Making a cheap BMS ABYC compliant

[RaymondR]

Originally Posted by rgleason

Raymond you ask about use of these two semiconductors, give us a picture, but dont say what they are or provide a link to a description. Then everybody in the know proceeds to discuss them. Is this intentional or just an oversight?

Skill and software limitations seasoned with a touch of laziness and bloody mindedness.

I just Googled "transient suppression devices", and used "Take Screenshot" and cropped that image. I used that image so that the part identification was illustrated so that others could Google the ID and get the full specifications.

[goboatingnow]

High power TVS solutions can be designed to reduce a full load dump transient to hornless levels. It’s not a tribal design excercixe but several TVs suppliers provide good application notes covering such design.

We will no doubt see the industry provide such solutions to allow the removal of lead starter batteries from the system.

[RaymondR]

"“13.5.6 If a shutdown condition is approaching, a BMS should notify the operator with a visual and/or audible alarm prior to disconnecting the battery from the DC system.”"

In my case I cannot see this as a very good solution.

When the engine is going, as a single hander, I am often stuck on the wheel and would be reluctant to either shut the engine down or go below and battery switch to "Off" or select another battery.

In addition I like to keep the engine cranking and battery charging system completely isolated from the house system and have a gas powered battery charger with a couple of belt driven alternators I use for house battery charging.

At the moment I have a mixed battery type house bank with the lithium batteries running the refrigerator and AGMs running all other house loads. So far I have just relied on solar to recharge the lithium and have been lucky to only have one partial fridge defrost when the lithium disconnected itself which I exploited to do a fridge clean out.

I was aware that a couple of overcast days coupled with the mainsail shading would cause the disconnect and did not use the gas powered battery charger on the lithium bank for fear of alternator disconnect damage.

My interest in finding a non LA solution to the disconnect transient problem is motivated by the fact that when the extant AGM house bank expires I intend to replace them with all lithium. I will then definitely need a solution to the transient problem or sit in the dark without TV whilst the fridge defrosts during or after a series of overcast days.

Having a lead acid battery included in my lithium house bank seriously offends my perception of "rightness" (although I'm generally not averse to Rube Goldberg solutions)

I once experienced a battery collapse in a house bank but noticed the voltage decline and disconnected the culprit whilst it was only warm. The thought of having say 400 amp hours of lithium (with consequent extreme current delivery capabilities) connected across a single shorted out LA, transient suppression battery tends to discomfort me a little.

Having the BMS provided with a pre battery disconnect, alternator regulator disconnect is in my opinion a good solution however neither the expensive surviving Victron drop-in, lithium, nor the Daily BMS I used to salvage the good cells from the other Victron lithium, nor the Daily BMS I purchased to DIY another battery from cells has this capability.

[newhaul]

Originally Posted by goboatingnow

.

We will no doubt see the industry provide such solutions to allow the removal of lead starter batteries from the system.

Possible but doubt it will happen in the next 30 years .

[newhaul]

Originally Posted by tanglewood

Personally I think an advance warning signal should be required, and I wouldn't be surprised to see it show up in the next revision. It is currently suggested, but not required. The challenge is that drop in batteries are a reality and aren't going away, and none I know of offer any sort of external communications or warning. So requiring it will render all those batteries and boats non-compliant. But that my be the pill that needs to be swallowed.

It will not be suggested ( ABYC has no authority to require anything) untill the big "drop ins" are ready to come online with a solution within their product.
Just won't happen not in my lifetime .

[goboatingnow]

Originally Posted by newhaul

Possible but doubt it will happen in the next 30 years .

Why not it’s not complex

[goboatingnow]

Originally Posted by newhaul

It will not be suggested ( ABYC has no authority to require anything) untill the big "drop ins" are ready to come online with a solution within their product.
Just won't happen not in my lifetime .

ISO has legal teeth.at MeTS al, the BMS people I talked to where aware of the advance warning requirement including several drop in suppliers

[newhaul]

Originally Posted by goboatingnow

Why not it’s not complex

While I agree it wouldn't be difficult it won't happen fast.
It's called capitalism. The drop ins won't do it unless they have to . Cuts into profits. The pleasure boating community is to small of a portion of that pie . At best they will sell you an external unit that purely alarms on specific voltage . But they have to figure out how to make it proprietary. That will take time. Aside from the fact that existing systems will out of necessity be grandfathered in .

