Boat Re-Wire

[scottar]

Who would have thought 12v circuitry would be so complex.

My new boat runs a very simple twin battery setup with everything running from a single battery and an isolation switch allowing you to switch to the 2nd battery in need. I don’t run an electric of course and Have a 175HP Evinrude G2 which has a high charging output. I’d considered changing the setup to have a dedicated house battery but after reading the above I think my simple setup would actually be best for my use. I needed to replace my 2nd battery so going a semi deep cycle high CCA option to cover both grounds. If I have a long run in the boat I’ll switch the isolator to Both to run batteries in parallel and charge both batteries - then switch back to single battery on isolator when I arrive.

Does the above sound reasonable?

Reasonable - Yes. There are plenty of boats run this way but the configuration is not without potential issues.

It depends a lot on your electronics and whether they are happy with the typical voltage dip that occurs when starting. Some gear is. Some really isn't. Going to a start / house configuration does away with this problem.

Another potential issue can be avoided by making sure you never rotate the selector switch with the engine running. These switches are normally a "make before break" configuration - meaning that connection with the second battery is made before disconnecting from the first. Provided this happens (and you never inadvertently turn the switch to off with the engine running - never a good thing) all is good. I have however seen where due to a bit of corrosion or otherwise, there is a momentary disconnect from the batteries during the act of turning the switch. Effects are instant and sometimes catastrophic in terms of failure to electronic devices and engine electronics. Making sure the engine is shut down before turning the battery selector is good practice IMO.

Changing your set up to a start / house type isn't complicated and with the G2 there are a couple of options. Easiest however is to change your battery selector to a blue seas 5511E (if it will fit in the same location) and add a VSR.

[Lovey80]

So second river trial last night closes off this stage of the little boat fit out. First run saw me with a broken neutral cutout switch that had me using a fuse to bridge across the plug to get it to start. That fixed I went for a run yesterday and into the evening.

The little 40Ah Winston Lithium battery pack that I installed down a little pocket at the back of the boat starts the 60hp Suzuki with ease. Shows how much the blokes at battery world Maroochydore know who said it would even start an outboard. The fitment is tight and a pain in the arse to get out, so here’s hoping it last a long time.

The 163Ah Calb battery pack I installed under the console is working well as intended. About 3h of spot locking on day one and about 4 hours of spot locking on day two without a recharge other than the nominal inputs from the outboard that accounted for probably two hours of run time has it sitting at 60% SOC.

I don’t think the Victron BMV712 smart shunt accounts for the power that is put back in by the outboard. Throughout the couple of hours the outboard is running, even though the outboard is able to only add 11.5amps per hour, I saw the both batteries increase in voltage and settle above where it was once turned off, but the state of charge shown on the app/gauge never went up at all. So I guess that gives me a little redundancy out on the water, though I have the alarms set at 20% SOC just in case.

I wasn’t happy with the VSR remaining closed (paralleled) while the engine wasn’t running. I know at 12.8v the starter battery will still start the outboard. But in the standard configuration, once the start battery hits 13.4 volts they remain as one large 200Ah battery until both are essentially 12.8V where the VSR opens the circuit to protect the start battery. Being lithium, at 12.8V the start battery is very low by that point. I just didn’t want that battery to be drawn from at all whilst I was fishing on spot lock etc.

So I found the ignition wire by using a test light to find out which wire gave the engine power when the key was turned to on and took the little red looped wire in the back of the VSR and cut it, extended it and spliced it into the loom wire. Now for both batteries to be paralleled, the 13.4V on the start battery needs to be met AND the ignition needs to be on. I hope this helps someone down the track that wants their VSR to do the same thing.

The whole time I had the engine running, including some minutes at WOT, the sounder read the device voltage as 13.8V maximum. While when the engine was off it read the same as the voltage as the voltage meter on the Victron gauge. This tells me that my outboard is putting out a maximum of 13.8V (Scottar is that a safe assumption??). If correct, my earlier concerns about the outboards stator potentially putting out too many volts and possibly damaging the lithium’s was unfounded.

I’m also assuming that the way I have the VSR set up, if I drain my house battery down low and start the engines then some of the draw from the house battery after the VSR parallels them, will come from the house battery. I can see this happening if I just turn the ignition on. The house starts to go up in volts and the start begins to drop. I’m hoping that this will in some way takes some pressure off the Suzuki stator and stop it from frying it. I’ll report back if there are any issues in that sense.

The 55Lb thrust from the 12v Minnkota seems to be more than enough to hold the little Webster in place and the shaft length is more than adequate. The largest draw I saw with it on was under 3Amps. That’s on lvl10 speed heading into the wind and current. On spot lock with no light etc on it varied between 1&2 amps.

