Epoch Made All What We Want

[rslifkin]

Originally Posted by CaptainRivet

Simple answer if manufacturer tells you to charge to 14.6V, charge to 14.6V as they tested that.
The amount of people think they do and know better then manufacturer out there is huge and the hokuspokus that 3,45 or 3,55V enlarges lifespan a lot. Fact is cells are speced to charge to 3,65V and the 3 major factor of depreciation is age, age, C-rate charged and discharged. The pontntial that you harm a battery when charging too low and not get enough time for too balance is much higher then the lifespan gain to charge to 3,55V.
BUT don't leave it charged at 3,65V and if possible cycle between 50 and 80%DOD with max 0.3C charge or discharge, that give you max cycles.

Depending on which datasheet you look at for the Epoch stuff, they all list 14.6V as the max charge voltage, but either list 14.0 - 14.6 as the charge voltage range or in at least one place they recommend 14.2V. Acceptable float voltage is listed as 13.6 - 13.8V in the specs, but that's definitely the upper end of the safe range.

If the Epoch batteries start balancing at 3.35 VPC (13.4V pack voltage) as listed earlier in the thread, then charging to 13.8 or 14.0V should be adequate for balancing purposes, but of course that should be monitored in use to confirm the cells aren't drifting out of balance.

[MV Intrigue]

Originally Posted by CaptainRivet

Simple answer if manufacturer tells you to charge to 14.6V, charge to 14.6V as they tested that.
The amount of people think they do and know better then manufacturer out there is huge and the hokuspokus that 3,45 or 3,55V enlarges lifespan a lot. Fact is cells are speced to charge to 3,65V and the 3 major factor of depreciation is age, age, C-rate charged and discharged. The pontntial that you harm a battery when charging too low and not get enough time for too balance is much higher then the lifespan gain to charge to 3,55V.
BUT don't leave it charged at 3,65V and if possible cycle between 50 and 80%DOD with max 0.3C charge or discharge, that give you max cycles.

Can you find any example of a ,manufacturer that recommends and operating range with Victron comms to set charge voltage to 14.6? Victron doesnt even recommend 14.6. Fact is they did test that and do not recommend using 14.6. No one does. Keep in mind Victron used to "certify" third part batteries using Victrons open source protocol. One such battery is the Pylontech. From Victron engineers they state explicitly to not to 14.6 or 3.65 for Pylontech. Thet also explicitly state not to use those parameters for their very own Victron batteries. See the following quote from Victron regarding their own batteries and system operation:

A clear indication of imbalance is that the BMS frequently disables the charger. On a well-balanced battery the charger would not be disabled – not even when the batteries are fully charged.

More detail can be seen with the VictronConnect App. Be aware that checking cell balance can be done only near the end of a charge. It’s best to wait for the battery voltage to reach 14.2V, and then check the individual cell voltages. They should all be between 3.50 and 3.60V. Over time they will all become equal at 3.55V. By that time the battery will be completely charged, and balanced.

Here is a screenshot showing a balanced battery. Note the battery voltage is at 14.2V; and the cell voltages are each exactly a quarter of that value at: 3.55V.

Found here: https://www.victronenergy.com/blog/2...CCR7O3E12h1E7Y


And that recommendation has nothing to do with cell life or cycle count. It has to do with system stability when using Victron enabled smart batteries and preventing nuisance warnings and inadvertent shutdown of the charge mosfets. There is no good reason to cycle a camper, boat or off grid system to 14.6. Not to mention it just wont work with Victron protocol.

IMO 14.6 or 3.65 cell charge voltage is for something like my golf cart where you put it on a dumb charger and charge it in the least amount of time and it doesnt matter if the charge mosfet shuts down at that top of the charge. Which it does. On a boat you just dont want to charge to that point for a myriad of reasons.

