LiFePO4 reference diagram, Alternator version

[newhaul]

Originally Posted by chowdan

First - thanks all for the comments and help and information.

Secondly - i will not feed into arguments or debates about whats right or wrong and to each their own on how they operate their boat - just like to each their own if they choose to drive a vehicle on a freeway at 80mph when its posted at 60mph.


I am going to be operating a system as Jedi has posted but I will be using an argofet - with my discounts it is negligeable cost and provides me with a failsafe mechanism that removes the stress/worry that my BMS settings may be slightly off or I make an oppsie mistake. When/if i decide to replace the starter with LFP i will re-evaluate and go from there. It wont be a difficult thing to do.

Batteries arrive today in a few hours. I return to the boat tomorrow evening from house sitting + all my other work/tasks to do means that I probably wont be starting the build until atleast next week(unless i return to dead batteries - likely).

BMS settings I am planning on using are as follows(still under research/investigation)

Batteries: 8xEVE 314ah MB31 cells (spec sheet that was sent to me says they pulled 331ah) - 2 x 4 = total 628ah @ 12v each.
BMS: 2xJK BMS - 4s 200amp w/2amp active balancer + bluetooth and heating pad capable

Max voltage: 3.65v
BMS Over volt charge cut out point: 3.60v
Charger "complete" absorption voltage: 3.55v
Charger Float: 3.40v
Load low voltage cut off: 3.0v
BMS under volt cut out point: 2.88v
BMS single cell under volt cut out: 2.63
Min low voltage: 2.55v


These numbers will be multiplied by 4 for things like the multiplus, balmar, mppt to get 12v basis numbers/settings. I will be relying on the multiplus & the MPPT(and likely the DC genset regulator though it probably wont ever run that long to get there) to get cells to 3.55v - IE into float. May bump numbers up/down a bit to reduce stress on them as dead of winter time my 700w solar gives me a glorious 50w of power if i'm lucky.

Apologize for the thread drift, but figured others who come across this at some point in the future might like to see planned settings

On some days yes but on others if your panels are articulated like mine you should be able to get at least 400 watts out of a 700 watt array. I can get 150 out of my current 200 watts last winter.
Other days there was nothing .
When I add my other 400 watts I'm thinking of wiring in series to bump the input to 24v which should increase my output at 12v

[CaptainRivet]

Originally Posted by newhaul

Looks to me like one 30 amp dc2dc for each AGM start battery .
Look at the drawing the heavy red vs the thin red lines
The alternator is on the same positive busbar as the lifepo4 bank

Yes clear the alternator goes to main positive busbar and therefor charges directly house. from main busbar via fuse the DC2DC are connected.
Which way DC2DC are connected is not clear but it's either of the one I stated.
In this case a surge protector is needed if BMS cuts charge otherwise you get a big spike that also reaches the install and not only the alternator.
Another import point going via argofet is beneficial to his reference diagram as the argofet will keep the potential damage then to the alternator and the spike does not reach the install.

[newhaul]

Originally Posted by CaptainRivet

Yes clear the alternator goes to main positive busbar and therefor charges directly house. from main busbar via fuse the DC2DC are connected.
Which way DC2DC are connected is not clear but it's either of the one I stated.
In this case a surge protector is needed if BMS cuts charge otherwise you get a big spike that also reaches the install and not only the alternator.
Another import point going via argofet is beneficial to his reference diagram as the argofet will keep the potential damage then to the alternator and the spike does not reach the install.

You must have missed the balmar external regulator he has installed in the system . Bet it is programmed to stop charging somewhere below 14v so as to not have an HVD situation .

I suggest going back and study his diagram in more depth. It will answer lots of what if questions,.
It did for me

[chowdan]

Originally Posted by newhaul

On some days yes but on others if your panels are articulated like mine you should be able to get at least 400 watts out of a 700 watt array. I can get 150 out of my current 200 watts last winter.
Other days there was nothing .
When I add my other 400 watts I'm thinking of wiring in series to bump the input to 24v which should increase my output at 12v

My panels are 42v panels if i recall correctly. 350w panels(2 of them) with their own victron controller.

I am glad to see you have articulating panels! Mine are up high on an atlantic tower arch and I've been dreaming/thinking about modifying them to be articulating. We are on a mooring ball in Eagle Harbor and during winter i think we have about 3 hours or so where the sun is high enough that I suspect we'd be able to get somewhere around 350-400w out of the array depending on the day. Theres a month or two were the sun barely crests the ridge of the south side of the island. I've got a ton of different things i'm doing currently so modding the tower to allow the panels to articulate isn't high up there currently, but its definitely on the list of things I would like to do! Very happy to hear that it actually significantly helps output.