The biggest draw on the boat comes from the Marco Fluid Tech Salt Water pump. On start up I saw it spike at 27Amps and runs at about 15amps in continuous operation. I am probably going to have to re-think using this to run my bait tank as I don’t want to be drawing that much power to keep the baits healthy.

I had to return the Hard Korr boat lighting kit I bought from Road Tech Marine. It lasted 24 hours after I’d run all the wires under the floor and through the gunwales only to have the remote control stop working. Also getting 1-2 and 1-3 way splitters and extension cables is a no go. It took me 3 days to get a response from them. It made using that kit not that desirable and it failing was a blessing. I do not recommend using this kit. The far cheaper kits from Kings are easier to use and far more robust with tons of splitters, extensions and dimmer switches. Let’s see how they last.

[baitable]

So second river trial last night closes off this stage of the little boat fit out. First run saw me with a broken neutral cutout switch that had me using a fuse to bridge across the plug to get it to start. That fixed I went for a run yesterday and into the evening.

The little 40Ah Winston Lithium battery pack that I installed down a little pocket at the back of the boat starts the 60hp Suzuki with ease. Shows how much the blokes at battery world Maroochydore know who said it would even start an outboard. The fitment is tight and a pain in the arse to get out, so here’s hoping it last a long time.

The 163Ah Calb battery pack I installed under the console is working well as intended. About 3h of spot locking on day one and about 4 hours of spot locking on day two without a recharge other than the nominal inputs from the outboard that accounted for probably two hours of run time has it sitting at 60% SOC.

I don’t think the Victron BMV712 smart shunt accounts for the power that is put back in by the outboard. Throughout the couple of hours the outboard is running, even though the outboard is able to only add 11.5amps per hour, I saw the both batteries increase in voltage and settle above where it was once turned off, but the state of charge shown on the app/gauge never went up at all. So I guess that gives me a little redundancy out on the water, though I have the alarms set at 20% SOC just in case.

I wasn’t happy with the VSR remaining closed (paralleled) while the engine wasn’t running. I know at 12.8v the starter battery will still start the outboard. But in the standard configuration, once the start battery hits 13.4 volts they remain as one large 200Ah battery until both are essentially 12.8V where the VSR opens the circuit to protect the start battery. Being lithium, at 12.8V the start battery is very low by that point. I just didn’t want that battery to be drawn from at all whilst I was fishing on spot lock etc.

So I found the ignition wire by using a test light to find out which wire gave the engine power when the key was turned to on and took the little red looped wire in the back of the VSR and cut it, extended it and spliced it into the loom wire. Now for both batteries to be paralleled, the 13.4V on the start battery needs to be met AND the ignition needs to be on. I hope this helps someone down the track that wants their VSR to do the same thing.

The whole time I had the engine running, including some minutes at WOT, the sounder read the device voltage as 13.8V maximum. While when the engine was off it read the same as the voltage as the voltage meter on the Victron gauge. This tells me that my outboard is putting out a maximum of 13.8V (Scottar is that a safe assumption??). If correct, my earlier concerns about the outboards stator potentially putting out too many volts and possibly damaging the lithium’s was unfounded.

I’m also assuming that the way I have the VSR set up, if I drain my house battery down low and start the engines then some of the draw from the house battery after the VSR parallels them, will come from the house battery. I can see this happening if I just turn the ignition on. The house starts to go up in volts and the start begins to drop. I’m hoping that this will in some way takes some pressure off the Suzuki stator and stop it from frying it. I’ll report back if there are any issues in that sense.

The 55Lb thrust from the 12v Minnkota seems to be more than enough to hold the little Webster in place and the shaft length is more than adequate. The largest draw I saw with it on was under 3Amps. That’s on lvl10 speed heading into the wind and current. On spot lock with no light etc on it varied between 1&2 amps.

The biggest draw on the boat comes from the Marco Fluid Tech Salt Water pump. On start up I saw it spike at 27Amps and runs at about 15amps in continuous operation. I am probably going to have to re-think using this to run my bait tank as I don’t want to be drawing that much power to keep the baits healthy.

I had to return the Hard Korr boat lighting kit I bought from Road Tech Marine. It lasted 24 hours after I’d run all the wires under the floor and through the gunwales only to have the remote control stop working. Also getting 1-2 and 1-3 way splitters and extension cables is a no go. It took me 3 days to get a response from them. It made using that kit not that desirable and it failing was a blessing. I do not recommend using this kit. The far cheaper kits from Kings are easier to use and far more robust with tons of splitters, extensions and dimmer switches. Let’s see how they last.

