DryCamper11
Hartford
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My 40 year old RV has just been upgraded to a 460 AH battery bank - 4X6 volt. It does not appear to have ever had any high amperage fuses. I've got an 80 amp PD charger and a 1200 watt MSW inverter. I'm thinking about adding two ANL 150 amp fuses, one for each pair of 6 volts, and possibly a 500A/50mv shunt for a battery monitor.
The inverter doesn't call for Class T fuses. Does this plan for two ANL 150 amp fuses seem reasonable? Should I put them in the negative line or positive? The 1/0 8' power cables to the inverter are well protected, but I've always worried that I might drop a wrench across those power cables and short them out. Any suggestions for improving the fusing, links for fuse holders and fuses, threads showing other installations, comments on dos/dont's, etc. would be much appreciated.
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2oldman
Winchester WA
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I'm sure one fuse in the 1/0 lines to the inverter would be fine. Pos or neg is fine. I don't know how a fuse would be placed to protect against dropping a wrench on the battery.
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smkettner
Southern California
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I would connect the batteries together direct, no fuse. I assume all four are installed close together.
Single 250 amp ANL should be fine with 1/0 but I would go 200 for a 1200w inverter. Fuse should be close to the battery terminal as practical and within 18".
Smaller branch wiring, such as RV main or PD80, should have its own fuse based on wire size not given.
By convention all switches and fuses should be on the positive side.
I get my stuff here when possible:
http://shop.genuinedealz.com/Marine%20Electrical%20Supply/Fuses%20and%20Blocks/
2001 F150 SuperCrew
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mena661
Southern California
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I just have fuses on the inverter and standalone converter as well as the OEM fuse between the batteries and OEM converter. I have no extra fuses on the battery itself. Like 2oldman, I don't see how a fuse can protect against shorts in the battery but I'm willing to hear why.
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DryCamper11
Hartford
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2oldman wrote:I don't know how a fuse would be placed to protect against dropping a wrench on the battery.
It won't help a wrench directly across the battery terminals, but if it's dropped from hot to the frame, current flow will be out of the hot to the frame and back in ground - a fuse in the negative would blow, as would a fuse in the positive or neg if I dropped it on the terminals at the inverter. Whenever I'm tightening or loosening battery clamps I think carefully about the metal handle of the wrench and what it's close to, and there are situations where working space is tight and a short is a real possibility.
The current design has three pairs of heavy cables going to the batteries. The inverter, the charger/converter and a jump start relay to the engine start battery.
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MEXICOWANDERER
las peñas, michoacan, mexico
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I used to cover batteries with a sliced-out mud flap if a custom cover was not available. I made sure to gob the terminals and posts with extra sealant because i knew the cover would trap some more corrosive gasses. Before rubber lug boots became available I would paint lugs and terminals on solenoids with liquid tape, and hang a curtain over top a buss bar. I don't like unprotected shorts.
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DryCamper11
Hartford
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mena661 wrote:I just have fuses on the inverter and standalone converter as well as the OEM fuse between the batteries and OEM converter. I have no extra fuses on the battery itself. Like 2oldman, I don't see how a fuse can protect against shorts in the battery but I'm willing to hear why.
My inverter has (IIRC) three 30 amp fuses on it. I don't know how they are connected. My new 80 amp converter/charger has three 30 amp fuses on it in parallel on the output. My original converter, which remains for backup, has smaller fuses for various output circuits and individual 30 amp fuses for backup charging of three battery systems - gen, coach and engine. There are no master high amperage fuses (>30A) of any type that I know of.
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2oldman
Winchester WA
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DryCamper11 wrote:I think carefully about the metal handle of the wrench and what it's close to I'd be looking at insulating the wrench handle.
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Son of Norway
Denver, Colorado
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I've had a couple of bad experiences with wrenches and battery posts. I went to using wingnuts (with lock washers) to attach battery cables. They are a lot easier to get on and off and don't require a wrench.
Miles
Miles and Darcey
1989 Holiday Rambler Crown Imperial
Denver, CO
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OnaQuest
Old enough to be a
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Joined: 01/15/2006
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If all four of your batteries are very very close together, then one large catastrophic fuse in the POSITIVE lead (very close to the battery) to the inverter is enough. If the two banks are physically separated by a few/several feet of cabling, then fuse each bank.
The purpose of this fuse is to protect the wiring/cable, from the battery to the inverter (load), in the case of a short to ground at the inverter end or anywhere along the cable path.
A blown fuse is better than a fire.
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