[newhaul]

Originally Posted by chowdan

My panels are 42v panels if i recall correctly. 350w panels(2 of them) with their own victron controller.

I am glad to see you have articulating panels! Mine are up high on an atlantic tower arch and I've been dreaming/thinking about modifying them to be articulating. We are on a mooring ball in Eagle Harbor and during winter i think we have about 3 hours or so where the sun is high enough that I suspect we'd be able to get somewhere around 350-400w out of the array depending on the day. Theres a month or two were the sun barely crests the ridge of the south side of the island. I've got a ton of different things i'm doing currently so modding the tower to allow the panels to articulate isn't high up there currently, but its definitely on the list of things I would like to do! Very happy to hear that it actually significantly helps output.

There is part of my advantage I am on a side tie dock in port orchard at railway panels mounted with sea dog rail mounts on my hard rail around the cockpit.

[s/v Jedi]

Originally Posted by newhaul

Looks to me like one 30 amp dc2dc for each AGM start battery .
Look at the drawing the heavy red vs the thin red lines
The alternator is on the same positive busbar as the lifepo4 bank

Exactly, he can’t even see where the alternator output goes nor understand that when the alternator charges the house batteries, that you don’t need a dc-dc charger doing the same from alternator to house batteries.

There’s two because there’s two of everything… redundancy

[s/v Jedi]

Originally Posted by chowdan

First - thanks all for the comments and help and information.

Secondly - i will not feed into arguments or debates about whats right or wrong and to each their own on how they operate their boat - just like to each their own if they choose to drive a vehicle on a freeway at 80mph when its posted at 60mph.

I am going to be operating a system as Jedi has posted but I will be using an argofet - with my discounts it is negligeable cost and provides me with a failsafe mechanism that removes the stress/worry that my BMS settings may be slightly off or I make an oppsie mistake. When/if i decide to replace the starter with LFP i will re-evaluate and go from there. It wont be a difficult thing to do.

Batteries arrive today in a few hours. I return to the boat tomorrow evening from house sitting + all my other work/tasks to do means that I probably wont be starting the build until atleast next week(unless i return to dead batteries - likely).

BMS settings I am planning on using are as follows(still under research/investigation)

Batteries: 8xEVE 314ah MB31 cells (spec sheet that was sent to me says they pulled 331ah) - 2 x 4 = total 628ah @ 12v each.
BMS: 2xJK BMS - 4s 200amp w/2amp active balancer + bluetooth and heating pad capable

Max voltage: 3.65v
BMS Over volt charge cut out point: 3.60v
Charger "complete" absorption voltage: 3.55v
Charger Float: 3.40v
Load low voltage cut off: 3.0v
BMS under volt cut out point: 2.88v
BMS single cell under volt cut out: 2.63
Min low voltage: 2.55v


These numbers will be multiplied by 4 for things like the multiplus, balmar, mppt to get 12v basis numbers/settings. I will be relying on the multiplus & the MPPT(and likely the DC genset regulator though it probably wont ever run that long to get there) to get cells to 3.55v - IE into float. May bump numbers up/down a bit to reduce stress on them as dead of winter time my 700w solar gives me a glorious 50w of power if i'm lucky.

Apologize for the thread drift, but figured others who come across this at some point in the future might like to see planned settings

The reasons I have for avoiding the ArgoFET do not include their cost. I provide optimal “reference diagrams” that are normally expensive anyway.

Here are the reasons to avoid the ArgoFET:

- extra losses. It sits in the big current circuit, introducing loss exactly where it hurts. All that loss results in tremendous heat output, to be dissipated by a heat sink.

- Prone to failure. If there’s one device that often fails it is the battery isolators. They have many fail modes from simple blown up MOSFET’s to high resistance at the terminals due to heat cycling. Also, they are the first to go with lightning strikes.

- incompatible charge profiles. A battery isolators should have the same battery chemistry on every output terminal. If breaking that rule isn’t a direct violation of ABYC then it is breaking the spirit in which their recommendations are written. Insurance will probably reject claims.


- not needed. There are excellent alternatives like I recommend.

[chowdan]

Originally Posted by s/v Jedi

The reasons I have for avoiding the ArgoFET do not include their cost. I provide optimal “reference diagrams” that are normally expensive anyway.