The outboard stator will eventually cook itself. Get yourself an infrared temp sensor and test the stator when charging a lead acid and a lithium, and get back with the temp difference (i already have)

[scottar]

The whole time I had the engine running, including some minutes at WOT, the sounder read the device voltage as 13.8V maximum. While when the engine was off it read the same as the voltage as the voltage meter on the Victron gauge. This tells me that my outboard is putting out a maximum of 13.8V (Scottar is that a safe assumption??). If correct, my earlier concerns about the outboards stator potentially putting out too many volts and possibly damaging the lithium’s was unfounded.

I would expect that with the engine being a modern one that the outboard would have a good regulation circuit - 13.8 would be considered a fairly standard charging voltage. At this voltage the thing that will eventually hurt the batteries is that the lithium will never be fully charged. Charging at home will be required. If it was going to put out too much voltage it would only be if the regulator failed or potentially if the BMS decided for whatever reason to disconnect - thus removing the load from the charging output.

Did you ever check with Suzuki about charging duty cycle?

[Lovey80]

The outboard stator will eventually cook itself. Get yourself an infrared temp sensor and test the stator when charging a lead acid and a lithium, and get back with the temp difference (i already have)

care to pass on the results for those that may be thinking of going down this route?

[Lovey80]

I would expect that with the engine being a modern one that the outboard would have a good regulation circuit - 13.8 would be considered a fairly standard charging voltage. At this voltage the thing that will eventually hurt the batteries is that the lithium will never be fully charged. Charging at home will be required. If it was going to put out too much voltage it would only be if the regulator failed or potentially if the BMS decided for whatever reason to disconnect - thus removing the load from the charging output.

Did you ever check with Suzuki about charging duty cycle?

Didn’t get around to talking to Suzuki. Both batteries will go on the Victron 15amp charger after each trip. It’s only on the camping trips away where I’d run a generator at times to top them up where I may not get a full recharge of both batteries every day. With such a low draw on this trolling motor I think I can get away with once every two days for the house battery. If not I’ll get a larger charger.

one thing that I’m confused about is the Victron lithium charge cycle. It charges up to 14.2v before reducing to a 13.5amp float cycle. If 14.6v is supposed to be 100% capacity this doesn’t make sense to me.

[baitable]

I have already mentioned the dc2dc setup previously and it was glossed over- get rid of your vsr. U can find out for yourself mate the easy way or the hard way.

[Lovey80]

I have already mentioned the dc2dc setup previously and it was glossed over- get rid of your vsr. U can find out for yourself mate the easy way or the hard way.

i went with the VSR after an auto-electrician told me the piddly 11.5amps coming from the outboard won’t be enough to make the DC-DC charger work effectively. Remember I have both batteries as lithium. Would I wire the DC-DC as if the starter was lead acid?

[Darren J]

i went with the VSR after an auto-electrician told me the piddly 11.5amps coming from the outboard won’t be enough to make the DC-DC charger work effectively. Remember I have both batteries as lithium. Would I wire the DC-DC as if the starter was lead acid?

Chris,
I would query the auto elec advice. DCDC chargers work well on lower current inputs. They take what is supplied and step up to the required voltage and then output as much as is available in terms of current. Eg. Any redarc DCDC that takes a solar input often will get 10a or less, but they continue to keep charging r ok the max output available.
If anything the auto elec thinking 11.5 is not much for recharging is be correct, but you can only top up with what you make... I would think the vsr, however it is set up, is more about prioritising the charge order, but it doesn’t seem to be achieving that how you want.


Sent from my iPhone using Tapatalk

[stevej]

I’ve only ever seen lithium’s used with a dcdc to charge the second battery

I doubt you alternator is enough to charge a second battery unless doing big multi hour runs
it’s just enough to cover capacity used to start the battery dash gauges lights radios and also to run the engine as it draws in some of the alternator output to run itself

i tried a vsr with my 50 hp Yamaha with a 16 amp alternator and it wasn’t enough to add any capacity to the electric outboard second battery so removed it and just charged back at home or camp

my understanding is if I went to a lithium electric battery which will draw up to 40amps input would burn out the alternator on the outboard

if your going lithium’s that can take bulk input charge 20 amps for cheap ones 40 plus for better ones

[NAGG]

Without going through all the previous replies - the big no no is running a leccy & sounder off the one battery - A leccy can pull 50 amps at a pinch ... that plays havoc with sounders.
Will your motor (via VSR) charge a lithium ...... I don't believe that outboards can as Lithium batteries want you to pump in the juice - hence why the use of DC/DC chargers .

