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diy solar

battery and system fusing size question

I have a 300 watt S 12v solar array , 3000 watt inverter charger and want to hook up to a 6000 watt Honda generator and cottage panel off grid . Outback 80 voltage reg . When I hook up generator hot wire I get E3 code short circuit . Any ideas.
 
As I said before when you first floated this idea in another thread, the battery fuses should be directly off the battery positive terminal of each battery and should absolutely come before the disconnect switchs.
You should be using a Victron power-in instead of a lynx distributor.
Be careful here, if you are connecting batteries in parallel you need the LYNX DISTRIBUTER and fused at battery NOT A LYNX POWER IN fused at battery. If you get a fault on the postive line on one of your batteries between the LYNX POWER IN you will blow the fuse at the battery but will still be having your other battery banks feeding the POWER IN and now your Line from your blown fuse is taking all that current, the cable is now not rated for all your parallel batteries capacity and will catch fire, also depending on your situation you might not even blow the fuses on the other batteries at the terminals either as it will be a combined load all going down that one cable. Using the LYNX DISTRIBUTER will prevent this from happening and blow the fuse on that fault cable preventing it from overloading after the 1000A Bus BAR in the DISTRIBUTER.
 
Be careful here, if you are connecting batteries in parallel you need the LYNX DISTRIBUTER and fused at battery NOT A LYNX POWER IN fused at battery.
I disagree.
Lynx power in is specifically intended for paralleling batteries.
If you get a fault on the postive line on one of your batteries between the LYNX POWER IN you will blow the fuse at the battery but will still be having your other battery banks feeding the POWER IN and now your Line from your blown fuse is taking all that current, the cable is now not rated for all your parallel batteries capacity and will catch fire, also depending on your situation you might not even blow the fuses on the other batteries at the terminals either as it will be a combined load all going down that one cable. Using the LYNX DISTRIBUTER will prevent this from happening and blow the fuse on that fault cable preventing it from overloading after the 1000A Bus BAR in the DISTRIBUTER.
I can't read that run on sentence right now.
Assuming proper AIC rating of the fuse at the battery, when it blows that battery circuit is isolated.

The reason the fuse is at the battery positive is to minimize the chance of a short upstream of the fuse.
The lynx distributor is is fused at the start of the branch circuit to isolated faults to a specific branch.
 
Put another way, the largest wire that is practical to land on the lynx power-in is 4/0 awg.

Lets say we get a dead short between the positive and negative busbar.
4/0 awg is good for 400 amps plus change.
It will likely be fused no higher than 400 amps.
400 * 3 is 1200 amps.
You may get a cascading failure but those fuses will blow before the wire melts.

The backplane will be just fine.
 
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I disagree.
Lynx power in is specifically intended for paralleling batteries.

I can't read that run on sentence right now.
Assuming proper AIC rating of the fuse at the battery, when it blows that battery circuit is isolated.

The reason the fuse is at the battery positive is to minimize the chance of a short upstream of the fuse.
The lynx distributor is is fused at the start of the branch circuit to isolated faults to a specific branch.
read it again, it is correct. In summary you still have a positive cable on the battery side which has only being isolated from the positive terminal of the battery. The positive cable still travels back to the POWER IN and if there are still other banks connected in parallel to BUS on the POWER IN they will still feed their combined current to the fault condition cable (without their terminal fuses blowing) WHICH IS NOT RATED AT THE COMBINED CURRENT of the other banks, hence in a slow burn fault condition will cause a fire. I can't make it any clearer appologies.
 
read it again, it is correct. In summary you still have a positive cable on the battery side which has only being isolated from the positive terminal of the battery. The positive cable still travels back to the POWER IN and if there are still other banks connected in parallel to BUS on the POWER IN they will still feed their combined current to the fault condition cable (without their terminal fuses blowing) WHICH IS NOT RATED AT THE COMBINED CURRENT of the other banks, hence in a slow burn fault condition will cause a fire. I can't make it any clearer appologies.
I see your point.

If the wire from one battery became disconnected and shorted to the negative busbar then the fault current from the other batteries would go through that single wire.

I can't imagine a slow burn condition but I will consider fusing at both ends.
 
Now the next problem...
The mega fuses used in the lynx distributer have a pretty low AIC rating and might not quench the arc.
 
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Now the next problem...
The mega fuses used in the lynx distributer have pretty low AIC rating and might not quench the arc.
I see your point.

If the wire from one battery became disconnected and shorted to the negative busbar then the fault current from the other batteries would go through that single wire.

