I recommend that you read thoroughly the specifications your charge controller. Pay attention to the input voltage specifications. A typical solar panel will have anywhere from 16 to 30 volts input to controller.
Grounding to the frame is asking for trouble. The frame should NOT carry current, in a short period of time all those connections to frame will corrode stop working.
The best thing to do is run a negative wire through out the trailer and use the solar, charge line, and converter to charge the house battery. No if your converter has smart charging feature this will all work.
FYI with LED lights and smart using of battery power you wont need solar unless you're going stay in one place for a couple of weeks.
Thank you. The converter and A.C. required grounding and was also grounded to the frame at the factory A.C. circuit breaker.. Would that also cause rust? I did tie into that original ground for the 12v common but no where else in the camper except at the inverter, which requires a ground and off the battery negative in the tongue box. I will be disconnecting that cable and will run an 8 guage negative wire from the battery negative to the converter negative where all my 12v negatives branch out from.. i have also been looking into using a 100amp current stunt off the battery negative as a place to connect the 8 guage wire and solar controller negative line to.
Thank you for your advice. The way I wired it, it shouldn't be a terribly difficult fix. Worth it if it prevents rust.
BTW: both the converter and solar controller have smart charging. My tow is the only dumb charging but as I understand it the 12v line from the TV is quite limited. Can that over-charge a battery if it is also powering.my fridge while in Tow?
Thank you. The converter and A.C. required grounding and was also grounded to the frame at the factory A.C. circuit breaker.. Would that also cause rust? I did tie into that original ground for the 12v common but no where else in the camper except at the inverter, which requires a ground and off the battery negative in the tongue box. I will be disconnecting that cable and will run an 8 guage negative wire from the battery negative to the converter negative where all my 12v negatives branch out from.. i have also been looking into using a 100amp current stunt off the battery negative as a place to connect the 8 guage wire and solar controller negative line to.
Thank you for your advice. The way I wired it, it shouldn't be a terribly difficult fix. Worth it if it prevents rust.
BTW: both the converter and solar controller have smart charging. My tow is the only dumb charging but as I understand it the 12v line from the TV is quite limited. Can that over-charge a battery if it is also powering.my fridge while in Tow?
First the corrosion isn't exactly rust, will eat the wire.
The grounding is required for safety purposed. If you look at the cable coming into the trailer from the 120VAC source you find a black wire, a white wire, and a GREEN wire. The green wire is safety ground should be only connected to the frame at a single point. The purpose is keep the trailer metal including the frame at the ground potential which prevents shocks. When connecting something to the frame in other places there cab be current flowing in the frame. The frame is steel or aluminum the spade or ring connectors are brass. Dissimilar metals create electrolysis which eats copper wire and creates more problems.
As I said earlier a single point is the best to prevent current flowing in the frame. Trailer wiring for 120VAC with all three wires to everything thus no 120 Frame current. Also for 12VDC side two wires go to every 12 volt item or outlet thus no frame current with one exception. The brake wires will have one side connected to frame and need to be repaired often.
__________________
Byron & Anne enjoying the everyday Saturday thing.
First the corrosion isn't exactly rust, will eat the wire.
The grounding is required for safety purposed. If you look at the cable coming into the trailer from the 120VAC source you find a black wire, a white wire, and a GREEN wire. The green wire is safety ground should be only connected to the frame at a single point. The purpose is keep the trailer metal including the frame at the ground potential which prevents shocks. When connecting something to the frame in other places there cab be current flowing in the frame. The frame is steel or aluminum the spade or ring connectors are brass. Dissimilar metals create electrolysis which eats copper wire and creates more problems.
As I said earlier a single point is the best to prevent current flowing in the frame. Trailer wiring for 120VAC with all three wires to everything thus no 120 Frame current. Also for 12VDC side two wires go to every 12 volt item or outlet thus no frame current with one exception. The brake wires will have one side connected to frame and need to be repaired often.
Most informative. My 120VAC wiring all grounds to the preexisting single factory ground connect, at the camper, and under the tongue box, at the inverter. I did also tie in the 12v negative to those points which I will now disconnect, run larger guage (8) wire between battery negative and the converter negative. All my 12v negatives converge at either the battery negative or the converter negative. That should prevent possible corrosion. This shouldn't be an exhausting fix because the frame was used in only 2 places for 12v negative. The 8 guage wire might be overkill but that is what I'll run.
As for function, both the 120VAC systems and 12v systems are working flawlessly. The entire 120VAC system has multiple GFCI's which all function properly, none of the 5 outlets are unprotected, and all 12v systems are presently working well. I am glad you brought up the corrosion issue and will address it. Thank you to all.
I started this script because of my concerns with the 12v system over the long haul (pun intended ntended). I've learned a lot so far and will use many of the suggestions. Separating our the solar controller will be most time consuming.
The solar controller is 30amp and 30amp breakers are used at each connection to it. Presently my mystery question is what the 12v output, not battery connection, is rated at. The specifications do not say. I hope since it is a 30amp controller all terminals are rated at 30amp. I haven't tested it yet, but with every 12v system working simultaneously, including lcd television, tablet, phones... I might still be under 30amps.
