27 replies to this topic

[ri-f]

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.

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.

 

Rich
 

 

[Wallowa]

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.

 

Rich
 

 

 

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]

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...

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.

 

Rich
 

[rando]

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.

 

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.  

[rando]

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...

 

 

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]

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.  

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.

 

- 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.

 

Edited by ri-f, 25 June 2021 - 12:01 AM.

[Lighthawk]

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.

Hey Chet

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.  20210620_173024.jpg   82.96K   22 downloads

[Lighthawk]

Phone app only attached first photo. Here's the breaker  20210620_173003.jpg   69.26K   19 downloads

[Wallowa]

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...

[Vic Harder]

However, with the Orion you can adjust the smart 'engine on detection' voltages to account for this voltage drop. 

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... 

 

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...