Basic camper set up

[xavvax]

Hello, I have a camper that I am looking to improve the solar capabilities of. The vast majority of the time I will be at campgrounds with electric hook ups so I won't be boondocking much but want the ability to if need be. I won't be using the AC while boondocking and any microwave usage would be minimal so the only significant draw would be the 10cuft 12v refrigerator.

Right after I bought the camper I bought a Renogy 200ah battery during prime day, bc it seems like a good deal but have since learned their products are pretty much always on "sale".

The camper came with a basic 30a Waaree charge controller (not lithium capable) and a 100w panel, I will need to add more panels

After doing some research I believe I need to (please correct me where wrong):
1. Replace the existing charge controller (just taking the wires out of the existing and plugging them into a new lithium capable controller)
2. Install inverter charger (2000w)
3. Run wires from the new 200ah lithium battery to inverter charger
4. Disconnect wire from shore power outlet (30a) to circuit panel
5. Run wire (10/3) from shore power outlet to charger inverter
6. Run wire from charger inverter to circuit panel.

I'm not sure on is where all I need to add fuses and what size fuses to add.

I know victron is king, but it's also about double the price as renogy so I am considering buying a renogy charge controller and a renogy inverter charger. I understand their customer service is poor and their products are a downgrade in quality but it's a pretty simple set up and I won't be using it often.

 

[Rocketman]

One other item I highly recommend is a shunt based battery monitor- like a Victron Smartshunt or BMV712 (there are others). This way you know how full or empty your battery is. With lithium the voltage curve is so flat, it is practically impossible to know where you are - (almost full looks very close to a most empty).

For solar your current panel will probably not mesh with the new panels- but if you are careful in the selection it might. Usually larger panels are better (cheaper per watt and fewer mounting brackets), but on RV’s it is always a challenge to get enough solar on the roof. Think about 400 to 600 to 800watts of solar.

Yes Victron is very nice - it is what I have in my MotorHome. Many of the less expensive Victron items (stuff for your build), have just dropped a lot in price. To me they are worth it.

Good Luck

 

[Rocketman]

Something I forgot to mention.

Draw out what you are planning to do - complete with with the equipment, wire (include the wire size), and where you plan to put fuses. Post it here and let others look at it. It is easier to follow a wiring diagram and spot something wrong or missing than to follow a verbal (typed) narrative.

On fuses, the fuse is to protect the wire- not the equipment.

Starting from the battery, people often have a class T fuse (system fuse), power shutoff, main cable, going to a buss bar, any wire that is smaller than the main cable needs an appropriate sized fuse, so if you are running 2/0 cable and a 300a Class T fuse, you can run that 2/0 to your inverter (it is protected by the Class T fuse), but you have a #6wire going to your mppt SCC, it needs a 50a fuse. You have a #6 wire going to you Dc house distribution fuse box - that needs a 50a fuse, you have a #10 wire going somewhere else, it needs a 30a fuse, etc.

Also make sure you cannot charge via solar the battery if the battery is below 32F, you can ruin it. I know the Victron mppt’s and chargers if get get temp data won’t charge, I don’t know about other brands.

Good Luck

 

[xavvax]

Follow up question on fuses. If I am only running 1 200ah battery and the max the BMS will allow is 100a to be pulled from the battery regardless of how much power the inverter is trying to pull. Is there any reason to have a fuse greater than 100amp?

If the fuse is to protect the wire would any wire rated for more than 100amps be fine? The distance from the battery to the inverter is going to be minimal, a foot or two at the most.

I saw a chart on battleborn's website that showed 2awg wire can handle up to 120 amps at that distance.

 

[Dave in AZ]

Follow up question on fuses. If I am only running 1 200ah battery and the max the BMS will allow is 100a to be pulled from the battery regardless of how much power the inverter is trying to pull. Is there any reason to have a fuse greater than 100amp?

If the fuse is to protect the wire would any wire rated for more than 100amps be fine? The distance from the battery to the inverter is going to be minimal, a foot or two at the most.

I saw a chart on battleborn's website that showed 2awg wire can handle up to 120 amps at that distance.

Well, if the BMS is 100, it will actually often let more. You need fuze 120A or so. Some have a surge ability before shutdown, for motor starts etc. For instance, I watched a test today of Redodo 12v 100Ah mini, with 100A BMS. It ran for 10 min fine at 101A, then he bumped up to 180A and it ran fine for 5 or so sec before shutdown.
You have to size fuse so it doesn't give nuisance burnouts under normal ops. This is why usually fuses are 120 or 125% of what they are protecting. Enough to allow short exceedances, but still blow before wire damage.

 

[12VoltInstalls]

If the fuse is to protect the wire would any wire rated for more than 100amps be fine?

I always fuse “as if” I was using wire sizes appropriate for the load, but for inverter and SCC/charger wiring I oversize the wire at least one size.
What I typically usually do is go two sizes larger for the inverter feed. Nothing every gets warm that way and I feel better

That’s not required, but it is def safe. Ymmv

 

[TacomaJoe]

Your 100A BMS is the limiting factor. I just ran out to my trailer and gave it a test with my microwave and found that mine draws 80-85A. That doesn't give you much headroom and I prefer not taxing the limits. If you are nuking something and the refrigerator kicks on along with any other 12V loads you may hit the limit and the BMS decides to save itself, putting you out of power completely.

I would add another battery in parallel so that your load gets split between them. I will also 2nd the vote for a shunt meter. In my case, I have a shunt that gives me the "at a glance" picture of my status and loads. My BMSs (3 in parallel) also have Bluetooth if I want to drill down into battery specifics.

 

[12VoltInstalls]

add another battery in parallel so that your load gets split between them

That’s a good strategy. That’s why I have three ‘big’ 12V LiFePo4 in parallel. They’ll never likely see over 50A draw each.

 

[mikefitz]

victron is king, but it's also about double the price as renogy

Not the solar controllers , the Victron Smart controller cost is similar to Renogy.

https://www.amazon.com/Renogy-Charge-Controller-Compatible-batteries/dp/B01MSYGZGI/ref=sr_1_1_sspa?crid=16UIR2W1U4Y97&keywords=renogy%2Bsolar%2Bcontroller&qid=1706652819&sprefix=renogy%2Bsolar%2Bcontroler%2Caps%2C452&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

https://www.amazon.com/SmartSolar-MPPT-100-Charge-Controller/dp/B073ZJ3L13/ref=sr_1_3?crid=2LXRA01V9F2JF&keywords=victron+solar+controller&qid=1706652946&sprefix=victron+solar+controller%2Caps%2C410&sr=8-3

The equipment supplier for RV and small hobby systems that produces majority of issues discussed on the forum is Renogy.

Wire size calculator,

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

Fuse selection,

Part 2: Select a Fuse and Fuse Holder For Your DC Product Installation - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com