I need more power Scotty!

[wuck]

^^^^ if you're planning on running your fridge on propane or 110v you might be ok. If you are planning on running your fridge on 12v. you probably won't last 4-5 days like you want.

Yea, a 3-way on DC will kill any reasonable battery in a day. Run it on propane.

We have the dual 6 volt system with 2, 100 amp solar panels and could not be happier...

Whoops, maybe 2 @ 100 Watt panels

 

[theway131]

What do you guys think about
this batterie for our application? https://www.vmaxtanks.com/SLR155-AGM-Solar-Battery-_p_66.html
I'm thinking about picking up 3 of these and wiring them in parallel for 465 ah. If I used 2 in parallel it seems like a better option compared to most 6v batteries wired in series with only 240ah, the vmax batterie in parallel would be 310ah!

 

[Vic Harder]

What do you guys think about
this batterie for our application? https://www.vmaxtanks.com/SLR155-AGM-Solar-Battery-_p_66.html
I'm thinking about picking up 3 of these and wiring them in parallel for 465 ah. If I used 2 in parallel it seems like a better option compared to most 6v batteries wired in series with only 240ah, the vmax batterie in parallel would be 310ah!

That's a lot of AH. You had 100 before, what makes you think you need more than 4x that?

 

[cwdtmmrs]

Not to mention 360 pounds...

cwd

 

[theway131]

Honestly reading this thread has got me thinking a lot about power consumption in the 12v system of the camper.
I have a norcold fridge that consumes something like 18amps per hour, not to mention loads from the heater, fan, and lights. But the real reason I'm interested in upgrading my battery bank is to run the 515 watt factory A/C in the summer. I don't want to use a generator for this either so I'm planning to install a solar array on the roof.

 

[Vic Harder]

515 watts? Wow. Is that even wired into the 12v system or just the shore power system?

Assuming you will run that for 4 hours a day to cool the rig off later in the day, you will still need (515/12)*4 = 172AH

That translates into 2x that much minimum for a daily draw and your 50% limit on the AGM batteries = 344 AH battery system.

And 1.5 times that for a solar array = 344*1.5 = 516watts of solar.

Maybe time to rethink your needs?

 

[PaulT]

Gasoline has much higher energy storage density than does either lead acid or lithium based battery chemistry. If AC is really that important, then a nice quiet Honda or Yamaha generator might be worth reconsidering.

Depending on where you camp, you could look into a swamp cooler unit.

Another option might be a small utility trailer to carry those large batteries and fold out frames to mount solar panels that can be aimed at the sun.

Either that or consider a much higher capacity propane cooling unit & just pretend the camper interior is a refrigerator.

Paul

 

[Vic Harder]

I got my solar panels, batteries and controllers this week. Built a storage unit under the cab over to hold the two 150w portables, test mounted the 265w panel on the roof, and made this board to hold all the electrics.

The board will go in the battery box, to the left of the batteries.

What you see here is (going clockwise, starting at the top left):
- 100A breaker - truck power will enter here via 100A breaker at the truck battery, 2g wire under the cab and up into the driver's side of the bed into an Anderson Power Pole connector, into the driver's side of the camper, over the water tank and into the battery box.

- Victron MPPT controller for the roof panel
- Victron MPPT controller for the portable panels
- Bolt between the two MPPT controllers is a home made "power buss bar"
- Shunt for the Victron BMV702 Battery monitor
- Ground buss bar
- 40A fuse for the portable panels
- 40A fuse for the roof panel
- ACR

The crimp on the very short wire from the ground buss to the shunt is the first one I did. Ugly, what?

Obviously some wires and connections are missing
- The two 40A fuses will be wired up to the roof (existing 10g) and an external plug (4g internally, then 10g MC4 cable)
- The lower connection on the shunt goes directly to the battery via a 2g wire
- Other side of the ACR goes to the camper battery +ve pole via 2g wire
- Other side of the 100A breaker goes to the 2g wire coming in from the truck
- Power buss still needs a wire going to the +ve of the camper battery... maybe just as far as the ACR to keep it tidy
- Inverter wiring is still to come, to the ground buss and positive buss.

In addition, the MPPT controller each have a black wire (bottom left of each controller) that goes to their respective control panels, and the shunt has a control wire going into it as well (black connector, very far bottom right of picture).

Question: Should the ground buss be terminated at a chassis ground too?

Did I miss anything?

 

[rando]

There is no harm in terminating the ground buss to the chassis, but it is not necessary. The negative wire of your plug in to the truck will serve this purpose. It also raises the question of what exactly chassis ground is in the camper.

If you have space, I would also consider a real positive bus, or a combination buss:
https://www.bluesea.com/products/2722/DualBus_Plus_150A_BusBar_-_1_4in-20_Stud_5_Gang
It will make your wiring much easier.

