RV Battery Tender

[Groundhog66]

Hello all!

I am trying to get set up with a battery tender for my travel trailer when it is in storage, and I am a bit confused.

I have 2 6V batteries in series, and the TT is wired for solar (has an input).

I purchased a 20W panel with controller from Amazon, but it seems to be reading incorrectly.

The controller is supposed to auto detect the voltage, but it is coming up with 24V, and I see no way to override this.

I sure would love some advice/input as to how I can get this dialed in, because it sure is easier than taking the batteries out each time to trickle.

 

[time2roll]

What controller? Can you post a picture of how the wires are connected? 20 watts will not overcharge the battery either way for quite some time. OK to try it and measure again in a few days.

 

[Bud Martin]

Did you connect the SCC to the battery first? do that with no panel connected yet.
What Voltage does the display of the SCC show for the battery Voltage?

 

[Groundhog66]

This is the controller that came with the panel, nothing fantastic, but I only plan to use it as a trickle charger.

https://www.amazon.com/EEEKit-Controller-Intelligent-Multi-Function-Adjustable/dp/B07R8TRJ8C/ref=sxin_16_ac_d_mf_br?ac_md=3-1-RUVFS2l0-ac_d_mf_br_br&crid=1QHK5YYWEAD00&cv_ct_cx=solar+controller&keywords=solar+controller&pd_rd_i=B07R8TRJ8C&pd_rd_r=a31de957-90fc-46ad-85e5-7189b9ef33ce&pd_rd_w=ANle9&pd_rd_wg=MxXBi&pf_rd_p=af56c395-f6ae-4741-98f7-37d0cc7c93ab&pf_rd_r=49QZ4GRCTPGJ9H3MF5GW&psc=1&qid=1648243477&sprefix=solar+controller%2Caps%2C153&sr=1-2-ed8a42d3-65f1-4884-a3a2-0dd6e83b6876

 

[12VoltInstalls]

If it doesn’t auto detect band there’s no menu option then it’s broken

That is a cheap clone pwm. A couple of them are decent software like the windyNation P30L. For ~$50 there’s a Epever 10A mppt on amazonian mercantile but for that small of a panel you ain’t probably going to reap mppt benefits. I’d get a P30L imho, probably return everything else and get a 50- or 100W panel.

 

[chrisski]

Unless you are pulling fuses I think you may need a 100 watt panel. If someone else chimes in on power requirements when parked, I’d like to know. It’s a pet leave of mine when I go to the RV dealer and they’ve had a trailer for two weeks and the battery is dead and they act as if that has never happened before. Happens every time.

I have a fifth wheel.

The parasitic draw on the system is 320 wh a day just to keep the battery charged, THere is some things in the trailer that just draw energy when turned off. The DC Stereo system is one. THat is about 12 watts running 24 hours a day. There’s a couple of other things. The 320 watts how much my Victron shunt says I charge per day consistently. A 20 watt panel won’t keep up.

Not much energy but it adds up.

 

[Rednecktek]

For $10, this little 10a PowMr actually lets you change some of the settings and can handle about 200w worth of panel. I've got a couple of the 30a versions that work just fine.

 

[12VoltInstalls]

got a couple of the 30a versions that work just fine.

Another clone
I’d get the 30A ones too. If the software is anything like WindyNation it’ll be great!

 

[Bobert]

You definitely want to physically disconnect the batteries from the camper even with a battery tender or just buy new batteries next year. My father in-law ended up with a freezer full of frost and a dead battery because the dealer left the fridge doors in transport mode and the fridge on. One thing overlooked or one mistake and it’s bye bye batteries.

 

[Groundhog66]

You definitely want to physically disconnect the batteries from the camper even with a battery tender or just buy new batteries next year. My father in-law ended up with a freezer full of frost and a dead battery because the dealer left the fridge doors in transport mode and the fridge on. One thing overlooked or one mistake and it’s bye bye batteries.