[newhaul]

Originally Posted by goboatingnow

ISO has legal teeth.at MeTS al, the BMS people I talked to where aware of the advance warning requirement including several drop in suppliers

Just because they are aware doesn't mean they will innovate see above

[goboatingnow]

Originally Posted by newhaul

Just because they are aware doesn't mean they will innovate see above

Well the advance alarm issue certainly had prominence. Everyone I talked too was aware said their bms was already compliant sonecsaid “ real soon now”. These were all drop in specialising in marine systems.

I agree that outside the marine space drop in vendors will be slow to change as there is little incentive.

[newhaul]

Originally Posted by RaymondR

"“13.5.6 If a shutdown condition is approaching, a BMS should notify the operator with a visual and/or audible alarm prior to disconnecting the battery from the DC system.”"

In my case I cannot see this as a very good solution.

When the engine is going, as a single hander, I am often stuck on the wheel and would be reluctant to either shut the engine down or go below and battery switch to "Off" or select another battery.

In addition I like to keep the engine cranking and battery charging system completely isolated from the house system and have a gas powered battery charger with a couple of belt driven alternators I use for house battery charging.

At the moment I have a mixed battery type house bank with the lithium batteries running the refrigerator and AGMs running all other house loads. So far I have just relied on solar to recharge the lithium and have been lucky to only have one partial fridge defrost when the lithium disconnected itself which I exploited to do a fridge clean out.

I was aware that a couple of overcast days coupled with the mainsail shading would cause the disconnect and did not use the gas powered battery charger on the lithium bank for fear of alternator disconnect damage.

My interest in finding a non LA solution to the disconnect transient problem is motivated by the fact that when the extant AGM house bank expires I intend to replace them with all lithium. I will then definitely need a solution to the transient problem or sit in the dark without TV whilst the fridge defrosts during or after a series of overcast days.

Having a lead acid battery included in my lithium house bank seriously offends my perception of "rightness" (although I'm generally not averse to Rube Goldberg solutions)

I once experienced a battery collapse in a house bank but noticed the voltage decline and disconnected the culprit whilst it was only warm. The thought of having say 400 amp hours of lithium (with consequent extreme current delivery capabilities) connected across a single shorted out LA, transient suppression battery tends to discomfort me a little.

Having the BMS provided with a pre battery disconnect, alternator regulator disconnect is in my opinion a good solution however neither the expensive surviving Victron drop-in, lithium, nor the Daily BMS I used to salvage the good cells from the other Victron lithium, nor the Daily BMS I purchased to DIY another battery from cells has this capability.

Lead start battery and dc dc chargers solve that issue . Why make it difficult. KISS.

[Simi 60]

I would like to think multiple batteries would be a solution as well.
It is our solution.

We have 3 X 24v batts

1 can comfortably run everything onboard as tested when installed when boat was on hard for maintenance in a shed so no solar.
We stayed onboard using everything as per normal

1 can shutdown due to ??? and 2 are left
2 can shutdown and 1 is left
The likelihood of 3 shutting down?

[s/v Jedi]

Originally Posted by tanglewood

Just to clarify, ABYC does not require or stipulate any advance warning prior to a BMS disconnect. The HVE event immediately begets the HVC action. It's an action of last resort. That's all the spec requires. Anything more is optional and at the discretion of the designer/builder.

Personally I think an advance warning signal should be required, and I wouldn't be surprised to see it show up in the next revision. It is currently suggested, but not required. The challenge is that drop in batteries are a reality and aren't going away, and none I know of offer any sort of external communications or warning. So requiring it will render all those batteries and boats non-compliant. But that my be the pill that needs to be swallowed.

Did you already post that you were wrong?

13.5.1 All lithium ion battery systems should have a BMS installed to prevent damage to the battery and provide for battery shutoff if potentially dangerous conditions exist.

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.

13.5.6 If a shutdown condition is approaching, a BMS should notify the operator with a visual and/or audible alarm prior to disconnecting the battery from the DC system.

