LiFePO4 reference diagram, 12V version

[s/v Jedi]

I modified the diagram for 12V house batteries. Asyou can see, much is the same. Changes:

1. House batteries from 4x 700Ah Winston cells, 9kWh each
2. BMS and Battery switch 12V versions
3. dc-dc converters are 12-12 versions
4. Inverter/charger is a 12V version

[luckyone]

Thanks,
I, for one, very much appreciate your efforts. As I plan a major upgrade this is very helpful. What changes would you make if you wanted to directly charge the house batteries from a large alternator. In my case the engine runs many more hours than the generator.

[s/v Jedi]

Originally Posted by luckyone

Thanks,
I, for one, very much appreciate your efforts. As I plan a major upgrade this is very helpful. What changes would you make if you wanted to directly charge the house batteries from a large alternator. In my case the engine runs many more hours than the generator.

I plan to make a diagram for that as well. You have two options: add a second alternator for the house bank, or replace the oem alternator with a bigger one. Either way also requires an external regulator and alternator-mounted temperature sensors, as well as a BMS that has a warning-level output to shut down the alternator field current before the BMS takes the battery offline, which would blow up the diodes in the alternator.

[twofingerpoi]

@s/v-Jedi

Would you be willing to share the source file for the diagram so that I might make some modifications? Really appreciate all the versions you have provided with additional details.

It would be useful for me to have a very minimal 12V system. I have a Beneteau 361 with two flooded house batteries and one starter, and nothing other than original 12V power systems. I plan to add a SmartShunt and some basic solar to maintain the batteries then upgrade over time.

[s/v Jedi]

Originally Posted by twofingerpoi

@s/v-Jedi

Would you be willing to share the source file for the diagram so that I might make some modifications? Really appreciate all the versions you have provided with additional details.

It would be useful for me to have a very minimal 12V system. I have a Beneteau 361 with two flooded house batteries and one starter, and nothing other than original 12V power systems. I plan to add a SmartShunt and some basic solar to maintain the batteries then upgrade over time.

This 12V version has two house and two starter batteries: simply delete one battery and switch and that’s it. This is a lithium forum so no flooded house batteries here.

I make these diagrams online at lucidchart.com, not with software on my computer, so there is no source file.

[twofingerpoi]

The boat had two brand new 4D batteries when I bought it in April '22, so it would be a shame to replace them so soon. I promise to replace them with proper LiFePO4 when they are near end of life.

In the meanwhile, I do use LucidChart, Miro and other such apps, so if you can share a link with view perms I can make a copy to edit.

[s/v Jedi]

Originally Posted by twofingerpoi

The boat had two brand new 4D batteries when I bought it in April '22, so it would be a shame to replace them so soon. I promise to replace them with proper LiFePO4 when they are near end of life.

In the meanwhile, I do use LucidChart, Miro and other such apps, so if you can share a link with view perms I can make a copy to edit.

Let me find out how that works… never did that before

[s/v Jedi]

Originally Posted by twofingerpoi

The boat had two brand new 4D batteries when I bought it in April '22, so it would be a shame to replace them so soon. I promise to replace them with proper LiFePO4 when they are near end of life.

In the meanwhile, I do use LucidChart, Miro and other such apps, so if you can share a link with view perms I can make a copy to edit.

Does this work?

https://lucid.app/lucidchart/721615e...-96dd28196f56#

[s/v Jedi]

Originally Posted by twofingerpoi

The boat had two brand new 4D batteries when I bought it in April '22, so it would be a shame to replace them so soon. I promise to replace them with proper LiFePO4 when they are near end of life.

In the meanwhile, I do use LucidChart, Miro and other such apps, so if you can share a link with view perms I can make a copy to edit.

I have one battery with 8x a Winston 400Ah lfp cell in series but my second battery is also an old one... it has 4x a Lifeline 400Ah 6V agm battery in series and it's still going strong.

It's best to replace one battery with lfp, then wait a couple of years before replacing the other one. This gives you better redundancy because they hopefully won't reach end of life at the same time

[gtpinhei]

Sweet system!

[fxykty]

Originally Posted by s/v Jedi

Does this work?



https://lucid.app/lucidchart/721615e...-96dd28196f56#

I get not authorised to view (:

[s/v Jedi]

Originally Posted by fxykty

I get not authorised to view (:

You must be a registered user and probably paying customer to get authorization.

[krid2000]

Originally Posted by s/v Jedi

as well as a BMS that has a warning-level output to shut down the alternator field current before the BMS takes the battery offline, which would blow up the diodes in the alternator.

What do you think of "Alternator Protectors" instead (such as this one) that buffer the voltage spike in case of a BMS cutoff?

Thanks
Dirk

[goboatingnow]

Originally Posted by krid2000

What do you think of "Alternator Protectors" instead (such as this one) that buffer the voltage spike in case of a BMS cutoff?



Thanks

Dirk

This will protect the alternator which can typically handle 40v spikes

The issue is any other electronics connected “ may “ not survive.

[krid2000]

Originally Posted by goboatingnow

This will protect the alternator which can typically handle 40v spikes. The issue is any other electronics connected “ may “ not survive.

Thanks, I hadn't thought of that!

Dirk