Alternator to LFP Bank or Start Batt?

[Martin S]

You are asking one of the key questions of a lithium installation, how to protect the alternator if the BMS triggers no charging of the lithium bank. I have go as far as research and design and like you I am uncertain of the right approach. Like many my design kept a lead acid starter, had the alternator connected to it and then fed from the starter to the lithiums with multiple DC/DC chargers. Whilst this seems the safest, it is a poor solution for charging the lithiums that can take rapid charging. I like your solution if it provides robust protection of the alternator. Some of the language in Charlie J s reply I did not understand, can someone spell it out without the acronyms. Any other comments on the robustness of the system.

[robertwcass]

Originally Posted by Poeme

With the intention of installing an LFP house bank, I recently upgraded to a Balmar SG200 monitoring system as well as their MC-618 regulator...all controllable and programmable with Bluetooth. To charge the start battery I'd be connecting the lithium bank to the start through a DC-DC charger (Victron Orion, also BT programmable).
I bought the Balmar items to carefully program the regulator and monitor the lithiums, with the alternator B+ going to them first...while letting the DC-DC charger keep the start battery happy. My thinking was that the start battery really needs no in-depth monitoring, just an eye on voltage.
But do I have this backwards?
The Victron manual schematics have the alt going to the start battery first, as well as many YT installation videos, which btw seem all to be van installations. It would be the Victron then that controls the charging of the LFPs, not the Balmar regulator.
Seems this would obviate the need for having upgraded to the Balmars.

I have a Balmar APM-12 on the alternator to protect it from LFP disconnects and Balmar tech support tells me this is adequate. OTOH it does make sense as additional protection to have the alt go to the start first as a load dump...I get that...and I presume I'd be able to monitor the lithiums through the Victron Bluetooth app. But...is one way clearly better than the other?
(BTW...120amp Balmar alternator, 300ah of Battle Born LFPs)
I appeal to the forum for your advice!

I just did this on my 1987 C&C 35 MK3. I used 2 12v Ampertime Plus 200ah batteries in parallel. I didn’t want to spend thousands upgrading my little yanmar 30gm belt system and purchasing a new alternator and regulator so I have my alternator connected to the start 12v lead acid. Connected to the start battery is a Victron 12/12 dc/dc charger which connects to my LiFePO4 bank, via a Busbar, which provides 30 amps while motoring. I have 2 200w 24v rich solar panels above the Bimini, each separate Victron controllers and a LG 335W 12v panel on the dodger, also connected to a separate Victron controller. This set up is way more affordable and provides all the charging I need. Eventually I will upgrade the engine pulley system, then later I will add a larger alternator and regulator. Or maybe not as I have yet to need anything more than what I have. I also added a 3000w Renogy inverter that runs all my power tools etc. The Ampertimes 12v 200ah pluses were $750 a piece. Good luck with your install, you will love it.

[Stu Jackson]

You guys continue to reinvent the wheel.


Have you read this?


https://marinehowto.com/drop-in-life...ated-consumer/

[donradcliffe]

I am going to deliver a Pac Cup boat back from Hawaii, and have been checking out their "upgraded" electrical system. The alternator charges an AGM start battery, with a voltage controlled combiner relay to charge their new (drop in 200 ahr brand X) LFP house battery. They also have 350 watts of solar hooked to the house. House load is a 12v fridge, plus navigation and LED lighting (no big current requirements). They upgraded the alternator to an 85 amp internally regulated one.

They have left the boat unplugged at the dock for over a month, and the solar is keeping everything charged. They have also done a mandatory 24 hr sail, and came back with full batteries.

It looks like the system will work, but I have been pushing them to test the alternator at the dock when the house battery is heavily discharged. After watching the youtube of the smoking alternator and seeing Mainsail's burnt up ones, I am REALLY pushing for a test where the alternator is putting out max output for at least an hour at various RPM, while monitoring charging current, alternator temperature, and voltage drop across charging wires/connections.

They are weight limited, and budget limited, but I don't want them to ruin their race
(or my delivery) with a broken electrical system.

[Stu Jackson]

Originally Posted by donradcliffe

..........




It looks like the system will work, but I have been pushing them to test the alternator at the dock when the house battery is heavily discharged. After watching the youtube of the smoking alternator and seeing Mainsail's burnt up ones, I am REALLY pushing for a test where the alternator is putting out max output for at least an hour at various RPM, while monitoring charging current, alternator temperature, and voltage drop across charging wires/connections.



.............................

Don, I think you already know the answer to that question, and it is very wise one to ask. Of course, at the dock for a month "load" is quite different than "at sea" "load."


Also, an 85 A alternator sounds suspiciously like a Hitachi, simply because of the rating. And we all know their shortcomings.


