it took us close to 70 hours to do it right. and mosty 6 for the lil stuff especialy to the 4 terminal blocks we put in and labeled everything.

As we were really going thru the whole sysetem . and I must admit boats never been better

 

[mitch184]

Plan is definitely shoot for overkill... my usualy tactic and why this project is taking so long. Usually I just shoot for a 1% when using actual calculators. For what its worth, I drew out a schematic of my basical wiring layout. I'm sure it will change a little.

 

[Aquaholic]

JUST did all this this fall when my tech could do it and we went big and better took out the 10 and 8 guage and went with 2 for alot of the main as he said bigger is better

Same here on my centre console boat. The main lead to the fuse block was so small, 14 gauge I think. Now its 2AWG, the voltage read out on my Garmin is much closer to the MercMonitor, was showing much less before the bigger wire install.

 

[wolf]

the voltage read out on my Garmin is much closer to the MercMonitor, was showing much less before the bigger wire install.

same here it used to read like 12.6 now 14.3 amazing how bigger is better . (for this instance ) LOL

 

[jim morrow]

Was the dual circuit battery switch hard to find or expensive?
I was following your circuit diagram to see if the house battery would charge. Seems it will. In the old days I used a battery isolater to charge the 2 batteries off of the main alternator from the I/O unit. Seems nowadays the set up might be better and more reliable with the 2 extra units in the circuits. the Orion smart and the victron smart units...

 

[mitch184]

Jim, no very easy to find. Blue seas P/N 5511e.

i think the biggest benefit from the new smart chargers is the ability to customize the charge for lithium vs agm vs lead acid. I went with the Orion XS 50 Amp dc-dc charger to charge my lithium house battery. Then a high power AGM starting battery.

 

[noluck]

Plan is definitely shoot for overkill... my usualy tactic and why this project is taking so long. Usually I just shoot for a 1% when using actual calculators. For what its worth, I drew out a schematic of my basical wiring layout. I'm sure it will change a little.View attachment 105036

the only thing i would do different is add a buss bar for your engine batteries and the one ground on the dc to dc charger, and not run them through the shunt for the house battery.

 

[mitch184]

Noluck, just curious as to why? I was worried that running all the grounds through the shunt would increase resistance, but turns out it's not even really measurable. But running them through the shunt is the only way to get a complete view of loads. Or so I thought. Did I miss something? Armchair researcher, here so I don't have first hand experience with these yet.

 

[noluck]

the problem is you will read the current from the starting battery as well as your lithium so you will not be able to measure SOC accurately on the lithium. you will need a shunt on the starting battery as well if you want to see the SOC on that battery. i do not use a shunt on my starting battery because it has no continual loads like the house. i just finished my solar system on my motorhome and upgraded to lithium for the house and led acid starting, and with the smart shunt you will need to make settings in the shunt to determine battery type and setting for lithium. if you search a video setting up the shunt you will see what i mean

 

[kaelc]

JUST did all this this fall when my tech could do it and we went big and better took out the 10 and 8 guage and went with 2 for alot of the main as he said bigger is better and use "closed end terminals" and heat shrink it took us close to 70 hours to do it right. and mosty 6 for the lil stuff especialy to the 4 terminal blocks we put in and labeled everything.

As we were really going thru the whole sysetem . and I must admit boats never been better

That just bumped your boat up to the “if I was rayvon” 3 of the members on this forum, boats I would buy!

I redid the stern electrical but didn’t replace the helm electrical yet. It sounds like it is worth it. I was going to tackle or start my solar upgrade this week but kid time thankfully got in the way!

 

[mitch184]

Noluck, I may have explained wrong. Just looked at my diagram and I have the shunt only on the house side. The starting side there is no shunt. It's probably not a bad idea to have a 2nd shunt on the starting battery but I was trying to minimize connections on that side to avoid any losses or resistance to the motor. The big merc draws a lot of amps. Maybe I need to read up some more.

 

[kaelc]

Noluck, I may have explained wrong. Just looked at my diagram and I have the shunt only on the house side. The starting side there is no shunt. It's probably not a bad idea to have a 2nd shunt on the starting battery but I was trying to minimize connections on that side to avoid any losses or resistance to the motor. The big merc draws a lot of amps. Maybe I need to read up some more.

If you have a victron it measures the voltage on a second battery with a small wire, so at least is helps troubleshoot why something isn't working connected to the starter battery.

 

[mitch184]

I also think the Mercury vessel view will monitor the voltage on the starting battery also. And yes, it's a victron monitor should have the wires.

 

[zurk]

dual circuit wont work with lithium.

 

[mitch184]

dual circuit wont work with lithium.

How so? I've seen quite a few installed. The only time you ever switch to combine is in an emergency starting situation. The rest of the time they are separate. The dc-dc charger hooked to the starting battery is what charges the lithium house. Unless I'm missing something.

 

[zurk]

dude ive tried this at least 3X and had problems 3X. the programming on the add a battery circuit only works with AGM or lead acids. it will flatline your lifepo4. ive even confirmed it with both the yellow and black kits.
what you should do it just do lifepo4 for both and add a sterling APD. https://www.sterling-power-usa.com/SterlingPower12voltalternatorprotectiondevice.aspx
Ditch the overcomplicated ACR. just go full lithium. full lithium works very nicely and as long as you use a good fusing system (class T) on terminals to the max rating of your BMS you will be ok. dump the victron smartshunt. with bluetooth smart lifepo4s you dont need it. dump the overcomplicated wiring. just do 0AWG from both lithiums to a blue seas dualbus hub at the back and one more in the front. then branch off those. one main trunk line, one bus connecting the batteries and everything will work great. use this as your start battery - https://dakotalithium.com/product/d...ar-truck-battery-plus-deep-cycle-performance/ and this one as your house - https://ca.renogy.com/pro-12v-200ah-smart-lithium-iron-phosphate-battery-w-bluetooth-self-heating/
ive got 4 boats with full lithium and zero problems for any of them. rip the lead bandaid off.

 

[mitch184]

Ahh. OK. I must have explained wrong. I'm not using an ACR at all. I'm just using the actual dual circuit battery switch. The switch only.

 

[noluck]

Ahh. OK. I must have explained wrong. I'm not using an ACR at all. I'm just using the actual dual circuit battery switch. The switch only.

i think he is calling your dc to dc a acr