Can I install the Blue Sea Systems MRBF Surface and Terminal Mount fuse block onto my LiFePO4 stud that is 5/16”? The terminal mount fuse block has a hole sized for a 3/8” stud. If it is okay to use it- do I need to do anything special to install it (ie: amy special washer or something?) so there is better contact? I had ordered this not realizing that the mounting hole is larger than my battery stud. Thank you for any advice you can give on this!
MRBF fuse block for 3/8” stud, is it okay to put on 5/16” battery stud?
- Thread starter jalordsun
- Start date
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Technically you could but it is not suggested. The bracket needs as much surface contact it can get and be tight to all its components.
They do make a 5/16 set.
They do make a 5/16 set.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Thanks for checking, but unfortunately that also has a 3/8” (m10) mounting hole as well. I appreciate the help though.
Ampster
Renewable Energy Hobbyist
I have smaller battery studs so I ran a short jumper from the 6mm stud to a big 3/8" stud to mount the fuse block and load and charging wires (not shown) that are protected by that fuse.
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Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Personally, I would not use 5/16 for the connection of the fuse. Cell (5/16 for M6) to battery Terminal Post (3/8) to MRBF Fuse to Batt Cable. Usually, Connectors such as shown below are used on battery cases or "boxes". It is really NOT Advisable to place the fuse directly on a battery cell but to run a cable from the cells to a connector.
Okay- I’d rather be safe than sorry. I think I’m just going to return the MRBF terminal mount fuse block and go with something else. I don’t mind the trouble and $ as long as I have a safe system in place. Thanks again for all of the feedback and advice!
Hi everyone! I had emailed Blue Sea before I posted the question here and was pleasantly surprised today to get an answer from them (lately I haven’t had luck hearing back from other companies’ customer support so I wasn’t optimistic). So what the wrote back to me was... “Thank you for the question. The 5191 should work fine. The tips of the threads that might come into contact from the stud do not make much difference. It’s the surface to surface landing of the tab onto the battery that counts in most cases there is plenty of area to conduct.” Just wanted to share their answer with everyone.
Is that a flexible bus bar on the battery to stud?
It mostly depends on the width of your battery mounting pad. Most batteries are large enough. For My Tested Solution. I made a ring from fine gauge solder wire. The solder wire I found is just under 2/32 inch measurement. There is a trick to making perfect 5/16 ring. Putting this ring on battery stud and allowing it to center the fuse holder, then a SS washer over the fuse holder I torque the Ny-Lok nut to hold the fuse holder tight to the battery.
I used this on a lead acid bank in use for 3 years with no measurable voltage drop across the connection. For LiFePo banks I use Class-T fuses.
I used this on a lead acid bank in use for 3 years with no measurable voltage drop across the connection. For LiFePo banks I use Class-T fuses.
