Working to finish up 12v Aux System, and have a few questions (1 Viewer)

TheGrrrrr

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So I have a Redarc BCDC1225D, Renogy 100ah LiFePO4, a Victron 712 Battery Monitor, A Renogy 1000w Pure Sine Wave Inverter, Blue Sea fuse block, Victron smart low-voltage disconnect, and a variety of inline fuses. All of this will be installed on/around my drawer system in the cabin.


My belief is that I need a 40a inline fuse between the starting battery and the BCDC on a 6awg cord as that is what is already running between the starting battery and the fuse block. Then would run POS+ from the BCDC to the LiPo with another inline 40a on 8awg as that is the output gauge from the BCDC. The ground from the BCDC would run to the fuse block ground which is connected to the chassis earth. The NEG- from the LiPo would run to the Shunt for the battery monitor then from there to another chassis ground point. The POS+ from the LiPo would run to the low voltage disconnect with another 40a inline on 8awg, then on to the fuse block for distribution. I would like to have the inverter downstream from the low voltage disconnect so would I connect the inverter POS+ to the low voltage disconnect, or can I wire the inverter into the fuse block like any other load?
 
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I would like to have the inverter downstream from the low voltage disconnect so would I connect the inverter POS+ to the low voltage disconnect, or can I wire the inverter into the fuse block like any other load?

I don't think it's a good idea to connect an inverter (any inverter) to the BlueSea fuse block. Their blocks are rated for a 100amp max (total) draw, and that can be theoretically exceeded with a series of accessories and an inverter. And I'd imagine there are lower-amp limitations to each terminal in the block, which may be too low for the inverter's max draw. Furthermore, I just don't see the point of connecting the inverter this way.

I would connect the inverter directly to the battery, through either an inline fuse or circuit breaker. Put the fuse/cb as close to the battery as physically possible (within reason). And of course, use appropriate-gauge wiring for your inverter's max amp draw and length of wire (determined by the physical location of your inverter).
 

TheGrrrrr

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I don't think it's a good idea to connect an inverter (any inverter) to the BlueSea fuse block. Their blocks are rated for a 100amp max (total) draw, and that can be theoretically exceeded with a series of accessories and an inverter. And I'd imagine there are lower-amp limitations to each terminal in the block, which may be too low for the inverter's max draw. Furthermore, I just don't see the point of connecting the inverter this way.

I would connect the inverter directly to the battery, through either an inline fuse or circuit breaker. Put the fuse/cb as close to the battery as physically possible (within reason). And of course, use appropriate-gauge wiring for your inverter's max amp draw and length of wire (determined by the physical location of your inverter).


This makes sense. Maybe I should get a 2nd low-voltage disconnect just for the inverter between it and the battery. The inverter has a remote power switch and will be kept turned off when not in use, just trying to protect against an accidental draw down of the battery to damaging levels if left on or accidentally bumped and turned on. Also, was worried about total draw on the fuse box, so thanks for the feedback there. The fuse box is running my fridge, USBs, HAM, 2 extra 12v ports, led strips under roof rack and lift gate cargo light, so not a ton of draw, but could add up in the unlikely event everything was running at once. I'll lean towards the safest route as I don't want a smoldering heap of LC in my driveway or campsite.
 

Markuson

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This makes sense. Maybe I should get a 2nd low-voltage disconnect just for the inverter between it and the battery. The inverter has a remote power switch and will be kept turned off when not in use, just trying to protect against an accidental draw down of the battery to damaging levels if left on or accidentally bumped and turned on. Also, was worried about total draw on the fuse box, so thanks for the feedback there. The fuse box is running my fridge, USBs, HAM, 2 extra 12v ports, led strips under roof rack and lift gate cargo light, so not a ton of draw, but could add up in the unlikely event everything was running at once. I'll lean towards the safest route as I don't want a smoldering heap of LC in my driveway or campsite.

Agree with connecting your inverter directly to the battery. You want the largest gauge wire you can muster from the battery to the inverter, and as short a you can make that wire to reduce voltage drop.

I run two massive 1 gauge wires to my SW 1500W inverter, and with my longer wire run, I needed every bit of the huge wire to keep voltage drop from tripping the shut off. Smaller draw will be less demanding, of course, but under full load, it makes a real difference.

One alternative for shorter runs from the battery is... Attach an extension cord from the inverters AC outlet to the device you are powering if the inverter ends up more forward than is handy for whatever device you are running. Once it’s creating AC, it’s less fussy. But getting the DC to the inverter is where it can get picky about voltage.
 
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sdnative

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Do you need an external low-voltage disconnect? The LVD in the BMS should disconnect on low-voltage.
 

Sandroad

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Agree with @TheGrrrrr on connecting your inverter directly to the battery. You want the largest gauge wire you can muster from the battery to the inverter, and as short a you can make that wire to reduce voltage drop.

