Positive ground pwm controller

its positive 'common'
ground is the wrong terminology ( even though they often use it in the advertising )

the solar panel positive input connection is common with the positive charge output connection
they control the charging thru the negative side of the controller circuit, the negative input and the negative output are isolated, the part that is switched and voltage controlled

and it works fine, unless you try to use two controllers from the same set of solar panels to charge too different battery banks, that are both frame grounded

because you end up with (2) common circuits, both neg and positive
and both banks are connected together all the time

personally i prefer controller with common negative that control charging thru the positive side, like everything else we use in an RV, converter, alternator etc..

I repeat my original questions, "Are they okay to use on trailer batteries that have the more common negative ground? Any special concerns?"

The terminology about common or ground came from Renogy, not me. If it is a big negative (pun intended), I will cancel the order.

Short answer is no they are not and yes you can if you address the special concerns. Such as; most if not all RV's have the negative side of the battery connected to the RV frame. Testing of the CC would need to be done to see if this is a problem. Much simpler to get the so called standard system or so called negative ground. Ground in this case means common reference.

Thanks. I will see if I can cancel my order. I did not realize that there were possible polarity conflicts.

TomG2 wrote:
Any special concerns?"

load controller feature if used can not include loads that use the chassis/frame for the neg.

Here is what led me astray. From the Amazon.com description:

"Renogy 50W Polycrystalline Starter Kit is designed specifically for customers new to solar. The Starter Kit is great for off-grid applications, such as RVs, trailers, boats, sheds, and cabins......."