FWC Electrical basics and upgrading to lithium!

[RnK]

Hi Vic, and thanks for the reply! The 3rd item on my list is a Victron Orion 12/12-30amp charger. Isn't that the dc-dc charger you are talking about?
I think the idea of running wire back to the cab from the camper is the way I'll go. Do you think a portable 100-160w solar panel will do the job (given our occasional more-than-2 day-stay and what seems to me to be a fairly light consumption load)?

 

[Vic Harder]

Missed that, sorry. Yes, that’s the dc-dc charger. I do not like portables… way too expensive for what you get. If you can stomach that cost, then yes, 160W is plenty. Don’t bother with the older 100W panels…. Those are very old tech by now. I can’t easily scroll up to see what else you said in this thread, but I find that we use about 40AH per day. If you can replenish that with your 160W portable panel, by getting 4+ of solid daylight a day, you are golden!

 

[RnK]

Thanks for the advice, Vic. Very much appreciated.

 

[RnK]

I'm waiting for all of my various orders of electrical components to arrive. In the meantime I was hoping Vic or one of you other electrical wizards might take a look at this plan and let me know what mistakes I might be making. Thanks in advance for any guidance!

 

[Vic Harder]

First problem = you diagram is too nice. Just kidding. I looked at the 50A breaker by the camper battery for a while, wondering if/where it should go, and while mine sits just before the Orion DCDC in mine, I can see some value in putting it where you did too. So, it looks fine so far!

 

[CreekRob]

I think I'd fuse the circuit from the panel since it might have significant amperage.

 

[RnK]

Hi CreekRob,
I'm not sure what you mean by the panel. The Orion charger?

 

[Vic Harder]

I think he meant the solar panel or solar controller. Yes, they can have significant current in them, and having a switch/fuse is handy when doing maintenance. I had sparks the other day from frayed solar panel wiring, so I can see the value. But if the controller is close to the batteries then I wouldn't bother with a fuse.

 

[RnK]

Sorry CreekRob, I should have known what you meant.
The controller on my 60amp Renogy that we have been using is on the back of the panel and from there just plugs into the rear of the camper. I think it is fused. I was hoping to upgrade with something portable since we use it so infrequently but I don't think that that older Renogy works with lithium. I will be looking for something similar but I don't know how many of them have their own controllers. I may have to buy a separate controller. I'll have to do some more research.

 

[Vic Harder]

I prefer not having a controller built into the panels. Feed the raw output into your existing controller if it has enough capacity for it.

 

[RnK]

Hey Vic,
My Hawk Shell did not come with solar and so did not come with a controller. The solar plug at the back of my camper goes straight to the battery. I guess I'll have to install a separate controller. I haven't researched whether there are portable controllers that you can put inline between the panel and the battery. If not, I guess I'll have to add one to the battery compartment. Like I said, more research!

 

[Vic Harder]

Battery compartment is where you want the controller, or as close to it as possible. You don't want to deal with voltage drop after the controller; therefore, best to have the long wires/voltage drop before the controller. You can also get much better commercial panels in the 580+W range for much less, like $200 USD.

 

[RnK]

Good advice about the controller location, Vic. I'm still hoping to go portable (storable) with the panel. I really don't want to mess with installing solar on the roof unless I have to. Up until now we have gotten by with a 75ah AGM and a 60w portable solar for when we stay somewhere for a day or two (fairly rare). I over-discharged this AGM and the last one by inadvertently leaving the system on in storage. With the new 100ah LiFePO I am hoping it will service our needs in a similar (hopefully better) manner, even with the addition of the ICECO JP40 fridge. The solar will only be used for those same occasions and will be used to slow down the discharge rate, not keep up with discharge rate. I may wait on buying a panel until I our first excursion to see how the LiFePO handles the load.
Many thanks for the input!
Robert

 

[ntsqd]

I've skimmed this thread and some of it brings a smile. This thread caught my eye because the 2GC AGM's are starting to go away and I've been looking at LiFeO as the likely option. For just us I think 100AHr is likely enough, but throw in the granddaughter and 200 may not be enough. Heated vs. not has been a concern.

Way back when I put in 6 ga. cables there was some push-back that I didn't need anything bigger than the 10ga. that the camper mfg supposedly supplied (older used Phoenix, so there was none). By my calcs at the time using the Ancor Resources page for reference, 6 ga. was as big as I needed to go for a less than 3% Voltage Drop at 30 amps over the roughly 25 foot total circuit length. A not much longer circuit length would push it to needing 4 ga. Doesn't take much voltage drop to really put the crimp on direct charging the camper batteries. DC-DC in those days really wasn't an economical option. With a non smart alternator truck I'd rather not go the DC-DC because when sitting in the yard I like that the solar will eventually close the ACR/VSR and pull up the starting batteries too. A DC-DC won't do that, and since the ACR/VSR's sold these days are, AFAIK, all dual direction sensing (unlike the single sensing VSR that I first used in the first camper and then gave away when I replaced it with a dual sensing) I can't put one in parallel with a DC-DC converter to charge the starting batteries with the camper solar. Going LIFeO might just force some compromises in other areas.

I put the ACR or VSR in/near the camper batteries as well. It doesn't matter where it is physically so long as it is in the circuit.

On the first camper I used weatherproof cord-grips to pass the cables thru the lower camper wall. On the second camper I used them again, but this time in an exterior electrical box because that made the most sense. I've been debating the need to do it at all with this camper

In our first camper a 100W panel more than kept up with the demand, which was mostly the compressor fridge. I used 8ga. to the camper roof with an exterior electrical box on the roof for the solar connection. The second camper came with a 160W panel installed, and it barely could keep up with the fridge. It was wired with all 10 ga. This third camper is getting two 200W panels.

 

[ckent323]

One should also consider joule heating when sizing wire between sources carrying sizable amounts of current, such as battery to battery connections. Joule heating has a time dependency and an online calculator can be tricky to find. The short current flow time factor (the time it takes to heat up to a temp that can damage the wire) is why battery jumper cables are often much smaller gauge than you might think they should be when looking at a wire sizing chart (if you crank for more than 30 or 45 second s you not only risk beurning up the jumper cables but also the starter. Neither is usually rated for continuous high current flow.

However, online charts for sizing wire (not voltage drop) , those with a distance calculation, should consider maximum safe current flow at a particular voltage.

I hope this is helpful.

Craig