Lithium battery bank install video

wildebus

Full Member
Excellent Video, Phil.
that Lynx distribution box is BIIGGGG! but very good. I am kinda tempted to use one of those when I install your old batteries in my van (assuming I can lift them!)

Got a question that I have been thinking about and your video reminded me of as you have the same potential situation. Not anything to do with the video so you might want to separate to a different thead?

How can you tell if an individual battery fuse is blown? (I mean without physically checking with a meter).
There is 12.xV on the battery side of the fuses from the battery. There is also 12.xV on the other side of the fuses from the other batteries. So if a fuse blows, how do you know (as nothing actually stops working)?
If one blows, the loads will then be shared across 3 batteries instead of 4, and then on a high load, another fuse will blow, and then another as the shared current per battery jumps up - leaving you with 4 blown fuses and no knowledge of which one went first (maybe pointing to an issue with a specific battery) to potentially start the chain reaction.
Not a critisism you understand, as I fully get the reason for fusing each battery and I am also wanting to fuse each one, but have the above situation in mind which I want to preemptively deal with.
I am thinking there must be a way using the fact the blown fuse is open circuit, so infinite resistance, rather than basing the check on voltage differential (the usual way on a live circuit), but not sure what a good way to do this is?
 

St3v3

Full Member
Very cool.

Ref the fuses blowing, won't the bms shut off on overcurrent before the other fuses blow? The fuse is there to protect the system from something going horribly wrong and a battery ending up short circuit isn't it?
 

Phil

Forum Admin
Very cool.

Ref the fuses blowing, won't the bms shut off on overcurrent before the other fuses blow? The fuse is there to protect the system from something going horribly wrong and a battery ending up short circuit isn't it?
I have fitted the individual fuses in case one of the BMSs fails. Potentially the other three batteries could reach a total of over 900 amps before they are disconnected. The cables are rated at 500+ amps I prefer to be safe.
 

Phil

Forum Admin
Excellent Video, Phil.
that Lynx distribution box is BIIGGGG! but very good. I am kinda tempted to use one of those when I install your old batteries in my van (assuming I can lift them!)

Got a question that I have been thinking about and your video reminded me of as you have the same potential situation. Not anything to do with the video so you might want to separate to a different thead?

How can you tell if an individual battery fuse is blown? (I mean without physically checking with a meter).
There is 12.xV on the battery side of the fuses from the battery. There is also 12.xV on the other side of the fuses from the other batteries. So if a fuse blows, how do you know (as nothing actually stops working)?
If one blows, the loads will then be shared across 3 batteries instead of 4, and then on a high load, another fuse will blow, and then another as the shared current per battery jumps up - leaving you with 4 blown fuses and no knowledge of which one went first (maybe pointing to an issue with a specific battery) to potentially start the chain reaction.
Not a critisism you understand, as I fully get the reason for fusing each battery and I am also wanting to fuse each one, but have the above situation in mind which I want to preemptively deal with.
I am thinking there must be a way using the fact the blown fuse is open circuit, so infinite resistance, rather than basing the check on voltage differential (the usual way on a live circuit), but not sure what a good way to do this is?
They do a full lynx version called a distributor and that has warning leds if the fuses blow.
 

nabsim

Full Member
I wonder how that works. I'm intriged :)
Could you not just put an indicator light on each line to either light up or go off when/if a fuse blows. They do it on fuse boxes now where an led lights up if it blows but never looked how it’s done, you would just need the led mounted remotely where you would see it
 

wildebus

Full Member
Could you not just put an indicator light on each line to either light up or go off when/if a fuse blows. They do it on fuse boxes now where an led lights up if it blows but never looked how it’s done, you would just need the led mounted remotely where you would see it
Nope, that wouldn't work as there would be common GND/0V, plus +12V either side of the fuse - one 12V from the battery with the blown fuse and one 12V from the other batteries. (So there is 12V both sides and therefore circuit would appear to be intact)
The chance of a blown fuse is very very remote anyway in normal operation so is not a great worry, but in this kind of setup it is very hard to check as well using normal methods as even using a DMM in the normal way won't give you the answer either.
Is it worth paying the extra £70 for the Lynx distributor with the fuse checking? It's a tough call as chances are you will never see a blown fuse anyway.
 

rab126

Full Member
if the led was on the out side of the fuse then to earth it should go out if the fuse blows as each is a single feed

rab
 

St3v3

Full Member
if the led was on the out side of the fuse then to earth it should go out if the fuse blows as each is a single feed

rab
The trouble is, one side of the fuse is connected to the +ve of battery 1, and the other side of the fuse is connected to the +ve of the other batteries. So, blown or not, both sides of the fuse will measure +12V to earth.
 

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