ramblinChet
Gone Traveling
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- Thread starter ramblinChet
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ri-f
Senior Member
I installed a Blue Seas 60 amp thermal circuit breaker (similar to the one you show) under the hood, next to the lead-acid battery on the driver side. I have a second one near my DC-to-DC charger in the camper, which is next to my LiFePo4 battery. I use both of them as switches to turn on/off the DC-to-DC charger, which I only use on occassion if the solar isn't enough - pretty rare. I also use Blue Seas thermal circuit breakers (different amperage) as on/off switches for my solar, as well as for an auxiliary fuse panel. These Blue Seas breakers are very convenient and well made, as all of their component parts.
Rich
Rich
Just had an 80 amp breaker like the one in your photo mounted on firewall driver's side about 2 feet from Tundra battery as part of the new BB battery [in Hawk] and Victron Orion Tr DC/DC install....second breaker in the DC/D-BB Battery circuit is 2 feet from charger/battery on the shelf where the removed BlueSea 7611 was previously mounted on passenger's side shelf under lid for battery box...this on a side dinette '16 Hawk. 4awg wire used.
I just figured out that I can easily use the breaker on the firewall to disconnect the DC/DC charger....will do this when Tundra AGM battery is on Battery Tender to prevent/stop float charge on BB battery in Hawk and will also disconnect on really hot days when battery temp is an issue and when solar is abundant since charger is in battery box and would add to heat.
Phil
Ps...Chet, I am uncertain...is that a Li battery under the hood and insulated? Are you using DC/DC charger on it or on a battery in a camper? Or does this have nothing to do with a DC/DC charger?
I just figured out that I can easily use the breaker on the firewall to disconnect the DC/DC charger....will do this when Tundra AGM battery is on Battery Tender to prevent/stop float charge on BB battery in Hawk and will also disconnect on really hot days when battery temp is an issue and when solar is abundant since charger is in battery box and would add to heat.
Phil
Ps...Chet, I am uncertain...is that a Li battery under the hood and insulated? Are you using DC/DC charger on it or on a battery in a camper? Or does this have nothing to do with a DC/DC charger?
Phil-Wallowa said:
When you installed the DC/DC charger what gauge wire did you go with? Also, did you make a new camper to truck connection in the bed of your truck? Did you do away with the Blue Sea ACR?
I keep tossing this idea around but the more I think about it just keeping the camper separate from my truck and relying on solar to charge doesn’t seem like a bad idea. I’ve lived through many power outages, not life and death. I like to keep things simple. Less stuff, less problems is my thought.
-Tom
ri-f
Senior Member
Keep it simple, with some redundant backup. Solar can handle most of your energy loads. If you find yourself under a heavy tree canopy for a few days and don't want to move, or in low-light, short winter days, a B2B charger can top your battery off in a few hours, on your way to the next camp. It's a nice option in the Pacific NW and higher latitudes, but not everyone needs it. If you do install a B2B, a 30 amp charger will work very well and won't stress out your alternator. Lot of people use Victron Orion because they have other Victron equipment and want to keep all their Victron components happy.. I prefer the Sterling Power Model 1230 B2B charger over the Victron, even though most of my other stuff is Victron. There are no heat buildup issues with the Sterling, that many people with Victron B2B complain about. As far as wire goes, I use 4AWG from under the hood and back to an Anderson connector mounted to the Flatbed headache rack, then 4 AWG into the camper to a bus bar where I switch to 6AWG to fit the B2B connectors. If you go with a 30 amp B2B then you could use 6 AWG all the way (even 8 AWG would work, but you'll limit your potential for full current a bit over a long run with anything less than 6 AWG. I like 4 AWG for the B2B because it won't limit your current through wire losses and, if you use a marine-grade 4 AWG cable it's flexible enough to route easily and isn't significantly thicker than 6 AWG. As far as the Blue Seas that comes stock with the camper, just bypass it. If you are using a LiFePo4 camper battery, the ACR 7611 is not recommended by Blue Seas. It's okay with an AGM, but not really compatible with Lithium. Anyway, the B2B will be much more efficient.Outnabout said:
Rich
Jon R
Senior Member
I have a crew cab long bed hd truck, and a Grandby with the battery at the rear, so it’s a longer wire run than most trucks. It’s a 2021 so it has a smart alternator. I have a Victron Orion 12/12-30. I used 6awg Ancor marine type IIi cable.
When the dc to dc converter is bulk charging the battery delivering 30 amps, the converter input voltage (coming from the truck at the battery compartment) is above 14 volts. Based on this, I think the 6awg wire is adequate. It also is convenient in that the Victron input connections will take up to 6awg.
