Need some help.....

[JJenkins5179]

Hey everyone. Looking for some assistance/guidance. I have a setup that was intended to allow my wife to brew a cup of coffee when we were dry camping/boondocking. I have 4 Battle Born 100 Ah, 12V batteries, a Victron 12/3000/120-50 2 x 120v Charger/inverter. Batteries are wired in parallel with 4/0 wire, positive wire has a 400A ANL fuse in line before it goes to a battery disconnect switch. From there is goes to a BMV-712 Smart shunt, Lynx distributor. The problem is anytime I try and run anything that consumes any significant power the system dies within seconds. I have checked all connections and they are tight and in the correct spot. All settings have been checked and appear to be right. From what I have seen it seems that I should be able to power a Keurig single cup coffee maker with the battery setup I have. And to make matters worse when I went out to verify everything was tight and secure I noticed that the wire from the ANL fuse holder to the disconnect switch had gotten very hot at some point but the fuse was not blown. I have checked all batteries independently and all are good and fully charged. I have included pics of what my settings are. Any help would be greatly appreciated! Thanks!

Josh

 

[Q-Dog]

Hey everyone. Looking for some assistance/guidance. I have a setup that was intended to allow my wife to brew a cup of coffee when we were dry camping/boondocking. I have 4 Battle Born 100 Ah, 12V batteries, a Victron 12/3000/120-50 2 x 120v Charger/inverter. Batteries are wired in parallel with 4/0 wire, positive wire has a 400A ANL fuse in line before it goes to a battery disconnect switch. From there is goes to a BMV-712 Smart shunt, Lynx distributor. The problem is anytime I try and run anything that consumes any significant power the system dies within seconds. I have checked all connections and they are tight and in the correct spot. All settings have been checked and appear to be right. From what I have seen it seems that I should be able to power a Keurig single cup coffee maker with the battery setup I have. And to make matters worse when I went out to verify everything was tight and secure I noticed that the wire from the ANL fuse holder to the disconnect switch had gotten very hot at some point but the fuse was not blown. I have checked all batteries independently and all are good and fully charged. I have included pics of what my settings are. Any help would be greatly appreciated! Thanks!

Josh

Can you clarify where the shunt is installed? Maybe a simple line drawing? or even some photos?

 

[DIYrich]

Did the fuse holder get hot, or the wire? Check the crimp on the wire connector. Check the torque on the connection to the fuse holder.

 

[Supervstech]

Hot equals resistance.

Take lots of pictures and post em here.

 

[HarryN]

It is almost certain that you have tripped at least one of the internal BMS in the BB batteries.

I have been down this road before myself.

Most likely this happened when you turn it on and the input caps charged up the inverter in a split second.

If you do it this way, it will work.

( neg bus bar ) -- ( battery A ) ---- ( breaker ) ----- ( positive bus bar )

( neg bus bar ) -- ( battery B ) -----( breaker ) ----- ( positive bus bar )

( neg bus bar ) ---( battery C ) ---- ( breaker ) ----- ( positive bus bar )

etc.

( neg bus bar #2 ) ---( significant load 1 ) ---( breaker ) ----- ( positive bus bar )

( neg bus bar #2 ) --- ( fuse block ) -----( breaker ) - ( positive bus bar )

Put the shunt in between the (neg bus bar ) and ( neg bus bar #2 )

Most of these can now be wired with 2 awg except for the largest load / inverter which will still require a full size wire.
_____________

When you wire it the way that you did, the most likely outcome is for the battery terminals to over heat from so much power passing through them that it damages the batteries from heat.

Having the breakers in the circuits is very useful because it allows an easy way to turn it on / off for each battery to re-set the BMS of that battery. There isn't any way to re-set the BMS of each one unless you can isolate them from each other.

Your fuse is most likely over heating because of the holder, but it also could be a slightly imperfect crimp on the wire terminal. They have to be really perfect to work at those currents. I buy large wires per-terminated because most people DIYers ( including me ) aren't set up to do the quality level required for 300 amps.

 

[JJenkins5179]

Crimps and nuts are all tight. So here are some pics.. a little messy in the compartment right now as I have been moving things around trying to diagnose the problem.

 

[HarryN]

Thanks for the photos - yes your battery terminals will over heat wired like that with the power passing through each terminal.

