Removed extra start battery. Replaced FLA house with Lithium

[Captain Starbucks]

In effort to make my boat a better fishing and camping tool, I've put her on a diet and boosted the juice.

I've never quite understood why boats with an option to parallel a house battery for engine starting also have an extra start battery. Seems like a lot of extra weight. I chose to remove the extra start battery and buy a brand new start battery. I bought flooded lead acid of the same size that was removed, but the most powerful one I could find. So now we're down to just two batteries, start and house.

Next, I removed the heavy FLA house battery and replaced it with China's finest 100 AH with built in Bluetooth. It's a Vairer brand found on Amazon for about $275. I'm not saying this battery was good or not, just saying I bought it and it's working well so far. It does have it's own shunt and has its own app so no need for a Smartshunt. I will say though, the Victron Smartshunt that I have for the 36 volt trolling motor bank is superior.

Now that I've chosen to different chemistry types of batteries that are going to be charged in the same charging system, it was time to figure out how to get them both safely charged. I opted for the Smartshore Marine (formerly Yandina) Combiner 100 Lithium. This device is a simple combiner that knows to combine the batteries when it detects charging, and separates them when it detects no charging. Simple as that and it's only $130 and light. The difference in the lithium vs not is the lithium combiner disconnects at a slightly higher voltage.

Aside from having the stern of the boat a little lighter (about 70 lbs), the biggest difference I notice is on the electric reels and overnights. I fish usually 600-800' deep and with the old battery setup, the reels would start to slow after fishing a hot spot for 20-30 minutes. Not bad, just start to slow. I'd start the engines and once the previously installed Blue Seas combiner closed (not available in lithium) the reels would sing. Now with the lithium, the reels sing full speed the entire time. Plus it's nice watching how many amps the reels are pulling and battery power with the frustrating built in shunt app.

Overnights, we only get the battery down to upper 80%. Granted, this is summer time and we're not using much power just a few lights, charging devices and running the diesel stove/heater all night.

Another nice thing is that the lithium battery gobbles juice when charging. It's fully charged in no time flat.

I did have to buy a different battery mount. Same brand, only need the longer plastic bolts. Attwood All-Plastic Group 27 Hd Battery Tray (Part #9098-5 By Attwood Marine)

 

[WCF]

What is the current draw/charging rate of the house battery when drained down? Since you have an app/built in shunt, I assume you have some numbers.

I tried to use a similar ACR with a similar setup and did not feel comfortable with the load on the outboard's charging system and how often the relay switched. Maybe just particular to my setup though.

 

[jkidd]

So how do you handle the near zero internal resistance of the Lithium battery?
You can burn up the stator.
The stator will deliver enough voltage to charge a flooded lead acid battery and can't charge an AGM or a Lithium battery to full capacity. It would eventually damage the agm battery unless you top it off with a charger on a regular basis. The Lithium battery likes being ran between 10% and 90% you will just lose capacity.

Please tell us why you choose to not use a DC to DC charger.

 

[T.R. Bauer]

My concern with any LIFEPO4 setup is frying the wiring and the alternator. It is enough of a concern that it has made me pause with installing one in my RV and live with the commercial FLA configuration I have now. With that said, I have an LIFEPO4 on my boat too for a house battery, but my ancient old charging system only puts out 10 amps per outboard....no concern with wiring or anything else because it doesn't do anything....pretty pathetic system really. Does that bluetooth shunt feature limit the charge amps as well as discharge? If so, that is pretty cool.

 

[WCF]

My concern with any LIFEPO4 setup is frying the wiring and the alternator.

This should not be a concern if you are using a configurable DC-DC charger. It does however add to the cost of using a LiFePO4 battery.

 

[thataway]

I am concerned with the voltages involved, that is does the engine "Alternator" put out enough, with out damage. The web site is not clear, but states:

Combiner 100L (For Lithium Batteries) switches
to charge mode when the Lithium battery being
charged reaches 13.8-Volts

. My confusion relates to the concept that the Li battery has to reach 13.8. It should be the engine start battery which gets to xxx voltage and then combines. As noted, there is very little resistance in the Li battery.

You have the Tom Cat with 2 150 hp engines. It is customary to have one engine start battery for each engine. Then you can have as many house batteries as you wish. Those engines can put out 35 amps at normal cruise speeds, and 50 at WOT.

The battery charger DC to DC--is to protect the engine charging circuit (alternator vs stator). From what I read, your Motor used a stator type of system, with the magnets in/on the flywheel. It is possible that your outboard each has two outputs per engine-one is the main charging circuit and the other is an auxiliary charging circuit,

AND for the DC to DC, to give appropriate amount of current to the li battery to their charging profile, which is significantly different for the li battery.

What information are you getting from the Blue Tooth on your battery. I have used some of the cheaper batteries on my portable power supply I use in my SUV to run my freezer--keeping frozen food cold on way from store to house. Or if traveling, the main entree's for my diet. I check out Will Prowse's review on any battery. (For the two on the last 25, I used two 100 amp hrs Battle Born.). I used Victron 702, Victron Multiplus 2000, (inverter) 80 (charging amps) and 50 (boost amps). the charger was Sterling 30 DC to DC, which is user programable.

