LiFePO4 reference diagram, Alternator version

[CaptainRivet]

The average from my galley is somewhere between 30 and 50AH a day at 12V. Add to that 30AH for the dishwasher all 3 days.
Yes the 2kg Sunday roast with oven vegetable will take 200AH, but you don't have to do that, I don't care as I can.
And it feeds us for 4 days so back to 50AH a day.

[s/v Jedi]

Originally Posted by CaptainRivet

The average from my galley is somewhere between 30 and 50AH a day at 12V. Add to that 30AH for the dishwasher all 3 days.
Yes the 2kg Sunday roast with oven vegetable will take 200AH, but you don't have to do that, I don't care as I can.
And it feeds us for 4 days so back to 50AH a day.

Stop using Ah, it is rookie level. The thing you try to talk about is called electrical energy and it is expressed in Wh or kWh.

[CaptainRivet]

Originally Posted by s/v Jedi

Stop using Ah, it is rookie level. The thing you try to talk about is called electrical energy and it is expressed in Wh or kWh.

I hate kWh and most are still 12V, AH I am used to and that works well to quickly calculate. Who wanna convert into kwh can do it...

[s/v Jedi]

Originally Posted by CaptainRivet

I hate kWh and most are still 12V, AH I am used to and that works well to quickly calculate. Who wanna convert into kwh can do it...

No, it just shows the amateur level of the discussion. Even silly appliance salesmen use kW and kWh.

[CaptainRivet]

Originally Posted by s/v Jedi

No, it just shows the amateur level of the discussion. Even silly appliance salesmen use kW and kWh.

Your opinion. I answered a question.

[newhaul]

Originally Posted by s/v Jedi

Stop using Ah, it is rookie level. The thing you try to talk about is called electrical energy and it is expressed in Wh or kWh.

I do have one question.
How did we drift from alternator charging of your lifepo4 banks and the various ways to wire that up. To how many kWh your or my electric galley uses ?
For info my electric galley needs underway works out to be 116wh to run my rice cooker every day for dinner.

[s/v Jedi]

Originally Posted by CaptainRivet

Your opinion. I answered a question.

That’s another problem, you confuse facts with opinions. It doesn’t matter what you think, or how many agree with you or how loud you are: facts stand unwaveringly

[CaptainRivet]

Originally Posted by s/v Jedi

That’s another problem, you confuse facts with opinions. It doesn’t matter what you think, or how many agree with you or how loud you are: facts stand unwaveringly

Facts I need in average 30-50AH with electric galley due to victron and BMS monitoring, no opinion.
And I know what facts are and opinions. And if majority believe in an opinion that is then an in reality an accepted fact too and not an opinion anymore.

[chowdan]

Jedi - Thanks for posting this. I am working through my setup currently as I am about to make the switch.


For people like me who dont have a BMS that is able to control a relay, I am going to be running my alternator through an argofet(victron) which means if my BMS shuts down, the alternator just pumps out to the starter battery.

I run a DC generator(170amp alternator), so i'm thinking ill be using 1 argofet and running both primary engine alternator & generator to a busbar then from that bus bar to the FET.

Thoughts on this? I do know that i will have a shorter starter battery lifespan, but that doesn't bother me, but i do question how the MC-614 & MC-618 that i have will be able to handle the transition in this event - IE if BMS shuts down and FET allows the alt to pump into the starter - will the alt just raise voltage until the battery or alt explode since the regulator will be looking at the lithium?

[CaptainRivet]

Originally Posted by chowdan

Jedi - Thanks for posting this. I am working through my setup currently as I am about to make the switch.


For people like me who dont have a BMS that is able to control a relay, I am going to be running my alternator through an argofet(victron) which means if my BMS shuts down, the alternator just pumps out to the starter battery.

I run a DC generator(170amp alternator), so i'm thinking ill be using 1 argofet and running both primary engine alternator & generator to a busbar then from that bus bar to the FET.

Thoughts on this? I do know that i will have a shorter starter battery lifespan, but that doesn't bother me, but i do question how the MC-614 & MC-618 that i have will be able to handle the transition in this event - IE if BMS shuts down and FET allows the alt to pump into the starter - will the alt just raise voltage until the battery or alt explode since the regulator will be looking at the lithium?