Are you sure that those are 4/0 wire ?

It looks like a number of the connections are getting hot.

 

[JJenkins5179]

It is almost certain that you have tripped at least one of the internal BMS in the BB batteries.

I have been down this road before myself.

Most likely this happened when you turn it on and the input caps charged up the inverter in a split second.

If you do it this way, it will work.

( neg bus bar ) -- ( battery A ) ---- ( breaker ) ----- ( positive bus bar )

( neg bus bar ) -- ( battery B ) -----( breaker ) ----- ( positive bus bar )

( neg bus bar ) ---( battery C ) ---- ( breaker ) ----- ( positive bus bar )

etc.

( neg bus bar #2 ) ---( significant load 1 ) ---( breaker ) ----- ( positive bus bar )

( neg bus bar #2 ) --- ( fuse block ) -----( breaker ) - ( positive bus bar )

Put the shunt in between the (neg bus bar ) and ( neg bus bar #2 )

Most of these can now be wired with 2 awg except for the largest load / inverter which will still require a full size wire.
_____________

When you wire it the way that you did, the most likely outcome is for the battery terminals to over heat from so much power passing through them that it damages the batteries from heat.

Having the breakers in the circuits is very useful because it allows an easy way to turn it on / off for each battery to re-set the BMS of that battery. There isn't any way to re-set the BMS of each one unless you can isolate them from each other.

Your fuse is most likely over heating because of the holder, but it also could be a slightly imperfect crimp on the wire terminal. They have to be really perfect to work at those currents. I buy large wires per-terminated because most people DIYers ( including me ) aren't set up to do the quality level required for 300 amps.

I know this might sound dumb but do you have pictures on what you are describing…lol. I know enough to make my life difficult and that is where I’m at. Thanks again!!

 

[JJenkins5179]

Definitely 4/0. Same wire I used for the batteries.

 

[HarryN]

I should but I don't have one handy:

Here is a starting point - in the text I posted - use a breaker like this one:

187-Series Circuit Breaker - Surface Mount 80A - Blue Sea Systems

Thermal circuit breakers provide heavy duty circuit protection for 25 to 200 Amp loads when switching and circuit protection are both required.

www.bluesea.com

for a bus bar, use something similar to this one:

PowerBar 600A BusBar - Eight 3/8"-16 Studs - Blue Sea Systems

Provides compact high-amp busing.

www.bluesea.com

 

[HarryN]

In the short term, put the wires on one side of the battery terminals, so the power does not "pass through" the terminal.

Have the connections on just one side of it, even though it is natural to want to do it the way that you did it.

The battery terminal I think is a type of bronze, so fairly low resistance, but not designed for passing 300 -400 amps.

There are others on the forum who have done this like you have where the current "passes through the battery terminals" and it melts things inside of the battery.

Ultimately change it to what I have drawn - will try to make a better diagram or something for you.

 

[HarryN]

Definitely 4/0. Same wire I used for the batteries.

Definitely 4/0. Same wire I used for the batteries.

I am not personally capable of making a crimp that can pass 300 amps and stay cool, but I can make pro quality 10 awg wire crimps all day.

That would require a hydraulic crimper and that is outside of my budget.

 

[JJenkins5179]

I am not personally capable of making a crimp that can pass 300 amps and stay cool, but I can make pro quality 10 awg wire crimps all day.

That would require a hydraulic crimper and that is outside of my budget.

I was able to grab one of Amazon, I feel as the crimps are strong as I couldn’t pull the wire out of the lug no matter how I tried but when i return home I’ll have some wire made up professionally just to eliminate the possibility of a bad crimp.

 

[justinm001]

What specific model is that fuse holder? Looks like it isn't rated anything close to what you're trying to put through?

 

[JJenkins5179]

Blue Sea, model 5503, allegedly rated to 750a. I currently have a 400a fuse in it.

 

[justinm001]

Blue Sea, model 5503, allegedly rated to 750a. I currently have a 400a fuse in it.

It looks like it wasn't torqued down or tight at all and was able to move so electricity was arcing around that metal bar melting the plastic and everything else.

Here's a lug from my 12v batteries when I forgot to tighten it all the way down after moving batteries around.