Coming Back to Lithium

[Dockhead]

It looks like I've killed by golf cart batteries after only 3 years of use . I was too lazy to reinstall my alternator regulator after changing my school bus alternator a few years ago, and I seem to have fried the batts motoring for a couple of days straight in the North Sea during a rare dead calm


But it's maybe not so horrible -- I am amazed at how the price of prismatic cells has fallen. The price is silly now -- when did the prices collapse? I can buy Eve Grade A cells for as little as €65/kWH -- INCLUDING VAT. So the cells for two 7.2kWH batteries are ridiculously under a Euro boat buck. Crazy. So even with the BMS's and contactors this is still going to be cheaper than replacing the lead.



So now it makes no sense whatsoever to run lead batteries in a cruising boat. Lead is dead, officially.


The Eve cells are a better shape for my battery boxes, and I can fit 16 of the 280AH or 304AH ones in a single box (I have two of them) -- with space left over for BMS's.


I was previously thinking about keeping one of my lead banks and making a kind of hybrid but with 14.4kWH (or even 15.6kWH) in a single box, I think there's no point. I would love to have some extra storage space.



I have studied Nick's (Jedi's) superb threads and I think I'll follow the architecture he's laid out, more or less. Mine will be a bit simpler than his because (a) no solar; (b) I'm not touching engine start systems which are completely separate with their own alternators and battery chargers.



So here's what I think it will look like:


1. Two batteries consisting of 8x each of the 280AH Eve cells.
2. Wakespeed WS500 alternator regulator
3. 2x REC Active BMS (because of good integration with the WS500 and with my Victron Multiplus).
4. 2x BMV-712's with their shunts, one each to each battery's negative lead.
5. Cerbo GX connected to the BMV-712's and to a Smart Shunt in the combined negative lead. Also connected to my Multiplus, and with a 5" monitor.
6. 2x Blue Seas bistable contactors, one on each battery's positive lead, for the low voltage cutoff and for isolating individual batteries.


How does that sound so far?


I have a couple of questions for whomever understands this:


1. Nick's diagram doesn't show (or I can't find) a means for low voltage cutoff. For cutting off the loads in case of a low voltage event. Wouldn't we want to have a third contactor between the positive bus bar and the panel? In the REC Active BMS manual, this contactor is shown (leading to "non-Victron equipment" which is evidently the loads).



2. Anyone have recommendation for the fuses? I like the fuses which mount directly on the battery terminal.


3. Are we satisfied now -- I remember this was controversial a few years ago -- that the alternator diodes are sufficiently protected in case of a high voltage event cutoff? Does the BMW cut the field wire soon enough? Or should we consider using something like the Sterling Alternator Protector? I remember everyone obsessing about this problem a few years ago.



4. Is Venus better than Cerbo?




Any other comments, suggestions, criticisms?

[Dockhead]

Another question I had -- the REC BMW comes in either 4 cells or 16 cells versions, so nothing for the 8 cells of a 24v battery. This is awkward, bulky and expensive for a 24v system.


Are there alternatives which integrate well with Victron and WS-500?

[fxykty]

Originally Posted by Dockhead

Another question I had -- the REC BMW comes in either 4 cells or 16 cells versions, so nothing for the 8 cells of a 24v battery. This is awkward, bulky and expensive for a 24v system.


Are there alternatives which integrate well with Victron and WS-500?

Tao Performance BMS (they call it an EMS) handles 8S 24V with two components: the regular BMS and an Extension unit. Between the two they have 8 cell voltage/temperature leads. Good CanBUS support and plays well with Cerbo.

[fxykty]

Originally Posted by Dockhead

It looks like I've killed by golf cart batteries after only 3 years of use . I was too lazy to reinstall my alternator regulator after changing my school bus alternator a few years ago, and I seem to have fried the batts motoring for a couple of days straight in the North Sea during a rare dead calm


But it's maybe not so horrible -- I am amazed at how the price of prismatic cells has fallen. The price is silly now -- when did the prices collapse? I can buy Eve Grade A cells for as little as €65/kWH -- INCLUDING VAT. So the cells for two 7.2kWH batteries are ridiculously under a Euro boat buck. Crazy. So even with the BMS's and contactors this is still going to be cheaper than replacing the lead.