Good luck, I hope they listen to you.


Safe journey.

[donradcliffe]

We tested the Pac Cup boat electrical system yesterday. The results were surprising, but shouldn't have been.

After drawing down the 200 ahr LiFe battery by 115 ahr, we started the engine. The battery combiner kicked in after 15 seconds and started charging the house battery. According to the Victron battery monitor, it was charging 20 amps at 1100 rpm to1600 rpm. The alternator case got up to 120 degrees F, and stayed there.

Owner "That's about what the old smaller alternator did".
Me "Did you upgrade the wiring from the alternator to the battery?
Owner "Upgrade Wiring? "

The dumb 85 amp Hitachi was putting out 14.4 volts at its output terminal, just like it was supposed to. The Victron said the battery was at 13.5 volts at its terminals. The good news was the wiring was not getting hot where we could see it. However, there are about 15 watts of heat being given off somewhere in the wiring and connections.

Its a two cylinder 15 hp Yanmar, and the original wiring looks to be about #10. The ground wire looks even wimpier, but I am assuming the alternator is case grounded.

I told him that the energy budget for the boat should be about 100-120 ahr/day, and his solar has been putting in 80 ahr on sunny days. He could live with what he's got, but will have to plan on motoring 2-4 hours per day.

The owner is very nervous about making any changes this close to his start, and he is overwhelmed by all the other boat projects that have to be done. I am planning on putting an automotive jumper cable on the hot and then the ground side between the alternator and the battery terminals to see what a wiring upgrade would do.

[smac999]

Originally Posted by Poeme

Yes this stumped me a bit...a Battle Born battery's BMS is internal with no coms out. BB tech support was absolutely terrific as I considered these batteries...so will pass this dilemma by them asap. Hope I didn't jump the gun. Thanks for keeping an eye on me smac999...optimistic to get this safely up and running soon.
BTW, and for anyone looking in...Class T fuses are recommended for lithium installations...but Blue Seas is OUT of fuse blocks for fuses 200amp and under. West Marine here has had them on back order since February. Supply chain issues I was told, can't get them manufactured...
Suppose I can continue with my ANL type in the meantime?

I have not seen class t fuses in stock for over a year. I would put a Mrbf on each battery.

[Thebaysailor]

I recently installed 612Ah SOK bats and left in place one AGM (all 12 v.) for my starter, windlass and thruster. I wired alternator to one Victron MossFet 4 terminal isolator. This allows full alternator pass through while keeping AGM charged, SOK house bank charged (internal BMS in each if three bats) plus fully protected my alternator against BMS shut down. All lines fused, upgraded and length balanced. Balmar 160 on serpentine with remote Regulator.

[wingssail]

Originally Posted by Stu Jackson

You guys continue to reinvent the wheel.
Have you read this?

https://marinehowto.com/drop-in-life...ated-consumer/

Finally I decided to look at this guy's stuff. AMAZING!!

More detail and technical information than I have seen anywhere. Just spent a few hours on the article about "drop-in" batteries. I leaned more than I have about this subject than from reading in the forum or elsewhere for years. I sent him a donation, first ever for me.

Now, I have a question (which I asked him by email):

HOW DO WE DO PROBLEM DIAGNOSIS ON THESE NEW COMPLEX INSTALLATIONS?

I've been cruising and living aboard my boat for decades and even though I have a dead simple boat in every way (except sailing instrumentation, on that one I've gone a little overboard) I spend quite a bit of time diagnosing problems. And almost every electronic device I have had has failed at one time or another. In my simple boat it is still hard to figure out what went wrong when all you know is, "Gramps, my phone won't charge."

Now we'll have boats with multitudes of BMS's with voltage sensors, temperature sensors, FET switching devices, MPPT's, Regulators, DC/DC chargers, Isolators, combiners, and much much more. It seems like a big ask to expect that a normal boat owner or operator will be able to diagnose this stuff and fix it. I met a guy with a New FP Cat with a (9kW) Integrel Alternator system. Fantastic system, amazing! I quickly determined that he did not know how it actually worked, beyond the 5" touch screen controller. I said how would you figure out a problem? He said, "I'd call London and send them pictures of the touch screen". Wow! You'd do that in Papua New Guinea? Later, while still in my area, his system failed His big alternator was slowing down the engine and he could not attain normal cruising speed under power. London had a local electronics guy visit the boat, several times. They could not find the problem after a week. Last I heard they thought the alternator bearings were going out. BS I thought, you'd certainly hear that and I'd be surprised that it would slow a 66hp Yanmar much.

I can certainly see a future where there are a lot of boats sitting idle because something is broken and nobody knows what is wrong (or which FET somewhere screwed the pooch).

