LFP Ext. Regulators: Why do Volts and Amps need to be sampled?

[rgleason]

S/v jedi In your diagram what is the black square just above the BMV? Some monitoring device?

[Statistical]

Originally Posted by rgleason

S/v Jedi. I agree, Thanks for the example.

but if someone wants to use somethimg like Battleborn drop-ins, an agm motorcycle battery to help protect a balmar or wakespeed external regulator would be better. Would that meet ABYC?

- Not something I want to do because I would like to charge at .5C at times.

There are alternator protectors I would use before trying to parallel a battery you don't need into things. They create an alternate load which clamps down on the voltage spike. Remember in a alternator voltage spike you have high voltage but essentially no current so clamping down that voltage spike is trivial.

[s/v Jedi]

Originally Posted by rgleason

S/v Jedi. I agree, Thanks for the example.

but if someone wants to use somethimg like Battleborn drop-ins, an agm motorcycle battery to help protect a balmar or wakespeed external regulator would be better. Would that meet ABYC?

- Not something I want to do because I would like to charge at .5C at times.

I don’t believe it does meet ABYC but I also believe nothing really bad would happen besides reduced lifespan of the LA battery.

I have LiTime batteries with internal BMS without any external signals and it’s just fine because I don’t charge it to the limit and trust the BMS to balance the cells when needed, plus I have multiple batteries.

Also, when you use a Victron BMV, after some observation and settings tweaking, you can program it to shut off charging when voltage gets too high or SOC gets to something like 95% or 97%, making sure it resets to 100% after shutting down the charging. I have never heard of HVC happening under that regime

[rgleason]

Ok Balmar APM 12 or 24 https://shop.pkys.com/Balmar-APM-12-...MaAoh6EALw_wcB

But look in the guestions about high or long duration spikes... I think a small LFA would be adviseable, even if non compliant with ABYC (for dropins).

[Statistical]

Originally Posted by rgleason

Ok Balmar APM 12 or 24 https://shop.pkys.com/Balmar-APM-12-...MaAoh6EALw_wcB

But look in the guestions about high or long duration spikes... I think a small LFA would be adviseable, even if non compliant with ABYC (for dropins).

Simple is good. I see zero value in complicating things with a battery you don't need and very likely will destroy in short order due to improper charging.

The number of manhours spent worrying about BMS disconnect vastly exceed the number of alternators damaged by BMS disconnect. The overwhelming majority of people will be fine even without an alternator protection device. A protection device provides additional and likely unecessary security.

Keep in mind if your lead acid battery has a high SoC then its charge acceptance will be very low meaning it won't be able to clamp down significantly on the voltage spike. This is especially true for a low capacity battery. A small lead acid battery at high SoC% may only have <20A charge accpetance. So your 170A alternator blasting along at 170A suddenly goes to 20A the voltage is going to spike. It is the same reason why DC loads can't help avoid a voltage spike. I mean technically they do but to be meaningful the alternator output would need to be very low and the DC loads very high.

[CharlieJ]

@Jedi #48

It isn’t easy to make sense of what ABYC does. Most of the “volunteers” who work there are sent by their employers who have a stick in the fire.

You just can't help yourself can you?

Those volunteers work their butts off to put out a document that will provide the minimum requirements for a safe system. Not just electrical or LFP, but propane, corrosion, field of vision, etc. And before the Standards are promulgated they are made available for public review and comment.

You just have to care enough about the industry to take part in the process.

[s/v Jedi]

Originally Posted by CharlieJ

@Jedi #48


You just can't help yourself can you?

Those volunteers work their butts off to put out a document that will provide the minimum requirements for a safe system. Not just electrical or LFP, but propane, corrosion, field of vision, etc. And before the Standards are promulgated they are made available for public review and comment.

You just have to care enough about the industry to take part in the process.

I stated simple fact.

[tanglewood]

Originally Posted by Battery Balance

You are wrong regarding different battery chemistry. You have not read E-13 and therefore misunderstand what Note 3 is referring to. If the question is whether Lead-acid and LFP are different chemistries, then it is very clear that they are different. But it is crystal clear that the Note 3 refers to lithium only (and there are more than ten different lithium chemistries).

I will explain further on and referring to the ABYC definitions:

ABYC Note 3: "Mixed battery chemistries are not suited for installation in the same battery bank"

Means that the same battery bank should not consist of different chemistries.