So now it makes no sense whatsoever to run lead batteries in a cruising boat. Lead is dead, officially.


The Eve cells are a better shape for my battery boxes, and I can fit 16 of the 280AH or 304AH ones in a single box (I have two of them) -- with space left over for BMS's.


I was previously thinking about keeping one of my lead banks and making a kind of hybrid but with 14.4kWH (or even 15.6kWH) in a single box, I think there's no point. I would love to have some extra storage space.



I have studied Nick's (Jedi's) superb threads and I think I'll follow the architecture he's laid out, more or less. Mine will be a bit simpler than his because (a) no solar; (b) I'm not touching engine start systems which are completely separate with their own alternators and battery chargers.



So here's what I think it will look like:


1. Two batteries consisting of 8x each of the 280AH Eve cells.
2. Wakespeed WS500 alternator regulator
3. 2x REC Active BMS (because of good integration with the WS500 and with my Victron Multiplus).
4. 2x BMV-712's with their shunts, one each to each battery's negative lead.
5. Cerbo GX connected to the BMV-712's and to a Smart Shunt in the combined negative lead. Also connected to my Multiplus, and with a 5" monitor.
6. 2x Blue Seas bistable contactors, one on each battery's positive lead, for the low voltage cutoff and for isolating individual batteries.


How does that sound so far?


I have a couple of questions for whomever understands this:


1. Nick's diagram doesn't show (or I can't find) a means for low voltage cutoff. For cutting off the loads in case of a low voltage event. Wouldn't we want to have a third contactor between the positive bus bar and the panel? In the REC Active BMS manual, this contactor is shown (leading to "non-Victron equipment" which is evidently the loads).



2. Anyone have recommendation for the fuses? I like the fuses which mount directly on the battery terminal.


3. Are we satisfied now -- I remember this was controversial a few years ago -- that the alternator diodes are sufficiently protected in case of a high voltage event cutoff? Does the BMW cut the field wire soon enough? Or should we consider using something like the Sterling Alternator Protector? I remember everyone obsessing about this problem a few years ago.



4. Is Venus better than Cerbo?




Any other comments, suggestions, criticisms?

Regarding your low voltage cutoff, we only stop the inverter and don’t worry about the DC loads - they can be turned off manually via the switch panel. The alternative is to have separate load bus and charge bus and use a disconnect on each. If you also have an inverter/charger (like Multiplus or Quattro) then a third bus is needed for a clean install. In our case, we don’t bother adding that complexity and have a single combined bus for loads and chargers and Quattro with one disconnect. One of your design decisions needs to be about how automated you want the system to be.

Regarding fuses, T-class I believe is required for the short circuit current potential of LFP. NH fuses also can work.

Regarding alternator protection, you have two situations: first the stop-charge command and second the high voltage disconnect. For stop-charge your BMS can command each component - in the case of the alternator that’s telling the regulator that charging can stop. The old school way was to cut either the field wire or the ignition wire, but a WS500 or Zeus regulator can handle the charge stop itself. In any case, the charge-stop command will always precede the battery disconnect command. No alternator protection needed.

[Dockhead]

Originally Posted by fxykty

Regarding your low voltage cutoff, we only stop the inverter and don’t worry about the DC loads - they can be turned off manually via the switch panel. The alternative is to have separate load bus and charge bus and use a disconnect on each. If you also have an inverter/charger (like Multiplus or Quattro) then a third bus is needed for a clean install. In our case, we don’t bother adding that complexity and have a single combined bus for loads and chargers and Quattro with one disconnect. One of your design decisions needs to be about how automated you want the system to be.

Regarding fuses, T-class I believe is required for the short circuit current potential of LFP. NH fuses also can work.

Regarding alternator protection, you have two situations: first the stop-charge command and second the high voltage disconnect. For stop-charge your BMS can command each component - in the case of the alternator that’s telling the regulator that charging can stop. The old school way was to cut either the field wire or the ignition wire, but a WS500 or Zeus regulator can handle the charge stop itself. In any case, the charge-stop command will always precede the battery disconnect command. No alternator protection needed.

Thanks very much! Very useful.


Concerning low voltage cutoff -- I forgot about the fact that we get charging AND load from the same leads to the charger/inverter (I have a Multiplus).


No, I certainly do not want to do the rewiring necessary to create a whole separate load bus.