I can't imagine a slow burn condition but I will consider fusing at both ends.
A good example would be something abrasive wearing through the conductor and causing a high resitance leak. This would increase over time. Then say for example you had 4 x 12v 130A batteries connected to the POWER IN on 150A fuses. The 4th bank gets a fault on the postive line to high resitance leak or short, the fuse on the battery terminal will blow. The fuse at 150A was correctly sized for the cable capacity of say 175A. You still have 3 x 150A 450A of potential current that can now pass down the 150A cable of the 4th battery postive cable to leak/earth etc without blwoing the FUSES on the other battery terminals. Now with depending on the C ratings of the battaries you would probably only get around 5 minutes at that discharge (still long enough to start a fire next to the bottle of whisky on the RV floor) as SLA drop off under heavly load and become crap efficiency, however if you are running Lithium then it's bumhole twiching time. In an RV or Marine environement this could be bad news. It's rare it could happen but for the extra $30 just use a LYNX DISTRIBUTER and the risk has gone.
Victrons view re their manual is that this is low risk, but from a common sense and economical view the $30 extra will save your RV or Boat and make that risk almost 0%. From my engineering point of view the POWER IN is a bad design and concept unless you want something with very low resistance on the BUS Bars. Victron products are great but this one is not so in my opinion. Cheers,
 
Now the next problem...
The mega fuses used in the lynx distributer have a pretty low AIC rating and might not quench the arc.
Correct, absolutley but not until your above 30VDC so more of a problem in 48V systems, I can't see it being a problem in most 12V RV Boat applications, but you are correct. T rated then becomes the go to, but in the real world none of this will probably happen anyway.
 
Correct, absolutley but not until your above 30VDC so more of a problem in 48V systems, I can't see it being a problem in most 12V RV Boat applications, but you are correct. T rated then becomes the go to, but in the real world none of this will probably happen anyway.
Somewhere way back I saw a plot of an LFP cell dead short.
Sorry I can't find it and I have looked.
For some number of seconds the current flow was ~100C until the cell started to vent.
The popular big blue prismatic cells here are 300amp hours.
300 amp hours * 100C = 30000 amps
Lets say that the added resistance to make an 8s battery drops the fault current to half.
That is still 15000 amps into a dead short at 24 volts nominal.
The mega fuses I've looked at are rated to quench ~2000 amps at 32 volts.
 
Somewhere way back I saw a plot of an LFP cell dead short.
Sorry I can't find it and I have looked.
For some number of seconds the current flow was ~100C until the cell started to vent.
The popular big blue prismatic cells here are 300amp hours.
300 amp hours * 100C = 30000 amps
Lets say that the added resistance to make an 8s battery drops the fault current to half.
That is still 15000 amps into a dead short at 24 volts nominal.
The mega fuses I've looked at are rated to quench ~2000 amps at 32 volts.
Yep, as Tesla owners found out, don't crash into a river, if you do crash you better be able to run. NSA probably see the Teslas from spy satellite when they go up in flames on the highway! There isn't really a way to contain it when it gets to a sizeable problem. Fuses are a bit like a prehistoric solution. Maybe we should have eject buttons just to disconnect and launch the whole pack away from the RV or dump it overboard in a boat. Probably more effective than a fuse.
 
Good info here guys!

For what it's worth, I'm using a Lynx Distributor at both ends (source/batteries and all my loads)
My two batteries are fused at the Lynx Distributor with MEGA fuses as intended by Victron AND fused with Class T fuses at the battery terminals.

Or I should say, they will be :) That's how I designed mine, finishing my battery enclosure now for final assembly.
 
The more I think about it I'm going to stay with the classic fuse at the battery terminal pattern.
However I am thinking about physically blocking off un-used ports on the lynx power-in.
 
Good info here guys!

For what it's worth, I'm using a Lynx Distributor at both ends (source/batteries and all my loads)
My two batteries are fused at the Lynx Distributor with MEGA fuses as intended by Victron AND fused with Class T fuses at the battery terminals.

Or I should say, they will be :) That's how I designed mine, finishing my battery enclosure now for final assembly.
Perfect, in the above application, Battery>terminal fuse or fuse holder nearest the postive terminal as possible (with an appropriate breaking capacity)>single DIN isolator(so you can add side by side in one enclosure if you have parallel banks)>Lynx Distributer with appropriate fuse per battery string. If you are really saftey concious then wear an bomb disposal outfit with acid proof layer, full breathing aparatus install an argon gas exitinguisher system and have copious amounts of calcium carbonate on hand if running SLA (if your cooking on lithium then probably jump in the outboard and watch the display from a proximity of 25km to be safe). Oh and a Breitling Emergency II for when you have to call for backup in the middle of the desert or sea depending on your mode of transport.
 
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The more I think about it I'm going to stay with the classic fuse at the battery terminal pattern.
However I am thinking about physically blocking off un-used ports on the lynx power-in.
Now I am going to make you think again! What if your batteries gas and your terminal fuse blows and ignites the gas! :ROFLMAO:
 
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