Small Boat BMS/LFP with backup

[Goboatingnow]

I wonder how much current these will use over 24hrs and how they compare to the more expensive Bluesea.

They are the exact same component. This TE product is the blue sea component.

The TE has the same “ economiser “ circuit which drops the current to 130 mA like the blue sea one

 

[Goboatingnow]

@Goboatingnow So is it a manual bypass switch for both relay coils CH "B" and DCH "C" or just one?

I would have at least one manual override for every remotely controlled or “smart “ disconnect device.

Where I had one combined disconnect ie CH and DCH , I would have two manual overrides to allow the CH bus to be reconnected while leaving off the CH bus.

 

[Tribune]

Really good content on here. This is going to help me huge while I plan my installation. I've been unable to find the TE contactors anywhere near $50. Would anyone have a link to provide.
Cheers

 

[Goboatingnow]

Really good content on here. This is going to help me huge while I plan my installation. I've been unable to find the TE contactors anywhere near $50. Would anyone have a link to provide.
Cheers

https://a.aliexpress.com/_mPQ9QVK. This is the 500A version smaller variants are a bit less , as you can see it’s the economiser version ( 130mA hold current )

 

[Tribune]

Perfect, thank you so much.

 

[Goboatingnow]

Perfect, thank you so much.

Shows you the blue sea markup for the exact same component !!

 

[Tribune]

Just ordered 4 with the aux contacts. Couple for the boat and couple for the plane I'm building.

 

[rgleason]

I would have at least one manual override for every remotely controlled or “smart “ disconnect device.

Where I had one combined disconnect ie CH and DCH , I would have two manual overrides to allow the CH bus to be reconnected while leaving off the CH bus.

Now understood. Thanks.

 

[Goboatingnow]

Now understood. Thanks.

I meant "leaving off the DCH bus" but I think you understood

 

[rgleason]

I would have at least one manual override for every remotely controlled or “smart “ disconnect device.
Where I had one combined disconnect ie CH and DCH , I would have two manual overrides to allow the CH bus to be reconnected while leaving off the CH bus.
I meant "leaving off the DCH bus" but I think you understood

Well when it comes to diagramming this, I find I need two relays! The two relay coils can operate together or separately. I need them in order to be able to have dual buses. Can you explain what you mean, so I can draw it?
Not comfortable with all the Bypass Switches, and the complicated Emergency FLA, but that's the way it is.

 

[svsagres]

Well when it comes to diagramming this, I find I need two relays! The two relay coils can operate together or separately. I need them in order to be able to have dual buses. Can you explain what you mean, so I can draw it?
Not comfortable with all the Bypass Switches, and the complicated Emergency FLA, but that's the way it is.


View attachment 108766

Actually, it's too bad you're not using the 7713 still, as you could do this even more simply. Just a switch on a jumper between your alternator and your starter, and a manual disconnect to the battery. If you want to swap over, just disconnect the battery, and then create the jump between the starter and alternator. Then your positives are all connected together and everything will run off your FLA. (you'd force the 7713 on manually in that situation).

That's basically what I have planned in mine, just that I have to manually install an 18" piece of 2awg.

 

[Goboatingnow]

Well when it comes to diagramming this, I find I need two relays! The two relay coils can operate together or separately. I need them in order to be able to have dual buses. Can you explain what you mean, so I can draw it?
Not comfortable with all the Bypass Switches, and the complicated Emergency FLA, but that's the way it is.


View attachment 108766

This is the correct way to do it , ( finally ) of you want redundancy and overrides. It offers the most flexibility and fail safe. The two busses CH and DCH can also be enabled remotely as both have contractor disconnects

The alternative is a single load and charge bus , with manual overrides that makes it into two busses CH and DCH. it offers most of the advantages but saves on a contractor and two switches

 

[Goboatingnow]

Actually, it's too bad you're not using the 7713 still, as you could do this even more simply. Just a switch on a jumper between your alternator and your starter, and a manual disconnect to the battery. If you want to swap over, just disconnect the battery, and then create the jump between the starter and alternator. Then your positives are all connected together and everything will run off your FLA. (you'd force the 7713 on manually in that situation).

That's basically what I have planned in mine, just that I have to manually install an 18" piece of 2awg.

