Replace genset with lithium batteries and a inverter...

[jmauld]

Just ordered four 280Ah cells from docan.

Now to start researching the BMS options.

 

[ttmott]

Just ordered four 280Ah cells from docan.

Now to start researching the BMS options.

Take a look at Overkill Solar's BMS - 120 amp continuous 4s 12 volt. Has low temperature and high temperature shutdown. Doesn't have a CAN Buss interface but a very good Bluetooth App interface.
They do have a USB interface for like 11 bucks.

 

[jmauld]

Without that can bus can it interact with victron equipment?

 

[ttmott]

Without that can bus can it interact with victron equipment?

It may but work involved but then again even if you were able to establish comm will Victron read it??? Victron uses several protocols of each are specific to a device/use. Here is some info for you -
https://www.victronenergy.com/uploa....pdf?msclkid=51c22d77af8a11eca239aaf5876af954

 

[jmauld]

I went back and forth with a few BMS units and eventually landed on the overkill unit. The iPhone interface is pretty nifty. I considered the rec BMS but couldn’t justify the expense or complexity.

My plan is to run my house loads through the BMS while the bow thruster and windlass will bypass it. The BMS will be able to disable these devices by incorporating it into a control loop with their solenoids.

After top balancing the cells, I’m currently discharging them to get an idea of their capacity.

I’m not 100% sure what I will do for a box yet. I’m leaning towards not using “active” compression on the cells since I will never cycle these cells 2500 times. I will probably do a fitment with them at 80% charge and use flexible busbars to account for any movement from discharging.

 

[jmauld]

Okay so one thing I do not like about the BMS is that it does not consistently track power in and out. It does sometimes. But then it will recalculate based off of cell voltage.

I’m not sure that it is the BMS or the app on the phone that is doing this function.

*I can’t complain too much due to the price.

 

[jmauld]

I’ve been making some progress on my battery build. Almost finished. Just need to order a terminal or distribution block.

Here are some progress photos

Also I’m looking at my never before used vacuum and I notice that this spot under the aft couch has everything I need. It has a 4/0 cable running from the current batteries to the bow thruster. I could cut that and stick the lifepo4 battery right on there. There’s also a 120v outlet for me to plug my 15A charger into. Plenty of space for more batteries too.

 

[douglee25]

How much of a concern is fire or explosion with lithium batteries this size?

I have a little side hobby with remote controlled cars. They use Lithium Polymer (LiPo) batteries. There is a risk for explosion or fire and they must be charged in special fire 'bags'.

Just curious.

 

[hughespat57]

LiFePo4 is Lithium Iron Phosphate considerably different chemistry the LiPo (properly Lithium Ion)
LiFePo4 is not quite as energy dense but much safer more stable.

 

[jmauld]

I’m not sure that I agree with this yet but some people argue that the lifepo4 batteries are as safe as agm batteries. They also do not off gas as much while charging, so they can go in the living quarters. I’m still doing what I can to make sure they stay within operating parameters.

they are considerably safer than lipo.

 

[jmauld]

If your boat (mine is this way) has twin 30 shore power inlets, you have to choose which AC bus your going to power off the inverter, or make some changes to you MDP AC wiring to limit what loads can be powered off the inverter. Its actually fairly easy to do. This is one of the limitations of the Victron Energy inverters, and the main reason I chose to go with a Magnum Energy MS2812 (it is capable of switching dual 30A AC shore power). And I really like the Victron stuff. I purchased a 24V Multiplus to replace the Magnum, but in the end, it was just a little to much to deal with to make it work. Like I said, lots of sub optimal choices...

I'm not following your comment about "capable of dumping over 500A, so it should run the bow thruster"??

One of the design criteria is you have to account for your largest load and design the battery system to handle it. Usually LiFePO4 batteries are limited to about 200A continuous, and 250 intermittently (like a few seconds), depending on the BMS you choose. You can parallel/series to account for this, but again, space, and proximity to all the components becomes an issue.

Is that inverter capable of starting your ac?