On large capacity cells, charging to the top of the range, and expecting each cell to hit a perfect 3.65 volts for a total of 14.6 pack volts is just not realistic. Cell variance at the top of the range will never be perfectly synced. Especially in something like a 300-460Ah battery. Dont forget...to hit 14.6 each cell will have to stay in perfect lockstep all the way to the top of the charge. That just doesnt happen in real life. One cell will always be highest and cause a cell overvolt well prior to hitting 14.6 total pack voltage. And balancing tends to get MORE difficult as you approach 14.6 not less difficult.

The community with the most experience with Victron enabled smart batteries is almost certainly Pylontech and Victron. Neither recommend a cell voltage of 3.65. And again...not because the cell cant handle it, but in practice, attempting to charge to that level makes Victron enabled system unstable at the top and likely to have cell overvolt. On boats we dont want unstable.

In addition, the capacity difference between 3.5 or 3.55 and 3.65 is non existent. You just aren't getting any more capacity at 3.65. But you are getting an whole lot more instability on a victron enable system. So why would anyone do it? No one does.

[MV Intrigue]

Originally Posted by SOLAR SUPPORT

It is obvious that there is a problem with the load distribution of the parallel Epoch 460 batteries you connected to the test set. Did you find the reason? Connecting the thick energy cables coming from the batteries in parallel connection in a Y or T shape may give better results. Similar to this experimental set, two 200Ah Lifepo4 batteries are connected in parallel on my boat. In this setup, the batteries are connected directly to the inverter. As a result of the clamp ammeter measurements I made separately from the terminals of both batteries during a total discharge of 100A, I observed that the load distribution was much more stable. Towards the end of the video, when the capacity of the Epoch batteries is 0%Soc, I can only make a guess for the strangeness seen in the measured current values ​​when the fan is running. At this time, an active or passive balancer, if any, may have been activated.

Mainly the variance was due to poor connections since that testing was done with cobbled together used cables of various lengths and quality. It was fine for testing though, I actuallly didnt change it because I just wanted to observe the behavior. I have all new Ancor 4/0 and 2/0 marine wire and Selterm lugs for when they actually go in the boat. At that time I will "fine tune" the distribution to get each battery as equal as possible for current draw.

Also...the Epoch, and most bluetooth batteries that have an internal shunt, arent very accurate when drawing very low currents. Thats one reason to go ahead and incorporate a Victron shunt even though the batteries have SOC meter. I find the Victron Smart shunt to be more accurate over time and you can adjust the low end current threshold. Its good to have both internal shunt and external shunt just to have a comparison. In addition you can set more warnings if you have a Victron shunt in the system with the Cerbo. So for the price to add a victron shunt it seems useful.

[SOLAR SUPPORT]

I don't think a meaningful conclusion can be reached by focusing on the cell or battery charge voltage upper limit. By measuring the voltage of each cell separately, BMS simultaneously observes all cells connected in series within the battery. One of the cells reaches full charge before the others and then quickly reaches 3.65 volts, but the BMS does not allow it to rise any further, abruptly shutting off the battery charge.

Can devices using Can Bus data track fast-running cells in the battery as quickly as the drop-in battery BMS? BMS does not decide based on the total voltage of the cells in series, it actually protects the fast-running cell by cutting off the battery charge. Exceeding the 3.65 Volt threshold by any of these cells triggers battery BMS. Meanwhile, the battery voltage may be somewhere between 13.8-14.6 Volts for 4s.

Even though whoever claims that cell balancing is not disrupted in every cycle and that the cells are "A" quality and super balanced, they cannot guarantee that these surprise BMS outages will never occur. Drop-in LFP batteries, especially those used in marine environments, experience this sooner or later. The important thing is that you have the necessary sustainable assurance when this event occurs. Like an Argofet battery isolator and the LA battery connected to it.

I really wonder if Victron or other integrated control systems can monitor the voltage of each battery's cells separately via Can Bus (I'm not talking about battery voltage) and turn off the alternator charge before the BMS cuts off the charge when necessary.

