Adding LiON to existing system

[PhysicsTeacher]

The YouTube Channel "Emily and Clark's Adventure" has been doing a series of tear-downs and reviews of cheaper LiFePO4 batteries. You can find the playlist at:


Also, Clark is a retired electrical engineer, I believe. He has developed a bank manager than can charge both lead acid and LiFePO4 batteries:

[C Buchs]

My batteries are set up like Starscream, one for starting and one for the cabin. I have a combiner that first charges the starting battery from the outboard then charges the cabin's battery. There is a charger that charges them both when hooked to shore power. They are both in the battery box aft of the galley.

I too am starting to need more power after adding a refrigerator. I'm thinking of adding a small lead acid battery inside the pedestal of my for a starting battery. Then I can free up the two Optima Blue Top batteries to run the cabin. This will require a new shore charger that can manage three batteries (this one https://www.amazon.com/gp/product/B08G3 ... X0DER&th=1 is $325), an additional battery (my ETEC 90hp says it needs 640CCA, $200 max, I haven't figured out what fits), and rewiring (I think I can use the combiner I have to connect the starting battery to the cabin batteries, I probably have the rest of the wire & connectors I'll need). So a $600 budget.

When/if I go LiFePO4 in the future, it will be in the cabin only. It will require a new shore charger, a DC-DC charger (to combine starting & cabin), and LiFePO4 batteries.

The Dakota Lithium batteries that say they can be used as starting batteries are about twice as expensive as the standard ones.

Starscream: What do you think of setting up a lead-acid starting battery to run your outboard and the LiFePO4 for the cabin?

Jeff

[Starscream]

My batteries are set up like Starscream, one for starting and one for the cabin. I have a combiner that first charges the starting battery from the outboard then charges the cabin's battery. There is a charger that charges them both when hooked to shore power. They are both in the battery box aft of the galley.

I too am starting to need more power after adding a refrigerator. I'm thinking of adding a small lead acid battery inside the pedestal of my for a starting battery. Then I can free up the two Optima Blue Top batteries to run the cabin. This will require a new shore charger that can manage three batteries (this one https://www.amazon.com/gp/product/B08G3 ... X0DER&th=1 is $325), an additional battery (my ETEC 90hp says it needs 640CCA, $200 max, I haven't figured out what fits), and rewiring (I think I can use the combiner I have to connect the starting battery to the cabin batteries, I probably have the rest of the wire & connectors I'll need). So a $600 budget.

When/if I go LiFePO4 in the future, it will be in the cabin only. It will require a new shore charger, a DC-DC charger (to combine starting & cabin), and LiFePO4 batteries.

The Dakota Lithium batteries that say they can be used as starting batteries are about twice as expensive as the standard ones.

Starscream: What do you think of setting up a lead-acid starting battery to run your outboard and the LiFePO4 for the cabin?

Jeff

Hi Jeff, I certainly thought about that. The criteria for this mod, for me, is minimum surgery on the existing system, and keeping set-and-forget functionality. I really don't want to remember to have to switch batteries depending on what I'm doing.

Right now, my #1 preference is to simply switch the existing two batteries to two of the 135A Dakota 1000 CCA dual purpose LiFePo4 batteries, and carry a jump-starter for the very unlikely situation where I burn through 270AH. In that case, I could do a simple swap, and leave the battery selector on BOTH for the rest of my life while saving 50lbs of weight. Essentially, I have to justify $3k CDN to never have to think about power or batteries again. It's tempting TBH.

[dustoff]

These two 26M owners' videos show how they upgraded their system to include Lithium Ion house capacity in pretty good detail. I can't recall either of them posting their stuff on the forum or Mods.





Maybe the site moderators can find a way to archive or add to the resources page some of this content or maybe just the hyperlinks if it hasn't been posted to this site by the original creators

Dustoff

[Starscream]

Mockup of the modified system, in action. New plan:

120V line from unused 120V shore-power breaker panel to a 2A NOCO lithium battery charger, for shore power charging of the lion.
2A NOCO battery charger wired to LION battery
Solar output switched from L.A. battery1 to the LION battery terminals.
Positive bus bar mounted to the battery (breaking some rule?), negative bus to follow.
Positive bus to D+ input wired through an on/off switch.
Positive bus and negative terminal to INPUT terminals of 20A DC to DC charger.
OUTPUT terminals wired to a small 5AH rechargeable battery I had lying around, measured about 3V so it's probably beyond rehab.

Voltage at the LION is 13.7, voltage at the dead battery is 12.84. So...working!!!?

I also embarked on an unscheduled project to bring good sound to the boat, so this setup will be convenient with a Garmin Fusion amp located adjacent to the LION battery. The Amp is very power-hungry and could quickly suck the main LA bank dry, so with this setup I can only run the amp if the LION battery has power; once it's discharged the amp will shut down. The Fusion Amp has to be located immediately adjacent to the battery with a 6ga (!) cable.