We use the camper as a playroom in the garage when not camping. My Kids love to sit in it and watch tv and sleep in it as easy camp outs (ins) during the off season. That is why decided to rework the heating system by pulling out the old catalytic heater, replaced it with a wall hung 120VAC unit, purchased a Propex hs2000 to use when outside boondocking off L.P.. This way we can keep doing our camp(ins) during the cold months since the garage isn't heated.
Future rust between the tongue box and frame is also a concern of mine. The tongue box is aluminum and bolted to the frame. I ran a few beads of silicone on the frame before I bolted it down to seal the gap and act as an insulator. But they still are connected via the bolts. Not sure what others do but hoping this is adequate. I know it's strong. I also do garage the camper.
I wouldn't get too optimistic about running the air conditioner off of a 2000W inverter. Even if it's enough to keep up with the steady draw, the initial "locked rotor amps" is going to be several times higher. Depending on whether 2000W is the peak or sustained load, that inverter might or might not be big enough.
That may also be pushing the limits of how much current the batteries can output without significant voltage sag. Even if they can stand up to it, you're likely to see a significant decrease in total capacity (Peukert losses).
That's not to say it definitely won't work, but if it does it won't be with a lot of margin. Thinks may get a bit toasty, and it may only work on cooler days and not hotter ones.
In terms of Lithium batteries, for trailer applications people usually stick with LiFePo4 chemistry rather than NMC, "LiPo", etc, because the nominal voltage is "close enough" to a 12V lead-acid battery for most applications. They need a slightly different charge profile, but not a DC-to-DC converter. LiFePo4 isn't as energy-dense and hasn't seen the same degree of price decreases compared to other chemistries, but the failure modes are much safer. Even drastically overcharging then puncturing them won't cause a fire. I'd actually argue it's an even safer failure mode than lead-acids, since they don't spew flammable hydrogen or spray sulfuric acid.
You're probably safe in terms of overcharging the battery from the tow vehicle. The opposite problem is actually a lot more common: there's enough voltage drop between the alternator and the trailer battery that it doesn't get charged much at all.
I wouldn't get too optimistic about running the air conditioner off of a 2000W inverter. Even if it's enough to keep up with the steady draw, the initial "locked rotor amps" is going to be several times higher. Depending on whether 2000W is the peak or sustained load, that inverter might or might not be big enough.
That may also be pushing the limits of how much current the batteries can output without significant voltage sag. Even if they can stand up to it, you're likely to see a significant decrease in total capacity (Peukert losses).
That's not to say it definitely won't work, but if it does it won't be with a lot of margin. Thinks may get a bit toasty, and it may only work on cooler days and not hotter ones.
It's not exactly the same application, but lots of people run their Dometic Penguin II 11,500 BTU AC with a Honda 2000W generator on their Escape Trailer. It works fine. The limitation is mainly altitude, as output power decreases quite a bit as you go higher. As for start up amps, Dometic makes a soft start kit that can help, but a MicroAir Easy Start is better. That device will allow you to run pretty much any smaller RV AC unit on a 2000 watt generator with ease.
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
Trailer: 2015 Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 5,156
Quote:
Originally Posted by Markz
Looks like the load terminals of this unit, HY-MPPT30, equal the charge terminals at 30amps each.
This brings up an interesting question. I just bought a similar solar controller that has a load connection also rated at the same value of the controllers rating (30 amps in your case). This controller has settings for the battery voltage at which the controller will disconnect the load on its load terminals, and another setting where it will reconnect the load after the battery has sufficiently charged and recovered to the set voltage. Along with the float voltage, these are all user adjustable.
So, in theory at least, using only the load terminals on the controller would effectively function to protect the battery from being overly discharged (and damaged). No such protection exists if loads are taking power directly from the battery (unless other arrangements are made). And since the controller (and controller load) ratings are 30 amps, and your trailer is wired for 30 amp service, it should be possible to use the controller’s load terminals to power the camper just as a converter would.
I do see a possible problem depending on what voltage settings are used. The controller only senses voltage and if the voltage dropped below the disconnect voltage, even for second, the trailer would lose all 12 volt power. Normal voltage drop (when fans kick on, etc.) might do that. Then when the load is disconnected the voltage would almost instantly come back up, the load reconnects, the voltage drops again, and it's a vicious cycle. Using the voltage of the battery under load is just not a good method for knowing the state of charge of the battery.
All this theory is moot however when the solar controller is a positive ground system and the camper is negative. In that case the loads must be isolated from the negative ground loads on the camper. So I still plan to just ignore the controller’s load terminals. Using a shunt and current monitor would be my preferred way to monitor the battery’ state of charge.
To your point:
"All this theory is moot however when the solar controller is a positive ground system and the camper is negative. In that case the loads must be isolated from the negative ground loads on the camper. So I still plan to just ignore the controller’s load terminals. Using a shunt and current monitor would be my preferred way to monitor the battery’ state of charge."