[wholybee]

Originally Posted by SOLAR SUPPORT

I don't think a meaningful conclusion can be reached by focusing on the cell or battery upper limit charge voltage. By measuring the voltage of each cell separately, BMS simultaneously observes all cells connected in series within the battery. One of the cells reaches full charge before the others and then quickly reaches 3.65 volts, but the BMS does not allow it to rise any further, abruptly shutting off the battery charge.

Can devices using Can Bus data track fast-running cells in the battery as quickly as the drop-in battery BMS? BMS does not decide based on the total voltage of the cells in series, it actually protects the fast-running cell by cutting off the battery charge. Exceeding the 3.65 Volt threshold by any of these cells triggers battery BMS. Meanwhile, the battery voltage may be somewhere between 13.8-14.6 Volts for 4s.

Even though whoever claims that cell balancing is not disrupted in every cycle and that the cells are "A" quality and super balanced, they cannot guarantee that these surprise BMS outages will never occur. Drop-in LFP batteries, especially those used in marine environments, experience this sooner or later. The important thing is that you have the necessary sustainable assurance when this event occurs. Like an Argofet battery isolator and the LA battery connected to it.

I really wonder if Victron or other integrated control systems can monitor the voltage of each battery's cells separately via Can Bus (I'm not talking about battery voltage) and turn off the alternator charge before the BMS cuts off the charge when necessary.

A BMS shutoff, even one due to cell voltage, should never happen, and if it does should not be a surprise. Yes, cell will drift out of balance, but that happens slowly over time. The balancing circuits in the BMS will keep them in balance, and if not, a user should should occasionally check cell voltages and see them out of balance weeks before they get so bad that a cell causes a BMS to cutoff.

The BMS sends a signal to stop charging via the CANBUS to the alternator and other chargers. There is no reason for other devices to monitor cell voltages, except to log them or display them to the user.

[SOLAR SUPPORT]

Originally Posted by wholybee

A BMS shutoff, even one due to cell voltage, should never happen, and if it does should not be a surprise. Yes, cell will drift out of balance, but that happens slowly over time. The balancing circuits in the BMS will keep them in balance, and if not, a user should should occasionally check cell voltages and see them out of balance weeks before they get so bad that a cell causes a BMS to cutoff.

The BMS sends a signal to stop charging via the CANBUS to the alternator and other chargers. There is no reason for other devices to monitor cell voltages, except to log them or display them to the user.

Let's remember the posts about APDs that are out of use and have to be purchased again, and it is recommended to keep a spare APD on the boat..Let me remind you that all of the APD damages occurred as a result of the Bms charging cut-off operations, which you claimed above were not a surprise.

While some advanced Drop-in battery BMSs can send a pre-warning signal to turn off all chargers with Canbus communication before cutting off the battery charge, in addition to the existing Canbus communication, BMS can also give an electrical pre-warning signal at the same time with a simple port hardware. All chargers that do not use Canbus could safely stop charging by simultaneously using the electrical pre-warning signal coming from this port. This hardware is needed to safely turn off the charge of an alternator without Canbus communication.

[wholybee]

Originally Posted by SOLAR SUPPORT

Let's remember the posts about APDs that are out of use and have to be purchased again, and it is recommended to keep a spare APD on the boat..Let me remind you that all of the APD damages occurred as a result of the Bms charging cut-off operations, which you claimed above were not a surprise.

While some advanced Drop-in battery BMSs can send a pre-warning signal to turn off all chargers with Canbus communication before cutting off the battery charge, in addition to the existing Canbus communication, BMS can also give an electrical pre-warning signal at the same time with a simple port hardware. All chargers that do not use Canbus could safely stop charging by simultaneously using the electrical pre-warning signal coming from this port. This hardware is needed to safely turn off the charge of an alternator without Canbus communication.

Show me the posts from users that have had an APD fail. There are many posts saying they will, but I have yet to see a post where they actually do fail. It is a myth that they are a single use device. They have a maximum voltage they can withstand, and can be used many times so long as that maximum voltage is not exceeded.