The "price of the question" is already much less now that the cells have become so cheap, so maybe not necessary to be a perfectionist here.


If we can trust the inverter to shut down when commanded by the BMW, then a low voltage disconnect of the panel -- and there is already a contactor for this in my system -- would solve this, wouldn't it.



And maybe an alarm. I don't think I will be using the inverter when off the boat.


How does the "charge stop command" from the WS-500 work? So the BMS will issue this command and the WS-500 will execute it, right? And the BMW does this a certain amount of time prior to triggering the high voltage cutoff relay?


So we trust the BMS to work in a way which won't blow the alternator. But wait a minute -- if the BMS successfully stops the alternator and charger/inverter from charging, then there will be no need for any high voltage cutoff in the first place, right? So maybe the high voltage cutoff isn't actually adding anything?

[fxykty]

High voltage disconnect, same as a low voltage disconnect and high temperature disconnect, are all last stage emergency disconnects by the BMS telling the battery connect contactor to open. In a well designed system and good components these actions should never be triggered as whatever is taking the system to one of those states will be stopped earlier by other BMS commands (or individual equipment settings).

I don’t know how the WS500 handles commands it receives via CanBUS but I assume it massages the field to stop charging when getting the external command. It likely already has internal settings to reduce and/or stop charging, so the BMS command may be belt and suspenders. My Balmer 614 regulators are dumb so I need my BMS to activate a relay on their ignition wires to stop charging - Wakespeed and Zeus regulators are much smarter.

Charge stop for example should be set to a lower voltage value than the high voltage cutoff - 3.55V cell versus 3.80V cell. But hey, you never know if your relay wiring fails, or relay fails, or …, so just in case the charge stop doesn’t work you still want the high voltage disconnect as your backup.

[Dockhead]

Originally Posted by fxykty

High voltage disconnect, same as a low voltage disconnect and high temperature disconnect, are all last stage emergency disconnects by the BMS telling the battery connect contactor to open. In a well designed system and good components these actions should never be triggered as whatever is taking the system to one of those states will be stopped earlier by other BMS commands (or individual equipment settings).

I don’t know how the WS500 handles commands it receives via CanBUS but I assume it massages the field to stop charging when getting the external command. It likely already has internal settings to reduce and/or stop charging, so the BMS command may be belt and suspenders. My Balmer 614 regulators are dumb so I need my BMS to activate a relay on their ignition wires to stop charging - Wakespeed and Zeus regulators are much smarter.

Charge stop for example should be set to a lower voltage value than the high voltage cutoff - 3.55V cell versus 3.80V cell. But hey, you never know if your relay wiring fails, or relay fails, or …, so just in case the charge stop doesn’t work you still want the high voltage disconnect as your backup.

OK, but maybe we need the alternator protector after all? The only way the HVC will be activated is if the BMS somehow failed to stop the charging. In that if it succeeds in activating the HVC contactor, it will blow the alternator.

[Kerry1]

Originally Posted by fxykty

High voltage disconnect, same as a low voltage disconnect and high temperature disconnect, are all last stage emergency disconnects by the BMS telling the battery connect contactor to open. In a well designed system and good components these actions should never be triggered as whatever is taking the system to one of those states will be stopped earlier by other BMS commands (or individual equipment settings).

I don’t know how the WS500 handles commands it receives via CanBUS but I assume it massages the field to stop charging when getting the external command. It likely already has internal settings to reduce and/or stop charging, so the BMS command may be belt and suspenders. My Balmer 614 regulators are dumb so I need my BMS to activate a relay on their ignition wires to stop charging - Wakespeed and Zeus regulators are much smarter.

Charge stop for example should be set to a lower voltage value than the high voltage cutoff - 3.55V cell versus 3.80V cell. But hey, you never know if your relay wiring fails, or relay fails, or …, so just in case the charge stop doesn’t work you still want the high voltage disconnect as your backup.

Re: "My Balmer 614 regulators are dumb so I need my BMS to activate a relay on their ignition wires to stop charging " Would you say the same of a Balmar MC-618 smart Alternator Regulator ? The reason I ask is I was going to fit a Zeus but by the time shipped to NZ it was cost prohibitive so went with the Balmar. I have LA batts at the mo, but will one day migrate to LiFePo system.

