ABYC and ISO Li reference diagram

[goboatingnow]

Originally Posted by newhaul

My biggest issue with you is your misrepresentating the ABYC and ISO . none of which are governing bodies nothing they say is a requirement . don't make it more than it is . now as to you . a while back you were on begging for info and sources . now you try to pass yourself off as some kind of an expert on the subject of LIFEPO4 banks .

You have even told me that you can't parallel Fla and lip but won't say why that is except your opinion . many do it all the time on here there is even a thread just for fla/ lfp hybrid systems. Heck even the ABYC and ISO recomend having Fla in the setup as a backup to automatically take the load when the rare event of some kind of lfp failure happens .

If you have something constructive to contribute please do just stop the badgering of others on here that may actually know more than either of us on the subject.

I’m not badgering. This part of the thread began because several people worked on a proposal on Diysolarforum to design a iso ABYC compliant system but that met the persons desire to have backups and overrides.

I’m merely defending that design as I believe it’s a good compromise.

ISO is specific it’s says NOT to connect different chemistries. I believe this is good advice for several reasons.

ABYC and ISO DO not allow any wiring between the safety relay and the battery except the bms. This means in practice loads and charge sources must be disconnected even if you have mechanisms which allow things to be connected afterwards.

I don’t care what “ many do “ I have seen way way too many crap electrical installs by people claiming they knew what they were doing and most of them predate ABYC and ISO specs.

You’ll also appreciate as a I am a time served EE that I will take my own technical advice in front of others unless they present good sound technical engineering reasons to justify an alternative. People telling me I don’t know what I’m talking about are just engaging in personal attacks.

So by all means present Cogent well thought out technical analysis. I’m well up to listening to those, but I’ll evaluate them in the light of my own extensive engineering experience not to mention 30 years of owning boats. ( and designing electronics for them )

Like I said ( and many others have said )

Lithium’s are safe rugged and reliable batteries. They are quite tolerant of poor charging situations provided the few key issues are avoided.

Hence a BMS disconnect is primary a last ditch “ things are up a creek “ issue , basically a disconnect occurs because something has gone seriously wrong.

So it’s nothing like” low fuel” lights as you opine. I fundamentally disagree with that perspective and I see no technical justification.

As for a bms contactor bypass this is a debatable area. I can’t agree with your opinion that a failed bms should render a lithium pack instantly unusable. Sure a bms must be fixed up T some point. But in the meantime on a boat away from technical repair it’s good engineering to allow a degree of manual bypassing.

RGleason was at particular pains to want prewired manual bypass and his system has two , one a bms bypass and the second is to switch in the SLA. There is an electrical interlock to prevent the Li and SLA ever paralleling. This conforms to ISO as the diagram specifically mentions ISO and ABYC compliance.

What others do Is for them to rationalise. That’s clearly a range of engineering solutions depending on the predilections of the designer.

Hence I’m not badgering I’m defending what I believe is an excellent diagram given the desired requirements of its owner. I started this thread so I’ll keep responding to it.

[s/v Jedi]

Originally Posted by goboatingnow

LVE is NOT “ low fuel “. LVE is defined by ABYC and ISO as the lowest allowable voltage by the cell manufacturer. In normal usage you should NEVER get near this level.

Not true, you make this up. Here is the paragraph:

13.4.11 LowVoltageEvent(LVE)-the condition where a cell, parallelstring, or bank has been discharged to a voltage below the manufacturer’s cell minimum voltage limit.

A fundamental difference!

Secondly ABYC and ISO require all connections except the BMS to be disconnected or BMS trigger.

I don’t understand this. If you mean that during LVC the charge bus must be disconnected in addition to the load bus then for all I know you are wrong. List the ABYC paragraph where you read this, I can’t find it.

ABYC and ISO are very nebulous of failed systems , but I would contend that a mechanism for bypassing the BMS must exist in extremis. Lightning can easily take out a bms

A manual override that defeats the BMS will disqualify your BMS for ABYC compliance.

Suggesting you carry 200Αh of SLA on the off chance once in 10 years is nonsense. Sheer nonsense.

Not if it is your start bank. You should also carry multiple house batteries, plus spare parts which may incl a BMS.

[newhaul]

Let's see imcarry a single 250ah lfp house battery , a spare BMS a spare MPPT solar controller, my start battery is a grp 24 which = 75ah approx.
But I'm also a 1963 columbia 29 defender . Should I have another house battery or just emergency capability of using my start bank .

[rgleason]

I am very sorry to have shared the last set of diagrams on this forum. I regard the personal attacks made to contributing memberss such as goboatingnow, as beyond the terms of this forum and I would prefer this thread be used for non-emotional, rational discussion.