[CaptainRivet]

Originally Posted by MV Intrigue

Can you find any example of a ,manufacturer that recommends and operating range with Victron comms to set charge voltage to 14.6? Victron doesnt even recommend 14.6. Fact is they did test that and do not recommend using 14.6. No one does. Keep in mind Victron used to "certify" third part batteries using Victrons open source protocol. One such battery is the Pylontech. From Victron engineers they state explicitly to not to 14.6 or 3.65 for Pylontech. Thet also explicitly state not to use those parameters for their very own Victron batteries. See the following quote from Victron regarding their own batteries and system operation:



Found here: https://www.victronenergy.com/blog/2...CCR7O3E12h1E7Y


And that recommendation has nothing to do with cell life or cycle count. It has to do with system stability when using Victron enabled smart batteries and preventing nuisance warnings and inadvertent shutdown of the charge mosfets. There is no good reason to cycle a camper, boat or off grid system to 14.6. Not to mention it just wont work with Victron protocol.

IMO 14.6 or 3.65 cell charge voltage is for something like my golf cart where you put it on a dumb charger and charge it in the least amount of time and it doesnt matter if the charge mosfet shuts down at that top of the charge. Which it does. On a boat you just dont want to charge to that point for a myriad of reasons.

On large capacity cells, charging to the top of the range, and expecting each cell to hit a perfect 3.65 volts for a total of 14.6 pack volts is just not realistic. Cell variance at the top of the range will never be perfectly synced. Especially in something like a 300-460Ah battery. Dont forget...to hit 14.6 each cell will have to stay in perfect lockstep all the way to the top of the charge. That just doesnt happen in real life. One cell will always be highest and cause a cell overvolt well prior to hitting 14.6 total pack voltage. And balancing tends to get MORE difficult as you approach 14.6 not less difficult.
You never harm a lifepo4 cell with charging to 3,65V (if the manufacturer is not explicitly stating different) but you short lifespan if you keep it at 3,65V.
The community with the most experience with Victron enabled smart batteries is almost certainly Pylontech and Victron. Neither recommend a cell voltage of 3.65. And again...not because the cell cant handle it, but in practice, attempting to charge to that level makes Victron enabled system unstable at the top and likely to have cell overvolt. On boats we dont want unstable.

In addition, the capacity difference between 3.5 or 3.55 and 3.65 is non existent. You just aren't getting any more capacity at 3.65. But you are getting an whole lot more instability on a victron enable system. So why would anyone do it? No one does.

As i said manufacturer spec and yes eg pylontech is know to charge lower to 3.55V.
Not victron is stating that, its pylontech, which actually is a commercial BMS that has its own charge voltage cutoff as well as an over-voltage cutoff and the BMS is also an battery optimizing device like my electrodacus BMS too means steering the show which can interfere with victron if eg charge is set higher then 3.55V, its not the cells, its the BMS that requires to use 3.55V.

But others, very simple: have a look at the cheap Li-time on their webpage. Manufacturer recommends 14.2-14.6V but all their own chargers,MPPT,DC2DC they sell are programmed to 14.6V.
So 14.6V it will be and the main reasons are a)passive balancer is small b) no communication so you only know when they cut out earlier. Means if you charge to 14.2V and it cuts out at at 14.0V you have already a massive imbalance (eg the 200AH li-time around 4AH deviation facing a tiny 100mA passive balancer, how long to balance??? Month) which the internal balancer won't be able to handle anymore, means cut open time, warranty voided. On 14.6V if it cuts at 14,4V you know you have a slight imbalance a give the passive balancer more time in the upper knee to sort this.

