Lithium Upgrade Design - Input Required

[UFO]

Originally Posted by fakinx

And just a note on BP220:
Using it in front of an inverter which can draw in excess of 220A alone not to account normal home use is a bit underestimated. You should seperate loads or be very aware of your usage not to exceed 220A load.
Of course you’ll be fine with some 1,6kVA inverter or similar but that’s about it.
If we’re talking 12V system that is.

OK so my inverter (3000W) has a Max peak load of 500A which is well above the BP220.


Is there anything out there that can take this load and be smart connected to a BMS if it needs to be cut off?

[UFO]

Originally Posted by UFO

OK so my inverter (3000W) has a Max peak load of 500A which is well above the BP220.


Is there anything out there that can take this load and be smart connected to a BMS if it needs to be cut off?

Think I have found the answer:


https://tbs-electronics.com/product/...ct-relay-500a/

[rma]

Originally Posted by UFO

Think I have found the answer:


https://tbs-electronics.com/product/...ct-relay-500a/

That latching relay looks perfect for the job. UFO, the other option, if your BMS is CANbus enabled, is to let a Victron GX device turn off the inverter. This configuration allows the inverter to bypass the load disconnect in the wiring but still be shut off before a low voltage disconnect. There are advantages and disadvantages to this. For simplicity, I think you're going with the right option.

[donradcliffe]

Originally Posted by UFO

Think I have found the answer:


https://tbs-electronics.com/product/...ct-relay-500a/

I couldn't get the link to work. What are the specs on that bad boy and how much does it cost?

[rma]

Originally Posted by carstendenmark

Wooh, now you guys scare me off a bit !
When just converting a sailboat to electric propulsion, with shore power and solar, I guess the system setup would be much more simple ?

That depends. Is your electric sailboat powered by lithium?

Originally Posted by carstendenmark

When a potential boat buyer reads this thread, he may think that a degree in electrical engineering is necessary to deal with such a system...

Nonsense! I'm a biologist (albeit a PhD) with no formal training in electrical engineering. It only takes a willingness to learn something new. All the information you need is out there and freely accessible. This thread has suggested lots of good links to get started.

I don't believe any of us have shared our knowledge or experience to intimidate others, but rather to help others understand this topic. As I and others have pointed out, there are some serious design considerations that need to be taken seriously in lithium systems. As long as you do a little research and don't fall susceptible to the half-assed "eh, it's good enough for my boat" mindset, anyone can do it.

[UFO]

Originally Posted by donradcliffe

I couldn't get the link to work. What are the specs on that bad boy and how much does it cost?

Strange the link still works for me. I am waiting on them to get back to me with a place to buy.


So far all I have found is the following at Euro 228 plus delivery.



https://www.combinoord.nl/elektricit...0a-/tb5074410/


I have attached their manual for it.

[LeighC]

Hi All,
I'm very interested in these threads also
I have also had a latching relay for years on my cheap BMS & it has always
worked OK but it worries me if it doesn't give a pulse to change its state when needed to protect the batteries.
The almost zero current draw after switching appears to be its major attribute.
I'm worried if a wire comes off it does follow the dead man principle like a N/O relay.
Any views on this would be great also.
Cheers - Leigh

[fakinx]

Latching relays are either one state or another. They need pulse or signal to switch and then settle without any (or almost none) current draw.
With LPO systems is always some equipment that can fail due to complexity in comparison to LA. One should design a system in such a way that no single equipment failure could cause catastrophic event and such a failure should clearly manifest itself.
Of course, there is no such thing as 100% secure so some risks are always involved.

[UFO]

Following on I have started a new thread about charging:


https://www.cruisersforum.com/forums...ml#post3362798

[parachute]

Lithiumm batteries have caughfire in planes and and cars.

Lithium-ion batteries commonly used in consumer electronics are notorious for bursting into flame when damaged or improperly packaged. ... "If the battery is damaged and the plastic layer fails, the electrodes can come into contact and cause the battery's liquid electrolyte to catch fire

List of UK Lithium battery fires: https://resource.co/article/lithium-...llion-annually

[UFO]

Originally Posted by parachute

Lithiumm batteries have caughfire in planes and and cars.

Lithium-ion batteries commonly used in consumer electronics are notorious for bursting into flame when damaged or improperly packaged. ... "If the battery is damaged and the plastic layer fails, the electrodes can come into contact and cause the battery's liquid electrolyte to catch fire

List of UK Lithium battery fires: https://resource.co/article/lithium-...llion-annually

Please stop spamming this thread - You have already said that and have been given an answer

[noelex 77]

Blueseas and Sterling both sell high power latching relays. From memory, the Blueseas model has a continuous rating up to 500A and the Sterling 640A.

The other option is a conventional relay/contactor with a coil economiser. These consume some power, but much less than typical relay. Expect around 2w for a relay that will handle 500A continuous. However, they are simple to switch (they don’t require a pulse), are reliable, and will only consume power in one state. This state can be when off or on depending on your requirements.

[UFO]

Originally Posted by rma

That latching relay looks perfect for the job.

Well you can't actually buy those relays for love nor money anywhere in the world


So my inverter can only have one remote input (Victron Phoneix 3K) which is currently occupied by a nice on/off and info panel in the salon - I could lose this and have it controlled by the BMS and run it on its own load bus, but I'd rather not do that.


So does anyone have any ideas of a relay or any type of unit that can deal with up to a 500A load (peak) and also have a remote on/off switch that the BMS can control?

[UFO]

Originally Posted by noelex 77

Blueseas and Sterling both sell high power latching relays. From memory, the Blueseas model has a continuous rating up to 500A and the Sterling 640A.

The other option is a conventional relay/contactor with a coil economiser. These consume some power, but much less than typical relay. Expect around 2w for a relay that will handle 500A continuous. However, they are simple to switch (they don’t require a pulse), are reliable, and will only consume power in one state. This state can be when off or on depending on your requirements.

Can you control the Blueseas/Sterling with a BMS?

[UFO]

Originally Posted by noelex 77

Blueseas and Sterling both sell high power latching relays. From memory, the Blueseas model has a continuous rating up to 500A and the Sterling 640A.

The other option is a conventional relay/contactor with a coil economiser. These consume some power, but much less than typical relay. Expect around 2w for a relay that will handle 500A continuous. However, they are simple to switch (they don’t require a pulse), are reliable, and will only consume power in one state. This state can be when off or on depending on your requirements.

Here is a PDF of the Sterling.


Am I reading this wrong, but it looks like I could connect the Remote On/Off manual switch to a BMS instead?