Myth of alternator damage cause by BMS disconnect?

[SOLAR SUPPORT]

Originally Posted by hjohnson

That's precisely what an integrated system does. The regualtor is getting a constant flow of data from the BMS via CANbus including the target voltage/current, the actual voltage/current, and status multiple times per second.

if there's an alarm, it kills the field. If the BMS directs 0A into the battery, it kills the field.

As the battery approaches 100% SoC, it fades out the current and voltage so that it doesn't overshoot and overcharge a cell or battery.

Advanced systems for control and monitoring purposes, such as solar energy, AC shore connection, alternator charging, as well as tracking the charge of battery banks and consumption of the inverter, may not be necessary for all sizes of boats. The benefits of these systems are undeniable, but it is not necessary or meaningful to install such advanced tracking and control systems on boats of all sizes. Therefore, a simple port that sends a warning signal before isolating the Lithium battery from the external environment is the necessary and missing battery hardware for every boat, caravan and vehicle to prevent serious problems. There must be a separate port that gives a preliminary warning signal within the global standard equipment of lithium batteries. Regarding lithium batteries, it should be added to the ABYC and ISO standards as a matter that battery manufacturers must comply with.

[CaptainRivet]

Originally Posted by SOLAR SUPPORT

Advanced systems for control and monitoring purposes, such as solar energy, AC shore connection, alternator charging, as well as tracking the charge of battery banks and consumption of the inverter, may not be necessary for all sizes of boats. The benefits of these systems are undeniable, but it is not necessary or meaningful to install such advanced tracking and control systems on boats of all sizes. Therefore, a simple port that sends a warning signal before isolating the Lithium battery from the external environment is the necessary and missing battery hardware for every boat, caravan and vehicle to prevent serious problems. There must be a separate port that gives a preliminary warning signal within the global standard equipment of lithium batteries. Regarding lithium batteries, it should be added to the ABYC and ISO standards as a matter that battery manufacturers must comply with.

correct and I think its already part of ABYC but thats not law, its still just recommendation.
The new JK inverter BMS in 200A with 2A active balancing for 230Euro has that function already together with 2 programmable relay port and with master and slave configuration of multiple batteries plus communicates to victron out of the box. sadly its only avaliable in 24V and 48V. I already made an request to supply a 12V version too as thats exactly what the still mainly 12V marine world needs.
would be helpful to send also the same request to info@jkbms.com
thats the BMS for a fair price we all waited for. As soon thats avaliable in 12V i will switch from ElectrodacusBms to it.

[rgleason]

Originally Posted by CaptainRivet

correct and I think its already part of ABYC but thats not law, its still just recommendation.
The new JK inverter BMS in 200A with 2A active balancing for 230Euro has that function already together with 2 programmable relay port and with master and slave configuration of multiple batteries plus communicates to victron out of the box. sadly its only avaliable in 24V and 48V. I already made an request to supply a 12V version too as thats exactly what the still mainly 12V marine world needs.
would be helpful to send also the same request to info@jkbms.com
thats the BMS for a fair price we all waited for. As soon thats avaliable in 12V i will switch from ElectrodacusBms to it.

Capt Rivit, thanks for that info, I was trying to decipher their webpage to understand what was available. Can you provide a link that is a comprehesible page on their website? I will write them too. Thanks.

[rgleason]

While others don't like the idea, using a Victron 200a argofet is a simple and direct way to provide additional protection (oddly Victron uses them too).

Originally Posted by sleepy

rgleason, i spoke to balmar they did not give me the warm fuzzy answer. they said the same thing! they suggested carrying 2 in case of failure that didnt make much sense to me.

[SOLAR SUPPORT]

In my opinion, this feature, which should be present in all LFP battery BMSs, is the two programmable relays found in the recently developed JK Inverter BMS. The relay can be used simply to cut the alternator rotor excitement current just before the LFP battery bms HVC. Unfortunately it is not available for 4s, but is available for 8s and 16s.

Andy from "Off-grid Garage" describe the settings of this relay
https://youtu.be/2hNrRzOVPoM?si=wRcmZ58RevSA-oQJ

Full Video:
https://youtu.be/eZX7CkEEq_8?si=F3fR-tqjZIjwlhfc

[CaptainRivet]

Originally Posted by SOLAR SUPPORT

In my opinion, this feature, which should be present in all LFP battery BMSs, is the two programmable relays found in the recently developed JK Inverter BMS. The relay can be used simply to cut the alternator rotor excitement current just before the LFP battery bms HVC. Unfortunately it is not available for 4s, but is available for 8s and 16s.

Andy from "Off-grid Garage" describe the settings of this relay
https://youtu.be/2hNrRzOVPoM?si=wRcmZ58RevSA-oQJ

Full Video:
https://youtu.be/eZX7CkEEq_8?si=F3fR-tqjZIjwlhfc

Fully agree on that, maybe write them also and request a 4S version of that BMS, the more do the higher the chance are they do it.