Chris

[Lovey80]

Without going through all the previous replies - the big no no is running a leccy & sounder off the one battery - A leccy can pull 50 amps at a pinch ... that plays havoc with sounders.
Will your motor (via VSR) charge a lithium ...... I don't believe that outboards can as Lithium batteries want you to pump in the juice - hence why the use of DC/DC chargers .

Chris

Well so far the trolling motor even at full tilt, is having no impact on the sounder at at. I’ve only been out in it for two short days and so far so good.

On the outboard charging. The short answer is absolutely yes the outboard will charge the lithium’s and it does. (Another member has been running a Winston start battery for 3 years without issue) It’s just not a very large output in my case with a little 60 Suzuki. From memory the couple of hours the outboard was running constantly it saw the batteries go from around 13.05v to 13.25v.

It was my understanding the need for dc2dc chargers in cars comes from paralleling a lead acid battery and a lithium together is problematic for one or both the batteries (also they provide the correct charge profiles for lithium’s). In my case they are both lithium. Adding a dc2dc charger won’t help my cause in the sense that the lithium/s wont see more juice as the dc2dc will have no where to get it from like it can in a car with a large alternator.

[Darren J]

I believe the DCDC is about correct voltage to suit the particular battery type. Specifically when people run a dual battery and the second battery is agm/lithium/calcium etc. They can require a higher voltage to fully charge, plus often the longer cable runs when relocated results in further voltage drop to be overcome. They will charge on lower voltage, but never properly and never reach 100%.

As a secondary function the DCDC acts as an isolator between start battery. Negates the need for a vsr. Fine on a Landcruiser, alternator pumps well over 100A, so when charging starts, both the start and secondary batteries can be charged.

Lithium’s can take on charge at a much higher rate, (one of their advantages, faster charging) but I understood they did necessarily need that every cycle. Someone might correct me if that is wrong? Lithium’s see charged and maintained by solar all the time. Never with big current supplies.

So a dcdc if used would be about proper voltage for the batteries, not “more power”.
Assuming the boat gets daily access to 240v, would it make sense to have a manual switch option to prioritise what is charged, typically do the start battery as much is needed, then top up the second when it is thought to be needed or available, say on trip where heavy use is expected. This switch could be after a dcdc set for lithium. It sounds like the outboard would do a lot of starts without any charging? This way you can prioritise where the small amount of charging output goes, depending on the specific use and trip you are expecting.

Service and maintain both batteries to 100% top up charge on 240v at home.

From what I have seen, charge at home is what most guys with big electrics (36v) are doing. I didn’t think they were charging on water, but I may be wrong.


Sent from my iPhone using Tapatalk

[Darren J]

Chris, to add, dcdc is definitely not just because the batteries are different types. It is about getting correct (higher than alternator) voltage g Th I specifically suit the battery chemistry.

Also don’t confuse the higher charge voltage a lithium needs, and their ability to take on higher current than other battery types, to mean the lithium will only charge with high current. High voltage but lower current gets it charged, just slower. Low voltage and high current never charges it properly.

Batteries will charge on lower than optimal voltage, just never to 100% full. in time that will also shorten the battery life.


Sent from my iPhone using Tapatalk

[Lovey80]

Thanks for the input Darren.

I’ve just installed an Enerdrive 40 Dc2DC in the truck as it has a solar panel and it’s working great so far.

The strange thing about the boat set up is the Victron charger (lithium profile) charges at 14.2v with reducing amps on the absorption phase then knocks back to 13.5amps on float. So after a night of charging the batteries are sitting on 13.5v. On the Victron forums on FB they’re telling me the batteries are at least north of 95% after this charge profile is complete and to not think of the SOC in terms of voltage in the same way as you would a lead acid or AGM.

The outboard is putting out 13.8v to both batteries. Day 1 I did very little running of the outboard (under an hour) and day 2 got about 2-2.5hours worth. The shunt accounts SOC as purely the Ah used since the 100% reset and was telling me the house battery was at 60%. This doesn’t account for any charging done by the outboard. So for the 163Ah battery I’d used 65Ah over the two days. Yet it only took 2 hours on the 15A charger to finish the full charge profile and be on float. This tells me the outboard has put in somewhere around 30-35amps over the say 3 hours of outboard run time. Which lines up pretty closely with what Suzuki says the outboard has available after running itself (11.5a).

I’ll be as religious as I can about charging both batteries on 240v each night and hope I don’t fry the stator.