I know there are techy fan boys who say modern stuff doesn't fail, but I think I'll keep mine simple.

[SOLAR SUPPORT]

Hello everyone, Two months ago I completed the transition from LA to Lifepo4 battery. Instead of making many additional investments for a Lifepo4 battery installation that is safe, long-lasting and performance-oriented,

I canceled the alternator on the engine as an alternative solution. A new alternator with external regulator, dc-dc charger, voltage sensitive relays, Thicker installation cables, technical projecting and assembly work required for their installation were not necessary for me.

The amount spent on a Lifepo4 conversion designed to use alternator charging can be higher than the cost of Lifepo4 batteries.

With much less than this investment, I doubled the solar energy system power on board by using high performance solar panels and a new solar charge regulator also necessary.

Of course, I did not forget the engine battery. The existing engine battery is charged every day between 14:00 - 15:30 by connecting to Lifepo4 batteries with an automatic timer relay.

There are some additional benefits that come with growing your solar energy system adequately. I no longer use propane gas for the kitchen. In addition, I do not lose engine power for charging with the alternator and save fuel.

[PaulCrawhorn]

If just connecting lead to LFP for charging, the lead will never get to 100% Full.

Not a problem for cheap Starters I suppose, as long as you replace them more frequently than you usually would.

Smaller boats simply do not have room for enough panels to go cruising off grid solar-only, especially away from the equator in winter or running an all-electric galley.

[goboatingnow]

Why? Because, should the alternator get disconnected for whatever reason, it can fry everything connected (my balmar alternator is very inexpensive considering ‘everything else’).

Could we please stop this bogey man talk. The OP has comprehensively dealt with this issue by installing the Balmar protection device , it’s far more efficient and cheaper for the alternator to charge the li system and then use a simple low power BtoB charger for the starter

[goboatingnow]

Of course, I did not forget the engine battery. The existing engine battery is charged every day between 14:00 - 15:30 by connecting to Lifepo4 batteries with an automatic timer relay.

And what happens when the engine battery has a higher voltage then the Li bank.

[goboatingnow]

Originally Posted by wingssail

Finally I decided to look at this guy's stuff. AMAZING!!

More detail and technical information than I have seen anywhere. Just spent a few hours on the article about "drop-in" batteries. I leaned more than I have about this subject than from reading in the forum or elsewhere for years. I sent him a donation, first ever for me.

Now, I have a question (which I asked him by email):

HOW DO WE DO PROBLEM DIAGNOSIS ON THESE NEW COMPLEX INSTALLATIONS?

I've been cruising and living aboard my boat for decades and even though I have a dead simple boat in every way (except sailing instrumentation, on that one I've gone a little overboard) I spend quite a bit of time diagnosing problems. And almost every electronic device I have had has failed at one time or another. In my simple boat it is still hard to figure out what went wrong when all you know is, "Gramps, my phone won't charge."

Now we'll have boats with multitudes of BMS's with voltage sensors, temperature sensors, FET switching devices, MPPT's, Regulators, DC/DC chargers, Isolators, combiners, and much much more. It seems like a big ask to expect that a normal boat owner or operator will be able to diagnose this stuff and fix it. I met a guy with a New FP Cat with a (9kW) Integrel Alternator system. Fantastic system, amazing! I quickly determined that he did not know how it actually worked, beyond the 5" touch screen controller. I said how would you figure out a problem? He said, "I'd call London and send them pictures of the touch screen". Wow! You'd do that in Papua New Guinea? Later, while still in my area, his system failed His big alternator was slowing down the engine and he could not attain normal cruising speed under power. London had a local electronics guy visit the boat, several times. They could not find the problem after a week. Last I heard they thought the alternator bearings were going out. BS I thought, you'd certainly hear that and I'd be surprised that it would slow a 66hp Yanmar much.

I can certainly see a future where there are a lot of boats sitting idle because something is broken and nobody knows what is wrong (or which FET somewhere screwed the pooch).

I know there are techy fan boys who say modern stuff doesn't fail, but I think I'll keep mine simple.

Very easy to diagnose most electronics problems as the unit is dead !! Fixing it might be a lot more difficult

The fact is there are loads of boat owners that can’t fix lots of things , engines , rigging , etc this just another item to the list they can’t fix

[SOLAR SUPPORT]

Originally Posted by goboatingnow

And what happens when the engine battery has a higher voltage then the Li bank.

This was not a problem because the system voltage is usually in the range of 13.5 to 13.9 volts during the hours when the Lifepo4 batteries and the engine battery are connected. To disable the alternator, it is necessary to have a reliable and adequately powered solar power system. Lifepo4 batteries are also sufficient in terms of capacity and efficiency.