LiFePO4 Electric Schematic for Review and Comments

[SV_FlyingTigress]

Hi Cruisers and those with higher Midi-chlorian counts way over 2500 (you know who you are). This is a draft diagram for general review and comments to identify/validate the the intended implementation of Dakota Lithium | Victron | Balmar gear on my P39. Contextually, we are also converting to 120 60HZ and increasing the wiring gauges to accommodate the amperage and adding an isolation transformer. This is the (draft) schematic my refitter is putting together (I am staying in the US to work to financially fund the refit/kitty) . I come from an aircraft maintenance / IT world, so some aspects of marine electrical are new to me and I am on the learning curve. Also, there are some items not yet added that are intended and labels. I have Lucid charts but I believe this is being built in another tool so don't have source files right now, but will convert them to Lucid/Visio. My goal is to just expose our design to hear, learn, consider and potentially integrate good ideas.

[s/v Jedi]

Originally Posted by Stephen_MO

Hi Cruisers and those with higher Midi-chlorian counts way over 2500 (you know who you are). This is a draft diagram for general review and comments to identify/validate the the intended implementation of Dakota Lithium | Victron | Balmar gear on my P39. Contextually, we are also converting to 120 60HZ and increasing the wiring gauges to accommodate the amperage and adding an isolation transformer. This is the (draft) schematic my refitter is putting together (I am staying in the US to work to financially fund the refit/kitty) . I come from an aircraft maintenance / IT world, so some aspects of marine electrical are new to me and I am on the learning curve. Also, there are some items not yet added that are intended and labels. I have Lucid charts but I believe this is being built in another tool so don't have source files right now, but will convert them to Lucid/Visio. My goal is to just expose our design to hear, learn, consider and potentially integrate good ideas.

No, this diagram is incorrect. This can’t come from a qualified Victron installer.

- the 120V input goes to the isolation transformer as well. The switch between 240/120 is done inside the transformer, either automatically or manually depending on the model transformer purchased.

- the relays running the alternator regulators must be controlled by the BMS, not by anything from the engine. When the battery goes into a LVC/HVC cutoff mode, the rectifier diodes in the alternators will burn out, so the BMS must shut it down before HVC.

- no busbars, no fuses where they are required

- how does the combiner switch work? I don’t think that is even possible

I really recommend you follow diagrams from Victron or my reference diagrams aimed at converting boats to LiFePO4, not what your installer presented you with. Being frank: find someone else.

I have attached some diagrams, there are threads started by me for every diagram I uploaded to the forum.

[SV_FlyingTigress]

Thanks Jedi, this is an early draft, but my understanding is that all shore power also went through the isolation transformer as well and that is one of the reasons I wanted to offer this early draft for "peer" review on CF to identify potential issues. I will share the feedback and very much appreciate it. I know we have victron DC to DC transformers and are using bus bars as well, they haven't been included in this draft (per pic) that we need to get integrated into the design documentation.

[s/v Jedi]

Originally Posted by Stephen_MO

Thanks Jedi, this is an early draft, but my understanding is that all shore power also went through the isolation transformer as well and that is one of the reasons I wanted to offer this early draft for "peer" review on CF to identify potential issues. I will share the feedback and very much appreciate it. I know we have victron DC to DC transformers and are using bus bars as well, they haven't been included in this draft (per pic) that we need to get integrated into the design documentation.

I understand your situation. I’m trying to tell you that your approach is not optimal. Instead of working from a blank page, or relying on your refitter, you should grab a complete diagram from either me or Victron… whoever has one that is the closest match to what you need, then modify details to match it to your situation.
Those diagrams have been used over and over and can be considered reference diagrams from which you should work. Deviation means experimentation and it has probably been tried and result in less optimal results before.

[catalystcat]

It actually may be a good thing that you took a crack at this, for educational purposes. It's a good way for some people to truly grok what's going on.

That being said, your doc needs a lot to really be a valid working document.

I would suggest you take your drawing and one of the reference drawings and see what is different, missing, or connected differently. That should reveal some areas where your design has holes and will highlight design choices or omissions pretty well. At the very least it is a pretty comprehensive checklist of thing to consider.

I think at the end of the day, you'll probably decide to take your components, translate them toward your preferred reference design, and evolve from there, rather than trying to re-invent the wheel from your current version.

Also, it may be helpful to group things (perhaps dashed outline). For example, I think you are assuming a DC bus. I think that might be the two blocks following the BlueSea DC fuses. But, I can't tell at this resolution and originally thought those were fuse blocks for Class T fuses. I am still not sure.