ABYC defines Battery Bank: "-two or more batteries connected in series to provide higher voltage, or in parallel to provide increased capacity"

The same Battery Bank is NOT a lithium Cell Pack and a Lead-Acid battery (often placed in a different compartment). These are two different battery banks according to ABYC definition.

Note 3 means that a lithium Cell Pack eg 3P4S as same battery bank must consist of cells of the same chemistry (actually also the same brand and size).
Note 3 can also mean that the 12 V drop-in (defined as block according to ABYC) must consist of the same chemistry in the same battery bank (actually also the same brand and size).

ABYC definitions and standard 13.6.8, attached below

Definition stated in the E-13 LITHIUM ION BATTERIES standard:
13.1.1 This standard addresses selection and installation of lithium ion batteries on boats, lithium ion battery system design (e.g., house battery bank, cranking, propulsion), and manufacturer safety information
13.4.2 Battery - a collection of cells (or blocks) wired in series (or series/parallel) and constituting a single physical unit.
13.4.3 Battery Bank - two or more batteries connected in series to provide higher voltage, or in parallel to provide increased capacity.
13.4.5. Battery Cell – a single unit device which converts chemical energy into electrical energy that is the fundamental building block of a lithium ion battery.
NOTE: A battery cell is designed to be rechargeable by way of a reversible chemical reaction.
13.4.6. Battery Management System (BMS)-a system designed to protect a lithium ion battery battery bank from hazardous situations such as overcharging or overdischarging, charging or discharging in high and low temperatures, etc

13.6.8. Battery Bank
13.6.8.1 Series and paralleling installations for battery banks shall comply with the battery manufacturer’s recommendations.
13.6.8.2. If a battery manufacturer specifies a voltage deviation limit between individual battery voltages, it shall be met before the batteries are paralleledor connected in series to prevent excessive battery to battery current.
NOTES:
1. If batteries are paralleled in an unbalanced state, extremely high paralleling currents can flow. If used, automatic paralleling devices should have an appropriate current-limiting capability. Manual switches, (e.g., a 1, 2, both switch or on/off switch) and automatic paralleling devices may not be appropriate.
2. Special attention to balancing is very important in larger battery banks.
3. Mixed battery chemistries are not suited for installation in the same battery bank

That's an interesting read of E-13, and probably worth submitting a formal Request for Interpretation. I can't speak for ABYC or offer any interpretation on their behalf, but as a member of the committee that wrote E-13, I can say with certainty that all the discussions were about combining LPF with Lead, and that the intent was to say that such a combination should not be done. I don't think there was ever any discussion about combining different Li-Ion chemistries. I, for one, never even considered that someone might do that. It was specifically to address the practice of paralleling LFP and lead.


It's a "note", and as such is informative, but not a requirement. That said, the draft ISO spec flat out prohibits it. I also expect that over time E-13 will convert various "recommendations" into full-on requirements.


One question a few people have asked is "what's the problem with paralleling lead with Li-ion?". It's a safety issue. Lead batteries short out and melt down much more often than you might think. It's usually contained and not a big deal, but if it's paralleled with a Li-ion bank there can suddenly be a whole lot of energy available to dump into that lead battery that is unprotected by the BMS. That's why it's recommended that they NOT be paralleled.

[s/v Jedi]

Originally Posted by tanglewood

That's an interesting read of E-13, and probably worth submitting a formal Request for Interpretation. I can't speak for ABYC or offer any interpretation on their behalf, but as a member of the committee that wrote E-13, I can say with certainty that all the discussions were about combining LPF with Lead, and that the intent was to say that such a combination should not be done. I don't think there was ever any discussion about combining different Li-Ion chemistries. I, for one, never even considered that someone might do that. It was specifically to address the practice of paralleling LFP and lead.

It's a "note", and as such is informative, but not a requirement. That said, the draft ISO spec flat out prohibits it. I also expect that over time E-13 will convert various "recommendations" into full-on requirements.

One question a few people have asked is "what's the problem with paralleling lead with Li-ion?". It's a safety issue. Lead batteries short out and melt down much more often than you might think. It's usually contained and not a big deal, but if it's paralleled with a Li-ion bank there can suddenly be a whole lot of energy available to dump into that lead battery that is unprotected by the BMS. That's why it's recommended that they NOT be paralleled.

