LiFePO4 reference diagram, Alternator version

[svloki]

My windlass load is the same as Jedi, 3500w. Lewmar says peak momentary load of 1,100 amps. I would not want to task those BMS internal FET's with so much load, even if they claim that can tolerate it.



The Bactrium BMS drives a contactor that can be virtually any size, but a rather expensive set of hardware. Anyone else have BMS recommendations?

[CaptainRivet]

Originally Posted by wholybee

Yes, that works fine. But the question was, if you reverse it Alternator->LFP-DCDC->AGM with the DCDC allow enough current through it to protect when the LFP disconnects. No, it will not. The DCDC will be blown up. You must do it as you say, with the Alternator directly connected to the AGM first.

Why would you do it this way?
What you can do is Alternator with surge protector->DC2DC charger or converter->LFP.
Then converter won't blow, done that with 12V alternator on 24V bank. The BMS switches the alternator sense wire off when 95% of SoC is reached, Alternatively you can also use A BMV702 or 712 programmed to 13.6V to cut sense wire with a relay, advantage is the shunt shows how much power really come from the alternator. In this case you can also use a much cheaper converter with 13.8V instead charger.
So BMV+converter is cheaper or equal then charger and you Don 't even need a lead anymore.

[newhaul]

Originally Posted by CaptainRivet

Why would you do it this way?
What you can do is Alternator with surge protector->DC2DC charger or converter->LFP.
Then converter won't blow, done that with 12V alternator on 24V bank. The BMS switches the alternator sense wire off when 95% of SoC is reached, Alternatively you can also use A BMV702 or 712 programmed to 13.6V to cut sense wire with a relay, advantage is the shunt shows how much power really come from the alternator. In this case you can also use a much cheaper converter with 13.8V instead charger.
So BMV+converter is cheaper or equal then charger and you Don 't even need a lead anymore.

I will keep my FLA
Alternator to fla to dc dc to LIFEPO4. Set dc dc to 13.8 so no HVC disconnect even possible . All is good why complicate a simple thing .
My boat and all

[wholybee]

Originally Posted by newhaul

I will keep my FLA
Alternator to fla to dc dc to LIFEPO4. Set dc dc to 13.8 so no HVC disconnect even possible . All is good why complicate a simple thing .
My boat and all

Yep, that is the best proven way to do it without upgrading the whole alternator charging system.

[wholybee]

Originally Posted by CaptainRivet

Why would you do it this way?
What you can do is Alternator with surge protector->DC2DC charger or converter->LFP.
Then converter won't blow, done that with 12V alternator on 24V bank. The BMS switches the alternator sense wire off when 95% of SoC is reached, Alternatively you can also use A BMV702 or 712 programmed to 13.6V to cut sense wire with a relay, advantage is the shunt shows how much power really come from the alternator. In this case you can also use a much cheaper converter with 13.8V instead charger.
So BMV+converter is cheaper or equal then charger and you Don 't even need a lead anymore.

You wouldn't. But someone asked if it would work, Alternator to LFP, with DCDC to AGM, and I said no. The DCDC will blow up if there is a load dump, and the DCDC will not protect against it.

Newhaul did it right.

[newhaul]

Originally Posted by wholybee

Yep, that is the best proven way to do it without upgrading the whole alternator charging system.

Full disclosure I did upgrade from the factory Mitsubishi 35 amp alternator to a 75 amp Chevy 3 wire .
Cut off switch in sense wire.

[wholybee]

Originally Posted by svloki

My windlass load is the same as Jedi, 3500w. Lewmar says peak momentary load of 1,100 amps. I would not want to task those BMS internal FET's with so much load, even if they claim that can tolerate it.



The Bactrium BMS drives a contactor that can be virtually any size, but a rather expensive set of hardware. Anyone else have BMS recommendations?

The REC Active BMS is highly regarded and what I would opt for if I had loads that made me hesitate with using FETs. It expensive, but if making the jump from FET to contactors, I think that is the way to go.

Electrodacus has a lot of fans, and I've heard nothing bad about it. Several on this forum love it. I believe it will control a contactor.

I have worked on and ripped out a system that used the 123/Smart BMS. Don't get that one. A friend suffered repeated cell module failures, and ultimately damage to his bank and everything needed to be replaced. It was junk.

[Cheyne]

I replaced one of my two Victron DCDC with the new Orion XS 50 amp. First impressions are very good. It runs way cooler than my old 30 amp. I'm going from my Valero 120 amp altenator on my Yanmar to a Optima Red Top to the DCDC to my house bank. The new DCDC also has VE.Direct so it plays nice with the rest of my Victron gear instead of just being a large negative number for my DC load.


