Quote:
Originally Posted by DannyClark
With the 2awg Gator? Did the factory do it this way to save money on wire? I don’t mind doing it that way, it’ll just make it a much larger project sourcing the wire and ring terminals. I’ll need to redo all of them to 2awg, correct? And I’m pretty sure 2awg isn’t going to fit on the positive bus either. I went to three different places to get the two I used for the 4awg inverter terminals. If what your doing falls outside of standard parts, no one inventories the oddball stuff. I miss radio shack.
Forgot to mention Silver, the inverter is 1000watt.
|
All info assumes cable run from battery to power junction area is 10' or less
I'll warn that I tend to over-engineer things, but I wouldn't call any of the items I'm recommending superfluous. I will warn that I am also not a certified electrician, but I do work in some (AC) power planning that gets validated by electricians at some point. I tend to err on the side of caution and am a fan of fuses/breakers, because having wiring or devices or batteries act as the fuse is more excitement than i enjoy. I have also self assembled many LiFEPO4 and LiPo battery packs including balancing circuitry, built my own chargers, etc. I wouldn't call myself an expert on automotive/marine/RV power distribution systems though, but I did a lot of planning after buying our AS to support our upgrades.
Do you currently have 4awg and 6awg wires running from the battery tray to the power junction area? Assuming the cable length is <10-feet, the BlueSea calculator app (on iOS) suggests that that 4awg would be good to 105amps...105amps or ~1200W, which may be inadequate for your aggregate load.
http://circuitwizard.bluesea.com (they also have a free phone app)
I would install Blue Sea 5191 fuse block and a fuse
rated for the wire size you pick on the positive terminal of the battery. Your batteries are capable of 400amps for 30 seconds, and I doubt you are going to run cabling that is capable of that. If you do want to upgrade then it seems 10' of 4/0 is ~$183, 1/0 is $98, 2awg is $75, 4awg is $0 as you already have it. Obviously if actual cable length is less it may be cheaper than the prices.
Outside:
I would run 1 positive and 1 negative cable from the battery tray to the power box. If you are upsizing the wiring from the battery into the trailer, you will also need to upsize the cabling between the batteries...but thankfully those short ones are relatively cheap and you could just go with 4/0 if you never want to think about it again (4/0 1-foot pair is $38, 2-foot $49). 4/0 is rated for 200amp, which matches the internal breaker of the battery...so the internal breaker would always protect the wiring. The Blue Sea 5191 is small enough that you should be able to easily fit it within the battery tray, I can't see enough in the photos for clearance for a breaker.
I would also just connect the solar back directly to the battery as it was before, doesn't really matter where you put it since they are already fused and represent such a minuscule energy source in comparison to the battery cabling.
Within the trailer:
I would have the positive terminate on something like a Blue Sea 187 series breaker. The 187 then also becomes a known actual power off/store switch for the trailer (keep in mind it will disconnect everything, including propane detector, break away brakes, etc). The breaker should be sized for the load the "output" wire size. (you can decide on the necessity of this breaker or going with a different way of connecting power up)
You should be able to re-use wiring in this area as you can.
Out of the output of the breaker I would run a 4 or 6awg to your store/use switch and a 2 or 4awg feed to the inverter. You can then connect the positive power feed for your BMS-712 to the input side of the breaker.
I would have the negative feed from the battery terminate on the BMS-712 shunt. Out of the load side of the shunt I would run a (matching size to positive) wire to the negative distribution bar and a matching gauge to the inverter.
I ended up ordering all of my stuff on Amazon for my install, and I pretty much did the above. I bought my power cables on Amazon as well, if you search for "Spartan Power cables" you will find them. They offer really high quality cables with ring terminals. I had to drill the 5/16" ring terminal out slightly to make it fit the BMS-712 shunt, FYI. Some of their cables may have 3/8" ring terminals.
In my case my wire runs were very short, as I moved my batteries under the front bed right next to the power terminals and upsized from the factory 6awg to 4awg with breakers/fuses to match.
The lowest cost option is to just use the 4awg and fuse it in the battery box for 100A, or a circuit breaker if you can fit it in there so that when you do load too much that you can just reset it. The DC load in your trailer, outside of the inverter, is likely pretty low. Assuming you have all LED lighting and you don't have a
12V capable fridge then it is really just if you ever hit the peak output of your inverter depending on what the voltage sag looks like...remember your inverter is rated in watts, and as voltage drops amperage increases.
Whatever fuse(s) you buy, be sure to buy a spare to have with you. If you ever use the spare, replace it when you can.
The temperature probe for the battery from the BMS-702 does work fine with the BMS-712, even though all of the packing says it is for the 702 only. Of course I not sure what it would look like to make that long enough to reach your batteries, and since you aren't operating a relay from the BMS-712 the temperature is purely informational (and may be used to help make SOC more accurate?). The BattleBorn itself will disable charging/load if your temperature falls outside of operational ranges.
If you want to add more complexity and a safety net, you could look at having the BMS-712 operate a disconnect relay...perhaps to disconnect your inverter at some threshold to allow preserving power for the actual necessity items (e.g. propane detector, lights, refrigerator). The BattleBorn internal BMS will protect the batteries themselves from under-voltage.
If you never use the inverter, then you could just remove it from the equation. I am not a fan of inverters, I have a portable one that I can plug in of I need to use the TV to watch emergency weather broadcasts or something...but I plan to operate on only DC power devices when we aren't on shore power.
This discussion reveals one of the many problems with the "suggest an inverter" threads where everyone just suggests getting the biggest you can buy, without understanding the implications of the cabling to power a 1000W or greater inverter. Most 1000W inverters have spec sheets requesting 2AWG wiring just for the inverter itself.
Linear Mode
