LiFePO4 reference diagram, Alternator version

[s/v Jedi]

Originally Posted by DeValency

Thanks s/v Jedi for the initiating the design and discussion. This is going to be a major resource to many of us upgrading to LFP and externally regulated higher power alternators. Thanks also to the other contributors in this thread for the good comments.

Being aware of the need to protect the alternator from a sudden charge termination by the LFP, Balmar's recommendations were programmed on my MC-618 - e.g. terminate alternator charging before the LFP BMS disconnects.

The second protection line as discussed here, by disconnecting the alternator control are of course almost the ultimate active safety feature.

In my case, I consider a passive protection as the starter batteries are staying as AGM, at least for now, and I also left, for now, two (relatively new) group 31 AGM house batteries, that are normally connected to the Victron ArgoFET 200A battery isolator one of the three separate outputs.
Meaning there is always some load on the alternator from the AGM batteries. This load may be minimal, as when the LFP reaches the targeted 13.8V (my BMS custom setting), the AGM is not yet 100% charged.

Comments? agree? disagree?

Thanks

Yes, a battery isolator with a LA on one or more outputs and LFP on another output, will protect the alternator. However, the alternator will only do a charge algorithm for one chemistry, meaning that the other one is not charged correctly. This is why my reference diagram uses dc-dc charging.

It is very easy to stop the alternator and the Balmar manual describes which connection to interrupt, which is simply done with a relay controlled by the BMS.

[PUDDLE JUMPER II]

Originally Posted by Dr.No

I The details are extensive: 4/0 cables to 400 amp T fuses (positive and negative - Nigel Calder personally said to use both in case of a lightening strike), then 600 amp negative mechanical, and positive RBS cutoff switches

A few Quick newbie questions=

1) How did you determine the right size of your T Class Fuses?

2) If there is some known calculation or chart-- please name drop so I can research and learn about this?

3) Is there a good sailing HOW TO Lithium YouTube channel you would recommend?

4) Do you have a diagram of your system posted some where? Please drop me a link?

Thank you in advance!

[goboatingnow]

Originally Posted by newhaul

Anchor lights are what a $10 photo cell is for

I use my mppt to tell all the boat systems it’s day or night. This winter that info will be on the nmea 2000 bus as well which means everything custom can access the status.

[goboatingnow]

Originally Posted by DeValency

Thanks s/v Jedi for the initiating the design and discussion. This is going to be a major resource to many of us upgrading to LFP and externally regulated higher power alternators. Thanks also to the other contributors in this thread for the good comments.



Being aware of the need to protect the alternator from a sudden charge termination by the LFP, Balmar's recommendations were programmed on my MC-618 - e.g. terminate alternator charging before the LFP BMS disconnects.



The second protection line as discussed here, by disconnecting the alternator control are of course almost the ultimate active safety feature.



In my case, I consider a passive protection as the starter batteries are staying as AGM, at least for now, and I also left, for now, two (relatively new) group 31 AGM house batteries, that are normally connected to the Victron ArgoFET 200A battery isolator one of the three separate outputs.

Meaning there is always some load on the alternator from the AGM batteries. This load may be minimal, as when the LFP reaches the targeted 13.8V (my BMS custom setting), the AGM is not yet 100% charged.



Comments? agree? disagree?



Thanks

It’s an engineering call

Firstly the paralleling of LiFePO4 with SLA is not recommended ( I posted battle born and manly batteries advice )

Secondly requiring dc dc converters to be rated to handle alternator SLA to Li is expensive.

Hence my personal engineering perspective is a proper smart alternator regulator is better ( for Li and LA) and the BMS could be equipped to provide proper charge source disconnection before HVE cutoff ( since an ABYC iso Compliant system needs advance warning of HVE. That warning can easily drive an smart regulator disconnect.

I really think this argument of alternator arbitrary disconnect is over played. A simple field coil relay disconnect is sufficient even if the stock alternator is retained . Listening. Here people are building whole alternative solutions merely to avoid dealing with proper alternator disconnect processes.

[newhaul]

Originally Posted by goboatingnow

I use my mppt to tell all the boat systems it’s day or night. This winter that info will be on the nmea 2000 bus as well which means everything custom can access the status.

