Lifepo4 Batteries

[Helmsman]

One of the things I have come across over and over in studying lithium is that it is really necessary to get get good quality cells that are sequential serial numbers and purchased from a reputable dealer. The same is true to get a really good BMS. Most of the really successful builds seem to go with an external BMS as opposed to a built in “drop in” battery. Can’t find the video, but a guy tested several and he showed the difference in the build quality (solders, etc) The drop in battery is marketing hype.

Another consideration is where you put your bank. An engine room is typically a no go, due to the heat. Lithium is sensitive to the heat.

[km1125]

Source of the post
....Unfortunately lithium is not all that good for use as stating batteries so those will remain the same. ...

Just so that statement doesn't develop some misconceptions for readers...

Lithiums CAN BE very good starting batteries, but they have to be "starting batteries" designed for high current usage. Just like lead-acid batteries can be starting batteries or deep-cycle batteries, lithiums can be configured either way too. They can typically be configured to deliver MUCH higher cranking amps at a higher voltage than lead-acid batteries It's just a matter of getting the right product for the right application.

[bud37]

Hmmm.....by the time you are done it almost sounds like a very expensive and complicated solution to a problem you don't have........

[Midnightsun]

If it were not a problem I would not be thinking about it. been anchored with solar for about 8 days now. Have some range anxiety going on as they say in EV talk. Trying to resolve this without adding another 250 lbs of batteries. I do like challenges so this is right up my alley.

[Helmsman]

If it were not a problem I would not be thinking about it. been anchored with solar for about 8 days now. Have some range anxiety going on as they say in EV talk. Trying to resolve this without adding another 250 lbs of batteries. I do like challenges so this is right up my alley.

Might want to check out Firefly Oasis Carbon Foam batteries. That might work for you and keep from upgrading the entire system.

[Midnightsun]

Got my batteries and charger however uped it from the 60a model to the 80a model from Progressive Dynamics. After some talk with both Sterling and Victron I will go with dual Victron energy DC to DC chargers which will replace my diode isolators. One for port engine alternator and the other for starboard and both terminating at the lithium bank for a total output of 60amps. These are pretty cool as they connect via bluetooth to your phonr along with all other victron energy devices so monitoring and changing parameters is fairly easy.https://www.victronenergy.com/dc-dc-con ... n-isolated

I have a Blue Seas SOC meter that will not work well any more but luckily I did keep my Blue Sea DC meter which will replace it for monitoring the new lithium bank, the port and starboard starting batteries and the generator battery as the unit can handle 4 inputs

I will replace the shunt from the previous SOC with a Victron Smart shunt which does bluetooth once again and I can get all the SOC readings from my iPhone. https://www.victronenergy.com/battery-m ... tery-shunt

Only issue I have now is what if an alternator goes on the blink, no way of connecting the 2 house banks with the isolators gone. Maybe a manually activated ACR between the 2 start batteries is the way to go to cover this issue.

May even change my solar controller to integrate the system to a Victron bluetooth unit. https://www.victronenergy.com/solar-cha ... -30-100-50

Oh boy, lots of wires and connections but in the end it will be awesome, I hope!

[Viper]

You don't believe in keeping things simple do you, or believe in the "less to go wrong" principle? After you get LI units installed, I'll get you going again and bring up the topic of super/ultracapacitor units and the new strides their making. How about hydrogen cells?

Love your projects Hans, keep up the good work

[Midnightsun]

If I do not keep my mind busy I will get crazier than I already am.

Bought a 20A AC breaker and a length of 10ga triplex tinned boat cable to handle the load of the 80a Lithium charger. Will be going to my local solar experts who carry the entire line of Victron stuff plus a lot more for advice. Just want to make sure I have not forgotten something or misunderstood something before I begin to install. May actually get this done before the end of season comes around.

[km1125]

Source of the post
....I have a Blue Seas SOC meter that will not work well any more ....

Wonder if you can elaborate on that. Does it use voltage as the primary tool for determining SOC instead of amp_in/amps_out?

Source of the postMaybe a manually activated ACR ....

Something 'oxymoronic' in that statement

You could just put in an "emergency combining relay" with a continuous duty rating. I'd add a big red (or some other color) light to it so it's obvious when it is activated so you don't inadvertently forget to disable when no longer needed.

[Midnightsun]

The SOC meter would work OK however it can only do a max of 3 batteries. The DC meter will do all four and the smart shunt will do the SOC for me. That being said, Monitoring voltage on a Lithium is sort of useless as the voltage remains rather constant until it's almost dead. In other words it will register 13.8v until there is about 20% left before it starts to move downward. This explains it pretty well. https://www.powertechsystems.eu/home/te ... asurement/

I did see the idiosyncrasy in that after I posted, should have said a manual relay then again is that not a simple on off switch.

This would be a rather simple install to interconnect the 2 start batteries if an alternator should fail. https://www.amazon.ca/Continuous-Battery-Isolator-Current-Mobile/dp/B08SW4XVNR/ref=sr_1_8?dchild=1&keywords=200a+relay&qid=1630263759&sr=8-8

OOOR, maybe stop overthinking this and just install this between the 2 start batteries for emergency use only if an alternator were to fail. https://www.amazon.ca/Disconnect-Vehicles-Waterproof-Isolator-Position/dp/B07SLKJXCG/ref=asc_df_B07SLKJXCG/?hvadid=335562268731&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9000604&hvnetw=g&hvpone=&hvpos=&hvptwo=&hvqmt=&hvrand=10374070302753769819&hvtargid=pla-784427114051&language=en_CA&linkCode=df0&psc=1&tag=googleshopc0c-20