positive ground mppt

[Manooti]

I ordered the positive ground mppt a while back before I even started setting anything up. I assumed it was all negative ground as that is/should be the standard but unfortunately i was wrong again. Missed the fine bold print lol

I saw some manufacturers suggest grounding the positive from the panels or the battery bank and not both. Some say dont ground anything. Also, dont use the "load" side of the mppt.

My issue is, im also going to use the AIMS 24v AC to DC charger so did I screw myself or is there some hope for me with this mppt?
Using the AIMS until I can sort this out

this is the one in question:

60 AMP 48V 36V 24V 12V MPPT SOLAR CONTROLLER w/ unlimited parallel capability - Sigineer Power

Model #: SR150V60A Free shipping to the USA, Canada & Puerto Rico by courier. The SR150V60A solar charger controller features LCD touch screen, unlimited parallel capability, automatic battery voltage recognition from 12Vdc to 48vdc, wide PV input range up to 150V, various battery charging...

www.sigineer.com

manual

https://www.sigineer.com/wp-content/uploads/2021/03/SR150V60A-Solar-Charger-Manual-2021.pdf

 

[OffGridInTheCity]

One thing that came up in a moderately recent post - you don't want to ground BOTH positive and negative as this may cause a direct short! So you need to go one way or the other consistently or don't ground at all. From my understanding, 12/24vdc is not risky (e.g. needing ground). Its when you get nearer 60v - e.g. 48v nominal systems is where a ground begins to be important.

 

[Manooti]

One thing that came up in a moderately recent post - you don't want to ground BOTH positive and negative as this may cause a direct short! So you need to go one way or the other consistently or don't ground at all. From my understanding, 12/24vdc is not risky (e.g. needing ground). Its when you get nearer 60v - e.g. 48v nominal systems is where a ground begins to be important.

Wish I saved that site earlier that showed what you can and can’t do but not sure how it would of mattered. Have to look for it again. It said don’t (positive) ground both the batteries and pv. Only one. We get a lot of lightning and storms here. I’d have to ground. We had 2 trees get hit my lightning directly next to house. One split in half, the other landed on house.

Would the ground from aims charger also affect it?

 

[OffGridInTheCity]

Wish I saved that site earlier that showed what you can and can’t do but not sure how it would of mattered. Have to look for it again. It said don’t (positive) ground both the batteries and pv. Only one. We get a lot of lightning and storms here. I’d have to ground. We had 2 trees get hit my lightning directly next to house. One split in half, the other landed on house.

Would the ground from aims charger also affect it?

Let's step back a bit. A PV array (1 or more panels) should be bonded / grounded - e.g. the panel frames and metal they are fastened to. This has nothing to do with pos and neg coming from the panel. For that, you should have a lightning arrestor (typically before the wires enter the house) that blocks surges down the pos + neg wires and shunts to the ground (a 3rd, separate wire).

Then you have PV pos and neg and a separate ground wire coming to the Charge Controller. On my charge controller, the pos and neg and ground are 3 separate things - so I don't ground pos or neg but rather hook the Charge Controller's ground to the overall ground. If you have 12v panels then not a big deal - but mine is 90v (MPPT) to 120v (VoC) and at that level shock is a real risk.
**It's possible you're is different - you should follow the manufacture's hookup instructions.

Finally you have pos and neg coming out of the Charge Controller to the battery (bank). This is typically 12/24/36/48v. For 12/24/36v you're not at very much risk from shock. As I mentioned above - its the 48v nominal where a 14s or 16s lithium battery can get near 60vdc fully charged that get's in the relm of real risk of shock. So 48v battery (banks) may ground the negative (typically).

I would not recommend grounding pos at charge controller and neg at the battery since the battery wires run directly back to the charge controller and will (likely) cause a dead short!!

I hope this helps move things forward a bit....

