Victron settings for charging combination Boat and LiFePo4

[bishoptf]

Here is what I have and trying to figure out what the best settings are for my setup. I will keep this short but I have a bassboat that has 4 batteries, 1 agm starting battery Interstate 31M-AGM - https://www.interstatebatteries.com/products/31m-agm (also runs a few loads basically livewells and some lights) and then three LifePo4 batteries all Powerurus 100ah batteries, one for house that runs all electronics and 2 are for the trolling motor. I am unable to store my boat at my house for several reasons but the main reason is that I am on a hill and its just a royal PIA to park so to get around not having it at my house I need a way to keep the batteries charged. I have several electronic devices that "combine" the starting batteries and the house and trolling batteries. I've had these for years in my older boat and they work pretty well for the most part, when voltage reaches a certain level on the starting battery it places the other batteries in parallel so the alternator in the engine charges all the batteries. If anyone is interested here are the devices that I am using, they are called combiners from smart shore marine, previously Yandina - https://smartshoremarine.com/products/battery-combiner-100-for-lithium-batteries and then for the trolling batteries - https://smartshoremarine.com/products/trollbridge-12x24-for-lithium-batteries

This works pretty well for the most part, as long as I am running the main engine all the batteries receive a charge and the newer engines even at idle put out a lot of amps. There are a few lakes that are trolling motor only lakes and when fishing one of them since I am unable to run the main engine I am unable to keep the batteries topped up. On board I have a 25amp victron charger single output marine smart IP67 charger - https://www.amazon.com/Victron-Energy-12-Volt-Battery-Bluetooth/dp/B07TMRJQTH but trying to figure out how to get it dialed in. Currently I have it connected to the starting AGM battery which once the voltage reaches the set level combines with the other batteries. The problem I am having is what settings I should use on the victron. I found out when charging and balancing my Powerurus batteries that they would not go over 14v when balanced so I had set the voltage on the victron to 14v but it appears that once the agm battery is hitting 14v it moves from bulk to absorption and then to float before the other LifePo4 batteries reach full charge. I am thinking of moving the victron leads to the house battery since that is usually the battery that is the lowest but I am also thinking that maybe I need to increase the voltage to 14.1 or 14.2 and/or setting the absorption time longer so it keeps the voltage set for a longer time. The other option is to just set the victron in power supply mode and set it to 14.1 volts.

I guess my question is when I have a combination of batteries what kind of charge profile should I use, I understand that I am wanting to charge the LifePo4 batteries over the agm and that it probably wants a higher voltage but it is what it is with my setup. Would putting the victron in power supply mode be the best way to get all the lithium batteries to get close to full?

Looking for any suggestions on how to optimize, @sunshine_eggo or anyone have any thoughts?

 

[sunshine_eggo]

12.8V LFP is mostly a "drop-in" replacement for 12V lead acid.

You can easily get LFP fully charged at 13.8V with a couple hours of absorption. For a faster charge 14.4V with a 30 minute absorption.

LFP should be floated at 13.5V to prevent low-current over-charge.

 

[bishoptf]

12.8V LFP is mostly a "drop-in" replacement for 12V lead acid.

You can easily get LFP fully charged at 13.8V with a couple hours of absorption. For a faster charge 14.4V with a 30 minute absorption.

LFP should be floated at 13.5V to prevent low-current over-charge.

Thanks for taking a look, if you remember I was the one trying to get these battery cells to balance out and you helped me figure out how to go about and do it. The bms of these batteries will shut off once they hit 14.0v, just the way they have it. Currently I have the victron connwcted to the starting battery and then the electronics put the rest of the batteries in parallel. I switched over to power supply mode and that seemwd to work much better, had it set to 14v. The house battery charged up appropriately like i felt it should but the two trolling motor batteries charged up they appear to hit 13.5-13.6 and just stop. According to the bluetooth app amps are still going in but they do not appear to be charging. Not exactly sure what the electronics are doing to interfere but the charger should see all the batteries as ine big battery. I need to figure out what is causing this, I increased the voltage to 14.1 and did see an increase on the trolling batteries so it appears that there is a voltage drop or something with the electronics. I attached a screenshot showing that the house got to 13.9v but the other 2 stopped at 13.5/13.6v. I let it run since it appears amps are flowing but 2 hours later there were at the same spot so I dunno whats going on.