[Starscream]

Hi MacFolks, I am hoping someone can help me with a curious problem that I'm having with this installation.

I transferred everything to the boat, as is, except the little 12V battery on the output side of DC to DC charger, as that's where the main battery bank will connect. I wired everything up except the main battery bank...and:

As soon as I connect the NOCO 2A lithium battery charger, it alarmed out on over-voltage. I measured the LION battery terminals and... 15.7 V !!! I disconnected the NOCO charger, but the 15.7V remained. I disconnected everything, and the LION battery is back to 12.7. Weird. I traced all the terminals, and found 3V between the INPUT terminals on the DC to DC charger, like it had charged a capacitor. I shorted the input terminals out and the voltage between the terminals went back to 0. Then I connected the DC to DC back to the battery, and it stayed 12.7, no problem. As soon as I plugged in the NOCO charger, it alarmed out again and the battery voltage jumped back to 15.7V.

I'm wondering if the DC to DC must have a common ground on the input & output terminals, and/or some sort of load on the output side to prevent this? I have zero clue as to why this is happening and AI hasn't helped at all. Need some real MacAI, if someone knows what's causing this?

[Jimmyt]

Does the manual for the dc-dc charger say it can be powered up without a load battery connected? That would be my first guess at the problem. The charger looks at the load to regulate the process.

I would have thought it would have a safety to lock out if there wasn’t a load, but maybe not…. Sounds like it’s trying to charge the non-existent very dead battery, which doesn’t give any voltage rise over time (cause it’s an open circuit).

Also, look at what you changed from mockup to install…

Happy hunting!

[Starscream]

Does the manual for the dc-dc charger say it can be powered up without a load battery connected? That would be my first guess at the problem. The charger looks at the load to regulate the process.

I would have thought it would have a safety to lock out if there wasn’t a load, but maybe not…. Sounds like it’s trying to charge the non-existent very dead battery, which doesn’t give any voltage rise over time (cause it’s an open circuit).

Also, look at what you changed from mockup to install…

Happy hunting!

Thanks Jimmy...

The only difference is that this time I don't have the load battery. I'll put that battery back in for a test before I hook up the main battery bank.

It will definitely power on no problem without a load. The jump to 15.7 volts happens immediately when I connect the charger to the Lion battery, and then it stays at 15.7 even if the charger is disconnected. I wasn't expecting this behavior at all

[Be Free]

Hi MacFolks, I am hoping someone can help me with a curious problem that I'm having with this installation.

I transferred everything to the boat, as is, except the little 12V battery on the output side of DC to DC charger, as that's where the main battery bank will connect. I wired everything up except the main battery bank...and:

As soon as I connect the NOCO 2A lithium battery charger, it alarmed out on over-voltage. I measured the LION battery terminals and... 15.7 V !!! I disconnected the NOCO charger, but the 15.7V remained. I disconnected everything, and the LION battery is back to 12.7. Weird. I traced all the terminals, and found 3V between the INPUT terminals on the DC to DC charger, like it had charged a capacitor. I shorted the input terminals out and the voltage between the terminals went back to 0. Then I connected the DC to DC back to the battery, and it stayed 12.7, no problem. As soon as I plugged in the NOCO charger, it alarmed out again and the battery voltage jumped back to 15.7V.

I'm wondering if the DC to DC must have a common ground on the input & output terminals, and/or some sort of load on the output side to prevent this? I have zero clue as to why this is happening and AI hasn't helped at all. Need some real MacAI, if someone knows what's causing this?

This model dc-dc charger requires that both sides be at the same ground potential. If they don't share a chassis ground (unlikely in a fiberglass boat) then they will require that the ground wires on both batteries be connected.

See page 9 of the manual.

[Starscream]

This model dc-dc charger requires that both sides be at the same ground potential. If they don't share a chassis ground (unlikely in a fiberglass boat) then they will require that the ground wires on both batteries be connected.

See page 9 of the manual.

Thanks Bill,

I read about the common ground and that's how the final system will work. It was really odd to have a 12V battery in front of me and a DC charger with no power source or other connections, and find 15.7 volts at the battery terminals. It actually climbed up past 16 volts at one point, and stayed there with only the battery and the DC to DC charger connected. I still don't understand how that can even work...? I was literally measuring 16V across the battery terminals with nothing else other than two wires going to the DC to DC charger, with nothing on the output side of that charger. Hurts my brain. With the DC to DC disconnected, there was a 3V residual charge on the terminals...ok, I kinda understand capacitance but not how that residual 3V causes 16V at the battery terminals. I thought maybe the 120V lithium charger was triggering the battery BMS to do something weird, but with the 3V left on the disconnected DC to DC, that can't be it.

