I'll put this in beginning RV because I think these are beginner's questions and I'm relatively new at this compared to some of you. If it's the wrong forum, mods please move it.My system is two 12V batteries, a 4000 Watt generator, and a 200 Watt solar panel plus a battery disconnect switch. I don't have an inverter on my rig, so I can't use 110-120 when I'm not running the generator or on shore power. The generator, shore power, and solar will recharge the battery.Can I use the solar to maintain the battery during storage? That would mean leaving the disconnect shut. As far as I can determine, the CO detector, thermostat in the off position, and 12V entertainment center (maintains time when turned off but connected to power, just like a radio in a car) are the only parasitic loads if I turn everything else off. The fridge power is a physical switch.I recently found my truck wasn't supplying accessory voltage to the 7 pin and I've rectified that (was missing a relay and fuse. Thanks Ford for not including that with the truck! /sarcasm). Now that I do have accessory voltage, will the truck charge the batteries on the road?Is there any harm in running my generator on the road to give it some run time? Can I run the AC on the road to give it some load?My plan in the future is to increase my battery capacity and add an inverter. I would like to be able to watch a movie with the family at night, but I'm thinking that it may be possible to add enough to run the microwave. Is this doable in a travel trailer? Thanks in advance for any answers.

The solar should easily maintain the battery bank during storage easily, assuming you store it somewhere with at least a little sunlight.You generally can run the generator while en route, and the air conditioner. People in motorhomes do that quite frequently if the dash air conditioning is insufficient to keep the interior comfortable. Difficulties may come if you're talking about e.g. a portable generator in the truck bed and a wire dangling between the trailer and the generator from the actual connections and so forth. I guess you're probably talking about a permanently installed generator, in which case there should be no trouble at all.The tow vehicle should now provide some charging power, but it would not be a bad idea to verify that. You can't generally expect to see a very large charge current. It's probably best to think of it as enough to keep up with the parasitic loads and the fridge control board than as a way to recharge a depleted battery bank, doubly so if you're not driving for many hours.An inverter to run the TV and DVD player would be very simple to hook up; you don't need a particularly big one for that. You could probably plug it into the 12V lighter socket at the television if your trailer happens to have one there, and not have to do any permanent wiring.Powering the microwave from an inverter is certainly possible, but to do it effectively you'd need a larger battery bank and a decent plan to charge it afterwards. Four batteries is probably about the minimum to reasonably use a typical microwave, and even then extensive cooking is asking a lot. It's often more effective to start up the generator for that if you are able to do so (or cook on the gas cooktop).

Solar should be direct on the battery, no switch. As long as there is some sun the battery should easily stay charged with 200 watts.Yes you may run the generator and air conditioner while rolling.tv is easy with 150 to 300 watt inverter and your existing battery pair. Microwave really needs 2000 watts sine wave mounted close to four+ batteries to drive it.If the generator is used to charge the battery verify the converter is putting 14.2+ volts on the battery. Many just trickle charge at 13.6 volts.The 12 Volt Side of life

smkettner wrote:Solar should be direct on the battery, no switch. As long as there is some sun the battery should easily stay charged with 200 watts.Yes you may run the generator and air conditioner while rolling.tv is easy with 150 to 300 watt inverter and your existing battery pair. Microwave really needs 2000 watts sine wave mounted close to four+ batteries to drive it.If the generator is used to charge the battery verify the converter is putting 14.2+ volts on the battery. Many just trickle charge at 13.6 volts.The 12 Volt Side of lifeThank you. If the solar goes right to the battery, that might explain why my batteries seem to stay fully charged after they've been sitting. And thanks for the link.

Just remember that leaving the battery connected while in standby you will continue to see parasitic drains from your RV unit. Alot of small things are still pulling power from the battery. In my case I see 1-2AMPS...Having the solar panels connected helps alot keeping the battery topped off. Typically a 120WATT Solar Panel will only produce around 5-6AMPS DC Current while in the high sun. In order to keep the batteries topped off the solar panel has to produce more DC current than your parasitic drains are pulling.Also keep in mind the solar panels only work good in high sun. In my case here on the East coast side I can only see around 5-6 hours of high sun. Out West you can see more sun obviously...

Have the solar panels go to the battery, have a disconnect from the battery to the trailer. This is what I do to keep my batteries topped off while its in the storage yard and the disconnect switch prevents any parasitic draws from happening.

Charging the battery | Good Sam Community

IDoMyOwnStunts
Explorer
Mar 18, 2016
westend wrote:
200 W of modules and a charge controller will keep your batteries better tended than many a 120V charger. I believe the suggestion to connect directly to the batteries was in reference to the OP's connections. He has the charge controller's output interrupted by the disconnect switch. The best resolution would be to wire the controller's output directly to batteries and, if a battery temp sensor is available, to connect that to batteries also. My little Morningstar controller changes the charge voltage automatically with temp changes. There is about a .3V -> .5 swing during the year.