I think you mean to have a bus bar between the Multiplus and the Batteries, though I am not sure of the connectivity or where the batteries would be fused/switched relative to the connections. Also, it is not clear how you would fuse this. (Saw your comment about including a bus bar after typing this).

There are a bunch more things like this (e.g. how you bring in the DC via the Orions, what actually controls the alternator disconnects and the battery disconnects; how your DC panel fits in) in addition to the things Jedi raised.

But, it's a good start and a good exercise, even if you may have to retrace a bunch of your steps.


One other bit of advice - spend adequate time doing/optimizing the physical layout once you have a solid design. You'll find things like cable lengths, mounting clearance, switch and fuse access, etc. depend on this, and these are the things you need to order/build/install. As a simple example, reorienting my battery disconnects relative to my batteries and Multiplus, relocating my MPPTs a little bit allowed me to remove 1.5ft from each of my 2/0 red cables and 1 ft from each of my black 2/0 cables. With 6 batteries, that's 15 feet of cable and a lot better airflow. It would really suck to build a bunch of cables with lugs and have to rebuild them for a different length.

[SV_FlyingTigress]

@catlystcat @jedi thank you for your review and comments. I am going through this exercise with the presumption that our implementation probably is not optimal and can benefit from being informed by your feedback with intent to integrate them. I have already sent Jedi's reference architectures and technical comments to my integrator as feedback.

[SV_FlyingTigress]

One specific question is, what are your thoughts on having the alternator field energized by relay at engine startup BY the house LFP bank such that is the BMS shuts down the LSF house bank, the field is collapsed and charging discontinues in the same event. Our BMS is the integrated Dakota Lithium BMS and we have the balmar center fielder. Can those be integrated such that DL BMS (as opposed to a custom external BMS as seems to be indicated in the reference architectures) can shut down alternator charging prior to Shutting down the batter for temperature or other reasons. I am calling Dakota on this and possibly Balmar, but would be interested in your comments.

Thanks,

Stephen

[s/v Jedi]

Originally Posted by Stephen_MO

One specific question is, what are your thoughts on having the alternator field energized by relay at engine startup BY the house LFP bank such that is the BMS shuts down the LSF house bank, the field is collapsed and charging discontinues in the same event. Our BMS is the integrated Dakota Lithium BMS and we have the balmar center fielder. Can those be integrated such that DL BMS (as opposed to a custom external BMS as seems to be indicated in the reference architectures) can shut down alternator charging prior to Shutting down the batter for temperature or other reasons. I am calling Dakota on this and possibly Balmar, but would be interested in your comments.

Thanks,

Stephen

I have the relays and them controlling the regulator and thus field current in the schematic. I have connected the relays to the BMS and in the text described how this should work. I have little knowledge of features of available BMS’s, but ai do know that any BMS, internal to the battery or external, must have this feature to comply with ABYC. If a drop in battery with BMS doesn’t have this feature, then it is not ABYC / ISO compliant and will probably be turned down by your insurer.

[SV_FlyingTigress]

Here is an updated schematic draft and rational on alternator protection for review and comments. This is NOT intended to be a reference diagram or architecture, this is offered purely for review and criticism etc with an eye to factoring in recommendations of the community to improve the design:




**********Begin Alternator Shutdown Event Protection *******
Battery Management System SV “Flying Tigress”
Your system consists of four (4) Dakota Lithium 277 AH batteries that are connected in parallel. The
following are the charge, discharge, and temperature limitations for the system.
Charge
Each battery has a charge limitation of <200 amps continuous and a surge of 300 amps for up to
60 seconds.
With four batteries in parallel, those numbers rise to <800 amps continuous and a surge of
1,200 amps for up to 60 seconds.
Charging systems include one (1) Balmar 250-amp alternator, one (1) Volvo 115 amp alternator,
and 800 watts (65 amps) of solar, and a Victron Multiplus 3000 inverter / charger capable of 120
amps charging capacity. Total conceivable charge = 550 amps.
This is theoretical only as never would all charging systems be operating at full output at the
same time.
Therefore, there are no combined charging systems on the vessel capable of reaching the limits
that could exceeded the BMS shutdown limits.

Discharge
Each battery has a discharge limitation of 200 amps continuous and a surge of 300 amps for up
to 10 seconds.
With four batteries in parallel, those numbers rise to 800 amps continuous and a surge of 1,200
amps for up to 10 seconds.
Discharge systems include one (1) Victron Multiplus 3000 inverter / charge capable of a 200-
amp continuous discharge, boat systems including refrigeration, air conditioning, and lighting
capable of an estimated 100 amps maximum continuous, and an anchor windlass capable of 100
amps continuous with a surge capability of 150 amps. Total conceivable discharge = 450 amps.
This is theoretical only as never would all discharge systems be operating at full load at the same
time.
Therefore, there are no combined discharge systems on the vessel capable of reaching the limits
that could exceeded the BMS shutdown limits.