No issue that works fine.
It just gets the charge it's requesting and the high resistance smoothen spikes qhen the LFP cuts off.
Also no issue for the balmar regulator on the gen and alt
. Due to the argofet the balmar regulator just see the combined battery of lead and lithium, the lead dominates with the resistance and is always connected (even if its dead) so your balmar won't do anything, it keeps the voltage or only very slightly rise it for a short periode of time depending on SOC of lead starter and then back to normal. No issue for starter or LFP.
But you should programm the absorption and float of the balmars accordingly that the LFP is not shutting off at all.
You simply can't run them in parallel as that would be too much current for the 200A argofet. Makes no sense to do this anyhow.
Regarding short lifespan of the starter, simply use a small 30W solar panel and connect to starter. That will keep it on higher float charge at any time.

[chowdan]

Originally Posted by CaptainRivet

No issue that works fine.
It just gets the charge it's requesting and the high resistance smoothen spikes qhen the LFP cuts off.
Also no issue for the balmar regulator on the gen and alt
. Due to the argofet the balmar regulator just see the combined battery of lead and lithium, the lead dominates with the resistance and is always connected (even if its dead) so your balmar won't do anything, it keeps the voltage or only very slightly rise it for a short periode of time depending on SOC of lead starter and then back to normal. No issue for starter or LFP.
But you should programm the absorption and float of the balmars accordingly that the LFP is not shutting off at all.
You simply can't run them in parallel as that would be too much current for the 200A argofet. Makes no sense to do this anyhow.
Regarding short lifespan of the starter, simply use a small 30W solar panel and connect to starter. That will keep it on higher float charge at any time.

Thanks for this @CaptainRivet!

I was also thinking that the regulator programming would be set so that BMS should never shut down in any sort of event so it should in theory be a moot point, but i figured theres events that could occur that i dont know about.

As for running both gen/engine at the same time - it should really never happen, and the only time it would happen would be if one alternator went down and I needed power generation.

Is the capacity limit on the argofet a HARD limit or is it a soft limit? IE if i push 300 amps to it, does it blow the argofet or does it just limit it to 200 amps? I assumed it was more of a soft limit where it just maxes at 200

[CaptainRivet]

Originally Posted by chowdan

Thanks for this @CaptainRivet!

I was also thinking that the regulator programming would be set so that BMS should never shut down in any sort of event so it should in theory be a moot point, but i figured theres events that could occur that i dont know about.

As for running both gen/engine at the same time - it should really never happen, and the only time it would happen would be if one alternator went down and I needed power generation.

Is the capacity limit on the argofet a HARD limit or is it a soft limit? IE if i push 300 amps to it, does it blow the argofet or does it just limit it to 200 amps? I assumed it was more of a soft limit where it just maxes at 200

Yes you need an immediate shutdown safety, so need to plan for that. Was more like a reminder.
One trick I use with argofet to get the lead starter battery better charged is I mount the argofet directly next to lead and use then a high temp isolated silicone cable for the long run to the LFP. The reason why high temp is I purposely dimension the cable smaller to reach a voltage drop of 0.2V and these cables with high temp isolation allow savely higher current on a smaller diameter. Then I set the alternator regulator these 0.2V higher on absorption and float. The FLA get then 14.2V absorption and 13.6V float while the lifpo 14.0V absorption and 13.4V float.
14V is as good as 13.8V for LFP but the FLA gets a better charge and life longer. I put a sticker on the argofet with this values, so also a mechanic or electrician knows what I did.

Regarding limit of argofet, I don't know as I always stay minimum 10% below rating on them as with all other equipment. Maxing out is always bad for longlivity and reliability.
Specs and manual don't state a peak or short term current rating or if it's hard limit.
Would be good to know how they behave in above spec, if hard limit and output caped or soft limit but how long and how much can I go over the rating?
The Mitsubishi 115A puts out 105A the first 2 till 3 minutes and then its internal temp protection dails it back to 80-85A. When using 2 in parallel I always use 2x200A argofet, it's just 30Euro price difference between 100 and 200A so I always get the bigger but would be actually curious to know if I can get by with only 1x200A argofet for the 2 alternators.