We have been discussing isolating the 12vdc system and not grounding it anywhere on the camper. After going through the instructions and learning about positive ground systems I thing this is a necessity beyond corrosion issues. The 12vdc system has a battery now; it doesn't need to be grounded. It didn't before either.
I also believe the controller has reverse polarity protection. If you were sure your 12v system is isolated from the frame would you use the load terminals?
I do think using a shunt and monitor is a safe bet, but it also negates many of the functions on the controller such as high and low battery cut offs, timers, and load monitoring at the controller or at the remote monitor. I am trying to keep that functionality if possible. As I rewired the entire camper I am pretty confident I can now isolate the 12vdc.
The only remaining unknown is the converter as I am not sure my converter, which is grounded on the A.C. side has any effect on my ability to isolate the 12vdc that it creates and it's internal wiring as it is completely integrated into the 12vdc sustem.. I plan on running some isolation tests as soon as I have a chance and will let you know. Yet despite all this concern I can't think of a single reason I would ever ground the controller's positive to the frame so this might be a moot issue.
My fall back position will be the shunt and monitor method.
"The limitation is mainly altitude, as output power decreases quite a bit as you go higher."
about running air conditioner with a gen set......
if you're at an altitude high enough to affect the generator.....why would you need air conditionning????.....assuming you need it to sleep.....I've never been at 5000' at night and been hot.....heck, the reverse is more like it......No?
"The limitation is mainly altitude, as output power decreases quite a bit as you go higher."
about running air conditioner with a gen set......
if you're at an altitude high enough to affect the generator.....why would you need air conditionning????.....assuming you need it to sleep.....I've never been at 5000' at night and been hot.....heck, the reverse is more like it......No?
just sounded weird to me
I used to laugh about this statement in the Subaru manual that dropped my towing capacity from 2700 lbs to 1500 lbs; "When towing a trailer on a long uphill grade continuously for over 5 miles (8 km) with an outside temperature of 104F (40C) or above." I thought where would it ever be above 104F on a long uphill grade! Until I drove out of the valley in Death Valley National Park in July. It gets hot on those hills. Cooler than the valley, but hot!
__________________
Dave (and Marilyn who is now watching from above)
Sharpsburg, GA
04 Dodge Dakota V-8, 17 Dodge Durango V-6, 19 Ford Ranger 2.3 Ecoboost
radar1-scamping.blogspot.com
"The limitation is mainly altitude, as output power decreases quite a bit as you go higher."
about running air conditioner with a gen set......
if you're at an altitude high enough to affect the generator.....why would you need air conditionning????.....assuming you need it to sleep.....I've never been at 5000' at night and been hot.....heck, the reverse is more like it......No?
just sounded weird to me
I personally have no plans of running the air conditioner off of the battery but as the unit is only 5000btu it should be possible for a very short period of time before the battery drains. The Fantastic Vent however is adequate when boondocking and doesn't kill batteries.
I have a 2000 watt gas generator that has no problem running the air conditioner or anything else in the camper. Though, I wouldn't want to try running the induction stove, microwave and air conditioner simultaneously off that 2000w gas generator. It probably would just shut itself off. My venture into solar stems from my lack of desire to bring the gas generator with us camping and my love of gadgets, boondocking, and problem solving.
I anticipate only short term use of the 1500w (3000w peak) onboard inverter. Such as running the induction stove to boil some water, cook some stir fry, or run the microwave to warm up leftovers. After such short use letting the battery fully recharge off the solar panels. This can all occur while boondocking off solar.
Well, it worked! Thank you everyone for all the tips. I isolated the 12v from the frame via an 8 guage wire run into the camper, hooked up the solar, and can now bypass the load terminals on the solar controller when desired.
Enchanted Mountains of Western New York State on the Amish Trail in Cattaraugus County!
Posts: 621
Quote:
Originally Posted by Byron Kinnaman
Before you tout Lithium Ion batteries I suggest there a lot of research about them. Fires are pretty common today. Just last night there was news story about a spinner that had LEDs power LI battery, probably LiPo, that caught fire. The engineers will get on under control soon but not quite yet. I have a 2200 mA Lipo to use with my QRP ham radio. It's stored and kept in a fireproof bag.
One must remember that lithium type batteries are not created equal. Some are very prone to fire hazard and some are not.
While I'm not a expert, I believe that LiFePO4 batteries are about the safest battery we can use in RVs. I've ran lead acid, AGM, Gel, and LiFePO4 batteries in various RVs. I think the follow web page explains it very well in laymen language: https://www.iib.co.il/upload/1529315153.pdf.
I chose to use Battleborn's 100Ah 12V Heated Battle Born Batteries because of their built in battery management system which protects the battery from improper charging, and because of their 10 year warranty. I've found their customer service to be excellent.
1986 Boler 1300 Voyager
The Mountain Egg AKA 2006 13' Scamp
Past Tents
"The Breeze"
Hags Hideaway
Linear Mode