I was incorrect. The solar panels and controller are not interrupted by the disconnect switch.
IDoMyOwnStunts
Explorer
Mar 18, 2016
Chandalen wrote:
Solar should NOT go directly to the batteries. EVER. You need a charge controller. The controller stops bleed back to the panels, and stops your batteries from OVERCHARGING.

Panels connected straight to batteries will overcharge and you will destroy the batteries.

There is a controller for the solar panels on my rig. They are manufacturer installed.
westend
Explorer
Mar 17, 2016
200 W of modules and a charge controller will keep your batteries better tended than many a 120V charger. I believe the suggestion to connect directly to the batteries was in reference to the OP's connections. He has the charge controller's output interrupted by the disconnect switch. The best resolution would be to wire the controller's output directly to batteries and, if a battery temp sensor is available, to connect that to batteries also. My little Morningstar controller changes the charge voltage automatically with temp changes. There is about a .3V -> .5 swing during the year.
Chandalen
Explorer
Mar 17, 2016
Solar should NOT go directly to the batteries. EVER. You need a charge controller. The controller stops bleed back to the panels, and stops your batteries from OVERCHARGING.

Panels connected straight to batteries will overcharge and you will destroy the batteries.

When you get an inverter.. make sure it is a PURE SINE inverter. These are NOT available at WalMart. Camping stores, Amazon, etc. will have them. As a general rule if the inverter does not say 'Pure Sine' it is not.

A microwave will run for **** on a standard inverter (modified sine wave). Also, sensitive electronics will be destroyed. (New Mac's will generally not run at all on a modified wave inverter.)

Thicker wire is better (8ga or larger) and never place an inverter in the same area as a battery bank unless the bank is sealed and vented.
austinjenna
Explorer
Mar 10, 2016
The 200 watt panel is going to produce 16 amps. What you don't want to do is overcharge the batteries when not in use. Your solar panel could potentially overcharge the batteries and that can kill a battery in short order. On my equipment that isn't used on a regular basis I use battery tenders, they will keep the batteries fully charged, but not overcharge them. Now if you don't have an AC source where you are storing your rig, the battery tenders obviously won't work

Just get a good solar charger that will charge the batteries and then maintain them and you wont need to worry.
RBPerry
Explorer
Mar 10, 2016
Can I use the solar to maintain the battery during storage?

The 200 watt panel is going to produce 16 amps. What you don't want to do is overcharge the batteries when not in use. Your solar panel could potentially overcharge the batteries and that can kill a battery in short order. On my equipment that isn't used on a regular basis I use battery tenders, they will keep the batteries fully charged, but not overcharge them. Now if you don't have an AC source where you are storing your rig, the battery tenders obviously won't work.
westend
Explorer
Mar 09, 2016
RoyB wrote:
Also keep in mind the solar panels only work good in high sun. In my case here on the East coast side I can only see around 5-6 hours of high sun. Out West you can see more sun obviously...
My polycrystalline module will harvest even before sun up or after sun down. It isn't much but there is some power being generated. Good power is being produced when the sun directly hits the panel.

Solar insolation amounts are more affected by latitude than longitude. If you're on the same parallel in Virginia or California, the amount of sun will be the same.
IDoMyOwnStunts
Explorer
Mar 09, 2016
A friend of mine and I were talking at lunch tonight and just throwing it out there that we could get a remanufactured battery from a Prius or something and have all the capacity we need. That would be a spendy battery, though. I'll bet somebody has done it.

Somebody mentioned a 12V plug near the TV. I do have one. Unfortunately, I don't have a 12V TV. I might think about replacing it with one. That would solve that problem.

About the solar, I do have a controller in the hallway. I've never checked it with the disconnect open. I will do that. It does show a numerical voltage readout for the battery. I think. It usually reads 13.4 day or night. Seen it as low as 12.6 before. I guess I'll need to trace some things out. I do have a multi-meter, so I'll cross check it.

And, yes, if I add an inverter, I'll do it close to the batteries with thick cables.

Thank you all for the info.
azrving
Explorer
Mar 09, 2016
As they said and a key point being 13.6 vs 14.4 volt converter. If yours only goes to 13.6 volts you may want to upgrade. It's an important part of cutting down on generator run time. Don't go by your monitor panel for battery condition, get a digital volt meter and basically stay above 12 volts. Using a digital volt meter do some checks at your converter vs at the battery bank to check for substantial voltage drops which increase charge times. Sometimes it helps to increase the wire size.

If you start doing regular discharges to 12 volts or so day after day you may need to watch you specific gravity or at least understand what is going on there so you are truly getting a full charge. As far as using an inverter and battery bank sizing read up on the Peukert effect and keep the battery cables short and big.
austinjenna
Explorer
Mar 09, 2016
Have the solar panels go to the battery, have a disconnect from the battery to the trailer. This is what I do to keep my batteries topped off while its in the storage yard and the disconnect switch prevents any parasitic draws from happening.

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