Cheyne

[CaptainRivet]

Originally Posted by wholybee

The REC Active BMS is highly regarded and what I would opt for if I had loads that made me hesitate with using FETs. It expensive, but if making the jump from FET to contactors, I think that is the way to go.

Electrodacus has a lot of fans, and I've heard nothing bad about it. Several on this forum love it. I believe it will control a contactor.

I have worked on and ripped out a system that used the 123/Smart BMS. Don't get that one. A friend suffered repeated cell module failures, and ultimately damage to his bank and everything needed to be replaced. It was junk.

Premium contactor BMS:
REC BMS or TAO, both will end up at the 1000Euro mark too. REC is great for victron integration, Tao is the only BMS I know explicitly made for boats and would be my goto if spending 1000Euro. It's made from the sailors Phil Tao for sailors and has several nice features no other BMS has.
Both go beyond a normal BMS and offer a lot of real battery optimization and reporting features with bus integration.
But this comes at the cost if the bus breaks the whole system is down and very complex to troubleshoot.
And here comes ElectrodacusBMS into place, it's philosophy is to switch all sources, charge and load at the source via their remote as spider in the web. This is a)very simple b) very reliable and safe: the remote functions are tested by the manufacturer and eg in case of victron to work 10years c)cheap as you just need a very tiny cable from the BMS to the source (I use cat 5 or 6 cables and chop off the rj45 connector), you also don't need big relays that are very expensive, have high standby loads and are prone to fail.
D)it is the spider in the web that controls also the charge sources which means it doesn't disconnect the battery but the charge source via its remote when eg full. Means you can eg use existing AGM chargers or cheaper DC2DC converters as they get simple switched off by BMS when battery is full. Also alternator, a little relay in the sense wire of the alternator and when full the BMS disconnects the sense wire so alternator ramps down savely, even in a desaster shut off.
E) electrodacus BMS is no current carring and only limited by the use of max 1000A shunts in current, which are connected to the positive terminal. You have am main shunt and a PV shunt or simply a load and a charge shunt, so all that gets in and out are measured. As desaster shutoff I have a BMV 712 shunt in the negative that also delivers all data to cerbo, means the whole victron infrastructure is on top of it but isolated from the BMS.
So to sum up all very simple and battery is always online, just everything around gets shut off.
And if the electrodacus breaks you can simply switch on all victron equipment by BT overriding the remote, non victron simply connect both cables of the remote wire together, switches on device. No complex bus, simple, effective and easy to trace in case of troubleshooting and to fix.
That's the positive about ElectrodacusBMS, which is around 200Euro.
The main negative is it can only steer one battery, means if you need more the 300AH you can either use the big 400-1000AH cells from Winston or sinopoly or make a bank from parallel cells. That's what I did, 4P4S setup of 272AH Lishen cells metricously matched in capacity and resistance from factory. To have 2p4S means 628AH with the new EVE you can do quite simple, just buy grade A RVE cells and an active balancer. But more then 2 parallel this setup is only for the lithium cracks who know what they do as the 4 parallel cells act as one and are monitored as one. To not run out of balance over time the cells must be of highest quality and metricously matched and the battery must be symmetrically build plus given more absorption time as the parallel cells only 100% even out in the upper knee.
Simply don't do it and bite the bullet and get the big winston cells in the capacity you want/need.
The other negative is minor as its kinda open source which means it's a bit more work to do, cabling is a bit tricky but the beginners guide teaches you how to do that, you need optocoplers or small SSR to drive big relays and you need to mount it into an IP67 box to protect from humidity in boats as its originally made for offgrid stationary use.
Legacy load bus (means your existing main cable that goes to your switchboard you use a SSR eg a victron BatteryProtect to switch it on/off. It doesn't have a main cut off relay as it switches all off at its source via remote.
The BMS the 6 contactor outputs itself can only do 100mA each which is more then enough to steer/cut remote of all victron equipement or many other remote curcuits. The outputs can be steered via a voltage threshold set as EOF, LCV or HCV or via a SOC threshold. Eg my alternator gets switched off at 95%SOC, the absorption is done by solar.

[CaptainRivet]

Originally Posted by Cheyne

I replaced one of my two Victron DCDC with the new Orion XS 50 amp. First impressions are very good. It runs way cooler than my old 30 amp. I'm going from my Valero 120 amp altenator on my Yanmar to a Optima Red Top to the DCDC to my house bank. The new DCDC also has VE.Direct so it plays nice with the rest of my Victron gear instead of just being a large negative number for my DC load.


Cheyne

What a waste of money and castration of the 125A Valeo running that via DC2DCs.

