Wuebben.2

I'm looking to add a battery to the cargo area of my JKU to run a fridge. I'm just now in the beginning stages of planning, so I'm doing a lot of research but it seems like the more I read the more I confuse myself.

What size solar charger would I need to run something like an ARB 50qt fridge that says it draws .87 amps per hour?

Would a 15 watt charger be able to keep up? According to my understanding 12volts x 0.87amp draw = 10.44watt...which would leave just over 4.5watts to recharge the battery.

ronjenx

That panel will give you full power only under the most ideal conditions. So, you can't use the math you used in your post.
Ideal conditions are very short-lived due to weather and changing angles of the sun from sunrise to sunset.
Connecting a 15 watt panel to the battery probably won't replace what the fridge draws, but will do a good job of lengthening the run time before you need to connect a regular charger to the battery.

I consider 15 watts is the point you would need to have a charge controller between the panel and the battery.

Valkyrie0002

You know the amp draw of the fridge, 21 amp hours per day. The battery is rated in amp hours, you don't want to drain below 80%. How many hours can your battery run the fridge. At best case how many hours per day would the PV and charger need to run to power the fridge and maintain the battery?

dstock

Your going to need a minimum of 60 watts and a solar charge controller to run an ARB indefinitely. Panels do not operate at 100% efficiency, and it's really all about the amps.

Do yourself a favor and head over to the Power section of Expedition Portal for your research.

Power Systems: 12v, Solar, Gen. - Expedition Portal

OnBelay

We have the same fridge freezer and are about to install a solar solution on our 2008 JK. We have decided on two roof-mount 50W EFTE flexible panels in parallel, a fender-mount accessory port to connect off-vehicle panels in series, and a Morningstar Prostar MPPT 40 charge controller (switched with a relay). The Prostar has really low RMI/RFI and meets FCC Class B standards, which is important for our communication equipment.

The solar panels are to run the fridge, maintain our dual Odyssey batteries, and power ham radios with the vehicle off. Please post up if you get your project done; we'll do the same. I've been looking for proper JK solar installs for months -- even on Expedition portal -- and can't find anything that we would consider replicating.

Wuebben.2

Thanks everyone, I think I've found the panel I'm going to use...now to figure out how to mount it. I have a JKU with a soft top. Any thoughts on mounts?

Here's the panel I'm planning on getting:

https://www.amazon.com/dp/B00NK8TQUY/ref=asc_df_B01JA6VYEA5381656/?tag=hyprod-20&creative=395033&creativeASIN=B00NK8TQUY&linkCode=df0&hvadid=241942867107&hvpos=1o9&hvnetw=g&hvrand=2528589006712304967&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9014942&hvtargid=pla-414130951359&th=1&psc=1

OnBelay

Lensun has good panels, especially the aluminum backed panels (better for heat). That being said, have you considered SunPower panels? They also have ETFE but without the price premium of Lensun. Most manufacturers OEM SunPower cells for their panels, as they are among the most efficient on the market (20-22 percent). Even Renogy resells the SunPower 100W flexible instead of making a version 2 of their previously ill-fated 100W flexible panel.

I am a bit leery of Lensun's customer service. I emailed them 2 months ago with questions re: a customized panel -- a service they tout -- and did not get an answer. Also, many of the Lensun testimonials are from folks who received perks/benefits from Lensun to perform the review.

Wuebben.2

Thanks for the heads up...the lensun panel I linked has controller option which is what I planned on getting. Thought it'd be easiest to get them both from the same company at the same time.

dstock

You don't have to mount it on the Jeep. It's more advantageous to have one with legs so you can move it around to get optimum sun. Usually I try to put the JK in shade and move the panel around to follow the sun. 15-20 feet of 10 gauge will give you plenty of leeway to move it around. Flat on a roof is not very efficient except when the sun is directly overhead.

OnBelay

The ETFE panels have a fish-eye lens of sorts that helps with the oblique light. An MPPT controller helps a lot, too. But in general, yeah, not as efficient if they are stationary ... and you have the heat factor as well.

I think the best option is to have both on and off-vehicle panels. My plan is 100W on the roof to maintain my AGM batteries with a PROPER charge at 14.7V-14.9V (e.g. above the JK's 14.4V alternator output) plus power ham radios while the engine is off. Then the portable panels for when I am overlanding.

If people want to run rigid panels, then the AM Solar Z brackets are the way to go. They let you tilt your panels, but allow you to secure them while flat and underway.

Edit: slightly off topic, but for the record I have a Noco Genius onboard charge controller to maintain the AGM batteries; the stock JK alternator just can't keep up with them.