Hey guys, I just got my first RV! My RV is a 97 Winnebago adventurer. I already own 150 watt solar panel array that charges a 110AH costco deep cycle. The RVs coach batteries are two 75AH deep cycles. I use a lot of electricity charging electric bicycles and other gadgets and am looking to add at least one, possibly 2 more 110AH batteries. My question is, is there a way to have all the batteries charged from the different sources? Id love the generator to be able to charge both banks, and the solar panels to be able to charge both also. I believe that is what a battery isolator is for, correct?If I hook up a battery isolator, do all batteries in the banks need to be the same AH rating? or can the one bank stay 150AH (2x75AH) since they are good and work, and the other bank be 220AH (2x110AH)Thanks for your time, I am super excited to be upgrading it!

How much current do you think the bicycles will draw? The generator can charge both banks but the solar should be able to do a better job than the converter that came with the coach. A good solar controller will charge at a higher amperage and maintain the batteries much better for a longer life. You don't have to have all the same batteries new at the same time but if there is a week battery it will be a draw on the rest of them. You could put in the isolator but it will mean the solar would not be charging the isolated array obviously. BTW, those amp hour ratings are to sell batteries so I wouldn't rely on those numbers too much.

Fixed Sight Training wrote:How much current do you think the bicycles will draw? The generator can charge both banks but the solar should be able to do a better job than the converter that came with the coach. A good solar controller will charge at a higher amperage and maintain the batteries much better for a longer life. You don't have to have all the same batteries new at the same time but if there is a week battery it will be a draw on the rest of them. You could put in the isolator but it will mean the solar would not be charging the isolated array obviously. BTW, those amp hour ratings are to sell batteries so I wouldn't rely on those numbers too much.I can set how much the charge rate is on the bike batteries, I use a Hyperion EOS 720 charger to charge them, which runs on 12V to 18V.Right now I just have a PWM solar charger, I plan on getting a MPPT one, but its not in the budget at the moment.. this is the one I have.PWM chargerYeah, the AH thing, just pointing out that the two banks would be different ratings all together.I thought the battery isolator meant it would charge both sets (the array), and then just not let them drain each other.

You can use a diode based isolator with an alternatorBut you can not use one with a solar controllerThe controller must be connected directly to the batteriesYou could install a switch between banks or use them all togetherWhich is what most of us with enlarged Battery banks doI do have a power connector which lets me unplug one bank then charge it sperately using a battery chargerMost of us have separate house and chassis systems, But leave all the extra batteries for the RV house system connected together

Just connect all the batteries in parallel and charge away. Multiple charging sources is not an issue but I think you need more solar. If you must charge from the generator verify you have a good system charging at 14.4+ volts.

smkettner wrote:Just connect all the batteries in parallel and charge away. Multiple charging sources is not an issue but I think you need more solar. If you must charge from the generator verify you have a good system charging at 14.4+ volts.I do plan on getting more solar, but since I just bought the RV, budget is low ;)In my experience with batteries, I have always been told it is bad to connect batteries of different AH rating, is that not the case in this situation?Also, if they are all in parallel, do I just hook up the solar charger right to them with all the other charger sources going in and it wont be a problem?

Adding Solar. | Good Sam Community

22 Replies

ShreddinPB
Explorer
Jun 25, 2015
pianotuna wrote:
yes

ShreddinPB wrote:
Should I just sell the 50 watt guys and get all 100 watt panels when I want to upgrade?

Thanks!
pianotuna
Nomad III
Jun 25, 2015
yes

ShreddinPB wrote:
Should I just sell the 50 watt guys and get all 100 watt panels when I want to upgrade?
ShreddinPB
Explorer
Jun 25, 2015
rjsurfer wrote:
Don't go nuts over looking for a quality MPPT controller, if you have the roof real estate you can just buy a 100-150 watt panel for the cost difference. Now you'll get 25-50 percent increase in output instead of the questionable 5-10 percent gain some people are always touting with MPPT. Panels are cheap!

Just but a decent PWM with enough future capacity so you won't be buying twice.

Thanks!
Someone over at another site said that MPPT could have issues with panels that have different wattage?
Right now I have 3x50 watt Renogy, my next panels will be the Renogy 100 watt ones. Is it possible to have them all in the same array, either in parallel or serial, either with PWN or MPPT? Or should they be 2 different arrays? Should I just sell the 50 watt guys and get all 100 watt panels when I want to upgrade?
rjsurfer
Explorer
Jun 25, 2015
Don't go nuts over looking for a quality MPPT controller, if you have the roof real estate you can just buy a 100-150 watt panel for the cost difference. Now you'll get 25-50 percent increase in output instead of the questionable 5-10 percent gain some people are always touting with MPPT. Panels are cheap!