What you state is also wrong that especially 300-460AH is never sync that good...well i have 4p 272AH=1088AH and mine 1088AH pack are sync to 3-5mV, pulling 500A i get max 10mV deviation. And these are budget 272AH lishen cells, manufacturer matched, from 2021, the 280 or 304AH EVE V3 that you now get are better quality.
With bigger cells its exactly the other way around.
Its especially the bigger cells that keep in balance because the C-rate for the cell is much lower (less stress=imbalnce) in 460AH then 100AH cells, if you eg have a 100A load its 0.21C for the 460AH while 1C for the 100AH cell. But you have to have a very good top balance which you only get going to 3,65V as the higher the more precise is the top balance. But if they get out of balance you need a bigger balancer to get them back on balance and i am sure Epoch took care of that. If you have 4x100AH in paralell the draw is not 100%evenly splitted between them and the weakest 100AH cell will draw the whole pack down.

Thats why i also recommend from 20years experience to get as big cells as possible to get to your wanted total capacity and as less as possible batteries or cells in parallel.

[SOLAR SUPPORT]

Originally Posted by wholybee

Show me the posts from users that have had an APD fail. There are many posts saying they will, but I have yet to see a post where they actually do fail. It is a myth that they are a single use device. They have a maximum voltage they can withstand, and can be used many times so long as that maximum voltage is not exceeded.

You can also find and review posts containing APD-related problems. Where does the need to use APD come from? APD is not a new device. When the BMS drop-in suddenly cuts off the battery charge, the damage that occurs to the alternator and sensitive electronic devices on the boat is the same as what happens when a person accidentally turns the manual battery selector switch while the alternator is running.

The main reason for using APD in Li battery infrastructure is to prevent this problem that occurs when BMS turns off battery charging while the alternator is charging at HVC, LTC, HTC or another limit cell value. Can APD meet possible high voltage protection many times? How many times does this event need to occur before the APD becomes unusable? 10? one hundred? one thousand? No one can know this. You probably will not be able to hear the warning alarm that sounds when the APD is out of use due to the engine sound. Meanwhile, the alternator charging will continue and the next uncontrolled shutdown of BMS will cost you a lot. Using a battery isolator and an LA battery connected to it eliminates these risks and the need for an APD.

My extra expectation from BMS is to receive an electrical warning before cutting off the battery charge before any cell protection action. This feature is necessary to prevent the formation of high voltage, which will eliminate the risks that threaten the alternator without canbus communication, as well as all other sensitive electronic devices on the boat. Since this feature is not yet available in drop-in batteries, it is necessary to follow the voltage settings of the alternator regulators and the drop-in battery HVC voltage, which can change over time. Setting the alternator external regulator charge cut-off voltage to a relatively low 13.7-13.8 volts is also an option.

[CaptainRivet]

Originally Posted by MV Intrigue

Can you find any example of a ,manufacturer that recommends and operating range with Victron comms to set charge voltage to 14.6? Victron doesnt even recommend 14.6. Fact is they did test that and do not recommend using 14.6. No one does. Keep in mind Victron used to "certify" third part batteries using Victrons open source protocol. One such battery is the Pylontech. From Victron engineers they state explicitly to not to 14.6 or 3.65 for Pylontech. Thet also explicitly state not to use those parameters for their very own Victron batteries. See the following quote from Victron regarding their own batteries and system operation:



Found here: https://www.victronenergy.com/blog/2...CCR7O3E12h1E7Y


And that recommendation has nothing to do with cell life or cycle count. It has to do with system stability when using Victron enabled smart batteries and preventing nuisance warnings and inadvertent shutdown of the charge mosfets. There is no good reason to cycle a camper, boat or off grid system to 14.6. Not to mention it just wont work with Victron protocol.

IMO 14.6 or 3.65 cell charge voltage is for something like my golf cart where you put it on a dumb charger and charge it in the least amount of time and it doesnt matter if the charge mosfet shuts down at that top of the charge. Which it does. On a boat you just dont want to charge to that point for a myriad of reasons.