Just as an FYI - I am not sure the 40A breakers on the solar lines are necessary. They are only protecting a couple inches of wire between the breaker and controller, and I am guessing the short circuit of the panels is < 40A so they will never trip anyway. I guess they do serve as an array disconnect, but a switch would also suffice.

 

[ntsqd]

Re; that short ground wire, it's too short and too straight. I suggest making a longer one that has at least two 90° bends in its routing. That will allow for vibration, thermal expansion/contraction, etc. This is common practice in hydraulic lines, but we tend to think of wires as flexible and not needing this precaution. When the wires become cables this thinking needs to be included.

 

[Vic Harder]

There is no harm in terminating the ground buss to the chassis, but it is not necessary. The negative wire of your plug in to the truck will serve this purpose. It also raises the question of what exactly chassis ground is in the camper.

If you have space, I would also consider a real positive bus, or a combination buss:
https://www.bluesea.com/products/2722/DualBus_Plus_150A_BusBar_-_1_4in-20_Stud_5_Gang
It will make your wiring much easier.

Just as an FYI - I am not sure the 40A breakers on the solar lines are necessary. They are only protecting a couple inches of wire between the breaker and controller, and I am guessing the short circuit of the panels is < 40A so they will never trip anyway. I guess they do serve as an array disconnect, but a switch would also suffice.

I was wondering about the 40A breakers myself. Handy Bob Solar has TWO for each controller, input and output. I thought that was nuts too.

That's a nice dual buss bar setup. I really have to watch shipping/duty costs in this build. If I can't find that locally, sourcing one-off items very pricey. I try to group all of my purchases coming from the USA. So, the bolt may have to do for this build!

 

[Vic Harder]

Re; that short ground wire, it's too short and too straight. I suggest making a longer one that has at least two 90° bends in its routing. That will allow for vibration, thermal expansion/contraction, etc. This is common practice in hydraulic lines, but we tend to think of wires as flexible and not needing this precaution. When the wires become cables this thinking needs to be included.

Good thought. I will make up a longer section for that ground. Thanks.

 

[rando]

I was wondering about the 40A breakers myself. Handy Bob Solar has TWO for each controller, input and output. I thought that was nuts too.

That's a nice dual buss bar setup. I really have to watch shipping/duty costs in this build. If I can't find that locally, sourcing one-off items very pricey. I try to group all of my purchases coming from the USA. So, the bolt may have to do for this build!

My opinions about 'handybob' are pretty much in line with my feelings about the Trimetric (which unsurprisingly, Bob is a fan of) - it does work, but there are better options out there with a far better user interface

 

[Vic Harder]

My opinions about 'handybob' are pretty much in line with my feelings about the Trimetric (which unsurprisingly, Bob is a fan of) - it does work, but there are better options out there with a far better user interface

LOL... yes, which is why you and I are both using Victron units. Hey, are you using the "load" connectors for anything?

 

[rando]

I am not using the load connectors, but only because my camper came pre-wired from FWC, and the converter and charge wire from the alternator is tied into the distribution block further downstream from my battery than my MPPT charge controller is. Unless I want to do some major rewiring, the charge current from both the alternator and converter would flow through the load terminals which would be a bad thin.

If I were in your situation where I was designing the wiring, I would use the load terminal. I would run all my loads through the load terminal. This would give you a programmable low voltage disconnect so that you couldn't kill your battery by leaving something on too long. Seeing you have two charge controllers, you can support up to 30A, and even get fancy with a two stage load shedding disconnect - connect low priority loads to one and set the disconnect voltage higher, and then more critical loads to the other with a lower disconnect voltage.

 

[wuck]

You do want the chassis connected, it's a part of the ground circuitry. If you have AC in the camper, the safety ground should also be tied in there.

Although there is a ground "harness" in my camper, a few things are also grounded directly to the chassis. Lets see, the furnace, flood and porch lights. All of the water pump current returned through that ground harness, and if the other appliances weren't tied to the chassis all of the return current would flow through a 14 to 10 AWG "harness". All eight circuits!

Ground wire "harness" with taps:

I overkilled it by running a ground wire back to the fuse block for each circuit - probably not necessary with the chassis being a big low impedance ground, but while I was wiring stuff . . .

The fuses in the solar panel are necessary. Yeah, the panel will never blow that fuse, but bad things can happen to the cicuitry with accidental shorts to other stuff. For example, my hawk was built without fuses on any of the solar panel/controller circuitry. The guy I bought it from proudly pointed out the new floor he had installed, a vinyl sheet that ran under both the water tank and the 130 # Lifeline AGM battery. Of course both had to be removed to install that floor. When he reinstalled the battery, I'm pretty sure he connected it backwards, blowing up both the controller and the bypass diodes in the solar panel. Fuses might have prevented some of the damage! As transistors tend to blow faster than fuses, the controller damage was probably inevitable. But, those bypass diodes would have easily withstood the short circuit current long enough to blow a fuse. (I replaced the shorted controller, and was able to save the panels by replacing the diodes).

