How is this for a power system? Solar vs battery balance?

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I have never heard of these things... wouldnt the built in Battery Management System in the BattleBorn batteries do the same thing?

(so be not needed) ?

The Victron Battery protection module is the control extension of the Victron BMV 712 you are already installing. If you are installing the one you might as well install the others also, or rely on the Battleborn BMS, but it is not recommended.

I just bought a lithium battery and plan on using it with just the built in BMS. Don't tell the others, I'll let you know how it goes.

 

[shade]

Based on Dreadlock's recent experience, maybe need to rethink this approach. Does this mean two methods of protection, or two modes of failure? If you are going to invest a well designed system to charge and control your lithium needs, why not chose a battery without a BMS to prevent a potential source of failure.

If you set the limits on the BatteryProtects appropriately, they do all of the work, with the internal battery BMS never having to cycle. If a BP were to fail, then the internal BMS should kick in. It's possible that both internal & external disconnects would fail simultaneously, but the odds are against it.

I call that redundancy, not a doubling of failure modes, but proceed as you see fit.

The Victron Battery protection module is the control extension of the Victron BMV 712 you are already installing. If you are installing the one you might as well install the others also, or rely on the Battleborn BMS, but it is not recommended.

I just bought a lithium battery and plan on using it with just the built in BMS. Don't tell the others, I'll let you know how it goes.

When an external BP fails, the internal battery BMS saves the day, and you buy a new BP for $100 or so.
When an internal battery BMS fails, the battery fails.

 

[LosAngeles]

Based on Dreadlock's recent experience, maybe need to rethink this approach. Does this mean two methods of protection, or two modes of failure? If you are going to invest a well designed system to charge and control your lithium needs, why not chose a battery without a BMS to prevent a potential source of failure.

I'm just the guy who is buying the Pop Up camper.... I'm letting Hallmark design the solar system. They have a ton of experience with these things.... they do lithium systems all the time... and seem incredibly knowledgeable on all this stuff. Me? Not.

so I am deferring to Hallmark. So far they have had good, and seemingly sensible.... and cost sensitive answers to all my questions - meaning when I suggested a $3,000 part for a similar part that costs $1,000 they explained why to *not* to waste the $2,000 difference....

so in other words - I dont have an answer for you, but Hallmark has a very good reputation from all my research, and speaking + emailing with Hallmark owners.

thanks.

 

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If you set the limits on the BatteryProtects appropriately, they do all of the work, with the internal battery BMS never having to cycle. If a BP were to fail, then the internal BMS should kick in. It's possible that both internal & external disconnects would fail simultaneously, but the odds are against it.

I call that redundancy, not a doubling of failure modes, but proceed as you see fit.



When an external BP fails, the internal battery BMS saves the day, and you buy a new BP for $100 or so.
When an internal battery BMS fails, the battery fails.

I am playing devil's advocate here in the design process.

As an end user that has had navigation, lighting and electrical systems fail in situations way more critical than having to drink warm beer or having your steaks defrost prematurely, I always look at ways any system can fail. If the redundant systems are in series and one the failure of one leads to a failure of the entire system, it something to consider going into the design of the system. If a system were to fail how can you troubleshoot it, how do you fix it and what are your alternatives or workarounds. A system that has more components there is an increased chance for things to go wrong and it becomes harder to troubleshoot.

The failure of your house battery system is not so critical in an Overlanding situation but it could ruin a trip, or shorten a vacation, so system reliability is something to consider.

 

[shade]

I am playing devil's advocate here in the design process.

As an end user that has had navigation, lighting and electrical systems fail in situations way more critical than having to drink warm beer or having your steaks defrost prematurely, I always look at ways any system can fail. If the redundant systems are in series and one the failure of one leads to a failure of the entire system, it something to consider going into the design of the system. If a system were to fail how can you troubleshoot it, how do you fix it and what are your alternatives or workarounds. A system that has more components there is an increased chance for things to go wrong and it becomes harder to troubleshoot.

The failure of your house battery system is not so critical in an Overlanding situation but it could ruin a trip, or shorten a vacation, so system reliability is something to consider.

Boats and airplanes are a different matter. In the case of critical loads on a boat, you may want to bypass disconnecting devices, as discussed here. You may also find point 5 relevant WRT battery selection:

#5 Non-Communicable BMS – This one is perhaps the most frustrating aspect on-board a cruising boat. For a trolling motor? Who cares.. It’s not powering anything critical. For a house battery, on a cruising boat that ventures off-shore, and is powering critical navigation and safety equipment, this can create a dangerous situation. A non-communicable BMS is one that can not communicate externally with the vessels charge and load systems, or even you the owner. It has no means of externally communicating or sending/sounding warning alarms or activating relays/triggers to properly and safely disconnect charge sources or give ample warning of an impending BMS disconnect. Some batteries are now featuring Bluetooth monitoring but this still requires you the owner to be watching it.

Back to auto-disconnects. When a BatteryProtect fails and no other harm is done to the system, it can simply be bypassed by attaching both cables to the same BP lug, or otherwise connecting them directly. Troubleshooting should be simple. If a BP should be connected and it isn't, a voltmeter will quickly show the fault.

When the internal BMS of an LFP battery fails or otherwise disconnects power, the battery may well be out of commission for some time.

While I realize that redundancy usually adds to complexity, the benefits may outweigh the disadvantages. In the case of auto-disconnects, I believe they do.