Thank you, I had hoped you would step in

[Battery Balance]

Originally Posted by tanglewood

That's an interesting read of E-13, and probably worth submitting a formal Request for Interpretation. I can't speak for ABYC or offer any interpretation on their behalf, but as a member of the committee that wrote E-13, I can say with certainty that all the discussions were about combining LPF with Lead, and that the intent was to say that such a combination should not be done. I don't think there was ever any discussion about combining different Li-Ion chemistries. I, for one, never even considered that someone might do that. It was specifically to address the practice of paralleling LFP and lead.


It's a "note", and as such is informative, but not a requirement. That said, the draft ISO spec flat out prohibits it. I also expect that over time E-13 will convert various "recommendations" into full-on requirements.


One question a few people have asked is "what's the problem with paralleling lead with Li-ion?". It's a safety issue. Lead batteries short out and melt down much more often than you might think. It's usually contained and not a big deal, but if it's paralleled with a Li-ion bank there can suddenly be a whole lot of energy available to dump into that lead battery that is unprotected by the BMS. That's why it's recommended that they NOT be paralleled.

Thanks Tanglewood for the comment. Interesting to learn about the ABYC statement regarding the Note 3 and also that it is still only informative.

We don't need to defend why we made a different interpretation about the wording of "same battery bank" but that wording seems to refer to other battery banks as well which are normally lead-acid (starter battery / bow thruster battery). The important thing for us (Battery Balance) is that the member of the E-13 committee confirms what is meant and then we can confirm that the X2 system can never have such a case as the Note 3 refers to.

Therefore, we can say that X2 BMS Pro will comply with ABYC including informative notes. We will also review the possibility of ABYC certificates after the launch of the new Pro version to eliminate more discussions on this topic.
--------
Reply to some of the comments regarding the X2 BMS Pro.
This version (Pro) will be launched after the summer and will replace the previous X2 BMS (design start 2017). We have chosen not to officially present features for Pro until it is launched and that is for competitive reasons. We will change the website but also the manual that will be official (the current one contains too specific details that we don't want to show to competitors).

The reason why we jumped into this thread, was that we received an email about a quote for a BMS for a system - instead of "small boat system" which is presented in this thread. The question also applied to whether the X2 BMS is compliant with ABYC and that question was then kicked on to this thread. On that occasion we then posted a reply.

We offer a system that has many features but also does not require several expensive devices that are included in "small boat systems". We estimate that the total system cost of what we offer with X2 BMS Pro is half versus "small-boat system" including REC + several Victron devices. The questioner can himself report a calculation of the total cost for the various systems.

We also want to point out that pre-alarm is a note in E-13. The X2 BMS was the first system on the market to introduce this as standard with flashing LEDs / Buzzers in multiple steps. Still few systems have this feature. Pre-alarm is not only important from a safety aspect, but makes it possible to safely utilize more of the capacity during sailing.

Most sailors in this thread seem to have BMS / lithium battery as a hobby / interest. You have probably designed good systems and we will not criticize your design or your hobby. We sell systems to sailors with high demands, but the X2 BMS Pro is probably not an option for those who have BMS as a hobby.

We cannot further discuss Pro version as not launched yet.
We now consider that the original question regarding whether the X2 BMS Pro is ABYC compliance settled.

// Wish everyone a nice summer and fair winds.

[rgleason]

Tanglewood. Thanks for clarifying this. That is why I asked about gow likely it is that an FLA in that situation would short out.

Tanglwood wrote:
It's usually contained and not a big deal, but if it's paralleled with a Li-ion bank there can suddenly be a whole lot of energy available to dump

[tanglewood]

Originally Posted by Battery Balance

Thanks Tanglewood for the comment. Interesting to learn about the ABYC statement regarding the Note 3 and also that it is still only informative.

We don't need to defend why we made a different interpretation about the wording of "same battery bank" but that wording seems to refer to other battery banks as well which are normally lead-acid (starter battery / bow thruster battery). The important thing for us (Battery Balance) is that the member of the E-13 committee confirms what is meant and then we can confirm that the X2 system can never have such a case as the Note 3 refers to.

Therefore, we can say that X2 BMS Pro will comply with ABYC including informative notes. We will also review the possibility of ABYC certificates after the launch of the new Pro version to eliminate more discussions on this topic.
--------
Reply to some of the comments regarding the X2 BMS Pro.
This version (Pro) will be launched after the summer and will replace the previous X2 BMS (design start 2017). We have chosen not to officially present features for Pro until it is launched and that is for competitive reasons. We will change the website but also the manual that will be official (the current one contains too specific details that we don't want to show to competitors).