Here are the reasons to avoid the ArgoFET:

- extra losses. It sits in the big current circuit, introducing loss exactly where it hurts. All that loss results in tremendous heat output, to be dissipated by a heat sink.

- Prone to failure. If there’s one device that often fails it is the battery isolators. They have many fail modes from simple blown up MOSFET’s to high resistance at the terminals due to heat cycling. Also, they are the first to go with lightning strikes.

- incompatible charge profiles. A battery isolators should have the same battery chemistry on every output terminal. If breaking that rule isn’t a direct violation of ABYC then it is breaking the spirit in which their recommendations are written. Insurance will probably reject claims.


- not needed. There are excellent alternatives like I recommend.

Hrm i had looked into argofet and didn't see much about failures, though I will say i did not look too deep nor have i talked to people in the industry of repair side of things to see what sort of failure rate they see, but interesting you bring this up as it was something i was thinking about.

Regarding extra losses, victron "claims" their argofet is 0.01v loss - seemed to me to be pretty insignificant. I'm running 4/0 cable on a 175a and 120a alternators with roughly 8 feet of length(round trip) - my starter also has its own 4/0 cable aswell.

As we discuss more and more and as I continue to think through the process/design/setup that i'll be doing, i do see how the argofet is not needed. Balmar will be set below the BMS settings so it will never see an overcharge state and therefore it will never achieve 100% SOC from the alternator. If the MPPT controller kicks in and dumps power in to get us into float for example - the balmar will back off and not pump into the battery as the relay is triggered.

The charge profile issue is also something i've been thinking about as well. With a DC/DC charger in on the house side pumping into the starter - wouldn't this effectively take over and therefore the FET will be pushing only to the house?


I have a large primary - 100hp yanmar for a 20t sailboat, i'm way over powered and I will be switching to a much larger alternator down the road and may even do a PTO clutch on the crank to drive a much larger generator to help load the engine more - i have far more power than what is needed for the vessel even with an overpitched prop. All that is said because it means that the ARGOfet is absolutely useless if I try to put a Delco Remy 40si(320a 12v alternator).....

I see why your design is the way it is and I totally understand it....maybe when i start the install I'll have spent enough time thinking it through and return the argofet. Theres a lot of "questions" that remain in place by using the fet, including what is the true failure rate and how does it handle over current on top of the fact that it fully limits your potential charge ability when you have large charging output in the DC world.

[s/v Jedi]

Originally Posted by chowdan

Hrm i had looked into argofet and didn't see much about failures, though I will say i did not look too deep nor have i talked to people in the industry of repair side of things to see what sort of failure rate they see, but interesting you bring this up as it was something i was thinking about.

Regarding extra losses, victron "claims" their argofet is 0.01v loss - seemed to me to be pretty insignificant. I'm running 4/0 cable on a 175a and 120a alternators with roughly 8 feet of length(round trip) - my starter also has its own 4/0 cable aswell.

As we discuss more and more and as I continue to think through the process/design/setup that i'll be doing, i do see how the argofet is not needed. Balmar will be set below the BMS settings so it will never see an overcharge state and therefore it will never achieve 100% SOC from the alternator. If the MPPT controller kicks in and dumps power in to get us into float for example - the balmar will back off and not pump into the battery as the relay is triggered.

The charge profile issue is also something i've been thinking about as well. With a DC/DC charger in on the house side pumping into the starter - wouldn't this effectively take over and therefore the FET will be pushing only to the house?


I have a large primary - 100hp yanmar for a 20t sailboat, i'm way over powered and I will be switching to a much larger alternator down the road and may even do a PTO clutch on the crank to drive a much larger generator to help load the engine more - i have far more power than what is needed for the vessel even with an overpitched prop. All that is said because it means that the ARGOfet is absolutely useless if I try to put a Delco Remy 40si(320a 12v alternator).....

I see why your design is the way it is and I totally understand it....maybe when i start the install I'll have spent enough time thinking it through and return the argofet. Theres a lot of "questions" that remain in place by using the fet, including what is the true failure rate and how does it handle over current on top of the fact that it fully limits your potential charge ability when you have large charging output in the DC world.

We have had plenty forum members with burned up units or molten cables/terminals. There’s a bad Youtube video as well. The heat cycles loosen the terminals which then overheat the next cycle due to high resistance.

The voltage loss at high load isn’t 0.01V but ten times higher, 0.1V At 200A this is a 20W power dissipation which is enough to heat the boat

And there is zero need for the unit. All the potential problems are self inflicted, imaginary. Even without any protection against a BMS HVC you are safer and much more reliable without an isolator than with it. I estimate the risk of a properly programmed regulator causing a HVC at least a thousand times smaller than a problem around the isolator or incorrect charging profile etc.

