Mecer 2400VA Inverter (Community Support) - Part 2

Finhobbyist said:
Breaker question:
With two parallel 100ah batteries; do you fit a 60amp breaker after each battery, or one 125amp breaker before the inverter? (what if the furthest battery has a short?)
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What informs the two choices of the fuse ratings?

I will assume you are using the 12V 720W mecer since you did not mention the inverter, the total current you can draw for 720W at 12V is 60A, that is the most you can draw from the batteries, regardless of how many they are, so the question of the 125A fuse can never arise in that application.
 
Finhobbyist said:
Breaker question:
With two parallel 100ah batteries; do you fit a 60amp breaker after each battery, or one 125amp breaker before the inverter? (what if the furthest battery has a short?)
Click to expand...
Batteries in parallel are equal distant to the busbars as the cables should be the same length to keep resistance equal.

Have 1 breaker (60amp or even less) between busbar and inverter. Have fuses on each positive as close to the battery as possible.
 
wingnut771 said:
Batteries in parallel are equal distant to the busbars as the cables should be the same length to keep resistance equal.

Have 1 breaker (60amp or even less) between busbar and inverter. Have fuses on each positive as close to the battery as possible.
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Thanks Wingnut
Will it cause a problem if you placed a breaker in between each battery?
 
Finhobbyist said:
Thanks Wingnut
Will it cause a problem if you placed a breaker in between each battery?
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Yes it's a problem, because you won't be breaking the circuit which is the whole point of the breaker, are you sure your batteries are in parallel? The in between thing an only work in series connection.

Don’t complicate it, just put one breaker in line with the positive going to the inverter.
 
TheChamp said:
Yes it's a problem, because you won't be breaking the circuit which is the whole point of the breaker, are you sure your batteries are in parallel? The in between thing an only work in series connection.

Don’t complicate it, just put one breaker in line with the positive going to the inverter.
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You will if you flip both breakers.
 
wingnut771 said:
As long as the resistance is equal I don't see why not, but the breaker would not be serving any purpose then and is illogical to do this.
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Maybe this is a stupid question: If your furthest battery has a short, wont it damage your closest battery in parallel before the breaker finally trips; or is this why you need a fuse at the furthest battery positive?
 
TheChamp said:
Remember, the closer the CB is to the battery, the better.
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Think that applies more to fuses.
Finhobbyist said:
Maybe this is a stupid question: If your furthest battery has a short, wont it damage your closest battery in parallel before the breaker finally trips; or is this why you need a fuse at the furthest battery positive?
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Please take a pic of your setup.
 
Finhobbyist said:
Maybe this is a stupid question: If your furthest battery has a short, wont it damage your closest battery in parallel before the breaker finally trips; or is this why you need a fuse at the furthest battery positive?
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There is no far battery with parallel connection.
 
wingnut771 said:
There is no far battery with parallel connection.
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Its not related to my system, just general mind wandering :)

So if any of the batteries in parallel has a short, the other batteries wont "absorb the short" and get damaged before the breaker trips?
 
Finhobbyist said:
Its not related to my system, just general mind wandering :)

So if any of the batteries in parallel has a short, the other batteries wont "absorb the short" and get damaged before the breaker trips?
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That's what the fuses are for. The breaker is more for maintenance and avoid sparks when connecting inverter and maybe preventing some overload if sized correctly. Did you watch that video?
 
wingnut771 said:
That's what the fuses are for. The breaker is more for maintenance and avoid sparks when connecting inverter and maybe preventing some overload if sized correctly. Did you watch that video?
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I did and it makes sense now. Thanks for the info :thumbsup:
 
wingnut771 said:
That's what the fuses are for. The breaker is more for maintenance and avoid sparks when connecting inverter and maybe preventing some overload if sized correctly. Did you watch that video?
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The sparks still happen in the breaker we just don't see it :)

Many fancy batteries cone with a precharge resistor

not the cheapies though, and some say that this inrush can damage inverters

So my logic is that if you do the cable tap you can't get that much amps so i redo the tap until i get no spark and then connect it

While a breaker flip means the amps can flow

I may be fooling myself and that the cable tap has no meaningful reduction

Meaning to get myself a fris resistor cause i am so scared of becoming a statistic

And how often do you do a connection on inverter empty capacitors once and naturally the totally flat disconnect i assume would pull the capacitors empty too

I don't know enough on this (salt)
 
leon.davibe said:
The sparks still happen in the breaker we just don't see it :)

Many fancy batteries cone with a precharge resistor

not the cheapies though, and some say that this inrush can damage inverters

So my logic is that if you do the cable tap you can't get that much amps so i redo the tap until i get no spark and then connect it

While a breaker flip means the amps can flow

I may be fooling myself and that the cable tap has no meaningful reduction

Meaning to get myself a fris resistor cause i am so scared of becoming a statistic

And how often do you do a connection on inverter empty capacitors once and naturally the totally flat disconnect i assume would pull the capacitors empty too

I don't know enough on this (salt)
Click to expand...
Even Andy doesn't bother with precharge anymore.
 
Brick enclosure. 9001 layers of fire retardant paint, and 69 of those fire balls... Although they will only activate with an open flame. Too late then. Currently looking at setting up something that will alert me directly/remotely of smoke. Also need a source some argon gas/extinguisher.

Not that I have seen a properly installed LiFePO4 going all thermal on itself.
 
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