Did you create a panel to separate inverter and non-inverter loads?

did you purchase a Multiplus or a Multiplus ii?

 

[dtfeld]

My inverter in capable of starting my ACs, but they are not connected at this time. However, when I do, I intend to use a soft start to reduce peak load. I’m looking to be able to run the front 8k btu only for about 6-8 hours.

As to wiring, you can separate out a “sub panel” if your inverter has an ATS. Look at Tom’s schematic on page 2.

http://www.clubsearay.com/index.php?threads/inverter-install.89992/

 

[jmauld]

How much of a concern is fire or explosion with lithium batteries this size?

I have a little side hobby with remote controlled cars. They use Lithium Polymer (LiPo) batteries. There is a risk for explosion or fire and they must be charged in special fire 'bags'.

Just curious.

 

[douglee25]

Sucker got hot!

 

[jmauld]

I was thinking this winter would be a good time to finish the inverter install. I think the Multiplus ii is the best option for me, but it’s a big sucker and finding a place to mount it in the cabin is more problematic than I thought it would be. There looks to be room under the aft sofa/bed for two battery packs and the Multiplus II, but there’s a warning against mounting the inverter in the same compartment as the batteries in marine applications.

I’ll keep digging apart compartments, but if you guys have any thoughts on mounting locations or an alternative to the Multiplus II that has similar functionality, please let me know. The engine room is not an option for me due to the gas motors.

EDIT: it looks like that Magnum Energy MS2812 that dt posted would work for me. I’ll spend some time reading through its manual.

 

[jmauld]

Doing more reading, the Multiplus II 2x120 bridges the neutrals together internally. Which poses a problem when plugged into shore power where the neutrals should remain isolated from each other. What am I overlooking here?

seems like the easiest solution is to keep the inverter on the generator side and use a charger from either the lead acid battery banks or shore power.

 

[km1125]

.... There looks to be room under the aft sofa/bed for two battery packs and the Multiplus II, but there’s a warning against mounting the inverter in the same compartment as the batteries in marine applications. ....

You could check with the manufacturer, but typically that is assuming the batteries are some type of lead-acid, most likely flooded lead acid where the fumes from the batteries can destroy the inverter in a short period of time. That would not be the case with Lithium or even SLA.

 

[jmauld]

You could check with the manufacturer, but typically that is assuming the batteries are some type of lead-acid, most likely flooded lead acid where the fumes from the batteries can destroy the inverter in a short period of time. That would not be the case with Lithium or even SLA.

That’s what I was thinking. Just wanted to get some feedback from some of you before asking a stupid question to the manufacturer. I also kind of suspect the support person will just restate what’s in the manual.

 

[Nater Potater]

You could check with the manufacturer, but typically that is assuming the batteries are some type of lead-acid, most likely flooded lead acid where the fumes from the batteries can destroy the inverter in a short period of time. That would not be the case with Lithium or even SLA.

Unless it's because the inverter utilizes some form of relay that could potentially ignite the combustible fumes from the lead-acid batteries. IIRC, someone mentioned early on that most inverters are not ignition protected and shouldn't be installed in the bilge for that same reason.

 

[ttmott]

Doing more reading, the Multiplus II 2x120 bridges the neutrals together internally. Which poses a problem when plugged into shore power where the neutrals should remain isolated from each other. What am I overlooking here?

Unless it's because the inverter utilizes some form of relay that could potentially ignite the combustible fumes from the lead-acid batteries. IIRC, someone mentioned early on that most inverters are not ignition protected and shouldn't be installed in the bilge for that same reason.

Only for gasoline powered boats.
The battery separation is for corrosion and hydrogen gas accumulation.
Another consideration is the inverter has an operating temperature range which discourages installation in an engine room.
The connection of the neutrals on the boat (inverter) on dual power sources can become an issue if the dock power is ground fault protected. The return current is now combined and can be higher or lower compared to the individual L1 and L2 legs which will trip the protection at the dock. I'm a bit suprised Victron didn't switch the neutrals also. In light of this I'd move to a Quatro which can integrate not only the batteries and shore power but also the generator.