There is a battery disconnect in the pass thru, so there is no draw when charging.

 

[Groundhog66]

For $10, this little 10a PowMr actually lets you change some of the settings and can handle about 200w worth of panel. I've got a couple of the 30a versions that work just fine.

Maybe I'll give that a shot, not a huge investment.

 

[Bobert]

There is a battery disconnect in the pass thru, so there is no draw when charging.

Just make sure it is a complete shutoff of the battery they aren’t always wired that way.

 

[Groundhog66]

Unless you are pulling fuses I think you may need a 100 watt panel. If someone else chimes in on power requirements when parked, I’d like to know. It’s a pet leave of mine when I go to the RV dealer and they’ve had a trailer for two weeks and the battery is dead and they act as if that has never happened before. Happens every time.

I have a fifth wheel.

The parasitic draw on the system is 320 wh a day just to keep the battery charged, THere is some things in the trailer that just draw energy when turned off. The DC Stereo system is one. THat is about 12 watts running 24 hours a day. There’s a couple of other things. The 320 watts how much my Victron shunt says I charge per day consistently. A 20 watt panel won’t keep up.

Not much energy but it adds up.

Batteries are disconnected vis the disconnect in the pass thru when charging in storage.

 

[Browneye]

100W panel with a 10a controller makes for a nice battery maintainer. You generally won't get more than 4-5A out of it anyway.
As mentioned, if your controller won't select proper voltage it is defective.

For GC2's you really do want proper charge voltage, boost float and equalize, to keep them in good health. That means either a plug in smart charger or a smart solar controller. Check electrolyte level monthly.

 

[Groundhog66]

100W panel with a 10a controller makes for a nice battery maintainer. You generally won't get more than 4-5A out of it anyway.
As mentioned, if your controller won't select proper voltage it is defective.

For GC2's you really do want proper charge voltage, boost float and equalize, to keep them in good health. That means either a plug in smart charger or a smart solar controller. Check electrolyte level monthly.

Any recommendations for a suitable combination?

 

[chrisski]

Renogy panels from Amazon and either a Renogy or Victron SCC.

Amazon.com

Amazon.com

Amazon.com

Tilt brackets are an example of mounting, but much cheaper options are available. Also cheaper options for SCCs, but you have to ask if you’ll stop there.

I saw some Renogy kits for sale over the counter at a camping store, and they seem double the price online.

 

[Browneye]

I already had black-framed panels on my RV roof - the Nature Power 215's that came from Home Depot, so I found a 100W black frame panel from B&H Photo - they still have them for ninety bucks:

https://www.bhphotovideo.com/c/product/1625761-REG/acopower_hy100_12m_100w_all_black_mono.html

Since it keeps my SLA's charged and they are in the old battery tray more or less outdoors, I got a Renogy Voyager - they're 10A and pwm, pretty water resistant, but no settings for lifepo4. The whole setup was cheap and easy to setup and works killer.

My starting bank setup. RV is a workhorse chassis with a GM 8.1L V8. The Victron Orion is also there for the dc to dc charging of the house lifepo4 pack.

 

[Mainehazmt]

I’ve been working this issue for oh 4+ years but going back many years too. My primary concern is to keep my Rv refrigerator working. you gotta have power for the control board to keep it going. I have to have my ice cream! Camper is only 7 miles away on the side of a lake on my wife’s family farm. I tried 25 watt panel and failed. Upgraded to harbor freight 100 watts of panel, also failed. Then 190 watt panel nope not good…. This year I have finally got it done. 2 190 watt panels, 40 amp mppt charge controller into 4 6 volt batteries. Ice cream stays nice and frozen.

 

[Browneye]

Whut??? An lpg fridge board pulls about 1A, if that. Like 6 or 8W or so. [shrug]

 

[Mainehazmt]

Whut??? An lpg fridge board pulls about 1A, if that. Like 6 or 8W or so. [shrug]

Just reporting my results