What kind of DC disconnects do you use?
Thanks
I wonder if we will ever see a next generation of m10 power in and distributors with massive venting like the class t power in hasā¦.perhaps a good use for 3d printers in the meantime? Also more likely to handle 1000A without melting down?
I agree that I want to know why an OCP has tripped. The self-resetting breakers used by RV manufacturers bother me. Those things could be tripping like crazy and nobody knows about it.
I do use breakers for certain circuits. There just isnāt enough room in an RV to put a fuse holder on each circuit. I can put in a DIN rail and mount a lot of breakers in a relatively small amount of space. I donāt go cheap on breakers. I use Midnite Solar.
The AIC of MEGA fuses is disappointing but Iām not using them immediately downstream of the battery so Iām not that concerned.
When I first commissioned my Quattro 48/3000 I didnāt have a pre-charge circuit. When the capacitors charged it blew my Class T fuse. No, it couldnāt have blown the less expensive CNN and MEGA fuses in the circuit, it just had to blow the Class T. I now how a pre-charge circuit and a slightly larger Class T fuse.
IMO PV disconnects for solar, Blue Sea battery switches (see here: PV 275A Isolator Switch dissasembly and comment - #9 by OGPS ) , Chint brand DC circuit breakers for small PV installations (20A or less and 60VDC or less), and sometimes Blue Sea (made by Carlington) miniature circuit breakers for small loads).
Indeed. We use a lot of MEGA fuses, too, for pretty much all loads downstream of the batteries. At the batteries we use Class T. What started all of this was a post by someone a year ago telling me about EF3 fuses and Iāve been wanting to test them ever since. If they work well enough, I can fit four of them in a Lynx PIN or Distributor and save cost and space from using multiple Class T fuse blocks. Since then, Victron has released the Lynx Class T PIN and that mostly resolved the reason I wanted to use EF3 in the first place. In large systems with a bunch of Quattro 10kVAās, batteries, and MPPT 450/200, we use solely Class T PINās with batteries, loads, and sources spaced evenly across the buss. EF3ās would be handy in small systems where I could intermix MEGA and EF3 on one Lynx PIN or Dist.
Thanks. Is this battery switch safe to disconnect the battery when there is 275A passing through?
El dg, 28 des. 2025 a les 17:09 Ed @ Off-Grid Power Systems - offgridps.com via Victron Community <notifications@victron.discoursemail.com> va escriure:
You shouldnāt switch ANY DC disconnect when 275A is passing through. Quies the system and then shutdown the batteries, loads, and sources.
This is the way to proceed in normal situstiond but i am aleays thinking in emergency cases when you have short-circuit, fire, etc. In this cases you donāt have time to apply standard orderly procedure.
For emergency situations, circuit braker seems safer. What do you think/recommend?
Thanks
El dg, 28 des. 2025 a les 18:00 Ed @ Off-Grid Power Systems - offgridps.com via Victron Community <notifications@victron.discoursemail.com> va escriure:
For emergencies, use the DC disconnects and donāt worry if arcing causes the switch contacts to get pitted. You can always replace them. However, consider using an emergency stop switch wired to remote on/off contacts on your equipment. One push of the E-stop switch will shut everything down quickly.
Iāve been using EF3 fuses for almost 6 months without any issues. 3x Multi RS 6000, 1x Smart Solar 450/200.
Total amps reach about 350-400A.
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Interesting your energency stop switch, specially for people that do not have technicall knowledge to switch off all the devices correctly.
In any case, an emergency stop switch wired to remote on/off the diferents systems: loads, inverter, solar charges and batteries will requiere in the solar and battery side a breaker/contactor able to be managed remotelly
Is this what you proposse?
On the other hand, switch off is easy but automatic switch on seems more dificult as normally to start the diferent systems/devices require a defined order.
Thanks once more
El dg, 28 des. 2025 a les 18:26 Ed @ Off-Grid Power Systems - offgridps.com via Victron Community <notifications@victron.discoursemail.com> va escriure:
According to the datasheet, the 200A fuse has an internal resistance of 0.0006875Ohm. With a current of 160A, the voltage drop computes as 0.22V, burning 17.6W. This is going to get quite hot. Iāve just ordered a bunch of 300A EF3 fuses as short circuit protection for the battery cables. They will replace the midi fuses and are a lot bigger than needed for normal operation, but they are there for short circuit protection only and thatās when the breaking capacity is needed. In normal operation, no fuse should ever trip.
Iām also interested in an automatic shut down procedure solution. Currently, people just shut down stuff at random under load.
Hi Ed.They switched it for a Class-T version so I canāt tell what the temperatures were. Sorry. However. This system was pulling in 120A for several hours, at times that the electricity prices were low enough to make some money out of it. And room temps were warm. Whatever that may mean.
I measured the resistance of several fuse links I had on hand. For the measurements I used a Finrisi HRM-10 meter. The fuses were measured directly, without a holder. Here are the values I obtained:
- Adler EF3 175A/200V DC - 0,37 mOhm
- Adler EF3 200A/200V DC - 0,29 mOhm
- Adler EF3 250A/200V DC - 0,21 mOhm
- Adler EF3 300A/200V DC - 0,16 mOhm
- Adler EF3 350A/200V DC - 0,13 mOhm
- ETI NH00 gBat 100A/80V DC - 0,74 mOhm
- ETI NH00 gBat 125A/80V DC - 0,56 mOhm
Unfortunately, I donāt have any spare 150A EF3 fuses available at the moment ā all of them are currently in service in some Power In or distributor. When I get a chance, Iāll pull one out and add it to the list.
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