In other words, your proposed setup with the ArgoFET is a

[CaptainRivet]

Originally Posted by s/v Jedi

The reasons I have for avoiding the ArgoFET do not include their cost. I provide optimal “reference diagrams” that are normally expensive anyway.

Here are the reasons to avoid the ArgoFET:

- extra losses. It sits in the big current circuit, introducing loss exactly where it hurts. All that loss results in tremendous heat output, to be dissipated by a heat sink.

The argodiode I agree lots of losses. argofet no, the losses are minimal. 20W with 200A is nothing compared to the ORION TR 30A which already has much more at just 30A.

- Prone to failure. If there’s one device that often fails it is the battery isolators. They have many fail modes from simple blown up MOSFET’s to high resistance at the terminals due to heat cycling. Also, they are the first to go with lightning strikes.

Good to have a cheap argofet go at lighting strike, protects the rest.
Never had an argofet fail but DC2DC yes several.
The argofet is much colder then the orion 30A heating brick. So if one is failing its the orion DC2DC.
I mostly use the 200A argofet on 115 or 125A alternator which puts out 105A for 2 to 5min and then scales back to 85A. That's why I have no problems, just don't use electronics on the limits. And at 105 or 85A the heat loss is <10W which is totally acceptable.

- incompatible charge profiles. A battery isolators should have the same battery chemistry on every output terminal. If breaking that rule isn’t a direct violation of ABYC then it is breaking the spirit in which their recommendations are written. Insurance will probably reject claims.

1) If you cut at 95% SoC charging profil is completely irrelevant and obsolete if it's a FLA,AGM or Lifepo4 regulator. You cut at approx 13.6 so it never reaches absorption stage any of the regulators. Absorption is done via solar or shorcharger with the right profil.
2) an isolator is exactly made for 2 different battery chemistry and ISO as well as ABYC states an isolator is needed when charging different battery chemistry. Your statement is completely wrong here.
3) The alternator always sees the lead so never under any condition you can get a surge spike.
And even if that happens the argofet protects the installation, that's not the case with direct LFP charging.
4) Absolutely no problem with insurance and fully inline with ABYC and ISO.
5) The Spirit of ABYC is long lost and misused from ABYC to make money on certifications and licence fees plus insurance to bail out of claims...and when a Nigel Calder who is one of their main authors recommends GG characteristics MRBF fuse for protection of starter instead the correct fuse for motor which is a time delay fuse for inductive loads that spirit is for the bin anyhow.
6) Never heard of any claim denied because an correct speced argofet/isolator was used to seperate 2 different battery chemistries and/or independent curcuits, I know plenty where insurance bailed out because NO isolator was used. And I was head claims at Allianz SE means worldwide, so I know how insurance works here. So that's a false statement too.
6) important is what works savely and argofet solution does.

- not needed. There are excellent alternatives like I recommend.

Each alternative has their pros and cons
1) the argofet solution is the simple, safest and most economical solution when you have a temp regulated alternator below 200A to safely get most from existing alternator and protecting installation at the same time
2) the lead starter ->DC2DC-> LFP charge "solution" is the one solution which is a pseudo protection because it actually doesn't protect the alternator by measuring the heat of the alternator, it just limits it to a guessed static output in 95% of cases what it can do savely. Very few actually measure the alt temp under different RPM and ambient heat how much the alternator can do. And even then thats a bandaid because its a static value. I know plenty alternator that went up in smoke with DC2DC in the heatwaves in Greece where motorsailing happened and the 50% rule of alternator guess was by far too much and alternator fried to death and owners ask "why did that happen, I have a DC2DC that protects the alternator", nope it doesn't protect the alternator, it just limits the output to a static guessed value assumed!!! To be enough to protect the alternator.
So in the spirit if ABYC that's is totally wrong but promoted by them. If the Victron Orion XS would have a temp sensor for the alternator and then scales back the DC2DC charge limit that would be a correct a proper protection, XS has all features for that current reduction already onbaord.
This solution is to be preffered for dumb small alternators without temp protection where conversion to external charging cost the same or more then the DC2DC and gain doing that is small..the prime example for that is the 85A Hitachi found on old Volvos which can do 50A with DC2DC and only 60-65A for external regulation, simply not worth doing that and going bigger adds right away min 400Euro for conversion to serpentine belt.
3) direct charging requires a fully externally controlled alternator which in case of newer volvos with MDI harms the engines warranty if used. It's the most expensive way and the most effective way. For alternators >200A that's the right way to go as losses with the other 2 solutions gets too high, that's why victron doesn't have a 300A version of the argofet. But below the losses are accepable. Direct charging its also the most risky way as a sudden disconnect of LFP house creates a spike that puts the whole installation at risk, not only the alternator. A surge protector must be used but it's not guaranteed it can fully cover the spike as thats again a guessed value that can be exceeded. For the seperate starter you need DC2DC charger to charge from LFP house to starter independent from chemistry. Also when LIFEPO4 starter as you need to isolate the starter curcuit from house curcuit or the starter gets discharged from house and the whole principle of the starter is obsolete.

