New Victron Multiplus install with Li Batteries

[scfoster]

Came across the posts by Steve Mitchell at SeaBits. Here is a description of the system he installed in his Beneteau, which is very similar to what I've envisioned.



A later series of posts last year describe the install in a power cruiser with Battle Born batteries.



I'm still trying to figure out the the pros and cons of using the Victron LiFePO4 batteries with the external BMS vs going with LiFePO4 that have the BMS embedded, like Battle Born.

[scfoster]

In engineering school they used to say "how do you eat an elephant" with the answer "one bite at a time".
There is a thread I'm following and posting to here.

So, I cancelled my Battle Born order and am starting over. I don't exactly know if I have to rip out the Xantrex Freedom 20 inverter/charger that came with the boat. It is capable of the 14.4V output that the Battle Born batteries would need. Once they are full, the BMS in each battery cuts off taking a charge, so a lower 'float' voltage would have no effect on them (the batteries), according to Battle Born.

Not so for the alternator. Right now there are two charging scenarios (1) shore charge which is controlled by a charging breaker onboard, and (2) engine powered charging via the Balmar 100A alternator with a MC-612 Voltage regulator and a Balmar DuoCharge.

Posted a question on the linked thread about whether the DuoCharge & MC-612 (regulator) would support charging a LiFePO4 house bank (Battle Born) with a FLA (flooded lead acid) engine start battery.

Chris, who works for Balmar, was kind enough to respond.

I ran this setup on our Wauquiez, but with a home brew LiFePo4 bank, and a sealed LA battery for start. It worked well, with a couple of notes.

1. Download the service bulletin from our website on programming a 614 to lithium. This was written for regs that were made before we added the LFP profile in software. The settings will work well for the 612 as well. Ensure that you have the voltage sense wire going directly to the battery post. It is a good idea to run the negative wire for the regulator to the neg battery post also: https://www.balmar.net/wp-content/up...nuary-2019.pdf

2. Wire up the Duo charge so it is turned on and off with your ignition.

Here is the diagram for the DuoCharge:

[scfoster]

Spoke to Balmar and they don't recommend using the DuoCharge as it will not adequately charge the engine battery.

[scfoster]

Cross post from this thread:

Battleborn has suggested charging voltages of 14.4v-14.6v. Lithionics is at 14.5v bulk. At either of these voltages, you will fully change a LA battery.

Actually, anything at 12.9v or up will fully change a LA battery, abit more slowly. At the low end of that scale, it will be very slow.

If you are using a traditional flooded battery for starting, you can equalize (with a shorepower charger) once or twice a year if you are worried about sulfation.

If your start battery is truly only being used for starting, it just does not get discharged much at all. Here is a video showing that from Mainesail:

https://www.youtube.com/watch?v=nrQX...ature=youtu.be

This is why the DDC, when used to charge a start battery from a house battery works well. It is not difficult to install, and is quite compact in size.

Chris

[scfoster]

I don't see why the DDC (Digital Duo Charge) won't work. I do spend a lot of time at the dock with shore power, so keeping the engine start battery will not be an issue.
Still going to add the Sterling Alternator Protection Device.
Going to go that route and see how it works. Worst case it's the cheaper battery that doesn't get charged. Per Chris' point it can be 'manually' charged a couple times per year for sulfation.

[scfoster]

Dropped the whole project until the boat is to be hauled out which is this coming week.
Purchased a Renogy 50A DC-DC charger with mppt, to allow for charging both batteries (engine and Li house) from the alternator. The bonus is this unit will also accept charge from solar panels.

[CharlieJ]

You know, of course, that by using one controller for all sources, you have simplified the system at the cost of introducing a single point of failure, aka, putting all of your eggs in one basket.

[scfoster]

Originally Posted by CharlieJ

You know, of course, that by using one controller for all sources, you have simplified the system at the cost of introducing a single point of failure, aka, putting all of your eggs in one basket.

On the surface maybe. Having a background in experimental flight testing at NASA and Boeing, I've been on the pointy end of failures. That's what ejection seats and parachutes are for.

The purpose of the DC-DC charger (DDC) is to provide power from the alternator through said DDC to both the engine start battery and the house bank, without blowing up the alternator.
With the included MPPT the solar cells can also charge both batteries.

If the DDC fails, then I can always bypass it to have the alternator directly charge the engine start battery. With a manual switch and the MC-612 (or 614) regulator including alternator temp sensor, I can also charge the house battery for short periods.

I would lose management of the solar power input but that's more of a nuisance, rather than dire failure. Given that I'm spending 99% of my time in range of a FedEx package, again it's not a failure mode that worries me.

The converse is also true. By increasing the number of individual components, with the associated wiring/connections. A LOT more failure modes are introduced than solid state electronics soldered to a board in a single box. Also, if said box fails, replace it. No troubleshooting connections required or figuring out which of multiple components has failed.