The reason why we jumped into this thread, was that we received an email about a quote for a BMS for a system - instead of "small boat system" which is presented in this thread. The question also applied to whether the X2 BMS is compliant with ABYC and that question was then kicked on to this thread. On that occasion we then posted a reply.

We offer a system that has many features but also does not require several expensive devices that are included in "small boat systems". We estimate that the total system cost of what we offer with X2 BMS Pro is half versus "small-boat system" including REC + several Victron devices. The questioner can himself report a calculation of the total cost for the various systems.

We also want to point out that pre-alarm is a note in E-13. The X2 BMS was the first system on the market to introduce this as standard with flashing LEDs / Buzzers in multiple steps. Still few systems have this feature. Pre-alarm is not only important from a safety aspect, but makes it possible to safely utilize more of the capacity during sailing.

Most sailors in this thread seem to have BMS / lithium battery as a hobby / interest. You have probably designed good systems and we will not criticize your design or your hobby. We sell systems to sailors with high demands, but the X2 BMS Pro is probably not an option for those who have BMS as a hobby.

We cannot further discuss Pro version as not launched yet.
We now consider that the original question regarding whether the X2 BMS Pro is ABYC compliance settled.

// Wish everyone a nice summer and fair winds.

It sounds like you have put together a good product, and I wish you luck with it.


You compare to a "small boat system, but I don't know what you mean by that. Can you explain?


Also, you should check with the moderators, but I think you should change your account to reflect your status as a commercial vendor. Otherwise it's generally poor form to be promoting your product here without such a disclosure.

[Duplexity]

Originally Posted by tanglewood

One question a few people have asked is "what's the problem with paralleling lead with Li-ion?". It's a safety issue. Lead batteries short out and melt down much more often than you might think. It's usually contained and not a big deal, but if it's paralleled with a Li-ion bank there can suddenly be a whole lot of energy available to dump into that lead battery that is unprotected by the BMS. That's why it's recommended that they NOT be paralleled.

May I ask, how much current are we talking about? 200 amps or more?

[Statistical]

Originally Posted by Duplexity

May I ask, how much current are we talking about? 200 amps or more?

Shorted 12V battery could pull well over 1,000A possibly over 2,000A for larger batteries. Now the good news is paralleled with another lead acid battery it coud never deliver that due to its own internal resistance but a LFP battery could at least until the BMS trips or the fuse blows. Regarding the fuse while not good practice I have seen plenty of boats without individual fuses on each battery instead just paralleling batteries and then having one master fuse. That would be a catastrophically bad idea in this scenario.

[Duplexity]

Originally Posted by Statistical

Shorted 12V battery could pull well over 1,000A possibly over 2,000A for larger batteries. Now the good news is paralleled with another lead acid battery it coud never deliver that due to its own internal resistance but a LFP battery could at least until the BMS trips or the fuse blows. Regarding the fuse while not good practice I have seen plenty of boats without individual fuses on each battery instead just paralleling batteries and then having one master fuse. That would be a catastrophically bad idea in this scenario.

Why not protect the lead-acid starter with a fuse (100 - 200 A)?
- If there was an internal short of the SLA that is parallel to the LFP, it could be protected with a fuse and 1000+ amps would be zero.

- If there should be an internal short of the SLA (Starter) which is parallel to the SLA (house), the house battery has the capacity to "dump" high current. However, it is lower, but a few hundred amps will mean that there will be a "melt down" if not protected with a fuse between the batteries.
- If a battery bank consists of several parallel SLAs, has a battery that has an internal short, then the other SLAs have the capacity to "dump" high current (say 300+ A). In this case, there will be a "melt down" because there is rarely protection with a fuse between them.

- It seems that ABYC notes are not completely consistent, if different situations of "load dump" are compared:
When several LFP blocks are parallel, protection ("appropriate current-limiting capability") is recommended between them to prevent them from charging each other, actually that load dump should not occur if the blocks have different state of charge (voltage).

The Victron smart battery has balancing built in, but the BMS and fuses are external. In this case, a fuse between each block that is parallel is sufficient, which is what Victron requires according to the manual.
Drop-in battery such as Battle Born has internal BMS with electronics that protect and interrupt. In this case, a simple mosfet / resettable fuse that protects against load dump between each block that is parallel is sufficient.