When the dc to dc converter is bulk charging the battery delivering 30 amps, the converter input voltage (coming from the truck at the battery compartment) is above 14 volts. Based on this, I think the 6awg wire is adequate. It also is convenient in that the Victron input connections will take up to 6awg.
Tom,Outnabout said:
Wires are 4awg and new connection plug is an Anderson mounted to bed wall....no isolator hence Blue Sea 7611 was removed...as stated above the Victron Tr Orion DC/DC is a 30amp model...with Bluetooth to my phone...agree that when lacking solar or 110v power the DC/DC will quickly reinstate the SOC used....redundancy.
Phil
ri-f
Senior Member
OP - Blue Seas 50 amp thermal CB is mounted to the fuse box under the hood on a 2nd gen Ram 2500. The fuse box lid can still be removed with the circuit breaker attached. Secure and as close to the battery as it gets. May not be the same set up on a new Ram,
Jon- as for using 4 AWG marine cable with a 30 amp DC-to-DC charger, I add in a few extra feet on my run for ease of install and some flexibility in running the wire. With a run of 25 feet (including some slack) 6 AWG is okay, but on the borderline of 4 AWG. So I went 4 AWG assuming a 3% critical loss. It's really not significantly different in terms of size and expense to use 4 AWG, so why not?
Also, 4 AWG can handle a larger DC-to-DC charger if you decided later to scale up, assuming you had a large, high-power alternator or a dedicated second alternator or weren't concerned with stressing out your stock HD alternator. 4 AWG would be at its limit for a 60amp charger on a 20 foot run.
One last thing about limiting wire size on a long run: you can use a smaller guage wire (e.g. 4 AWG instead of 2 AWG) that is still safe, but has a less critical loss of efficiency, about a 10%, to actually limit the current if you wanted, say, 45 amps of current instead of the full 60 amps. In other words, if you wanted more than the 30 amp charger could provide, but didn't want the load and stress of a 60 amp charger on a stock alternator. There are plenty of options and more than one way to install a safe and effective DC-to-DC charger, and it all depends on your priorities, existing equipment under the hood, and mods you're willing to do.
Rich
Jon- as for using 4 AWG marine cable with a 30 amp DC-to-DC charger, I add in a few extra feet on my run for ease of install and some flexibility in running the wire. With a run of 25 feet (including some slack) 6 AWG is okay, but on the borderline of 4 AWG. So I went 4 AWG assuming a 3% critical loss. It's really not significantly different in terms of size and expense to use 4 AWG, so why not?
Also, 4 AWG can handle a larger DC-to-DC charger if you decided later to scale up, assuming you had a large, high-power alternator or a dedicated second alternator or weren't concerned with stressing out your stock HD alternator. 4 AWG would be at its limit for a 60amp charger on a 20 foot run.
One last thing about limiting wire size on a long run: you can use a smaller guage wire (e.g. 4 AWG instead of 2 AWG) that is still safe, but has a less critical loss of efficiency, about a 10%, to actually limit the current if you wanted, say, 45 amps of current instead of the full 60 amps. In other words, if you wanted more than the 30 amp charger could provide, but didn't want the load and stress of a 60 amp charger on a stock alternator. There are plenty of options and more than one way to install a safe and effective DC-to-DC charger, and it all depends on your priorities, existing equipment under the hood, and mods you're willing to do.
Rich
It doesn't quite work that way. Using smaller diameter wire between the truck alternator/battery and the DC-DC charger will actually slightly increase the current draw on the alternator/battery, not decrease it.ri-f said:
It is a little bit counter intuitive, but one of the main reasons to install a DC-DC charger is to overcome wire losses that limit charging to the battery. As long as the input voltage is within the specified range (typically something like 8 - 16V) the DC-DC charger will take the input voltage and boost (or buck) it to the specified output voltage at the specified output current. As a result, a lower input voltage (ie if there is more loss on the wires) will result in a higher input current in order to provide the same output voltage/current.
As an example, say you have a 30A DC-DC charger and are charging your battery at 14V - the output power is 420W. Now assume the DC-DC is the typical 90% efficiency, then the input power is about 460W. Lets say your alternator is putting out 13.5V and you have super fat wires to the DC-DC (~no voltage drop), then the current draw on the alternator is 460/13.5 = 34A.
Now assume skinnier wires and a 10% voltage drop. The DC-DC will still be drawing 460W, but now the voltage at the DC-DC is 12.2V, so the current is 460/12.2 = 38A. Not a big increase, but certainly not a decrease.