Temperature
The Dakota Lithium BMS system will shut down if internal temperature reaches 180 degrees F.
The system internal temperature is affected by charge and discharge and a relative measure can
be obtained at the main battery terminals.
Battery temperature sensors are provided by the Balmar regulators and the Victron Multiplus
Inverter / Charger.
The sensors for the Balmar 618 regulators can be programmed to reduce or turn off alternator
charging when a preprogrammed temperature (125 degrees F) is reached. This feature would
thus prevent continued charging and the resultant battery heat increase and prevent a BMS
shutdown.

Alternator Safety
Alternators and regulators are at all times connected only to the Lithium battery system. Relays
connected to each engine determine when the engine is running or stopped and turn regulators
on or off accordingly. If power is lost on the Lithium system by such as a BMS shutdown, power
would also be lost to the regulators and the alternators would be shut down.
As discussed above, the only feasible event that may result in a BMS shutdown would be high
battery temperature. Should that occur, alternators would already be shut down by the battery
temperature sensors prior to reaching a temperature sufficient to trigger the BMS shutdown.

********** End Description ********

[s/v Jedi]

Originally Posted by Stephen_MO

Here is an updated schematic draft and rational on alternator protection for review and comments. This is NOT intended to be a reference diagram or architecture, this is offered purely for review and criticism etc with an eye to factoring in recommendations of the community to improve the design:




**********Begin Alternator Shutdown Event Protection *******
Battery Management System SV “Flying Tigress”
Your system consists of four (4) Dakota Lithium 277 AH batteries that are connected in parallel. The
following are the charge, discharge, and temperature limitations for the system.
Charge
Each battery has a charge limitation of <200 amps continuous and a surge of 300 amps for up to
60 seconds.
With four batteries in parallel, those numbers rise to <800 amps continuous and a surge of
1,200 amps for up to 60 seconds.
Charging systems include one (1) Balmar 250-amp alternator, one (1) Volvo 115 amp alternator,
and 800 watts (65 amps) of solar, and a Victron Multiplus 3000 inverter / charger capable of 120
amps charging capacity. Total conceivable charge = 550 amps.
This is theoretical only as never would all charging systems be operating at full output at the
same time.
Therefore, there are no combined charging systems on the vessel capable of reaching the limits
that could exceeded the BMS shutdown limits.

Discharge
Each battery has a discharge limitation of 200 amps continuous and a surge of 300 amps for up
to 10 seconds.
With four batteries in parallel, those numbers rise to 800 amps continuous and a surge of 1,200
amps for up to 10 seconds.
Discharge systems include one (1) Victron Multiplus 3000 inverter / charge capable of a 200-
amp continuous discharge, boat systems including refrigeration, air conditioning, and lighting
capable of an estimated 100 amps maximum continuous, and an anchor windlass capable of 100
amps continuous with a surge capability of 150 amps. Total conceivable discharge = 450 amps.
This is theoretical only as never would all discharge systems be operating at full load at the same
time.
Therefore, there are no combined discharge systems on the vessel capable of reaching the limits
that could exceeded the BMS shutdown limits.

Temperature
The Dakota Lithium BMS system will shut down if internal temperature reaches 180 degrees F.
The system internal temperature is affected by charge and discharge and a relative measure can
be obtained at the main battery terminals.
Battery temperature sensors are provided by the Balmar regulators and the Victron Multiplus
Inverter / Charger.
The sensors for the Balmar 618 regulators can be programmed to reduce or turn off alternator
charging when a preprogrammed temperature (125 degrees F) is reached. This feature would
thus prevent continued charging and the resultant battery heat increase and prevent a BMS
shutdown.

Alternator Safety
Alternators and regulators are at all times connected only to the Lithium battery system. Relays
connected to each engine determine when the engine is running or stopped and turn regulators
on or off accordingly. If power is lost on the Lithium system by such as a BMS shutdown, power
would also be lost to the regulators and the alternators would be shut down.
As discussed above, the only feasible event that may result in a BMS shutdown would be high
battery temperature. Should that occur, alternators would already be shut down by the battery
temperature sensors prior to reaching a temperature sufficient to trigger the BMS shutdown.

********** End Description ********

No, this is not correct. The regulators must be shutdown -before- a HVC, not after a HVC like described here. This diagram will burn out the rectifier diodes from the alternators first HVC event.

