Determing existing solar cable size

[Toddhom]

I am replacing my solar panel and upgrading my electrical system. My Eagle is a 2000 and did not come pre-wired for solar. One of the previous owners added a small solar system with an 80 watt panel, a real basic charge controller and a 55ah AGM battery. I have a new 160 watt panel, Victron 100/20 MPPT charge controller, with a Blue Seas ACL and a Victron BMV battery monitor ready to install. I'm trying to figure out if the existing wires from the panel to the charge controller are big enough. The cable does not have an AWG size label on it. It only says RVB 300/300V 2x2.5mm2 on it. Can someone tell me what size AWG wire that is?
Also,
I only have an icebox now. I want to install a refer. The existing AGM battery is only a year and a half old, an Optima D-34 yellow top 55ah. I'm installing a new refrigerator. I understand I'll need a bigger battery. I was wondering if I can buy another same size and spec battery and use two 55ah batteries instead of buying a new 100ah or more size battery. Besides the refer I only have some LED lights and a fantastic fan. I may want to add a furnace down the line a also have the ability to plug in a laptop. A have other questions but this is a good start.

Todd Homchick

 

[lmwilco1]

That is 14g wire. It sounds on the small size for the solar panel.

Louis

 

[Toddhom]

Thank you, That's what I need. So I believe I should order some 10 AWG

 

[rando]

It is definitely on the small side, so you will loose some power due to losses in the cable, but it is still within spec and will work.

With a 160W panel, you will typically be operating at a maximum power point of ~8A and ~20V. Assuming ~ 25' roundtrip of 14AWG, you will loose about 5% at peak solar output, less when not operating at peak.

I am not sure it would be worth it to me to replace the wire as it can be a real pain to fish it through the roof and behind the lift panels, but it is your time!

 

[craig333]

The optima is a hybrid battery. Not the deep cycle you want. 110ah may be enough, or not. Can't have too many amp hours but too little and you'll be back telling us you're unhappy with your system. Rest of your system should work well.

 

[Toddhom]

Yeah I'm think 200ah, any recommendations? I can only afford AGM

 

[Vic Harder]

Toddhom, from the email you sent me...

Sounds like you are off to a good start with the parts you have. Since you are "upgrading" your Eagle, it would be good to know what you have in there already.

To the questions you hinted at:

Wire size (inside the camper?)
The wire size in most of our campers is 18-10g depending on the circuit. The biggest draw is the fridge, which takes 5A worst case. 14g wire is big enough for that, so you could use 14g everywhere and be safe.

The only exception would be to the fuse panel from the battery, which should have wire thick enough for the total draw. 20A - 30A is a good guess there and 8g is a good bet there, since it is rated at 24A continuous. This site is where I got the wire sizes from - https://www.powerstr...m/Wire_Size.htm


I don't have a fuse/breaker between the battery and my fuse panel, just one of those push in switches that FWC/ATC use. A 30A breaker would work just as well.

Stunts (I assume you meant shunt?)
The Shunt wiring is pretty straight forward in theory, but is one that still catches me too! For example, I had the whole camper running great, and needed to charge up the battery (solar not working because it it is in the garage). I couldn't figure out why the charger didn't seem to be increasing the SOC %, until I realized I had simply hooked the charger up to the battery terminals. Doh, the ground cable from the charger needs to go through the Shunt too! Moral of the story, EVERYTHING is grounded to the one side of the Shunt (or a ground bus if there are too many wires to terminate there) and the ONLY thing connected to the other end of the Shunt and to the -ve terminal on the battery is the ONE wire connecting those two things.

This link and pictures might be helpful - https://community.vi...o-separate.html

Battery
100AGM gives you 50AH of usable power. If you can recharge every day, that is plenty for a fridge/lights/fan/furnace. 40AH is what I estimate I use with everything on. I also like to be able to stay in one place for 2 days, in the rain... so, no charging. That means I need 80AH usable. This is an example of a high quality AGM battery in your size range https://www.trojanba..._135_AGM_DS.pdf

160W Solar (PV) panel
You have this already. That's a great start. 160W of solar is "rule of thumb" big enough to recharge 80W of battery daily. So, you are in the ballpark.

Victron 100/20 MPPT
According to this site (where I buy most of my stuff) https://shop.pkys.co...oth_p_7182.html
That controller can handle 290W of solar. Meaning you could add a 100W portable panel if you needed to. Good start!

7622 ACR
Great unit. I had mine in the camper battery compartment. I think in my new build I am going to move it to under the hood. The CLUNK when it (dis)connects is quite loud! You don't have to wire up the remote switch for it to work. What kind of truck are you putting it in? If it has a smart alternator, things get more interesting. Either way, to get the maximum use from the alternator charging and this ACR, you will want to upgrade the wiring from the truck to camper. The (12g?) wire the factory installs is a joke. Good enough for the running lights, but NOT to actually charge the battery. I have 2g welding cable in mine, but that's overkill. 4g is good enough. You will also want two breakers. I used Blue Sea 285 series 100A breakers in my builds - https://shop.pkys.co...ies_p_1657.html
Try to mount these 6" to 12" away from the batteries at either end (under hood and in camper) so that those thick wires are protected.

For disconnecting the camper from this so I can take the camper on/off, I used Anderson Power Poles. This site might help you find those - https://powerwerx.co...rs-sb175-175amp

That's all I can think of to dump on you right now.... ask more questions!