20 replies to this topic

[Jack]

I will be installing a Victron DC-DC charger to take care of the Ranger's smart alternator. Since I plan to switch over to LiFePO4 in the near future, I will take care of the Iota at the same time with a shore power controlled relay to switch input to the Dc-DC between the Iota and the Alternator. My Iota has the built-in IQ4 for AGM, so it's voltage (13.6V) is too low for LiFePO4.

 

This involves taking off the front panel to the kitchen unit. So if I'm digging in this deep, I'd like to put a shunt on the input to the master 12V switch so i can monitor my DC power usage.

 

Has anyone gotten to the back of the master switch? I have a 2015 Fleet (similar, I believe to all models after)?

 

Side comment: The Victron DC-DC, like most of their stuff, is microprocessor controlled and uses Bluetooth for control (setting parameters, etc.) and readout. Their Bluetooth is industrial strength because they, in fact, sell the bulk of their products into the industrial world and Bluetooth is their interface to the CAN bus network and some other industrial networks. CAN bus is the dominate industrial network. They offer a WiFi to Bluetooth adapter so their equipment can be easily interfaced to a private network or even the internet. It's even possible for me, with my cell phone in the camper (with cell signal and their App) to monitor and control the Victron gear from home - if I could come up with a scenario that made any sense to do it.

[Vic Harder]

Jack, the shunt goes between the negative terminal of your battery and every other ground.  Meaning, all grounds go to one side of the shunt, and the other end of the shunt goes to the neg term on your battery.  

The switch you speak of is in the positive side of the circuit.  NOT the right place to put a shunt!

[veryactivelife]

I’m in the process of replacing my FWC truck to camper wiring with 4AWG and installing the Victron DC-DC. You’re correct that the Iota voltage is too low for Lithium batteries. Mine will charge them, but very slowly and only up to about 98% according to my BMV.  The Iota does seem to Maintain the batteries at 98% even with running the fridge and Fantastic Fan. I’ve confirmed this by turning the solar controller off and observing the battery monitor.

 

i don’t fully understand what you are doing with the relay and why the Iota is connected to the alternator. I’ve removed my FWC wiring, except for the marker lights wire and my new wires will go from the truck battery directly to the Victron Orion Smart DC-DC and then to the camper batteries. The ground will go via my shunt. Unless I’ve missed something this should work.

 

Dean

[Jack]

True, the shunt would normally go on the negative side, but I plan to isolate it to a simple readout meter.- I am not optimistic on getting to a single negative line to the load. In either case, I need to get behind the master switch.

 

The Iota and the alternator are switched by the relay for input to the DC-DC. The Iota, if powered, energizes the relay coil to connect the Iota to the DC-DC. If the not energized (no shore power) the relay connects the alternator to the DC-DC. Two birds, one DC-DC.

 

I'm planning to mount the DC-DC on the outside of the camper right in front of the battery compartment (Fleet front dinette). If you look at the drivers side port to the rear tie-down, it is the other side of that wall to the left of the port. There is plenty of room there. I have used this space around the tie-down for storing canned foods, coffee and other "stuff" for about 15 years Given the places we go and the way we drive, we don't get much dust there and it is always dry. The DC-DC rating is IP00 (no protection) but I do plan to caulk around the cover and the terminal insert just for good measure.

[veryactivelife]

My understanding is that the Victron Orion Smart is a one way charger, truck to house battery and not reversible as some other dc-dc chargers are. Is there a different Victron charger that you plan to install? The need to charge your truck battery from the Iota seems very unlikely. I carry a lithium jumper pack in the event my truck batteries are dead.

[Jack]

The Victron DC-DC is only one direction - which is what I want. The output of the DC-DC goes to the battery. The relay selects one of two inputs: Iota if shore power, otherwise the alternator. The Charge Controller connects directly to the battery. If I have power from any of these sources, I charge the battery / power the load. Sorry, I should have included the schematic on the original post.

 

The DC-DC charger and the 10 gauge wire from the truck to the camper max at 30A Even doubled to 60A, I can't start the truck using this path. The solution is very simple - I used it once. I carry 20' jumper cables and just jumped the two batteries

 

 

Edited by Jack, 30 May 2020 - 07:57 PM.

[camelracer]

If you're using the Victron solar controller load outputs you can monitor your current usage and not need a shunt on the master switch.

[veryactivelife]

The Victron DC-DC is only one direction - which is what I want. The output of the DC-DC goes to the battery. The relay selects one of two inputs: Iota if shore power, otherwise the alternator. The Charge Controller connects directly to the battery. If I have power from any of these sources, I charge the battery / power the load. Sorry, I should have included the schematic on the original post.

 

The DC-DC charger and the 10 gauge wire from the truck to the camper max at 30A Even doubled to 60A, I can't start the truck using this path. The solution is very simple - I used it once. I carry 20' jumper cables and just jumped the two batteries

 

 

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Thanks for clarifying your goal for the relay switch. I’m not convinced it’s necessary, but don’t see any downside. In my setup the the 3 methods of charging, solar, Iota and DC-DC are all wired individually directly to the battery positive and to the shunt on the negative side. The Iota is on it’s own circuit breaker and can be turned off if required.

 

You might find that the FWC 10AWG is inadequate. Based on the Victron manual 4 or 6 AWG would be recommended depending on length of run. I’ve heard of a couple of other FWC owners finding that the 10 was not working for them in this application.

 

Dean

[ckent323]

Relative to going larger than 10 gauge wire with Victron controllers:  The screw terminals of the Victron Controllers I have used (75/15 and 100/20) do not readily accept wire larger than about 10 gauge.  

An appropriate sized round crimp on ferrule or flat lug might work but I have not tried.

https://community.vi...e-and-mppt.html

Edited by ckent323, 31 May 2020 - 08:08 PM.

[Jack]

veryactivelife, if your Iota has the lithium IQ4, no need to run it through the DC-DC. Or if you have the external IQ4 AGM, you can swap it for the lithium IQ4. I also read that if the IQ4 is external, you can remove it and adjust a pot to set the Iota for a constant 13.8V

I have the built in IQ4 AGM. The Iota outputs a float voltage 13.6V The lithium wants 13.8V for float The Iota with IQ4 AGM will still charge the lithium battery, but not fully and not optimally. Since the relay sets me back all of $15 it was an easy and cheap way to "convert" the Iota to a lithium charge profile.

ckent323, I'd have to look at my 30A MPPT - it's behind the front panel (with bluetooth, I don't need to see it). I recall it was easy to wire it, so it probably will at least accept 8 gauge. The DC-DC looks like it will accept 6 gauge.

FWC runs 10 gauge from the solar panel connection on the roof and this will easily handle as much panel as you can get on the roof. (At higher wattages, connect two panels in series and run 24V to the charge controller). The maximum power point for panels is around 17V. That's a maximum 20A at 340W of 12V panels. The round trip run from the panels to the charge controller is about 30', resulting in a voltage drop of .67V or a loss of about 12W. If you go to 7 gauge wire (half the resistance of 10 gauge), your loss only drops to 6W. The cost of 12W more of solar panel is much cheaper than the cost of 8 gauge wire. I don't even want to think about what it would take to rewire the camper.

Edited by Jack, 31 May 2020 - 10:08 PM.