Caution: Diodes:

Good plan on the short ground replacement, I had mine pull out on a washboard road. It was connected between the battery and ground buss, the battery was shifting around a bit. I entered the camper to a screeching LP/CO detector, and a refrigerator running on 9 volts under load - the wire was still kind of in contact

 

[rando]

You do want the chassis connected, it's a part of the ground circuitry. If you have AC in the camper, the safety ground should also be tied in there.

Although there is a ground "harness" in my camper, a few things are also grounded directly to the chassis. Lets see, the furnace, flood and porch lights. All of the water pump current returned through that ground harness, and if the other appliances weren't tied to the chassis all of the return current would flow through a 14 to 10 AWG "harness". All eight circuits!

Ground wire "harness" with taps:

P1050421r.JPG

I overkilled it by running a ground wire back to the fuse block for each circuit - probably not necessary with the chassis being a big low impedance ground, but while I was wiring stuff . . .

The fuses in the solar panel are necessary. Yeah, the panel will never blow that fuse, but bad things can happen to the cicuitry with accidental shorts to other stuff. For example, my hawk was built without fuses on any of the solar panel/controller circuitry. The guy I bought it from proudly pointed out the new floor he had installed, a vinyl sheet that ran under both the water tank and the 130 # Lifeline AGM battery. Of course both had to be removed to install that floor. When he reinstalled the battery, I'm pretty sure he connected it backwards, blowing up both the controller and the bypass diodes in the solar panel. Fuses might have prevented some of the damage! As transistors tend to blow faster than fuses, the controller damage was probably inevitable. But, those bypass diodes would have easily withstood the short circuit current long enough to blow a fuse. (I replaced the shorted controller, and was able to save the panels by replacing the diodes).

Caution:

P1010685r_1.JPG Diodes:

2015-04-18_16-54-49_602r.jpg

Good plan on the short ground replacement, I had mine pull out on a washboard road. It was connected between the battery and ground buss, the battery was shifting around a bit. I entered the camper to a screeching LP/CO detector, and a refrigerator running on 9 volts under load - the wire was still kind of in contact

Not to be too pedantic, but fusing between the panel and the controller really isn't necessary. In the case of your incident, the fuse should have been between the controller and the battery, which may have saved your controller (maybe) and your panel diodes. The Victron charge controllers are protected against both a short or reverse polarity, so a fuse between the battery and controller isn't necessary in this specific case as long as the wire runs are very short.

 

[Vic Harder]

I am not using the load connectors, but only because my camper came pre-wired from FWC, and the converter and charge wire from the alternator is tied into the distribution block further downstream from my battery than my MPPT charge controller is. Unless I want to do some major rewiring, the charge current from both the alternator and converter would flow through the load terminals which would be a bad thin.

If I were in your situation where I was designing the wiring, I would use the load terminal. I would run all my loads through the load terminal. This would give you a programmable low voltage disconnect so that you couldn't kill your battery by leaving something on too long. Seeing you have two charge controllers, you can support up to 30A, and even get fancy with a two stage load shedding disconnect - connect low priority loads to one and set the disconnect voltage higher, and then more critical loads to the other with a lower disconnect voltage.

I dunno Rando. Let's say I wanted to run my inverter on one and the normal DC stuff on the other, K?
The max load on these outputs for the 75/15 is only 15 amps. My small 350 watt inverter could draw nearly 33 amps at full load, and the 15A load limit would shut down the inverter at 180watts output (less 20% for due to 89% efficiency of the inverter).

And if the other is connected to the DC fuse panel, that could work. I anticipate a max draw of close to max draw of 12.5 A if the furnace, fans, lights and fridge are all on. TWO appliances kicking on at the same moment could cause an excess of 15A though, and since I was planning on only one fuse/distribution panel, I don't see how I can make that work.

Certainly the typical fuse panel in a FWC has way more combined anticipated load than 15A.

Thoughts?

 

[Vic Harder]

You do want the chassis connected, it's a part of the ground circuitry. If you have AC in the camper, the safety ground should also be tied in there.

Although there is a ground "harness" in my camper, a few things are also grounded directly to the chassis. Lets see, the furnace, flood and porch lights. All of the water pump current returned through that ground harness, and if the other appliances weren't tied to the chassis all of the return current would flow through a 14 to 10 AWG "harness". All eight circuits!

I overkilled it by running a ground wire back to the fuse block for each circuit - probably not necessary with the chassis being a big low impedance ground, but while I was wiring stuff . . .

14g ground harness. That's a joke, especially when the Blue Sea 12 position fuse panel most FWC come with is rated at 100A, and each individual fuse position can handle up to 30A. Yikes.

Doing each one with its own ground isn't overkill in my books.

 

[rando]

It all depends on your loads. No need to run your inverter through this as it should have its own low voltage disconnect. For my set up, I max out at abut 12A with my furnace, fridge, water pump and lights all going.