The valeo has internal temp protection and doesn't need limiting by a DC2DC charger as it protects itself.
You can either use
A) an argofet splitting diode and charge in parallel your lead starter and LFP. This way the Valeo delivers around 80-85A safely. Means with 150Euro for the 200A argofet you get 80A charge vs 300Euro for an XS plus 2x250Euro for the old 30A bricks delivering you 50A and wasting energy.
B) you get the Nordkyn VSR200 and convert it this way to an externally regulated alternator without modifying the alternator. Like this you can directly charge the LFP and delete your lead or replace it with a lithium starter. Or if you still wanna keep the dreaded old lead you can use one of your old 30A DC2DC to float the starter from the LFP house.
That solution is 300Euro for 90-95A charge from your Valeo 125A.
The DC2DC is waste of money and has 0 advantage and many disadvantages with the Valeo 125A and the 115A Mitsubishi.

[Cheyne]

You provide great comic relief. Keep it up.

Originally Posted by CaptainRivet

What a waste of money and castration of the 125A Valeo running that via DC2DCs.

The valeo has internal temp protection and doesn't need limiting by a DC2DC charger as it protects itself.
You can either use
A) an argofet splitting diode and charge in parallel your lead starter and LFP. This way the Valeo delivers around 80-85A safely. Means with 150Euro for the 200A argofet you get 80A charge vs 300Euro for an XS plus 2x250Euro for the old 30A bricks delivering you 50A and wasting energy.
B) you get the Nordkyn VSR200 and convert it this way to an externally regulated alternator without modifying the alternator. Like this you can directly charge the LFP and delete your lead or replace it with a lithium starter. Or if you still wanna keep the dreaded old lead you can use one of your old 30A DC2DC to float the starter from the LFP house.
That solution is 300Euro for 90-95A charge from your Valeo 125A.
The DC2DC is waste of money and has 0 advantage and many disadvantages with the Valeo 125A and the 115A Mitsubishi.

[newhaul]

Originally Posted by Cheyne

I replaced one of my two Victron DCDC with the new Orion XS 50 amp. First impressions are very good. It runs way cooler than my old 30 amp. I'm going from my Valero 120 amp altenator on my Yanmar to a Optima Red Top to the DCDC to my house bank. The new DCDC also has VE.Direct so it plays nice with the rest of my Victron gear instead of just being a large negative number for my DC load.


Cheyne

Sounds like it works great for you .

Some don't seem to get the my boat my choice your boat your choice bit personally I like it simple and bulletproof

[CaptainRivet]

Originally Posted by wholybee

You wouldn't. But someone asked if it would work, Alternator to LFP, with DCDC to AGM, and I said no. The DCDC will blow up if there is a load dump, and the DCDC will not protect against it.

Newhaul did it right.

DC2DC won't blow up as its only limiting whats coming in and you can connect it to a 300A alternator, just 50A would come from the Orion XS but the diodes of the alternator would unless they are avalanche diodes which the 115A Mitsubishi has, expect the 125A Valeo too as its Valeos copy of it.
What else would blow up depends on where the alternator is connected exactly. If to the main charge bus or even worse a common bus for all then all thats connected there eg MPPTs won't as also limited on the input, but eg cheaper HF inverter or sensitive electronic at the nav desk could.
Directly connected to terminals of dropin depending on peak rating of the mosfet BMS that could be affected if peak is lower then the spike. Just dependent if it happened under full load and how big the spike is. The AGM won't protect anything as isolated by the DC2DC.

[CaptainRivet]

Originally Posted by newhaul

Sounds like it works great for you .

Some don't seem to get the my boat my choice your boat your choice bit personally I like it simple and bulletproof

Neither simple, nor bulletproof.
Simple is connecting both in parallel out 1 and out 2 to the argofet, alternator to in and forget about it. Nothing to adjust or to worry about.

No losses, no wrong parameter you can set, no charge limit that castrate the alternator and half the cost for nearly double the output plus no output if the DC2DC is broken.
If the AGM breaks and gets an internal cell short (most common due to sulfaltation) and you charge AGM directly via alternator then to 50A DC2DC to LFP, the AGM will get a thermal runaway. In parallel to an LFP via argofet, it won't as it has no load on it and therefor only very small discharge but protects with its high resistance if the LFP switches off. That's why if you use a DC2DC take a FLA, that will only gas out while an AGM will get thermal runaway, not many know...
Don't know anyone who broke an argofet but several who killed an DC2DC.

It's simple you didn't know the Valeo has internal temp protection and protects itself and thought it's a dumb alternator that need to be limited in output by a DC2DC to protect it.

[newhaul]

Here is an honest question for those that may actually know and please concise answers please
Limited bandwidth and all
I can get a 12v 1500 watt PMA how good would that do for charging my 250ah 12v lifepo4 house bank running directly off a small engine in a belt drive genset type setup?will it survive ?
I can get a 2kw unit as xwell for not much more .