Keep in mind that because ABYC is not widely published and you cannot read it for less than about $190, we all are subject to misinterpretation and ignorance, unless we have access.

In addition to that, ABYC has set out its requirements after lots of thought and consideration and tests of a relatively new battery. So there may be things that need to be clarified.

Having gone through this process with some wonderful help from many others, including Goboatingnow, I am quite confident about the operation of this system, and I am pretty sure it would meet ABYC.

I will entertain suggestions for how I should submit this diagram for review by ABYC. I actually have said that ABYC should have example diagrams that are acceptable, that are public facing and not behind a firewall.

So please "Cool your jets", I am still trying to learn and in this environment it is difficult to separate out all the noise from facts and logic.

And I will no longer post here if it continues. Sorry.

[goboatingnow]

Originally Posted by s/v Jedi

Not true, you make this up. Here is the paragraph:



A fundamental difference!



I don’t understand this. If you mean that during LVC the charge bus must be disconnected in addition to the load bus then for all I know you are wrong. List the ABYC paragraph where you read this, I can’t find it.



A manual override that defeats the BMS will disqualify your BMS for ABYC compliance.



Not if it is your start bank. You should also carry multiple house batteries, plus spare parts which may incl a BMS.

You add merely “ interpreting ABYC « I am too , my interpretation. Differs from yours that’s all

Abyc don’t make any comments one way or the other re a failed bms.

Yor ML relay with a override would also breach ABYC on your reading

My lve settings would by the lowest allowed cell voltage as specified by the battery supplier


ABYC requires everything connected to thx battery to be disconnected if a safety trip occurs.

Look the diagram developed as a reference for the thins RGleason felt was important to him, including built in prewired bypass “ get you home “ options.

I think it would pass ABYC and hence I’m happy enough. Others may differ that’d fine, experts often disagree of certain aspects of things. I’m my saying this is the only way to do things but it’s “ one “ good way

[newhaul]

Ok I'm going to say it one more time for those that don't seem to get one simple fact .
( my main pet peeve)
THE ABYC IS NOT A GOVERNING BODY THAT CAN SET ANY RULES/ REQUIREMENTS. ALL THEY CAN DO IS MAKE RECOMENDATIONS.

[newhaul]

Originally Posted by rgleason

I am very sorry to have shared the last set of diagrams on this forum. I regard the personal attacks made to contributing memberss such as goboatingnow, as beyond the terms of this forum and I would prefer this thread be used for non-emotional, rational discussion.

Keep in mind that because ABYC is not widely published and you cannot read it for less than about $190, we all are subject to misinterpretation and ignorance, unless we have access.

In addition to that, ABYC has set out its requirements after lots of thought and consideration and tests of a relatively new battery. So there may be things that need to be clarified.

Having gone through this process with some wonderful help from many others, including Goboatingnow, I am quite confident about the operation of this system, and I am pretty sure it would meet ABYC.

I will entertain suggestions for how I should submit this diagram for review by ABYC. I actually have said that ABYC should have example diagrams that are acceptable, that are public facing and not behind a firewall.

So please "Cool your jets", I am still trying to learn and in this environment it is difficult to separate out all the noise from facts and logic.

And I will no longer post here if it continues. Sorry.

All I see wrong with your diagram is there is no physical disconnect between the solar panels and the controller.
Don't know if the ABYC or the ISO recomend it or not . I do know that most controller manufacturers and most solar panel manufacturers do recomend it .
It's like the main breaker in your home power distribution panel to isolate the home system from the power charging supply .

[s/v Jedi]

Originally Posted by rgleason

I am very sorry to have shared the last set of diagrams on this forum. I regard the personal attacks made to contributing memberss such as goboatingnow, as beyond the terms of this forum and I would prefer this thread be used for non-emotional, rational discussion.

Keep in mind that because ABYC is not widely published and you cannot read it for less than about $190, we all are subject to misinterpretation and ignorance, unless we have access.

In addition to that, ABYC has set out its requirements after lots of thought and consideration and tests of a relatively new battery. So there may be things that need to be clarified.

Having gone through this process with some wonderful help from many others, including Goboatingnow, I am quite confident about the operation of this system, and I am pretty sure it would meet ABYC.

I will entertain suggestions for how I should submit this diagram for review by ABYC. I actually have said that ABYC should have example diagrams that are acceptable, that are public facing and not behind a firewall.

So please "Cool your jets", I am still trying to learn and in this environment it is difficult to separate out all the noise from facts and logic.

