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pda1 avatar image
pda1 asked

Fuse size between Victron 150/60 and 24v 100 AH batteries?

What size fuse should be placed between my (soon to be owned) Victron 150/60 mppt? The controller will be charging 2 in series 12v batteries equaling 24v 100AH.

If the answer depends upon wire size, would you please specify what wire size I should use? The 150/60 will be about 6 feet away from the battery bank.


Thank you

fuses
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3 Answers
seb71 avatar image
seb71 answered ·

If the answer depends upon wire size

The fuse rating only depends on the wire size that fuse is supposed to protect. The fuse should blow at a current which the wire can still safely carry. But it should not blow at a normal current (maximum current that wire is expected to carry).

SmartSolar 150/60 can charge the battery with maximum 60A. The battery terminals can take wires up to 35 mm^2 / AWG 2 (copper). For short wires (and hanging in the air, not enclosed in conduit), you can use 25 mm^2 /AWG 4 (copper). Of course, cross-reference with the wire manufacturer data before buying.

If you have a smaller PV array - less than 1700W for a 24V system - (which would never be able to generate enough power and as a consequence the charger will never be able to charge with 60A), then you can use smaller wires (smaller cross-section).

The 150/60 will be about 6 feet away from the battery bank

Is that the distance in straight line between the charger and the battery or the actual wire length (positioned in place)?

2 comments
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seb71 avatar image seb71 commented ·
Ah, and also use busbars.
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pda1 avatar image pda1 commented ·
The "6 feet" is a straight line such as if the MPPT were mounted on the wall and the batteries located on the floor.
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marcve avatar image
marcve answered ·

I think it is more important to first know how fast you are allowed to charge your batteries. With most lead acid batteries this around 10% of the total capacity which would be 10 Amps in your case. So, if you charge with 10 Amps you could use a ± 10 amp fuse.

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seb71 avatar image seb71 commented ·
That method completely ignores direct use of PV solar energy during the day.
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pda1 avatar image
pda1 answered ·

My batteries are Battle Born LiFePo 12v 100ah which will be put in series.

The reason I got a Victron 150/60 is because I will probably be adding more panels to the array in the future once I see how the current design operates.

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