Just but a decent PWM with enough future capacity so you won't be buying twice.
pianotuna
Nomad III
Jun 24, 2015
Do an energy audit. I suspect using a generator is going to be the winner. Even using 10 watt led's a 50 person camp is going to be a LOT of kilowatt hours. You have been there before, so it should be possible to 'ball park' energy needs.
westend
Explorer
Jun 24, 2015
westend wrote:
If you read closer you will find that the wind turbine linked to will supply 900W at wind speeds of close to 100 MPH. At low wind speeds it will supply a fraction of that, probably under 100W at 12+ V. It is not a serious generator but a bauble for naive wind aficionados. Yes, you can use any amount of charge controllers in parallel.

A better solution for charging would be to add solar modules and batteries to match your use. Many with only small solar systems have their batteries fully charged by noon.

The expense of an MPPT charge controller doesn't have to be endured by those using nominal 12V modules. If you migrate to 24V nominal panels, then MPPT becomes a necessity.

The first step in proper solar system design is to assess your total power needs. Add up all the devices and their power needs. Add in some fudge factor for design purposes.

Good luck with the solar.

First, I'd bypass small wind setups unless you envision becoming a user and experimenter. I am one so know the path. The real deal is that anything with less than a 10' prop span and not at least 15' in a tower is not going to produce much power. Even with that, you need sustained wind. I've been at this awhile and am still striving to find a good DC generator for my application (am on my third or fourth generator).

More tilting modules will get you some good charging power. For a lot of lights (use LED's exclusively) you will probably need more batteries. 6V golf cart batteries are about the cheapest storage solution ($$/AH).

Since this year's BM thing is about mirrors, you may want to experiment with mirrors and lenses. A good fresnel lens will spread a lot of light.

Good luck with your festival rig. Let us know what the outcome is.
time2roll
Nomad
Jun 24, 2015
ShreddinPB wrote:
In my experience with batteries, I have always been told it is bad to connect batteries of different AH rating, is that not the case in this situation?
In an extreme case you are right. No group 29 parallel with a motorcycle battery. However in the case of RV batteries anything from Group 24 to 8D in parallel is just fine while in use. Charging and Using the batteries will be fine. If stored without a float charge would be the time to separate.

ShreddinPB wrote:
Also, if they are all in parallel, do I just hook up the solar charger right to them with all the other charger sources going in and it wont be a problem?
Multiple charging sources work fine together. Considering the number of batteries the multiple sources will only work in your favor to keep them charged and provide maximum power while in use. In parallel slows the individual battery charge or discharge and increases efficiency based on the Peukert Effect (wiki that if needed).
ShreddinPB
Explorer
Jun 24, 2015
MrWizard wrote:
get a generator, spare fuel, extra air filters for the genny,
solar is going to get so dusty on the Playa as to be almost un-useable
mount them so they can tilt at the sun, some of the dust will fall off,
wash them every morning, to get maximum yield

maybe use LED rope/strip lighting for area lighting, instead of spots
the illumination will be more spread out for the watts used

from what i have read the playa is a good place for wind turbin power, but investigate, some wind forums, or burning man blogs, to find something that works
skip the flashy websites adv wind power

She has a perfectly working onan 6500, I just want to use it as little as possible. I will get extra air filters, good idea.

I chose the spots because of the way the shade structure is, ropes dont work well. I do have some rope leds that will be going inside the RV however ;)

I did buy tilting mounts, they should be in Friday.
I frequent eplaya.com, just thought id ask here since you guys are so RV savy ;)
I appreciate all the information!
MrWizard
Moderator
Jun 24, 2015
get a generator, spare fuel, extra air filters for the genny,
solar is going to get so dusty on the Playa as to be almost un-useable
mount them so they can tilt at the sun, some of the dust will fall off,
wash them every morning, to get maximum yield

maybe use LED rope/strip lighting for area lighting, instead of spots
the illumination will be more spread out for the watts used

from what i have read the playa is a good place for wind turbin power, but investigate, some wind forums, or burning man blogs, to find something that works
skip the flashy websites adv wind power
ShreddinPB
Explorer
Jun 24, 2015
westend wrote:
If you read closer you will find that the wind turbine linked to will supply 900W at wind speeds of close to 100 MPH. At low wind speeds it will supply a fraction of that, probably under 100W at 12+ V. It is not a serious generator but a bauble for naive wind aficionados. Yes, you can use any amount of charge controllers in parallel.

A better solution for charging would be to add solar modules and batteries to match your use. Many with only small solar systems have their batteries fully charged by noon.

The expense of an MPPT charge controller doesn't have to be endured by those using nominal 12V modules. If you migrate to 24V nominal panels, then MPPT becomes a necessity.

The first step in proper solar system design is to assess your total power needs. Add up all the devices and their power needs. Add in some fudge factor for design purposes.

Good luck with the solar.

Thanks for the input!
My main use for the RV is Burning man, I go every year and this year will be my first with an RV. I do other camping trips and festivals also, but the main is Burning man.
With that said, I would like to be able to provide power for lighting our 50 person camp from the RV. I have been testing small 10W LED lamps and plan on using those along with the stuff in the RV, So really, my power needs are as much as I can get ;)

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