And I will no longer post here if it continues. Sorry.

I always try to not do personal attacks even when facing such from a member… I think the back and forth between me and gbn has no ill intentions from either side. In fact, I believe it is what leads to better end results.

Attached is a text that can be considered the ABYC recommendations. It supports everything I wrote before. When I write that your manual override fails the requirements, it is because they do, not because I like to make things a struggle for you or gbn. Likewise, my manual operation of the BlueSea RBS also fails the same requirements. I don’t know what to say, it is what it is and remember, those are recommendations, not code.

I hope you keep posting here, incl, explaining what goes on with the solar fuses. We post here in thus thread because we don’t want to go to the DIY solar thread.

[s/v Jedi]

Originally Posted by goboatingnow

You add merely “ interpreting ABYC « I am too , my interpretation. Differs from yours that’s all

Abyc don’t make any comments one way or the other re a failed bms.

Yor ML relay with a override would also breach ABYC on your reading

My lve settings would by the lowest allowed cell voltage as specified by the battery supplier


ABYC requires everything connected to thx battery to be disconnected if a safety trip occurs.

Look the diagram developed as a reference for the thins RGleason felt was important to him, including built in prewired bypass “ get you home “ options.

I think it would pass ABYC and hence I’m happy enough. Others may differ that’d fine, experts often disagree of certain aspects of things. I’m my saying this is the only way to do things but it’s “ one “ good way

Please list the paragraph that you interpret to mean that a charge bus must be disconnected during LVC. I have uploaded the ABYC text in the post above.

[rgleason]

Thanks after reading the uploaded TE-13
I have learned a couple of things.
1. LVD and HVD (disconnect) are not defined and I should use LVC and HVC (for Cutoff)! This is difficult for me as I instantly think of "Connection". LVE is "event". I finally got that.
2. They often refer to Lithium-Ion Batteries and I don't really think of those as a good use for our environment. We are using LiFePo which are totally different in the way they fail.

3. It is pretty clear that the committee has not thought much about after an LVE, LVC, HVE, HVC what needs to happen, or they can't agree yet. My diagram tries to take the thought process a little further, and provide an option for SLA temporary backup power, and once the LFP has been investigated and the likely cause determined, allow getting it back on line after changes have been made.

This is a perfectly reasonable goal, which even the use of the ML-RBS switch is doing, as Jedi points out. The paragraph which is of concern is:

13.7.7Noelectrical connections should be made directly to alithium ionbattery that would bypassaBMS or the protection relays.
EXCEPTION:Connections made specifically per thebattery manufacturer’s instructions.

Jedi you blasted this diagram initially because of this ABYC paragraph, not knowing that your use of the ML-RBS had the same problem, if you just look at this paragraph alone, it seems definitive.

CF Post #48
Originally Posted by s/v Jedi View Post
I held the diagram against ABYC recommendations and it appears that the manual switch violates 13.7.7
13.7.7 No electrical connections should be made directly to a lithium ion battery that would bypass a BMS or the protection relays.
The switch clearly bypasses the protection relays.

Goboatingnow wrote:

Firstly an open switch is not connected to the battery. That’s in plain sight.
Secondly both iso and ABYC recognise the need for overrides
“13.5.3 Consideration should be given to providing alternative power for critical systems (e.g., engine starting,
navigation lights, etc) if a BMS shuts down the battery.“
Thirdly the RBS ML has a integrated override that in theory violates your pedantry

A Manufacturer can do this, but not a DIY install? How fair is that? It seems like the committee has tried to exclude reasonable post "cutoff" over-charge and discharge options to those designing and executing DIY installations. Is this just because it's too messy for them to deal with technically?

What about a BMS manufacturer who expects there to be some form of recovery process? For example, we could write REC BMS and ask them to review the diagram to allow that to be a part of their "system"?

It seems to be that that would be reasonably fair, because this clause penalizes any manufacturer who does not have an entire "system" for market such as Lithionics or Victron, and it gives Drop-in-Lithium an advantage, yet they only do half the job and generally provide no advance communication or relay control for alternators etc.

The final thing we could do is write the committee for an interpretation with a yes / no question, rather than beat each other up about interpreting this need.

[goboatingnow]

Nick and I can go back and forth I’ve no problem in general as he argues from an engineers perspective. I however reserve the right to disagree with him on engineering grounds.

Yes we all accept

(A) both ABYC and ISO specs on Li have no force of law ( yet anyways)

(B) they are in my opinion both “ initial “ stabs at lithium and they are quite poor at their first pass . They also don’t differentiate the safer LFP batteries despite the rather ridiculous letter recently from ABYC

[goboatingnow]

Having said all that I’m currently designing A BMS and an lithium systems orientated alternator controller

My engineering take is
* Safety first
* manual overrides on all critical systems.