I do appreciate your input about this. People have to understand that when you decide on an approach, it can have unintended consequences, sometimes serious.

Always, always, always, check with experts on the subject. People that do it for a living. I can't stress that enough.

Charlie, thanks.

[scfoster]

Finally pulled the trigger and purchased from Battleborn:
3 100Ah batteries
Victron Multiplus 12/3000/120-50 120V
Cerbo GX
GX touch 50
BMV 712

Also got a Victron MPPT 100/30 to go with the (2) HQST 150W solar panels.

Previously purchased the Renogy DCC50S 12V 50A DC-DC charger with MPPT.

Modified the repurposed Victron schematic, to show addition of the solar panels.

Adding a bow thruster and electric windlass. Will more than likely power both from one lead acid starter battery since it will be in the bow area. Will need to figure out how to charge that battery from the alternator at the same time as the engine start battery.

[s/v Jedi]

Originally Posted by scfoster

Finally pulled the trigger and purchased from Battleborn:
3 100Ah batteries
Victron Multiplus 12/3000/120-50 120V
Cerbo GX
GX touch 50
BMV 712

Also got a Victron MPPT 100/30 to go with the (2) HQST 150W solar panels.

Previously purchased the Renogy DCC50S 12V 50A DC-DC charger with MPPT.

Modified the repurposed Victron schematic, to show addition of the solar panels.

Adding a bow thruster and electric windlass. Will more than likely power both from one lead acid starter battery since it will be in the bow area. Will need to figure out how to charge that battery from the alternator at the same time as the engine start battery.

Your main switch 3 at the starter battery.... add another one for the forward battery, connecting to the same point (alternator, dc-dc converter) as switch 3. Alternatively you can get an A, B, Both, Off switch and set starter battery to the A post, forward battery to B and the alternator to common. Normal setting would be Both.

[scfoster]

Originally Posted by s/v Jedi

Your main switch 3 at the starter battery.... add another one for the forward battery, connecting to the same point (alternator, dc-dc converter) as switch 3. Alternatively you can get an A, B, Both, Off switch and set starter battery to the A post, forward battery to B and the alternator to common. Normal setting would be Both.

Thanks.
The Balmar Alternator is paired with a DuoCharge so I'll probably set up the forward battery as the 2nd battery to be charged off the alternator.
The 300Ah LiFePo4 house bank will be charged using the Renogy DC-DC unit.

Forgot to mention purchased a Victron Blue Smart charger for the battery while connected to shore power.

[s/v Jedi]

Originally Posted by scfoster

Thanks.
The Balmar Alternator is paired with a DuoCharge so I'll probably set up the forward battery as the 2nd battery to be charged off the alternator.
The 300Ah LiFePo4 house bank will be charged using the Renogy DC-DC unit.

Forgot to mention purchased a Victron Blue Smart charger for the battery while connected to shore power.

Ah, no DuoCharge in your schematic! Still, the method with just a switch (or two) allows you to operate the windlass from the starting battery or to start the engine from the fwd battery as each provide a backup to the other and you can isolate one if it goes bad and use the other for everything temporarily

[scfoster]

Originally Posted by s/v Jedi

Ah, no DuoCharge in your schematic! Still, the method with just a switch (or two) allows you to operate the windlass from the starting battery or to start the engine from the fwd battery as each provide a backup to the other and you can isolate one if it goes bad and use the other for everything temporarily

Good points. I'm updating the schematic and will post.
The thought crossed my mind to forego a dedicated battery in the bow and just run monster cables from the engine bay (under the companionway stairs) forward to the windlass and bow thruster. 99% of the time, when I use either, the engine will be running.
Would also add a switch to allow engine emergency start from the house bank.
It's 22' straight distance from the engine start battery to the windlass, so about 25ft of cable.
200amps at 25' requires 3/0 cable. The bow thruster is rated for 370A so 400A to be safe.
I shouldn't have slept through those EE classes.

[scfoster]

Of course I could step up the voltage then step down at both ends, say 48V to reduce the wire size.
Anyone done that?

[DeValency]

Interesting development here... And it got complicated over time, even with my engineering background.

With my own upgrade to LFP, have decided, for now, to use a DC-DC charger from the existing (and to be staying for now) 300A AGM bank or the AGM starting battery to the new (additional) LFP 300A bank. One of the reasons is that i don't want to replace the alternator yet - quite strange how the Volvo-Penta TMD-31, 100HP originally came with a 65A alternator only.

The 50A shore power charger has three separate outputs each can be set for the required profile. The solar will continue to charge the house AGM bank (for now)

The bow thruster and windlass will continue to be connected to the AGM bank for now.

Will start moving 12VDC circuits to the new LFP and evaluate the impact on charging/discharging.

Trying to keep it as simple as possible.

- comments are always welcome!
Thanks