On large capacity cells, charging to the top of the range, and expecting each cell to hit a perfect 3.65 volts for a total of 14.6 pack volts is just not realistic. Cell variance at the top of the range will never be perfectly synced. Especially in something like a 300-460Ah battery. Dont forget...to hit 14.6 each cell will have to stay in perfect lockstep all the way to the top of the charge. That just doesnt happen in real life. One cell will always be highest and cause a cell overvolt well prior to hitting 14.6 total pack voltage. And balancing tends to get MORE difficult as you approach 14.6 not less difficult.
You never harm a lifepo4 cell with charging to 3,65V (if the manufacturer is not explicitly stating different) but you short lifespan if you keep it at 3,65V.
The community with the most experience with Victron enabled smart batteries is almost certainly Pylontech and Victron. Neither recommend a cell voltage of 3.65. And again...not because the cell cant handle it, but in practice, attempting to charge to that level makes Victron enabled system unstable at the top and likely to have cell overvolt. On boats we dont want unstable.

In addition, the capacity difference between 3.5 or 3.55 and 3.65 is non existent. You just aren't getting any more capacity at 3.65. But you are getting an whole lot more instability on a victron enable system. So why would anyone do it? No one does.

As i said manufacturer spec and yes eg pylontech is know to charge lower to 3.55V.
Not victron is stating that, its pylontech, which actually is a commercial BMS that has its own charge voltage cutoff as well as an over-voltage cutoff and the BMS is also an battery optimizing device like my electrodacus BMS too means steering the show which can interfere with victron if eg charge is set higher then 3.55V, its not the cells, its the BMS that requires to use 3.55V.

But others, very simple: have a look at the cheap Li-time on their webpage. Manufacturer recommends 14.2-14.6V but all their own chargers,MPPT,DC2DC they sell are programmed to 14.6V.
So 14.6V it will be and the main reasons are a)passive balancer is small b) no communication so you only know when they cut out earlier. Means if you charge to 14.2V and it cuts out at at 14.0V you have already a massive imbalance (eg the 200AH li-time around 4AH deviation facing a tiny 100mA passive balancer, how long to balance??? Month) which the internal balancer won't be able to handle anymore, means cut open time, warranty voided. On 14.6V if it cuts at 14,4V you know you have a slight imbalance a give the passive balancer more time in the upper knee to sort this.
Its not to maximize capacity, its to harden and robust your system andd see with this surprise boxes without communication early enough you have a problem.

Thats differnet with pylontech or epoch where you have access to the cell voltages and see of you get a runner/imblance. Here i would also use manufacturer spec but not the max. As you said correct 3,55V cutoff is a good value and actually the standard for dropins with communications as well as DIY ones. You see if your system stays in balance if not you can always go higher or lower balancer cut in voltage to give it more time.
Eg mine i started with 3.55V but deviation went slightly up over time, so i used 3,6V which got it stabilized. Then i went down step by step to 3.58V which is the lowest voltage the system is kept in balance with my usage and charge.

What you state is also wrong that especially 300-460AH is never sync that good...well i have 4p 272AH=1088AH and mine 1088AH pack are sync to 3-5mV, pulling 500A i get max 10mV deviation. And these are budget 272AH lishen cells, manufacturer matched, from 2021, the 280 or 304AH EVE V3 that you now get are better quality.
With bigger cells its exactly the other way around.
Its especially the bigger cells that keep in balance because the C-rate for the cell is much lower (less stress=imbalnce) in 460AH then 100AH cells, if you eg have a 100A load its 0.21C for the 460AH while 1C for the 100AH cell. But you have to have a very good top balance which you only get going to 3,65V as the higher the more precise is the top balance. But if they get out of balance you need a bigger balancer to get them back on balance and i am sure Epoch took care of that. If you have 4x100AH in paralell the draw is not 100%evenly splitted between them and the weakest 100AH cell will draw the whole pack down.

Thats why i also recommend from 20years experience to get as big cells as possible to get to your wanted total capacity and as less as possible batteries or cells in parallel.

[wholybee]

Originally Posted by SOLAR SUPPORT

You can also find and review posts containing APD-related problems. Where does the need to use APD come from? APD is not a new device. When the BMS drop-in suddenly cuts off the battery charge, the damage that occurs to the alternator and sensitive electronic devices on the boat is the same as what happens when a person accidentally turns the manual battery selector switch while the alternator is running.