So which of the 3 solution is the best depends on your install and needs.

[CaptainRivet]

Originally Posted by s/v Jedi

We have had plenty forum members with burned up units or molten cables/terminals. There’s a bad Youtube video as well. The heat cycles loosen the terminals which then overheat the next cycle due to high resistance.

The voltage loss at high load isn’t 0.01V but ten times higher, 0.1V At 200A this is a 20W power dissipation which is enough to heat the boat

And there is zero need for the unit. All the potential problems are self inflicted, imaginary. Even without any protection against a BMS HVC you are safer and much more reliable without an isolator than with it. I estimate the risk of a properly programmed regulator causing a HVC at least a thousand times smaller than a problem around the isolator or incorrect charging profile etc.

In other words, your proposed setup with the ArgoFET is a

Not aware of that posts here with argofets and lots of problems.
Well that answered the OPs question if it's a hard limit..it is more then hard, better use it max to 75% (means at the beginning when the alt is cold and puts out more) and not in the engine room.
As I wrote I use them mostly with 50% of their rating and never had a problem. Most likely the issues with heat cycling and melted was because they used them over spec or at the limit spec plus mounted in the engine room close to the engine. The manual and spec is very bad from victron for argofet.

Thank you for bringing that to my awareness with the mosfets blew is a common issue.
I assume for that sales price of the argofet the mosfets used are not calibrated so it's basically the same issue as with mosfet BMS. Means also when using 2 or more of the argofets in parallel, derate them further by 1/3 of the rating. Again should be in the manual but isn't.


The argofet had 20W heat loss at 200A, the victron orion TR DC2DC 30A more then double at 30A...

[s/v Jedi]

You have lost your way Rivet. My recommendation is to have a direct circuit from alternator to house battery and only one post ago you claimed you understood that but now you start rambling about losses in a 30A dc-dc charger again. You lost it.

No, my setup has zero loss apart for cabling, crimps etc.

[newhaul]

Originally Posted by s/v Jedi

You have lost your way Rivet. My recommendation is to have a direct circuit from alternator to house battery and only one post ago you claimed you understood that but now you start rambling about losses in a 30A dc-dc charger again. You lost it.

No, my setup has zero loss apart for cabling, crimps etc.

I thought you were the OP and i didn't see any questions asked to be answered . The opposite you posted your system in attempt to help others . Answering so many questions along the way with these 17 pages. Heck I was the first question and you promptly answered it over 2 years ago in post 3 .

I'm sure there is a watt or two lost in the dc2dc but by then the start bank is back to fully charged and the dc2dc is basicly in idle position . And then there is no heat build up so no losses to speak of .

[Fore and Aft]

I have read most of these lithium threads and I wondered if you have a DC-DC charger on your start battery. Could you possibly give the charger its own on/off switch instead of wiring it to the engine ignition switch? That way if you are doing hours of motoring then you could switch it off and give the alternator a chance to cool down.
If that was possible then could you wire your wind generator to the start battery and when its working turn on the DC-DC charger. I am just curious about that.
Cheers

[newhaul]

Originally Posted by Fore and Aft

I have read most of these lithium threads and I wondered if you have a DC-DC charger on your start battery. Could you possibly give the charger its own on/off switch instead of wiring it to the engine ignition switch? That way if you are doing hours of motoring then you could switch it off and give the alternator a chance to cool down.
If that was possible then could you wire your wind generator to the start battery and when its working turn on the DC-DC charger. I am just curious about that.
Cheers

This is one of the reasons for having a switch on the alternator sense wire in my setup.
As to wind generators mine is an airx 400 which has its own internal charge controller circuitry. So it is connected directly to the charging bussbar for my lifepo4 house bank