Ran out of time to finish the wiring today to see if it works with the output side of the DC charger connected.

[Jimmyt]

Thanks Bill,

I read about the common ground and that's how the final system will work. It was really odd to have a 12V battery in front of me and a DC charger with no power source or other connections, and find 15.7 volts at the battery terminals. It actually climbed up past 16 volts at one point, and stayed there with only the battery and the DC to DC charger connected. I still don't understand how that can even work...? I was literally measuring 16V across the battery terminals with nothing else other than two wires going to the DC to DC charger, with nothing on the output side of that charger. Hurts my brain.

The charger converts incoming dc to ac; then steps the voltage up or down as needed and converts it back to dc (simplistically speaking). There are capacitors (as you surmised), and all sorts of other components required to pull this off. And, it was designed to work under a given set of conditions. I wouldn’t be surprised that you saw 16 volts at the charging terminals for the load battery - without a battery connected (assuming that I understand what you saw; and the conditions under which you observed it).

There aren’t a lot of gadgets that I read and follow the instructions for. This would be one of those gadgets.

Here’s an article that might give a better explanation of their operation: https://wis-tek.com/blogs/knowledge/how ... arger-work

[Starscream]

Whelp... I connected the main bank to the output side of the DC to DC and everything works fine again.

I still can't imagine how the DC to DC just boosted my LION to 16+V... would mean that the LION should be accepting a charge from the DC to DC that had no independent power source? Or maybe the BMS on the LION boosted the voltage for some reason when the 120V Lithium charger was connected. Doesn't happen when there's an output battery, so false alarm. Appreciate the replies.

I added a 3-way switch to the output of my solar charge controller, so that I can choose to charge the main battery directly if I ever think I need to send the solar directly to the main bank instead of to the main bank through the LION and DC to DC, although I have a hard time imagining that condition. Since I had to wire the battery grounds together, I figured I might as well do that at the output of the solar charge controller, and was easy to add a 3-way on the positive wire.

The wiring on this 26X tho... it's getting outta control. Trying to document it but there are so many little details; fuses, switches, USBs, lights, that I don't know if I'll ever complete the docs. Here's what I have now.

Without having tested the system, I think I've successfully added about 80AH of LION (after charging inefficiencies) which will run down first to about 9V before my lead acid bank has to start contributing. All charging happens automatically, and the battery selector never has to be touched: starting is automatically on a Lead Acid Battery, and all house loads are automatically on solar, shore power, or the LION battery. The main lead acid bank can be charged via alternator, shore power, solar (solar requires a flick of a selector), or from the DC to DC charger powered by the LION battery, which is recharged via solar or shore power.

The D+ switch allows me to shut off the DC to DC completely for storage.

[Jimmyt]

Whelp... I connected the main bank to the output side of the DC to DC and everything works fine again.

I still can't imagine how the DC to DC just boosted my LION to 16+V... would mean that the LION should be accepting a charge from the DC to DC that had no independent power source?

Great! Glad it’s working!

Still not sure I understand what you had hooked up and where you took the 16 volt measurement. Was it at the terminals of your LIon battery? If so, was your 120 v charger connected to the LIon? If it was just the LIon and the dc-dc charger, then I’ll have to do some more looking..

In any case, glad it’s working!

[Be Free]

If I thought about it long enough I could probably tell you exactly why you got the readings you saw but it makes my head hurt to do that sort of stuff these days.

I can tell you that the lithium battery runs around 13V and you had a mystery 3V. That's probably why you had 16V at the battery but I can't tell you exactly where the 3V came from. I can tell you that most of the "stuff" that Jimmy was describing uses components that run on 3VDC so that's probably not a coincidence.

With the input and output of the converter calling different potentials "zero" you are lucky that you didn't lose any of the "magic smoke".

[Starscream]

Great! Glad it’s working!

Still not sure I understand what you had hooked up and where you took the 16 volt measurement. Was it at the terminals of your LIon battery? If so, was your 120 v charger connected to the LIon? If it was just the LIon and the dc-dc charger, then I’ll have to do some more looking..

In any case, glad it’s working!

Thanks for the feedback fellows.

Yeah, the LION battery read 16+V while it was only connected to the DC to DC charger, and there was nothing else connected to either the battery or the DC to DC. The situation was triggered when I added a 120V AC Lithium battery charger to the LION battery. Immediately the 120V AC charger errored on "high voltage" and shut down, at the same time that the LION battery voltage jumped over 16V. I disconnected the 120V AC charger, but the 16+V remained. I couldn't figure it out so I disconnected the DC to DC charger, which brought the LION back to 13V, but left a residual charge of 3V on the input terminals of the DC to DC.

I mean, it doesn't matter now that everything's wired up and working fine. It was such a weird situation I just couldn't understand the readings on the multimeter.