Will have to do more work and see if I can figure it out, appreciate the input as always

 

[sunshine_eggo]

Thanks for taking a look, if you remember I was the one trying to get these battery cells to balance out and you helped me figure out how to go about and do it. The bms of these batteries will shut off once they hit 14.0v, just the way they have it.

Is it at 14.0V, or does it shut off there because a single cell goes over-voltage?

Currently I have the victron connwcted to the starting battery and then the electronics put the rest of the batteries in parallel. I switched over to power supply mode and that seemwd to work much better, had it set to 14v. The house battery charged up appropriately like i felt it should but the two trolling motor batteries charged up they appear to hit 13.5-13.6 and just stop.

According to the bluetooth app amps are still going in but they do not appear to be charging.

This may be because the current for each battery is below the threshold the BMS will measure/report. If the charger is still feeding current, and there's no way it's going into something else (consumed by house loads), the batteries are still charging.

Based on the included picture it does say current is going in, and they are at 100%. That's just an indication the SoC is not correct, and there is more charging to be had, but it won't indicate more than 100%.

Not exactly sure what the electronics are doing to interfere but the charger should see all the batteries as ine big battery. I need to figure out what is causing this, I increased the voltage to 14.1 and did see an increase on the trolling batteries so it appears that there is a voltage drop or something with the electronics. I attached a screenshot showing that the house got to 13.9v but the other 2 stopped at 13.5/13.6v. I let it run since it appears amps are flowing but 2 hours later there were at the same spot so I dunno whats going on.

Will have to do more work and see if I can figure it out, appreciate the input as always

Epochs have been shown to be vulnerable to some significant imbalances and seem to have very poor balance behavior (only balance when charging is enabled). This could explain the deviations you're seeing.

Are the trolling batteries reporting any kind of protection condition?

 

[bishoptf]

Here is my summary posting that documented what we found with the powerurus bms, its a doozy - https://diysolarforum.com/threads/powerurus-12v-100ah-hour-bms-balancing-information.97509/

Is it at 14.0V, or does it shut off there because a single cell goes over-voltage?

On the house battery I do not see the bms shutting it off. The bms will trigger if a single cell goes over 3.6 OR the average voltage hits 14.0v so about 3.5v per cell, I proved tha in my balancing trials, just how they have it programmed which is lame but is what it is.

Is it at 14.0V, or does it shut off there because a single cell goes over-voltage?






This may be because the current for each battery is below the threshold the BMS will measure/report. If the charger is still feeding current, and there's no way it's going into something else (consumed by house loads), the batteries are still charging.

I have breakers after the batteries to shut off house/trilling motor there are no loads when I am charging, breakers are tripped after I. Done fishing for the day to stop and drain while sitting.

Based on the included picture it does say current is going in, and they are at 100%. That's just an indication the SoC is not correct, and there is more charging to be had, but it won't indicate more than 100%.

Yeah just doesnt seem to be increasing the cell voltages, its really odd. Only time I daw it increase the cell voltages is when I changed the victron to supply 14.2v.

Epochs have been shown to be vulnerable to some significant imbalances and seem to have very poor balance behavior (only balance when charging is enabled). This could explain the deviations you're seeing.

Are the trolling batteries reporting any kind of protection condition?

The trolling batteries bms never trip based on what the app is stating. I've attached a screenshot that shows one battery mos state but they are both the same. I was to lazy to get my meter since i think it would be interesting to take readings on both the trolling batteries and see what it said. I just think its odd that the house battery acts as I would expect, its just the trolling batteries. Again I did see the voltages kick up on the trolling motor batteries when i increased the voltage on the victron app. Maybe if I set it to 14.2v and see what that does, my guess the house battery charge mos will kick in. My other guess is lime you stated the soc is way off and they just need a good bit more time.

Planning to take it out tomorrow and I will put it on the charger for a couple more hours and see where that gets me.