The main reason for using APD in Li battery infrastructure is to prevent this problem that occurs when BMS turns off battery charging while the alternator is charging at HVC, LTC, HTC or another limit cell value. Can APD meet possible high voltage protection many times? How many times does this event need to occur before the APD becomes unusable? 10? one hundred? one thousand? No one can know this. You probably will not be able to hear the warning alarm that sounds when the APD is out of use due to the engine sound. Meanwhile, the alternator charging will continue and the next uncontrolled shutdown of BMS will cost you a lot. Using a battery isolator and an LA battery connected to it eliminates these risks and the need for an APD.

My extra expectation from BMS is to receive an electrical warning before cutting off the battery charge before any cell protection action. This feature is necessary to prevent the formation of high voltage, which will eliminate the risks that threaten the alternator without canbus communication, as well as all other sensitive electronic devices on the boat. Since this feature is not yet available in drop-in batteries, it is necessary to follow the voltage settings of the alternator regulators and the drop-in battery HVC voltage, which can change over time. Setting the alternator external regulator charge cut-off voltage to a relatively low 13.7-13.8 volts is also an option.

Again, show me an example of an APD actually failing? Many people have theorized it can/will happen, but I have seen zero examples of it actually happening.

My LFP battery is 4 years old, is still perfectly in balance, and never have I had an HVC event. Not once. Now, I know they can happen, buy gosh, if you have a battery and it happens 10, or a hundred times, holy smokes the owner is very negligent and/or the battery was installed and setup very badly.

When you combine the very low chance of an HVC event with the very low chance of an APD failing, well, I think the system would be safe.

The other thing that isn't mentioned. A load dump doesn't automatically happen when the BMS disconnect happens. The load dump happens when the BMS happens AND there is a very high charge current. If an HVC event occurs, the battery is 100% full, or at least one cell is, and the others very close. Charge current will have dropped by that time, probably to a level that a load dump, if it happens, will likely be small.

[SOLAR SUPPORT]

Originally Posted by wholybee

Again, show me an example of an APD actually failing? Many people have theorized it can/will happen, but I have seen zero examples of it actually happening.

My LFP battery is 4 years old, is still perfectly in balance, and never have I had an HVC event. Not once. Now, I know they can happen, buy gosh, if you have a battery and it happens 10, or a hundred times, holy smokes the owner is very negligent and/or the battery was installed and setup very badly.

When you combine the very low chance of an HVC event with the very low chance of an APD failing, well, I think the system would be safe.

The other thing that isn't mentioned. A load dump doesn't automatically happen when the BMS disconnect happens. The load dump happens when the BMS happens AND there is a very high charge current. If an HVC event occurs, the battery is 100% full, or at least one cell is, and the others very close. Charge current will have dropped by that time, probably to a level that a load dump, if it happens, will likely be small.

I'm sorry, I'm not as optimistic as you. I had an LA crank battery and AGM service batteries connected to the battery isolator on my boat in the past. I remember a few times I accidentally isolated my AGM service batteries using my manual battery switch while the alternator was running. I know what happened during this incident: nothing.

Afterwards, I had drop-in batteries whose cells became unstable within a year and the HVC voltage decreased from 14.5 volts to 13.7 volts. I solved the cell imbalance problem by opening these and adding smart active balancers. I have now become able to monitor the cell voltages of these batteries, which used to have no communication with the external environment.

I usually keep my Alternator off as there is enough solar power on the boat. When the engine is running, the small on-off switch I added to the rotor excitation circuit of the alternator is usually in the off position. The alternator usually runs idle when the engine is running. I really don't know how many times the BMS circuit of two 200Ah drop-in LFP batteries connected in parallel has triggered HVC in the past while the alternator was on. What I am sure of is that neither my alternator nor any of my sensitive electronic devices were damaged.