[s/v Jedi]

Originally Posted by chowdan

Jedi - Thanks for posting this. I am working through my setup currently as I am about to make the switch.

For people like me who dont have a BMS that is able to control a relay, I am going to be running my alternator through an argofet(victron) which means if my BMS shuts down, the alternator just pumps out to the starter battery.

I run a DC generator(170amp alternator), so i'm thinking ill be using 1 argofet and running both primary engine alternator & generator to a busbar then from that bus bar to the FET.

Thoughts on this? I do know that i will have a shorter starter battery lifespan, but that doesn't bother me, but i do question how the MC-614 & MC-618 that i have will be able to handle the transition in this event - IE if BMS shuts down and FET allows the alt to pump into the starter - will the alt just raise voltage until the battery or alt explode since the regulator will be looking at the lithium?

Yes, in that setup you run the alternators in parallel into a FET battery isolator. If your alternator regulators have a battery temperature sensor then this needs to be attached to the starter battery. I highly recommend to also use a temperature sensor on the alternators, which is supported by Balmar.

Pin 9, Voltage sense must be connected to the busbar (you can use a powerpost product from BlueSea instead which is more compact) that connects the alternators in parallel. Use a multimeter to compare voltage at the ArgoFET input and outputs… it will be less than 0.1V difference and you simply configure the regulator higher to compensate for the voltage loss.
Don’t connect voltage sense to the battery as the normal setup is because this would cause problems if the ArgoFET has a failure.

I now recommend a different setup. In your case I would connect the oem alternator to the start battery and the additional alternator to the LFP. To disconnect the alternator from the LFP in case of the BMS doing a cutoff, you can use a simple automotive relay in the regulator ignition wire on terminal 3, the brown wire iirc. Use the relay Normally Closed contact so that normally the regulator sends the field current to the alternator.
To drive this relay, I recommend a manual switch in series with the contact available on the back of a Victron BMV battery monitor. The alternator will work if both the manual switch is on and the BMV contact is on. The switch gives you manual control and you can program the BMV contact for automatic function, i.e. close contact when SOC is higher than 95%

This isn’t hard to do and you don’t need an ArgoFET and you have correct charging profiles for each battery and you have manual control. Win-win-win

[chowdan]

Originally Posted by CaptainRivet

Yes you need an immediate shutdown safety, so need to plan for that. Was more like a reminder.
One trick I use with argofet to get the lead starter battery better charged is I mount the argofet directly next to lead and use then a high temp isolated silicone cable for the long run to the LFP. The reason why high temp is I purposely dimension the cable smaller to reach a voltage drop of 0.2V and these cables with high temp isolation allow savely higher current on a smaller diameter. Then I set the alternator regulator these 0.2V higher on absorption and float. The FLA get then 14.2V absorption and 13.6V float while the lifpo 14.0V absorption and 13.4V float.
14V is as good as 13.8V for LFP but the FLA gets a better charge and life longer. I put a sticker on the argofet with this values, so also a mechanic or electrician knows what I did.

Regarding limit of argofet, I don't know as I always stay minimum 10% below rating on them as with all other equipment. Maxing out is always bad for longlivity and reliability.
Specs and manual don't state a peak or short term current rating or if it's hard limit.
Would be good to know how they behave in above spec, if hard limit and output caped or soft limit but how long and how much can I go over the rating?
The Mitsubishi 115A puts out 105A the first 2 till 3 minutes and then its internal temp protection dails it back to 80-85A. When using 2 in parallel I always use 2x200A argofet, it's just 30Euro price difference between 100 and 200A so I always get the bigger but would be actually curious to know if I can get by with only 1x200A argofet for the 2 alternators.

That makes sense. I am most likely going to be adding a DC-DC charger that will just be programmed to manage the start battery and be hooked on the house battery unswitched distribution bar so I am not super concerned about the house degrading tooo much. I run 4/0 cabling on everything from batteries to chargers(2000w inverter/charger, alternators, starters, batteries to busbars etc). I dont see any meaningful voltage loss as everything is supposed to be 2/0 but I had 4/0 so thats what i went with. Your approach is definitely an interesting one and I haven't seen that approach. It wouldn't make sense for me to pull new wires at this point.