Ok but question .
How does your MPPT know if it's day or night ? Or are you using power in to control? If so then a thunder storm may tell your boat it's night time.
Problem is the output of the mppt is limited in capacity.

[s/v Jedi]

Originally Posted by newhaul

Ok but question .
How does your MPPT know if it's day or night ? Or are you using power in to control? If so then a thunder storm may tell your boat it's night time.
Problem is the output of the mppt is limited in capacity.

I guess he did it the same as me: program it’s relay for day detection. If it becomes too dark for that algo, then it’s time to turn on the night and anchor lights

[newhaul]

Originally Posted by s/v Jedi

I guess he did it the same as me: program it’s relay for day detection. If it becomes too dark for that algo, then it’s time to turn on the night and anchor lights

I can do the same but the issue would then be the false signals as well as the amp limit of the controller. Mine is 30 amps limit out.
For my use it would work but wiring in a photocell on the mast is easy. As only the anchor light needs to be on at night .
Dang what a drift we have

[s/v Jedi]

Originally Posted by newhaul

I can do the same but the issue would then be the false signals as well as the amp limit of the controller. Mine is 30 amps limit out.
For my use it would work but wiring in a photocell on the mast is easy. As only the anchor light needs to be on at night .
Dang what a drift we have

I don’t think you have the programmable relay… there is no amp rating, it’s just signaling contacts to tell microcontrollers or other relays that it’s dark outside.

See 3.12, 6th option in attached manual page

[newhaul]

Originally Posted by s/v Jedi

I don’t think you have the programmable relay… there is no amp rating, it’s just signaling contacts to tell microcontrollers or other relays that it’s dark outside.

See 3.12, 6th option in attached manual page

I am running an Epever tracer 3210 the internals only allow for up to 30 amps output. I could use it as a signal to operate a relay but why? A simple photocell does the job .
Afterall what else really needs to be on at night all the time when not at a dock aside from the anchor light?

[s/v Jedi]

Originally Posted by newhaul

I am running an Epever tracer 3210 the internals only allow for up to 30 amps output. I could use it as a signal to operate a relay but why? A simple photocell does the job .
Afterall what else really needs to be on at night all the time when not at a dock aside from the anchor light?

But we have Victron controllers so we don’t even have to buy and install any photocells… just click on the config option and be done

[newhaul]

Originally Posted by s/v Jedi

But we have Victron controllers so we don’t even have to buy and install any photocells… just click on the config option and be done

At least double the cost yes .

I didn't need to I could have used the MPPT to control it but why?
What else needs be on at night but off all day?

[s/v Jedi]

Originally Posted by newhaul

At least double the cost yes .

I didn't need to I could have used the MPPT to control it but why?
What else needs be on at night but off all day?

My night lighting

This is an ongoing project for me as we are replacing the ceiling aboard, which includes all lighting. I’ll have pictures and electronic designs later

The thing is that you don’t have solar controllers that include day detection so you need to install a sensor. For those who have that built into their solar controllers, they only need to enable it in the settings, which is much easier than installing sensors and at zero cost.

[newhaul]

Originally Posted by s/v Jedi

My night lighting

This is an ongoing project for me as we are replacing the ceiling aboard, which includes all lighting. I’ll have pictures and electronic designs later

The thing is that you don’t have solar controllers that include day detection so you need to install a sensor. For those who have that built into their solar controllers, they only need to enable it in the settings, which is much easier than installing sensors and at zero cost.

I have that setting in my controller but I only want to control 1 light like that so makes no sense to do the extra wiring for that one item .
You have to do more than just enable it you have to wire to the Relay for the load you want controlled by it . Unless it missing something.

[Baronkrak]

Originally Posted by goboatingnow

Firstly the paralleling of LiFePO4 with SLA is not recommended

You keep repeating the same; can you present some technical evidences to support your claim?

[s/v Jedi]

Originally Posted by Baronkrak

You keep repeating the same; can you present some technical evidences to support your claim?

There is nothing in ABYC to support that statement, but it is fact that you can only charge one chemistry correctly and are shortening the lifespan of the other.