Given the TE contactors are $40 and are fail safe ( the 7713 isn’t and costs a fortune ) the diagram offers the most flexibility and redundancy

Manual overrides should not simply attempt to “ force on “ the contactor . They should operate by bypassing it completely , for example if a bad surge took out the Electronics in the 7713 , the control circuit would be dead and the 7713 wouldn’t respond to a manual reconnect process. The manual bypass switch as shown is far superior

 

[rgleason]

I've made some changes and cleaned up the notes a little in this new diagram. I'd like to find a way to show the @svsagres alternatives for "B" Bluesea RMS Latching Switch and "C" Smart BatteryProtect 65 with some pro/con notes

1. Pro: Uses less LFP power (how much daily?) and has a built-in switch
   1. Blueseas ML-RBS 12vdc 7713 8mA when OFF, 13mA when ON, about 0.013a x 24 hours = 0.325 amps/day
   2. Victron Smart Battery Protect 65, on 1.5 mA, off 0.6 ma, 0.0015a x 24 hours = 0.036 amps/day
   3. Whereas the (2) Coil Powered Relay's 0.13a x 24 hours = 3.12amps/day x (2) = 6.24 amps/day, significantly more.
2. Con: May not meet strict/rote insurance adherence to ABYC & ISO. May not be quite as "fail safe" because a one is a mosfet and latching is used.
3. Con: Cost of Latching relay with switch Blueseas ML-RBS 12vdc 7713 $291

Diagram Changes:

1. Revise notes at bottom, alphanumeric id's
2. Clarify BMS Emergency operation and manual overrides and emergency switching.
3. Improve Emergency Switch for SLA, reducing it to one switch.

Questions outstanding directed towards @svsagres regarding operation, Please see Post #196 noting the Questions shown in Brown. Both of you have been outstandingly patient and helpful. Many Thanks.

PS: Regarding using short jumpers, you'll need two jumpers one heavy one and one lighter one for the DC Panel.

 

[rgleason]

@Goboatingnow wrote:

The two busses CH and DCH can also be enabled remotely as both have contractor disconnects

Yes, I suppose I could show a smaller 12v 6a bypass switch for each relay coil as well, but wouldn't that be overkill and somewhat confusing? Would these be powered from the LFP or not?

 

[Goboatingnow]

@Goboatingnow wrote:

Yes, I suppose I could show a smaller 12v 6a bypass switch for each relay coil as well, but wouldn't that be overkill and somewhat confusing? Would these be powered from the LFP or not?

I would not bother with coil based bypass switch , the full monty bypass manual is better

 

[Tribune]

Mbta?

 

[rgleason]

Mbta?

fuse type. Perhaps is should be changed to Mrbf Marine Rated Battery Fuse

MRBF Marine-Rated Battery Terminal Fuses | West Marine

Check out our MRBF Marine-Rated Battery Terminal Fuses and more from West Marine!

www.westmarine.com

MRBF Terminal Fuse Block - 30 to 300A - Blue Sea Systems

Easily and economically satisfies ABYC 7 circuit protection rule by mounting on a 3/8 battery post, battery switch or bus bar.

www.bluesea.com

LATER: Have changed it. Thanks.

 

[Tribune]

Thank you sir.

 

[Goboatingnow]

I've made some changes and cleaned up the notes a little in this new diagram. I'd like to find a way to show the @svsagres alternatives for "B" Bluesea RMS Latching Switch and "C" Smart BatteryProtect 65 with some pro/con notes

1. Pro: Uses less LFP power (how much daily?) and has a built-in switch
   1. Blueseas ML-RBS 12vdc 7713 8mA when OFF, 13mA when ON, about 0.013a x 24 hours = 0.325 amps/day
   2. Victron Smart Battery Protect 65, on 1.5 mA, off 0.6 ma, 0.0015a x 24 hours = 0.036 amps/day
   3. Whereas the (2) Coil Powered Relay's 0.13a x 24 hours = 3.12amps/day x (2) = 6.24 amps/day, significantly more.
2. Con: May not meet strict/rote insurance adherence to ABYC & ISO. May not be quite as "fail safe" because a one is a mosfet and latching is used.
3. Con: Cost of Latching relay with switch Blueseas ML-RBS 12vdc 7713 $291

The TE relay is $45 , is fail safe and draws 130mA holding current , around 3AH per 24 hours.

Way better

Diagram Changes:

1. Revise notes at bottom, alphanumeric id's
2. Clarify BMS Emergency operation and manual overrides and emergency switching.
3. Improve Emergency Switch for SLA, reducing it to one switch.

Questions outstanding directed towards @svsagres regarding operation, Please see Post #196 noting the Questions shown in Brown. Both of you have been outstandingly patient and helpful. Many Thanks.

PS: Regarding using short jumpers, you'll need two jumpers one heavy one and one lighter one for the DC Panel.


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