The correct diagrams have been posted.

[goboatingnow]

Originally Posted by Stephen_MO

Here is an updated schematic draft and rational on alternator protection for review and comments. This is NOT intended to be a reference diagram or architecture, this is offered purely for review and criticism etc with an eye to factoring in recommendations of the community to improve the design:









**********Begin Alternator Shutdown Event Protection *******

Battery Management System SV “Flying Tigress”

Your system consists of four (4) Dakota Lithium 277 AH batteries that are connected in parallel. The

following are the charge, discharge, and temperature limitations for the system.

Charge

Each battery has a charge limitation of &lt;200 amps continuous and a surge of 300 amps for up to

60 seconds.

With four batteries in parallel, those numbers rise to &lt;800 amps continuous and a surge of

1,200 amps for up to 60 seconds.

Charging systems include one (1) Balmar 250-amp alternator, one (1) Volvo 115 amp alternator,

and 800 watts (65 amps) of solar, and a Victron Multiplus 3000 inverter / charger capable of 120

amps charging capacity. Total conceivable charge = 550 amps.

This is theoretical only as never would all charging systems be operating at full output at the

same time.

Therefore, there are no combined charging systems on the vessel capable of reaching the limits

that could exceeded the BMS shutdown limits.



Discharge

Each battery has a discharge limitation of 200 amps continuous and a surge of 300 amps for up

to 10 seconds.

With four batteries in parallel, those numbers rise to 800 amps continuous and a surge of 1,200

amps for up to 10 seconds.

Discharge systems include one (1) Victron Multiplus 3000 inverter / charge capable of a 200-

amp continuous discharge, boat systems including refrigeration, air conditioning, and lighting

capable of an estimated 100 amps maximum continuous, and an anchor windlass capable of 100

amps continuous with a surge capability of 150 amps. Total conceivable discharge = 450 amps.

This is theoretical only as never would all discharge systems be operating at full load at the same

time.

Therefore, there are no combined discharge systems on the vessel capable of reaching the limits

that could exceeded the BMS shutdown limits.



Temperature

The Dakota Lithium BMS system will shut down if internal temperature reaches 180 degrees F.

The system internal temperature is affected by charge and discharge and a relative measure can

be obtained at the main battery terminals.

Battery temperature sensors are provided by the Balmar regulators and the Victron Multiplus

Inverter / Charger.

The sensors for the Balmar 618 regulators can be programmed to reduce or turn off alternator

charging when a preprogrammed temperature (125 degrees F) is reached. This feature would

thus prevent continued charging and the resultant battery heat increase and prevent a BMS

shutdown.



Alternator Safety

Alternators and regulators are at all times connected only to the Lithium battery system. Relays

connected to each engine determine when the engine is running or stopped and turn regulators

on or off accordingly. If power is lost on the Lithium system by such as a BMS shutdown, power

would also be lost to the regulators and the alternators would be shut down.

As discussed above, the only feasible event that may result in a BMS shutdown would be high

battery temperature. Should that occur, alternators would already be shut down by the battery

temperature sensors prior to reaching a temperature sufficient to trigger the BMS shutdown.



********** End Description ********

One must assume that for safety sakes HVC and LVC BMS shutdown events will always occur when least expected. Battery faults themselves produce these faults.

Hence to protect your alternators they will have to instructed by the BMS to stop charging just before the BMS disconnects.

[SV_FlyingTigress]

Originally Posted by s/v Jedi

No, this is not correct. The regulators must be shutdown -before- a HVC, not after a HVC like described here. This diagram will burn out the rectifier diodes from the alternators first HVC event.

The correct diagrams have been posted.

Thanks Jedi. As I noted earlier I do see the diagrams, and also as noted, have provided them to my installer along with your comments, and as also stated, as a person on the learning curve here I am trying to understand *what your diagrams imply specifically for my vessel and installation, not just what your diagrams indicate for a generic vessel* as this is not an academic exercise. I am trying to understand failure modes, likelihood, impact and risk so that I can determine when, where, if and how to extend my installation to address gaps. Guatemala is expensive and difficult to get parts into. I would rather make modifications after moving the vessel to the US next year, but seek to understand failure modes and risks for context.

Ok, so if I infer correctly high *temperature* BMS shutdown failure mode has been adequately dealt with as the Balmar regulators monitor the battery temperature and can be (and are) set to a much lower threshold than the Dakota BMS. As stated they are currently set to shut down the alternators at 125 deg F whereas the BMS would shutdown the batteries at around 180 deg F. Is that correct or am I missing a likely and significant failure mode?