 

[T.R. Bauer]

My concern with any LIFEPO4 setup is frying the wiring and the alternator.

This should not be a concern if you are using a configurable DC-DC charger. It does however add to the cost of using a LiFePO4 battery.

You're right. My issue on the RV is where to put the thing out of the weather near the battery bank. On my boat with my whopping 10 amp charging system? Yeah....it get charged at home.

 

[Captain Starbucks]

I figured there would be a few questions on the install. I'll do my best to try to answer them.

Why not a dedicated Lithium charger? For one, you simply don't need one IF the lithium bank is separate from the house/start bank at rest. I will agree that a dedicated lithium battery charger is the way to go, but the reality is, you are just getting optimization. My electric car charges itself every time I back off the accelerator. Is that optimum for its charging profile? of course not, but it sure works.

What is the current draw/charging rate of the house battery when drained down? Since you have an app/built in shunt, I assume you have some numbers.



I tried to use a similar ACR with a similar setup and did not feel comfortable with the load on the outboard's charging system and how often the relay switched. Maybe just particular to my setup though.

The current draw I've seen up to 40 amps. The thing with the Yandina combiner is that it is constantly shutting off and turning on. It knows when it's getting warm and simply turns itself off. On the built in shunt on my house battery, it will show charge, then no charge. A short while later, it shows charge again.

I don't understand what you mean by "not comfortable with the load on the outboard". If it's rated for it and so is the wiring, use it. That's what its there for.

So how do you handle the near zero internal resistance of the Lithium battery?
You can burn up the stator.
The stator will deliver enough voltage to charge a flooded lead acid battery and can't charge an AGM or a Lithium battery to full capacity. It would eventually damage the agm battery unless you top it off with a charger on a regular basis. The Lithium battery likes being ran between 10% and 90% you will just lose capacity.

Please tell us why you choose to not use a DC to DC charger.

To handle the near zero resistance of the lithium, I have a flooded lead acid in the circuit IN THE CHARGING CONFIG ONLY. I say that in caps because I believe this is the part a lot of folks don't understand. (there is no AGM in my circuit). So say both batteries are nearing capacity, the lithium's internal BMS battery monitor system says I'm full and turns itself off (which they do, that's the BMS part working) now the FLA is also at capacity and the primary battery in the system, it does what a normal lead acid does and dumps power to ground. No issues at all.

I am concerned with the voltages involved, that is does the engine "Alternator" put out enough, with out damage. The web site is not clear, but states:

Combiner 100L (For Lithium Batteries) switches
to charge mode when the Lithium battery being
charged reaches 13.8-Volts

. My confusion relates to the concept that the Li battery has to reach 13.8. It should be the engine start battery which gets to xxx voltage and then combines. As noted, there is very little resistance in the Li battery.

Bob, the way the combiner works from Yandina/Smartshore, is that when either battery in my start/house circuit gets to the 13.8 volts, the combiner closes the switch and puts them both in charge mode. On the flip side, when the engines (or battery charger) is shut off, after a few minutes both batteries disconnect and run in their own circuits. Start sits there and does nothing at all until I call for engine start. House runs everything else. Once I start either engine again, the combiner closes and starts charging again. Engine shut down, after a few minutes disconnects. Works just like the Blue Seas combiner, but just has a slightly higher resting voltage disco switch.

I believe Bob also asked about the info the Li app gives. I can get a screenshot later, but it tells the basics:

State of charge
Total battery voltage
Individual cell voltage
Current in/out
Power in Watts
Volt high
Volt low
Volt delta
Average volts
Battery cycles

Also via the app, the battery can be turned on or off meaning I can remove it from the system entirely. I can also have it in the system providing power, but turn off the ability to charge.

It also shows trends of charge history in volts and amps.

To further complicate the matter, my house bank, once detecting a charge, and when I throw a manual switch for a different set of reasons, adds in my 3 Alibaba delivered 65 amp hour LifePo4 12 volt batteries that run my 36 volt bow mounted trolling motor. This system also has its own shunt and it's own dedicated charger of sorts. It's not a charger, but a series parallel switch that allows my house bank to charge my 36 volt bank in parallel at 12 volts. When I disconnect the charging switch, the system goes into series mode automatically and delivers 36 volts.

All of this works beautifully. I'm not an EE but I do a whole lot of electrical design engineering and execution at work so this stuff is just plain fun for me.

Rob

 

[Captain Starbucks]

Here's a screenshot of the app that controls the built in shunt in the Viaer Chinese battery from Amazon. It works fine, but not nearly as smooth as the Victron app.


Here is a screenshot of the Victron app that controls the Smartshunt in my trolling motor battery bank. Here, it is in the charge config by showing 12 volts charge at the top. Once it's done charging, it automatically goes to 36 volt series mode through the Trollbridge 36.