Adding a Forth & Fifth LiFePo4 Battery

Adding a LiFePo4 Battery

We have a 300Ah of 12.8v LiFePo4 Battery Bank consisting of 3 100Ah 12.8 Batteries in Parallel.

Because we have the power, we're converting our Propane Gas Cooker to an Induction Cooktop and an Air Fryer Combo Oven. That's a bit much for 300Ah, even adding one more battery would make a substantial difference.

Our 3 batteries can be charged at 50Ah each, or 150Ah and that is less than the output of our 100Amp Alternator. Although, when we had the alternator tested a couple of years ago, the shop ran it up to 150Amps and we have it tuned down to 75% by our Balmar 618 external regulator.

Ok, so what do I need to change in order to add a 4th or even a 5th battery.

First all of the batteries have to be similar. The original are all Chins 100Ah 12.8v Smart LiFePo4 Batteries and they only have around 30 cycles out of 2000+. I have just purchased 2 identical batteries. When they arrive I'm going to disconnect the existing 3 batteries, charge the new battery with an standalone charger and then put all of the batteries in parallel for 24 hours. They should balance out within a few millivolts of each other. Then I'll reconnect the batteries.

The fuses in the Positive lines are to protect the wiring, so they will limit the Amps below the Ampacity of the existing wires.

Adding the additional batteries should not be an issue. We're not looking to get higher ampage, but more Amper hours. ie. The ability to run our Inverter to power our Air Conditioner or our Electric Induction cooktop or the Air Fryer combo for a longer time.

Where to locate the new batteries?

This is a challenge, the existing battery box is not large enough to add any more batteries, so they will have to be located elsewhere. There is a storage area immediately forward of the battery box, it's currently used for fluid storage ( Oils and Greases ) and a few miscellaneous things, easily moved to a new location.

How to connect the new batteries.

The cables from the Bus Bars must all be the same length to each battery. So I'll make up 2 sets of Positive cables and negative cables to match the length of the existing cables. 

In order to keep the wires all the same length, I'll update the wiring to the following diagram.

The Battery +ve cables will all be the same length and so too the -ve cables. I may have to make all new cables if the existing cables are too short to reach the new battery terminals. 

The Battery On/Off switch will be replaced by a 1,2,Both,Off switch. The new Busbar will have similar 100A MRBF fuses just like the existing +ve Busbar. This will allow isolation of either of the battery banks.

The new Switch should fit inside of the hole for the existing switch and it can be flush mounted, should be an easy swap out.

The terminal block fuses are 100Amp MRBF fuses

However, the Alternator has a max output of 100Amps and the Victron Multiplus has a max charging current of 120Amps. The Multiplus has a max output of 3KW but we'll never normally reach the max, the Multiplus would draw 250Amps at Max inverter output.

Using the BoatHowTo website wiring calculator, it confirms that 4/0 AWG cable size.

I need to check the cables to the Inverter. The Ampacity of 4/0 AWG is 300amps. So that wire size would be good. The connections on the Multiplus are M8 Bolts. I have a hydraulic crimper that has M8 crimp dies ( for lugs that have a 8mm diameter).  

Expensive! 4/0 Cable is required to go from the Connection to the System all the way from the Battery Selector Switch. That's about 10' or 20' round trip. Checking online, 20' is about $180 but have to get 30' ( 15' +15' ) just to ensure there is enough cable and that's $270 ( 15' of 4/0 Red & 15' of 4/0 Black, I could not find Yellow on Amazon, but did on the Pacer Group website, and it is available by the foot and is local in Fort Lauderdale. Win Win. 

So the switch and the fuse terminal blocks will be from Amazon and the cable will be from Pacer Group.

This is coming together nicely.  I contacted Chins about the 5 batteries in Parallel and they advised that I follow the procedure I had described above.

Now I just have to wait for the arrival of the Chins. They are shipping from California and it is Holiday week ( Christmas ) so I don't expect them for at least 7 days. Of course, then it will be New Years mid week, so that might delay them a few more days. So it looks like they will arrive in January, I'll order the other items then and should be able to put this all together by the end of January.  Then it will be time to remove the Propane system. I'm actually getting excited to be making this upgrade.

I'll add a link here to the next post on this project.

See you on the water!

Paul

New Dock - New Fenders

Our new dock needs a big fender

The old dock height was a bit lower than the new dock ( hey, this is South Florida and just about every dock rebuild results in raising the height of the dock to maintain the structural integrity of the Sea wall), and the tidal range is also slightly higher ( closer to the coast ).

So I purchased an Inflatable Fender from Amazon. A friend had purchased something similar for his 44' Tollycraft before starting in the Great American Loop and by all accounts is still going strong.

I chose the long cylindrical version and must admit it's pretty good for $100.

The fender seems really well made, welded seams, strong attachment points ( SS D-Rings ), however!!!

The inflation valve is not the same as on our Zar Dinghy and I have an adapter for the Zar on our Electric Inflator pump, it does not fit the valve of the Fender! Grrr. The nearest I could find was on Amazon.

It does not fit with that Orange seal, but I replaced that with an 'O' ring and that works just fine, the leakage from the valve during inflation is not enough to be any issue at all.

I'll have to figure out an easy method of switching the adapters over from the Fender Adapter to the Dinghy Adapter, right now I'm using Gorilla Tape It's not that we use the inflator pump that often.

My only concern is that the material (PVC) may decay due to UV in the South Florida Sun, so time to upgrade the fender before it's first use.

Using Sailrite Boat Blanket material, I made a cover that includes most of each end.

It's a simple cover, darts at the ends to wrap it around the curved ends and 2" Velcro Hook material to close the cover around the fender.

The plan is to hang the fender over the edge of the dock between two pilings.

We'll only take the fender with us if we are planning to raft up with another boat, that's typically about once a month.

All of our other fenders are covered in the same material. It has lasted without any deterioration since 2016 = 8 years. So the new fender should last.

The result is impressive enough that we'll buy a second fender, I have plenty of the material to work with.

See you on the water.