BMS shutdown via exceeding *Charging* amperage threshold (if that factor *directly* managed by the Dakota BMS as opposed say to being managed as a function of temp etc...) is implied by the installer as structurally prevented in the current installation because the combined charging capacities are well below house bank charge rate thresholds. Is that correct or am I missing a likely and significant failure mode?

BMS shutdown via exceeding Voltage thresholds ("HVC" ?) seems to me to be the outlier and not directly addressed by the alternator protection documentation sent to me and which I provided. I would like to understand where the high voltage could/would likely come from. (I'm presuming regulator failure or something like that but am interested in your thoughts).

For context I have been talking to Dakota and they recommend if one wants alternator protection to implement a victron external BMS. I am trying to gather information from them on how they do it and awaiting documentation on exactly how two separate BMS's controlling the same battery bank can be effectively and safely integrated. Again for now I am trying to understand risks as a function of vulnerability>likelihood of event>impact. Thank you to anyone for your thoughts, and thanks Jedi & GBN et al.. again for your diagrams and suggestions.

[PaulCrawhorn]

Originally Posted by goboatingnow

to protect your alternators they will have to instructed by the BMS to stop charging just before the BMS disconnects.

Requires way over-engineering.

Just keep a lead batt on the engine/alt circuit. Usually the Starter, two birds one stone.

Otherwise can be a small cheap "sacrificial" unit, just replace every 2-3 years even if never needed.

[goboatingnow]

Originally Posted by PaulCrawhorn

Requires way over-engineering.

Just keep a lead batt on the engine/alt circuit. Usually the Starter, two birds one stone.

Otherwise can be a small cheap "sacrificial" unit, just replace every 2-3 years even if never needed.

One mans way over engineering is another’s good engineering , people spending $$$$$$$$ on lithium yet somehow baulk at installing a proper alternator.

[s/v Jedi]

Originally Posted by Stephen_MO

Thanks Jedi. As I noted earlier I do see the diagrams, and also as noted, have provided them to my installer along with your comments, and as also stated, as a person on the learning curve here I am trying to understand *what your diagrams imply specifically for my vessel and installation, not just what your diagrams indicate for a generic vessel* as this is not an academic exercise. I am trying to understand failure modes, likelihood, impact and risk so that I can determine when, where, if and how to extend my installation to address gaps. Guatemala is expensive and difficult to get parts into. I would rather make modifications after moving the vessel to the US next year, but seek to understand failure modes and risks for context.

Ok, so if I infer correctly high *temperature* BMS shutdown failure mode has been adequately dealt with as the Balmar regulators monitor the battery temperature and can be (and are) set to a much lower threshold than the Dakota BMS. As stated they are currently set to shut down the alternators at 125 deg F whereas the BMS would shutdown the batteries at around 180 deg F. Is that correct or am I missing a likely and significant failure mode?

BMS shutdown via exceeding *Charging* amperage threshold (if that factor *directly* managed by the Dakota BMS as opposed say to being managed as a function of temp etc...) is implied by the installer as structurally prevented in the current installation because the combined charging capacities are well below house bank charge rate thresholds. Is that correct or am I missing a likely and significant failure mode?

BMS shutdown via exceeding Voltage thresholds ("HVC" ?) seems to me to be the outlier and not directly addressed by the alternator protection documentation sent to me and which I provided. I would like to understand where the high voltage could/would likely come from. (I'm presuming regulator failure or something like that but am interested in your thoughts).

For context I have been talking to Dakota and they recommend if one wants alternator protection to implement a victron external BMS. I am trying to gather information from them on how they do it and awaiting documentation on exactly how two separate BMS's controlling the same battery bank can be effectively and safely integrated. Again for now I am trying to understand risks as a function of vulnerability>likelihood of event>impact. Thank you to anyone for your thoughts, and thanks Jedi & GBN et al.. again for your diagrams and suggestions.

Stephen, you are looking at details but those should only be addressed after the fundamentals are good. Also, you have to decide if you want to comply with ABYC recommendations.

Simply said: a BMS is required to send out warning signals about an imminent LVC or HVC. This is before the BMS actually disconnects the battery. In case of a:
- LVC warning: the battery is empty. Using this warning signal, you must automatically switch off things like an inverter.
- HVC warning: the battery, or maybe just one internal cell, is overcharging. Using this warning signal, you must automatically switch off things like an alternator or solar controller (any charge source).

If this works well, the actual LVC or HVC may be avoided, and for sure battery life is extended.

For batteries with internal BMS, this means it must have external connections for this. Also, some BMS’s don’t have these warning signals: they are not allowed under ABYC and ISO setups.