In general a DC-DC charger lets you run smaller wires to the camper and still get good charging to the battery. Technically the wires only need to have sufficient ampacity to support the DC-DC without worrying about voltage drop, but in practice it takes careful configuration of the 'engine running detection' algorithm if you are going to use smaller wires with higher voltage drop.
ri-f
Senior Member
In terms of the cabling, I’m simply saying to get thick and short cable INTO the BTB as the BTB can be quite voltage sensitive and might shut off if it’s not getting enough input. If the cable run is going to be longer than 4m away or you want to play it safe, I’d be looking at, minimally, 6 AWG and preferably 4 AWG with a 30 amp BTB. Limiting wire size isn't my preference, but it is an acceptable alternative for some people.rando said:
Rich
ri-f said:
Never thought of the Victron Tr Orion needing a specific input voltage...but like you say my DC/DC 30 amp charger will be good to go w/4awg and my Tundra 130amp alternator can easily handle the load...mostly all this is adjustable with Bluetooth anyway to keep everything up and running by setting the trigger voltages...
ri-f
Senior Member
Yep. I don't imagine you'd have any issues getting full, continuous current back to your B2B with your 130A alternator, unless it's a smart alternator that drops the output below the minimum B2B theshold on occassion. As I've said, I don't use an Orion, mine is a Sterling 1230, so what applies to me might be different for you. I have a 125 amp alternator and run 4 AWG all the way back to where I swap in 6 AWG near the B2B. My Alternator puts out between 13.8v and 14.2v, consistently, while idling, or while underway. I've never had an issue with low voltage cutting out the B2B on my Sterling due to wire size or alternator peculiarities. I can also fully adjust the settings on the Sterling and it has a dedicated LiFePo4 algorithm with a fast 4-stage charging profile. I doubt you could override the required minimum input setting to the B2B. You'd have to check your specs to see the minimum requirement. The Sterling B2B turns on at 13.6v and turns off at 13.3v.Wallowa said:
Rich
There is no issue going with thicker cables. I wanted to make it clear that using thinner cables won't reduce the current the DC-DC draws, so that no one ends up buying a too large DC-DC charger for their alternator with the thought of using thin wires to adjust it down.ri-f said:
Wallowa said:
The Orion 30A will operate with an input voltage anywhere between 7 and 17V, it is really not very sensitive to this, which is kind of the point of the DC-DC. In terms of wiring you are only limited by the ampacity of the wiring, which means 10AWG would probably be OK, and 8AWG or larger would definitely be OK. The one issue you may run into is that with a low output alternator, the voltage drop in the wiring may be enough that the Orion thinks the engine has stopped and the converter will shutdown. However, with the Orion you can adjust the smart 'engine on detection' voltages to account for this voltage drop. 4AWG is definitely overkill and you won't have an issue.
ri-f
Senior Member
Like I said, I use 4 AWG and a 30 amp Sterling B2B. 4 AWG is not overkill, it's just the next step up and provides a healthy margin, which I happen to like. That's my opinion. It works for me and it has worked for a lot of other people. It's also my opinion that using thin wire wouldn't deliver full voltage and current on a 25-foot run and would, in fact, limit the potential of a Sterling B2B.rando said:
- The relationship between resistance and wire length is proportional.
- The relationship between resistance and the area of the cross section of a wire is inversely proportional.
- When resistance is increased in a circuit, the current decreases as a result.
Lighthawk
Weekend warrior
Hey ChetramblinChet said:I need to mount two Blue Sea series 285 circuit breakers under my hood near the battery and am interested in hearing your suggestions. My goal is to mount them near the battery which is located on the drivers side towards the back. Here is a close-up shot that shows the general area.
Here is one of the circuit breakers - they are maybe 4.5" x 4.5"
If you have any previous experience doing something similar, have pictures to share, or just some useful ideas please share all. Thank you.
We had 6gun 12volt install our Victron DC/DC and they mounted the 80A breaker on the lid of the fusebox adjacent to the battery. View attachment 40510
Lighthawk
Weekend warrior
Phone app only attached first photo. Here's the breaker
Lighthawk said:Phone app only attached first photo. Here's the breaker20210620_173003.jpg
YUP, KP and crew also installed all my BB 100Ah [heated] conversion and three Victron devices plus an 80 amp breaker....they know their stuff and did excellent work...
Within limits, rando. For example, if you have to adjust the "engine on detection" to less than ... 12.7 volts to overcome the voltage drop, then how will the Orion know that the engine is NOT running when you turn off the truck? The standby voltage of the fully charged AGM starting battery is 12.65 or so...rando said:
In such a case I would think you would have to wire in the voltage detect wire, or use the remote switch, to manually enable the Orion.
At least, that is my theory...
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