What Class T fuse for my Ruixus ?
- Thread starter GregM
- Start date
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
The size fuse depends on the max load/Charge the system will draw from/to the battery.
Forgive my ignorance, but how do I figure that out?
DIYrich
Solar Wizard
Inverter rating in watts divided by 45v gives you amps drawn from the battery when the battery is at low charge.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Tell us more about your system. It is 48 Volt so I assume the only thing hooked to the batteries is the inverter (with integrated chargers).
Typically, with this setup, the max load current will be larger than the max charge current, so we need to calculate the max load current.
Start with the size of the inverter. (I will assume it is a 6000W inverter. The actual wattage of your inverter can be substituted in the calculations.). The max current draw will be when the battery is low so I will use 48V for the voltage. Using Ohm's law we see that the current will be 6000W/48V = 125A.
A fuse should be sized for 125% of the max continuous current so the fuse should be 125A * 1.25 = 156A. This would round up to 175A for the next available fuse size.
Note: You could probably get away with a 150A fuse if you don't expect to max out your inverter, but you risk nuisance trips.
Using the NEC ampacity chart, the wire should be sized to handle the max fuse size.
We can see from the chart that it would be a 2/0 wire.
Typically, with this setup, the max load current will be larger than the max charge current, so we need to calculate the max load current.
Start with the size of the inverter. (I will assume it is a 6000W inverter. The actual wattage of your inverter can be substituted in the calculations.). The max current draw will be when the battery is low so I will use 48V for the voltage. Using Ohm's law we see that the current will be 6000W/48V = 125A.
A fuse should be sized for 125% of the max continuous current so the fuse should be 125A * 1.25 = 156A. This would round up to 175A for the next available fuse size.
Note: You could probably get away with a 150A fuse if you don't expect to max out your inverter, but you risk nuisance trips.
Using the NEC ampacity chart, the wire should be sized to handle the max fuse size.
We can see from the chart that it would be a 2/0 wire.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
The 18Kpv is a 12KW inverter.
Going through the numbers gives a continuous fuse size of 312A. I would have 2 2/0 wires each with it's own 150A fuse. The 18K pv has two positive and two negative battery lugs so it is reasonably easy to do it this way.
Going through the numbers gives a continuous fuse size of 312A. I would have 2 2/0 wires each with it's own 150A fuse. The 18K pv has two positive and two negative battery lugs so it is reasonably easy to do it this way.
I found this fuse-block/fuse at Amazon.
Would it be ok with a single run of 4/0?
Would it be ok with a single run of 4/0?
tomy2
escape artist
I am adding the same Riuxu batteries with cart and am shopping for 15ft. of wire to connect to a 600 amp busbar that feeds two EG4 3k watt inverters. Windy Nation has a chart that says their 4guage wire will handle up to 160 amps. Would it then be to code? And secondly, I currently have four EG4100AH batteries hooked to the busbar and that same 4guage wire to the inverters. Will I need to upgrade that wire?
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Robbert
Solar Enthusiast
Had those as well. They might be perfectly fine. However after comparing these fuses with other class-t fuses, I replaced them.
The fuse block and the fuses themselves are just a world of difference compared to other class-t fuses and blocks.
These ones are small and flimsy.
What did you replace them with?
tomy2
escape artist
I decided to go with Windy Nation. They sell the cable in 3' increments if you get the ends installed, which since I don't own a tool for that, seems the prudent approach. Also no shipping cost. They also sell a ANL 200 AMP Fuse, which is better than the Chinese ones on amazon. Their cable is flexible, and the specs are to high standards, with competitive pricing.
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Robbert
Solar Enthusiast
I purchased the Blue Sea fuse block with matching fuses.
For your reference I added a couple of pictures that show the differences between the two kinds.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
I will assume you are in the US and need to comply with the NEC code.
As you can see, even 90c rated wire does not go anywhere near 150A
So how did they come up with 150A? I suspect it was from ABYC. The American Boat and Yacht Council uses a much more permissive ampacity chart.
Yes I second the Blue Seas T-Fuse Block and Fuses are very good quality. Make sure to get the correct matching fuse block for the fuse.
Robbert
Solar Enthusiast
Indeed getting matching fuses is important. I found out the hard way
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