positive ground vs negative ground charge controllers?

[TWIH]

OK school me on the differences please. 

I thought most everything automotive was negatively grounded but while shopping/reading/adding to my ever growing Amazon wish list, I noticed a Renogy (I don't have brand preferences) 20 amp mppt charge controller which says that it is positive ground. 

"Renogy Rover 20 Amp 12V/24V MPPT Common Positive Solar Charge Controller Regulator Compatible with Lithium Sealed, Gel, Flooded Batteries and Bluetooth Module..."

So, what's the issue now? Seems most of them are negative grounded...

And are these 3 commenters correct when they say that the load terminals will deliver 24v out (instead of 12v that most dc appliances/things need)?

Question #1: "If a connect my panels and my batteries to 24 v what will be the voltage that I'll receive in the in load terminals?"
(spelling mistakes fixed)
Answer#1: Let say solar panel produce 36Vdc
And battery voltage is 27Vdc
The load terminal is about 27Vdc
By joe on February 4, 2021


The positive load terminal is a switched output off the battery terminal. So 24v in -> 24v out. The grounds are common.
By ransomii on May 25, 2020


Question #2: "Are the load terminals regulated to 12V, or do they just pass through the battery voltage?"
Answer #2: I'd bet they pass thru the battery voltage which may be 14.5V at times, maybe 13.0V or less if they have a drain without enough charge power coming in, they don't keep it at an exact 12.0V. If someone sets up a 24V battery system, the load terminals would be at 24V as well, so that hints to me it can't be regulated to 12.0V exactly.
By Thomas H. Lawler on October 18, 2017


*Me thinks that would fry/damage/release magic smoke if I connected a 12v something to the load...?

[TWIH]

Ok so google search reveals a post on a DIY Solar Forum about the positive vs negative charge controller. An answer said:
"May 4, 2020
#8
To expand on @fat_old_sun's comment: a "positive grounded" aka "common positive" controller simply means that the solar panel positive and the battery positive and the controller's load terminal positive are all connected in common; i.e. the controller is using low-side switching using cheaper/more powerful N-channel FETs.

Note the controller grounding does not have anything to do with the chassis grounding - in both the above examples the chassis is negative earth. It DOES matter if both the panels are grounded for some reason (in addition to the battery); i.e. so long as at least one side of the system is floating - as it should be - then either system will work."

So it sounds/reads like IDM (it don't matter).
I still have the load out voltage question though...

[Abnorm]

The solar charge controller takes whatever Voltage the panels produce and converts that to the voltage of the battery bank (+ a little to charge)

The Load terminals will have whatever V the battery side is producing with some limits

That Q&A is confusing the 12/24 aspect of the renogy product

[Blacktank]

there are old cars that are positive ground

[Wayne49]

British vehicles in the past used positive ground. I remember something about less corrosion in fog. But that could be an old codger's tale.

And then they went and used Lucas electrical parts.

A Lucas three way switch has OFF, ON, and FLICKER.

[Scott7022]

Ahhh Lucas electronics. Run away run away. We used to call it the prince of darkness.

Pulled loads of wrench’s on Triumphs.


Sent from my iPhone using Tapatalk

[Gr8ful]

Know why the serve warm beer in England? Lucus makes reftidgeration also.

[Matlock]

^^ Now that's funny.

I had a 46 Plymouth business coupe with a positive ground. 6 cyl ran like a raped ape, only rust was the exhaust. Remember someone saying it was the positive ground that resisted rust, I have no idea.

To the OP, I have no idea what's the deal with a positive grounded controller.

[rvpopeye]

They only make them to confuse solar newbs ?? lol
Stick with what you know ,,,happy life.

[Blacktank]

first off there is no ground on a 12v system,there is a positive and a negative,the "ground" thing started in the automotive world bringing a/c terms,where there is a ground,in to the d/c world,what they do is the positive is a wire and then they use the chassis and body as a wire to for the negative instead of running another wire,so using the term"ground" for the positive or negative is incorrect

so have no idea why so called electro experts making solar stuff would refer to either as the ground