I run two massive 1 gauge wires to my SW 1500W inverter, and with my longer wire run, I needed every bit of the huge wire to keep voltage drop from tripping the shut off. Smaller draw will be less demanding, of course, but under full load, it makes a real difference.

One alternative for shorter runs from the battery is... Attach an extension cord from the inverters AC outlet to the device you are powering if the inverter ends up more forward than is handy for whatever device you are running. Once it’s creating AC, it’s less fussy. But getting the DC to the inverter is where it can get picky about voltage.
Good advice. A big-a** inverter like 1000 watts can draw 100A from the DC supply, which means big-a** wire and a big-a** fuse.
 

Sandroad

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Do you need an external low-voltage disconnect? The LVD in the BMS should disconnect on low-voltage.
The LVD in the BMS protects the battery from damage and for the Renogy is at 10V. I agree on the lack of need for a separate LVD, unless there is a need for a higher LVD (like something connected that doesn't like that low a voltage).
 

Markuson

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Just curious what you guys are running that would require 1000W or 1500W of AC power.

I’ve run a full power microwave, believe it or not... (I get teased, haha). 1500 watt heat gun. I run those with the engine running, btw. Many smaller items.

Surprising how often a heat gun has come in handy, including wiring and reshaping skirting in the field.
 

TheGrrrrr

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The inverter comes with 4awg 3ft cables. I guess I need to put a 100amp fuse on the battery side of that. I didn't think about the BMS handling the LVD functions, so I cancelled that order, saving me $80. Thanks for that. I am running extension cords to two outlets on the face of my drawer wings for the AC side of stuff, so I should be able to get my inverter within 3ft of the battery. The good news is the battery arrived this morning and I was worried about fit in the drawer wing... BUT IT FITS LIKE A GLOVE!!!!!!!!!

Amazon product
IMG_1190.jpeg
 
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Looks like a great fit. Make sure you secure that battery so it doesn't go flying (and kill someone) in case of an accident.
 

TheGrrrrr

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Looks like a great fit. Make sure you secure that battery so it doesn't go flying (and kill someone) in case of an accident.


Honestly its such a close fit that if not for the rounded corners on the battery it wouldn't have worked. I'll probably bend some metal to put a brace over the top, and maybe some heavy strength velcro on the bottom. Outside of a violent flip/rollover with more than one rotation, this thing isn't going anywhere as-is.
 

sdnative

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Nice! I am putting mine in the same spot. I am using two smaller batteries so they will fit the space better. The group 27 sized battery was attractive but the fit was a little too tight IMO. I didn't want to scuff up the plastic side panel or have the battery rubbing on the metal drawer side.
 

CharlieS

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I believe the BCDC needs to be direct to the battery (with an in-line fuse). If memory serves, 8 ga is good as long as less than 1 meter.
 

TheGrrrrr

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I’ve run a full power microwave, believe it or not... (I get teased, haha). 1500 watt heat gun. I run those with the engine running, btw. Many smaller items.

Surprising how often a heat gun has come in handy, including wiring and reshaping skirting in the field.


I couldn't decide between 1000w, 1500w and 2000w and went with the 1000w specifically so I wouldn't be tempted to bring my Vitamix and Kurig along for trips. I would like to find a mini coffee maker that would work under 1000w, preferably utilizing k-cups, but I have a Aeropress that works just fine in my camp drawer. I'm mostly using the AC for charging batteries (chainsaw, drill, large bluetooth speaker, vacuum cleaner, laptop, drone batteries etc.) and for the situation that I haven't thought of where DC isn't an option.
 

Markuson

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The inverter comes with 4awg 3ft cables. I guess I need to put a 100amp fuse on the battery side of that. I didn't think about the BMS handling the LVD functions, so I cancelled that order, saving me $80. Thanks for that. I am running extension cords to two outlets on the face of my drawer wings for the AC side of stuff, so I should be able to get my inverter within 3ft of the battery. The good news is the battery arrived this morning and I was worried about fit in the drawer wing... BUT IT FITS LIKE A GLOVE!!!!!!!!!

Amazon product
View attachment 2360565

Potential problem there, as that is directly against the A/C recirculate intake grill (directly to the left of the battery in your photo) and if I remember correctly, the actual intake doesn’t extend forward of that even though the grill shapes imply that they do. You do not want to restrict air flow at that intake. I would suggest you consider the other side, or see if you can do anything g other than be fully flush with that left panel grill.
729FBCEE-B66B-47FB-997A-4883E4AD1BDA.jpeg
 
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sdnative

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Potential problem there, as that is directly against the A/C recirculate intake grill (directly to the left of the battery in your photo) and if I remember correctly, the actual intake doesn’t extend forward of that even though the grill shapes imply that they do. You do not want to restrict air flow at that intake. I would suggest you consider the other side, or see if you can do anything g other than be fully flush with that left panel grill.

Much less room on the PS.
 

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