13.7.7 No electrical connections should be made directly to a lithium ion battery that would bypass a BMS or the protection relays.

13.7.8 All battery output circuits should have overcurrent protection as per ABYC E-11, AC & DC Electrical Systems on Boats.

13.7.9 A battery system disconnect switch (or switches) should be readily accessible without reaching over the battery (see ABYC E-11, AC & DC Electrical Systems on Boats, battery switch requirement).

13.9.2 Redundant Protection - A BMS should be equipped with HVC and LVC actions in response to an HVE or LVE when the programmed functions in the charging sources, inverters, or inverter/chargers, etc fail to do so.

13.9.4.1 Means of protection should not disconnect critical loads without prior warning and should not stop the charging source in a manner that causes damage to the charging device.

13.9.7 A BMS or system design should ensure that parasitic loads will not result in an LVE.

I am not even going to respond to those who say “should” is not “must” other than this: The ABYC gives recommendations, they are not code. There is no “must” anywhere. You should just admit that you were all wrong stating that ABYC does not require all that I copied above, instead of twisting and spinning words just to keep arguing.

In order to comply with ABYC:

- you must have fuses
- you must have a main battery switch
- you must have a BMS
- you must have multiple batteries
- your BMS must be able to do HVC, LVC as well as temperature related cutoff.
- your BMS must have prior warning to cutoff events
- your BMS must turn off the alternator prior to cutoff events
- you can not run power solenoids because they can cause LVC so you must have MOSFET or latching solenoid options.

[newhaul]

Originally Posted by s/v Jedi

Did you already post that you were wrong?

13.5.1 All lithium ion battery systems should have a BMS installed to prevent damage to the battery and provide for battery shutoff if potentially dangerous conditions exist.

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.

13.5.6 If a shutdown condition is approaching, a BMS should notify the operator with a visual and/or audible alarm prior to disconnecting the battery from the DC system.

13.7.7 No electrical connections should be made directly to a lithium ion battery that would bypass a BMS or the protection relays.

13.7.8 All battery output circuits should have overcurrent protection as per ABYC E-11, AC & DC Electrical Systems on Boats.

13.7.9 A battery system disconnect switch (or switches) should be readily accessible without reaching over the battery (see ABYC E-11, AC & DC Electrical Systems on Boats, battery switch requirement).

13.9.2 Redundant Protection - A BMS should be equipped with HVC and LVC actions in response to an HVE or LVE when the programmed functions in the charging sources, inverters, or inverter/chargers, etc fail to do so.

13.9.4.1 Means of protection should not disconnect critical loads without prior warning and should not stop the charging source in a manner that causes damage to the charging device.

13.9.7 A BMS or system design should ensure that parasitic loads will not result in an LVE.

I am not even going to respond to those who say “should” is not “must” other than this: The ABYC gives recommendations, they are not code. There is no “must” anywhere. You should just admit that you were all wrong stating that ABYC does not require all that I copied above, instead of twisting and spinning words just to keep arguing.

In order to comply with ABYC:

- you must have fuses
- you must have a main battery switch
- you must have a BMS
- you must have multiple batteries
- your BMS must be able to do HVC, LVC as well as temperature related cutoff.
- your BMS must have prior warning to cutoff events
- your BMS must turn off the alternator prior to cutoff events
- you can not run power solenoids because they can cause LVC so you must have MOSFET or latching solenoid options.

If you wish to be compliant but as I stated it is not required the ABYC is not a governing body it is an advisory board.

That being said I have been searching for a high voltage audible alarm that doesn't cost 200 bucks but can't find one . All seem to just be concerned with low voltage. .

[s/v Jedi]

Originally Posted by newhaul

If you wish to be compliant but as I stated it is not required the ABYC is not a governing body it is an advisory board.

That being said I have been searching for a high voltage audible alarm that doesn't cost 200 bucks but can't find one . All seem to just be concerned with low voltage. .

I have posted about how to setup a Victron BMV to send alarms on low voltage, high voltage and cell balance.

For visual per cell monitoring: https://www.amazon.com/dp/B07797N9BG