It appears absolutely no one really has an answer of how does a argofet handle over current situations. I also go one size up typically in situations like this and I would easily purchase a single 300amp one if they made them as space constraints plus pulling extra wiring is the main thing i'm trying to avoid(though I may have to just run 2x200's if i can't get a definitive answer).

No one on victron community has had this answer questioned and my post also has gone un-answered unforunately.

The manual is pretty bare - it states "maximum alternator" which is 200amps(100 for the 100 version), however they dont talk about what actually happens when you go over......Theres got to be people running 250+ alternators on LFP systems and NOT running 5x50 DC-DC chargers - this seems absolutely nuts. Sure a wakespeed + REC BMS is the ideal solution but what about the tens of thousands of dropin batteries that have been sold. Someones got to have gone down this route.

Both my alternators are in fact derated - my 175amp is derated down to 120amps and the primary's alternator is derated to around 90amps, but as they heat up, they settle around 110-118 & 75-85 depending on ambient temps(winter they pump more with the cold ambient temps). I guess in theory i could derate both of them a tad further to keep the maximum output of both combined to 200amps for the "emergency situation" where they both might be running at the same time......Realistically i only need it to drop 10amps to bring it to the 200, and if i upgrade the primary engine alternator to a bigger one then just go down the route of running new cables and maybe by then they'll have a bigger FET to handle 200+?

[chowdan]

Originally Posted by s/v Jedi

Yes, in that setup you run the alternators in parallel into a FET battery isolator. If your alternator regulators have a battery temperature sensor then this needs to be attached to the starter battery. I highly recommend to also use a temperature sensor on the alternators, which is supported by Balmar.

Pin 9, Voltage sense must be connected to the busbar (you can use a powerpost product from BlueSea instead which is more compact) that connects the alternators in parallel. Use a multimeter to compare voltage at the ArgoFET input and outputs… it will be less than 0.1V difference and you simply configure the regulator higher to compensate for the voltage loss.
Don’t connect voltage sense to the battery as the normal setup is because this would cause problems if the ArgoFET has a failure.

I now recommend a different setup. In your case I would connect the oem alternator to the start battery and the additional alternator to the LFP. To disconnect the alternator from the LFP in case of the BMS doing a cutoff, you can use a simple automotive relay in the regulator ignition wire on terminal 3, the brown wire iirc. Use the relay Normally Closed contact so that normally the regulator sends the field current to the alternator.
To drive this relay, I recommend a manual switch in series with the contact available on the back of a Victron BMV battery monitor. The alternator will work if both the manual switch is on and the BMV contact is on. The switch gives you manual control and you can program the BMV contact for automatic function, i.e. close contact when SOC is higher than 95%

This isn’t hard to do and you don’t need an ArgoFET and you have correct charging profiles for each battery and you have manual control. Win-win-win

That explains a lot on how your drawing is designed. I have a cerbo GX and the BMV, so the cerbo could easily control that relay.

As for the wiring process running the main engine alt to the start and the gen alt to the house, i am not a huge fan of this as that'd mean the alternator really isn't doing much to help my house charge up while motoring. Winter time in PNW doesn't produce solar for us and we sometimes motor or motorsail for 2-3 hours to fight currents and what not, and it'd be ideal to be able to capture the energy from the alternator without having a bunch of DC/DC chargers.

I know i posted a moment ago(before seeing this message), but what about running both alternators to an argofet like discussed, but running the balmar charge profile for LFP and running relay's like you mentioned, but utilizing the small dc-dc victron charger. I think its a 9amp charger. This would mean we'd be focusing 100% on the LFP and relying on the DC-DC charger to maintain/handle the proper charging of the starter and provide all the extra benefits including the cutoff that having the rely in place has.

EDIT:
Reviewing your drawing, i think my proposal of running the primary & dc gen to an argofet with a DC/DC charger from house to start would be completely fine. The FET sole purpose would be functioning as an alternator protector in this instance it appears, but would effectively be how your drawing is except the ALT's run to the FET which runs to LFP/Start.

Might be a waste of an additional $120 as it's not entirely needed, but it sure would be a piece of mind thing though.