[Loredo]

Me having installed the Wakespeed, if I were you I'd have a second and third thought about it. The HI is really obsolete / difficult to work with. Yes, they do have the app thinghy you can use on a cell phone but when you compare the values you set and what's then in the saved file you will be surprised...
Once done the WS works and works well! But getting there...
For disconnects, keep in mind that the BMV 712 has a programmable relay in it.

[Dockhead]

Originally Posted by Loredo

Me having installed the Wakespeed, if I were you I'd have a second and third thought about it. The HI is really obsolete / difficult to work with. Yes, they do have the app thinghy you can use on a cell phone but when you compare the values you set and what's then in the saved file you will be surprised...
Once done the WS works and works well! But getting there...
For disconnects, keep in mind that the BMV 712 has a programmable relay in it.

What's the "HI"?


Concerning the BMV 712 -- I note that the REC BMS also has shunts behind each battery, and also evaluates SOC etc. Are the BMV's superfluous if you're using a BMS like this?


I do like the idea of a separate device with authority to hit the cutoffs.



I note that the Blue Seas 7700 contactor, which is bistable, takes a pulse on one wire to close, and a pulse on the other wire to open. So I presume it could be controlled by BOTH the BMS AND a BMV 712.

[fxykty]

Originally Posted by Dockhead

OK, but maybe we need the alternator protector after all? The only way the HVC will be activated is if the BMS somehow failed to stop the charging. In that if it succeeds in activating the HVC contactor, it will blow the alternator.

If your BMS fails in sending the stop-charge command it will likely fail to send the disconnect command. If you’re worried about that, get the Sterling APM.

Of course, you could also have a manual switch on or near your engine control panel that turns off the regulator, or if the regulator has the function, turns off charging. Not everything has to be automated!

[fxykty]

Originally Posted by Dockhead

What's the "HI"?


Concerning the BMV 712 -- I note that the REC BMS also has shunts behind each battery, and also evaluates SOC etc. Are the BMV's superfluous if you're using a BMS like this?


I do like the idea of a separate device with authority to hit the cutoffs.



I note that the Blue Seas 7700 contactor, which is bistable, takes a pulse on one wire to close, and a pulse on the other wire to open. So I presume it could be controlled by BOTH the BMS AND a BMV 712.

The BMV 712 is not necessary in your case. If you already have them, series or parallel relay activation is possible (you have to decide if you want both devices to send a disconnect for disconnect to happen, or either device to trigger the disconnect regardless of what the other device is doing).

If you don’t already have them, don’t bother.You already have the SmartShunt to provide you with the overall system view and Victron controls.

[PippaB]

The BMV 712 could be a backup LVC disconnect signal if you like, but it will only disconnect on series/bulk low voltage. The BMS should disconnect both on series low voltage and cell low voltage. For cells that are top-balanced one cell will inevitably lead the way on the bottom end, and you want the LVC to do its job before that single cell gets in the danger area, the BMV 712 can't do that.

[kmacdonald]

With the low cost of Eve cells and excellent uniformity you could make a strong argument to even eliminate the BMS. Just get a programable good external alternator regulator and call it good. Skip the expense and complexity. Its really that simple.

[dannc]

I have been watching a series of videos on YouTube presented by the guy, Al, who created the initial WakeSpeed. The first several videos I have watched are covering alternators, batteries, CAN busses, etc, and I managed to learn quite a bit though I know a fair amount about the subject. He has barely covered WakeSpeed so far but there are other videos I am going to watch that go into more detail I highly recommend the videos, but they are hours long if one starts at the start of the class, so it takes some effort to find the time. There are shorter videos about WakeSpeed but Al's class covering boat power equipment is excellent. Al is a cruiser and problems with charging his batteries is how he came up with the WakeSpeed device.

WakeSpeed will have a new version this fall that is Bluetooth capable which should help those who had trouble with setting a configuration.

https://www.wakespeed.com/product/ws...tor-regulator/

I ran across the videos on YouTube but they are listed on the WakeSpeed website, https://www.wakespeed.com/learn/

The Morgan's Cloud website has quite a few articles about WakeSpeed and one about Arco Zeus regulator. The few dollars it cost to subscribe to Morgan's Cloud is well worth it, but even more so, to read the articles about these regulators.

https://www.morganscloud.com/?s=wakespeed