Blue seas battery disconnect

[Greybeard]

Real basic question here but I have a blue seas battery isolator/disconnect. It's rated for 350amp continuous at max 36v.
I'm now running a 48v setup and most the disconnects I see for sale all say 12v to 48v
Would there be a problem running this on a 48v setup? Right now I will only have one bank fused at 200amp but I plan to buy cells for a second 48v bank and fuse them both at 150 or 175a each.

 

[gnubie]

What's the particular model switch you are looking at?

Without seeing the details you may find... that the 48V rating is the maximum nominal battery voltage. If you get the technical specs for the switch you'll see its absolute rating is higher than that but the recommended use is for no more than a 48V battery system.

Once the exact switch is known it may be possible to dig up technical data on it.

Take care that you get a genuine item, there's lots of fakes of bluesea stuff out there.

 

[Greybeard]

It's model 9001E-BSS

Features & details​

• Selector 4 Position. Switches isolated battery banks to all loads or combines battery banks to all loads
• Ignition protected—safe for installation aboard gasoline powered boats
• IP66 waterproof, ISO 8846 and meets ABYC requirements
• Terminal Stud Size: 3/8" - 16
• Continuous rating: 350A, Maximum voltage: 32V DC

 

[Greybeard]

Am I wrong thinking that 36v x 350amps is 12,600 watts.

So as long as I stay under 48v x 262.5 amps it should be the same shouldn't it?

I'm only running a 5000w invertor so it's not going to hit much over 100amp

 

[gnubie]

The voltage rating is important. It says max volts is 32VDC so you should not be using it to switch more than that. 36V exceeds the rating, 48V more so.

Obviously the amp rating is important too but the amps at 48V isn't exceeding that spec.

 

[Hedges]

A switch doesn't know anything about watts. It's mostly an amps device, dissipating I^R power (a few watts) by self heating.
While switch is closed, main issue with volts is whether the user is safe touching it. The peak voltage of a 48V battery may cross the magic threshold where people start to worry about safety, but rating it for 32V stays below that. 32V is probably meant for a 24V battery and you will approach twice that.

The main deal regarding voltage for a switch is interrupting current flow. If you open it with current flowing, could draw an arc and just keep burning. If you only use it to switch between sources while inverter is shut down, not likely to fail. But no guarantees.

Poking around I don't readily find anything with higher voltage rating.
You can get Anderson connectors with suitable voltage and current rating. Still not meant to make/break hot, but this could be a way to avoid using anything beyond its rating.

If there is no issue having two circuits closed at once, you could use two breakers. You're still in a range of current (100A or so) where those are available.

 

[Greybeard]

Yea I bought this when I was still planing to do a 24v system. I didn't see one for 48v except for a few shady looking ones on Amazon. I thought about anderson connectors too. I really was just putting it in as a way to shut one bank off if I needed to work on it or had a problem

 

[Hedges]

AC switches rated for the voltage will hold off DC voltage as well, but can't interrupt it. I was looking up some 600V 200A rotary switches I have. Couldn't find my model at the vendor's site, but found smaller ones. They referenced some European classification under which they were fully rated for DC voltage and current if cold switched. Hot switching, their ratings for current were drastically reduced as voltage went up.

 

[JoeHam]

I would suggest 250v rated breakers from Schneider or Midnite Solar or .....

 

[Greybeard]

I'm running fuses instead of breakers. Just looking for disconnects. I'll find something.

It's cheaper to buy spare fuses then spare breakers ? I'm buying backups of everything and sending it all to the Philippines for my house there

 

[Dzl]

Real basic question here but I have a blue seas battery isolator/disconnect. It's rated for 350amp continuous at max 36v.
I'm now running a 48v setup and most the disconnects I see for sale all say 12v to 48v
Would there be a problem running this on a 48v setup? Right now I will only have one bank fused at 200amp but I plan to buy cells for a second 48v bank and fuse them both at 150 or 175a each.

I would think whatever speculation and advice you receive here would be superseded by the manufacturer specifications. Blue Sea is a reputable brand, I would trust what they say.

 

[Zil]

Blue Sea has switches rated for 48 volts. Some of the same e series you have. The voltage rating is the ability of the switch to break a current without arcing. Important with DC. I recommend you get a different Blue Sea switch, they are the best. But you can use what you have if you switch off loads before opening the 32v BS switch. Same for closing the switch.

 

[AussieSim]

The bluesea 2 position switches are rated to 48V, their 3 and 4 position only 32V

 

[Hedges]

"Maximum Voltage 48V DC"

Single Circuit ON-OFF with Locking Key - Red - Blue Sea Systems

300 Amps continuous rating for outboards and small gasoline or diesel engines.

www.bluesea.com

Which may mean "for use with up to 36V batteries"
That seems to be a common trolling motor.
Maximum charging voltage of a 12V battery is about 16V.
Three in series for 36V would be 48V maximum.

With two of these for your two batteries, at least you won't be going as for beyond ratings. A 48V (lead acid) battery probably sits at 54V to 56V much of the time.