What if I was using APD instead of Battery Isolator? I don't know that exactly either. However, these uncontrolled drop-in LFP battery BMS outages are not pleasant at all. In order to prevent these outages from being a surprise, I wonder if battery manufacturers partially do what needs to be done and support systems that use Canbus infrastructure, while ignoring millions of users who do not have Canbus infrastructure.

You admit that there are problems with cell balance in LFP batteries over time, but you underestimate the negative consequences of this. It is known that the LFP battery does not need less current as it fills up, like the LA battery, and that it draws the highest current that the alternator can give until the BMS turns off the battery charge to protect a single cell. If APD devices had a meter, you would of course be able to understand how many times they were exposed to high voltage load dump and at what time they gave up.

[wholybee]

Originally Posted by SOLAR SUPPORT

I'm sorry, I'm not as optimistic as you. I had an LA crank battery and AGM service batteries connected to the battery isolator on my boat in the past. I remember a few times I accidentally isolated my AGM service batteries using my manual battery switch while the alternator was running. I know what happened during this incident: nothing.

Afterwards, I had drop-in batteries whose cells became unstable within a year and the HVC voltage decreased from 14.5 volts to 13.7 volts. I solved the cell imbalance problem by opening these and adding smart active balancers. I have now become able to monitor the cell voltages of these batteries, which used to have no communication with the external environment.

I usually keep my Alternator off as there is enough solar power on the boat. When the engine is running, the small on-off switch I added to the rotor excitation circuit of the alternator is usually in the off position. The alternator usually runs idle when the engine is running. I really don't know how many times the BMS circuit of two 200Ah drop-in LFP batteries connected in parallel has triggered HVC in the past while the alternator was on. What I am sure of is that neither my alternator nor any of my sensitive electronic devices were damaged.

What if I was using APD instead of Battery Isolator? I don't know that exactly either. However, these uncontrolled drop-in LFP battery BMS outages are not pleasant at all. In order to prevent these outages from being a surprise, I wonder if battery manufacturers partially do what needs to be done and support systems that use Canbus infrastructure, while ignoring millions of users who do not have Canbus infrastructure.

You admit that there are problems with cell balance in LFP batteries over time, but you underestimate the negative consequences of this. It is known that the LFP battery does not need less current as it fills up, like the LA battery, and that it draws the highest current that the alternator can give until the BMS turns off the battery charge to protect a single cell. If APD devices had a meter, you would of course be able to understand how many times they were exposed to high voltage load dump and at what time they gave up.

An isolator is a fine solution. But that doesn't mean that and APD would have failed.

There was something wrong with your batteries or your charging practices. Needing an active balancer is an indication of bad cells. Cells will drift over time, I did say that, but slowly, and the passive balancing in every BMS will take care of it.

Decent BMS's allow you to monitor them via bluetooth, and know that the cells are balanced, that no disconnects have happened, etc.

[SOLAR SUPPORT]

Originally Posted by wholybee

Needing an active balancer is an indication of bad cells. Cells will drift over time, I did say that, but slowly, and the passive balancing in every BMS will take care of it.

Yes, always optimism. Bms technology stands out with its new equipment every day. You are probably aware that all BMS manufacturers that have made a name for themselves in the last few years now include active balancers that work integrated with BMS.

[rgleason]

M/V Intrigue wrote:

Below is a link to some Epoch 460ah bench testing. There are a few other videos as well on the channel.

https://youtu.be/oUcjefQ8TAU?si=GN9T1NC7rIex4djk

Which I just viewed for the third time. Thank you M/V Intrigue.
I appears that those Epoch batteries are successfully using Canbus, DVCC to communicate via the CerboGX canbus connection, to control the Inverter.


I would be wonderful if someone could confirm that the Epoch BMS will properly control the Regulators, (preferably the Wakespeed WS500 and the Zeus).


If the inverter is properly responding, can we start to hope that the regulators will follow Epoch BMS instructions? It would be great to have a positive confirmation though.



Thanks.