[wholybee]

Originally Posted by CaptainRivet

Fully agree on that, maybe write them also and request a 4S version of that BMS, the more do the higher the chance are they do it.

You might only need to order it that way, directly from JK instead of through a dealer. You would probably also have a minimum order. But I think the work is done. At least some 4S boards have a spot for the relay connector, it just isn't populated or available in the firmware. So if someone asked for 1000 of them, they would possible just accept the order and build them.

Maybe if enough requests went to a dealer, that dealer might be willing to place the order.

[CaptainRivet]

Originally Posted by wholybee

You might only need to order it that way, directly from JK instead of through a dealer. You would probably also have a minimum order. But I think the work is done. At least some 4S boards have a spot for the relay connector, it just isn't populated or available in the firmware. So if someone asked for 1000 of them, they would possible just accept the order and build them.

Maybe if enough requests went to a dealer, that dealer might be willing to place the order.

Ordering via their webshop directly or via their own aliexpress webshop. I don't know dealers they sell them...
Dealers have their own version like eg mueller energy a special version of the 4S with 250A and active balancing.but also missing all the communications.

That would be another way...i think 100 will do it.
Its not only the relay, its also the communication and master/slave communication.
I assume they could just modify the firmware of the 8S version to a 4S version as it supports already dual voltage 24 and 48V.

[wholybee]

Originally Posted by CaptainRivet

Ordering via their webshop directly or via their own aliexpress webshop. I don't know dealers they sell them...
Dealers have their own version like eg mueller energy a special version of the 4S with 250A and active balancing.but also missing all the communications.

That would be another way...i think 100 will do it.
Its not only the relay, its also the communication and master/slave communication.
I assume they could just modify the firmware of the 8S version to a 4S version as it supports already dual voltage 24 and 48V.

I always assume that an aliexpress shop is actually a dealer, and not the manufacturer. Maybe I am wrong. But contacting them directly, not though either Aliexpress or the webshop, and asking for exactly what you want.

The 8S version with a firmware mod would certainly be an easy way to go.

[CaptainRivet]

Originally Posted by wholybee

I always assume that an aliexpress shop is actually a dealer, and not the manufacturer. Maybe I am wrong. But contacting them directly, not though either Aliexpress or the webshop, and asking for exactly what you want.

The 8S version with a firmware mod would certainly be an easy way to go.

You are wrong in this case...stangewise the aliexpress store shows many more direct contact emails to sales and support while their own homepage and webstore just the typical info@jk-BMS.com mass email. Looks like aliexpress is very important channel to them.
That also how andy from OGG communicates and orders his stuff.

[SOLAR SUPPORT]

It is pointless that all Lithium battery manufacturers make their BMS designs by neglecting the safe use of the alternator for charging the batteries. It is obvious that the alternator that charges the battery and the devices connected to it also need protection, as well as the need for the Bms HVC feature to protect the lithium cells.

Although it is a simple fact that the majority of all Lithium batteries produced as drop-in will be used in vehicles such as boats or caravans, it is strange that this need is not met by any manufacturer for 4s batteries. It is equally important that the charge controller connected to the Lithium battery charged with solar or shore energy cuts off the charge before BMS HVC. Solar & AC-DC charge regulators also need to have a safe shut off switch & port to control this event.

The difficulty of accessing the rotor excitation of new alternators and the fact that they cannot be turned off directly with a simple switch depending on the user's choice when the alternator's energy is not needed seem very meaningless.

Therefore, it is very meaningful that JK first added two programmable relays to their newly developed BMS for 24V and 48V systems. This is the beginning for DIY developers.

[Pete7]

Originally Posted by SOLAR SUPPORT

It is pointless that all Lithium battery manufacturers make their BMS designs by neglecting the safe use of the alternator for charging the batteries.

You are assuming that the majority of LFP batteries are charged from an alternator. There are many more uses for LFP batteries than yachts and RVs. We may be just a small part of the market share and until recently the requirement hasn't been seen as important.

Pete

[SOLAR SUPPORT]

Originally Posted by Pete7

You are assuming that the majority of LFP batteries are charged from an alternator. There are many more uses for LFP batteries than yachts and RVs. We may be just a small part of the market share and until recently the requirement hasn't been seen as important.

Pete

Key word is "drop-in" Lithium for boats or RVs

[CaptainRivet]

Originally Posted by SOLAR SUPPORT

Key word is "drop-in" Lithium for boats or RVs

RV is a big market, around 10x of marine....
Well and drop in has 2 categories:
1.dumb surprised boxes without any communications like LI-time which are mostly fine with RV use who's most used charge source is alternator...the main market for wakespeed....
2. with external BMS communications like the epoch or the top notch valance (preferably used by highly regulated emergency operators like rescue, medical, fire brigade....)