RGleasons criteria were for “prewired “ overrides. ( I had suggested a man with a jump leads!!)

Hence we looked at what overrides are needed. In his case two. (A) where a faulty bins **** down the battery and (b) a means of deploying his SLA starter battery to run his loads and also it to be charged.


His is a sophisticated system , way more then more will install with high end alternator controller ( wakespeed) good integrated BMS ( Rec ) and the whole thing integrated into Victron Cerbo.

This is way way more then most on this forum are doing.

To simply point fingers and say “x” feature is or not ABYC or iso is a side show.

In relation to separate charge abd dyschsrgr busses I have no particular opinion. I would opine that leaving a charge bus connected while the bms activated the load bus disconnect is not ABYC compliant.

But for me it’s “ safety first “ not ABYC

LVE HVE , over current and over-temp ARE CRITICAL safety trips. These should never occur on a properly constituted li battery

Hence I have consistently argued that post such a trip a manual inspection of the battery bank should occur. After that YOU as captain decide how to restore operation , either in bypass modes or selective load and or charge source application. I don’t care.

What I do care is safety trips are treated seriously and the BMS should never simply reconnect anything automatically.

[s/v Jedi]

As you can see, I always said that the manual override violates ABYC. I never said that my setup is conform ABYC, I think this started after you assumed I thought my setup is conforming. Truth is that I don’t care, I am not a great fan of ABYC at all; I recognize what they get right and often much better worded than I can, so I go with it for that but when I see no logic for my specific application, I do not hesitate to change things because I know exactly what I am doing and why I can change it for that specific case. Scientific approach means doing what you know is right and being ready to defend it, while hoping you considered every possible viewpoint and nobody comes up with something causing you to facepalm :-)

You are correct that ABYC threw all Lithium chemistries on one heap, creating a document that is flawed. If in the workgroup, my biggest point would have been that only LiFePO4 is allowed and work from there.

Also, they only consider a common bus BMS, instead of a separate charge and load bus BMS, which is superior. This is a mistake and I expect them to clarify with something like “showing simplest option, separate bus is fine”. There have been others voicing this as well and this is one of gbn’s mistakes imo.

I still see a fundamental difference between our setups around manual override and am convinced ABYC members, as well as involved experts will agree: your setup has incentives to defeat BMS function and use manual override instead; mine does not.

I still want to point out that I find these discussions completely normal, even when heated at times and think you guys ridiculing it on another forum uncalled for.

[rgleason]

I still see a fundamental difference between our setups around manual override and am convinced ABYC members, as well as involved experts will agree: your setup has incentives to defeat BMS function and use manual override instead; mine does not.

I would be interested in exactly why you think this. I am certain that it is not just because its your design, but you've got to have some precise reasons to hold this opinion. So why not let us know your thinking? In the interest of learning... and not throwing bombs.

[wholybee]

My opinion on the override is this:
An override, if present, should NEVER be used unless you have investigated the cause of the BMS disconnect. In a critical situation when the BMS unexpectedly disconnects, you will be focused on getting power back, and so the correct action will always be to switch to the backup bank, not override the BMS.
When the situation is calm and you have time to investigate, you could then jumper around the BMS if the cause was found to be a BMS failure and wouldn't need a bypass switch for that.
Regarding ABYC adherence generally. There are several ways in which my system is not compliant. But I understand what that means, and what the ramifications are. That is key. If you have a strong understanding of your system and the ramifications of your deviating from the standard, then details like bypass or not, or common buss or separate buss can be adjusted to suit the owner.
I think there is argument/discussion resulting from T-13 being poorly written. As I read it, there is nothing that requires a common bus vs. separate busses. But I do see how it is poorly written and someone else might interpret it that way. Also, the goals/requirements of a BMS on a LiFePO4 bank are different than other chemistries. On LFP, the BMS protects the battery. It isn't a safety device like a fuse is. It doesn't prevent fires or have any other safety function. Compared to the more volatile batteries, where the BMS is necessary to prevent a fire.
It is very easy to say "safety first" but that is a never-ending spiral. There must be a point where you say it's good enough. IMHO, if an LFP install is considerably safer than the Lead Acid bank it replaced, then that should be considered adequate. ABYC rules be damned. If you inadvertently convince people to stay with Lead Acid because the safety rules are too onerous, then you aren't really putting safety first. Of course, it's great to encourage addition safety measures, but demanding them is excessive and counterproductive.