 

[Manooti]

Let's step back a bit. A PV array (1 or more panels) should be bonded / grounded - e.g. the panel frames and metal they are fastened to. This has nothing to do with pos and neg coming from the panel. For that, you should have a lightning arrestor (typically before the wires enter the house) that blocks surges down the pos + neg wires and shunts to the ground (a 3rd, separate wire).

Then you have PV pos and neg and a separate ground wire coming to the Charge Controller. On my charge controller, the pos and neg and ground are 3 separate things - so I don't ground pos or neg but rather hook the Charge Controller's ground to the overall ground. If you have 12v panels then not a big deal - but mine is 90v (MPPT) to 120v (VoC) and at that level shock is a real risk.
**It's possible you're is different - you should follow the manufacture's hookup instructions.

Finally you have pos and neg coming out of the Charge Controller to the battery (bank). This is typically 12/24/36/48v. For 12/24/36v you're not at very much risk from shock. As I mentioned above - its the 48v nominal where a 14s or 16s lithium battery can get near 60vdc fully charged that get's in the relm of real risk of shock. So 48v battery (banks) may ground the negative (typically).

I would not recommend grounding pos at charge controller and neg at the battery since the battery wires run directly back to the charge controller and will (likely) cause a dead short!!

I hope this helps move things forward a bit....

This is crazy. Didn’t know about the lightning arrestor. I’m just keeping batteries at 24v so I could use the Ac-dc charger which is 12v/24v.
So pretty much just use the lightning arrestor and not ground anything to make this mppt work?

 

[OffGridInTheCity]

This is crazy. Didn’t know about the lightning arrestor. I’m just keeping batteries at 24v so I could use the Ac-dc charger which is 12v/24v.
So pretty much just use the lightning arrestor and not ground anything to make this mppt work?

I'm describing a permanent, PV array installation -> charge controller -> battery -> inverter 'home' setup.

Sounds like you might have more of a solar generator setup? For example, maybe you can disconnect / take the panels down during a storm type of thing to avoid lightning?

If you want to pursue this, perhaps you could describe your situation in more detail
- Panels/sizes - are they permanently mounted?
- Is this on your home or a shed or an RV or ?
- What model is your charge controller?
- What size (ah) is your 24v battery ?
- How is the power consumed - thru an inverter? is it a permanent setup?

This would help others chime in, perhaps say things a bit differently, and get you the info you want

 

[Manooti]

I'm describing permanent, PV array installation.

Sounds like you might have more of a solar generator setup? Maybe disconnect / take the panels down during a storm type of thing? Grounding not that important?

If you want to pursue this, perhaps you could describe your situation in more detail
- Panels/sizes - are they permanently mounted?
- Is this on your home or a shed or an RV or ?
- What size (ah) is your 24v battery ?

This would help others chime in, perhaps say things a bit differently, and get you the info you need

Haha steep learning curve. Learned a lot but still looks like I need to study more.

Permanent panels to be mounted outside. 220 or 230 watt have to look at specs again but I got 4 used panels. Going to bury cable with conduit and pass through to basement.

Batteries are diy. 8s 24v @100ah. Deligreen bms.
Have only 1 cycle on batteries with bms and might add another set for 24v 200ah before I put them to use.

Just trying to run the necessities when things go south. Charge with both panels and/or generator if need be.

Maybe buy another mppt? Would that be idiot proof? Lol

 

[OffGridInTheCity]

Haha steep learning curve. Learned a lot but still looks like I need to study more.

Its not really that bad - but it's good to understand grounding

Permanent panels to be mounted outside. 220 or 230 watt have to look at specs again but I got 4 used panels. Going to bury cable with conduit and pass through to basement.

OK, then it's as I described above. Its you're choice! but code/good-advice is as described. What the lightning arrestor does is stop any *huge surge* from going down the wires into the house . They're easy to hookup but cost $100 - here's an example - https://www.altestore.com/store/enc...lar-solar-surge-protection-device-115v-p9546/

In my case, the panel frames and metal array holding them are grounded to the house ground - e.g. the bare copper wire that runs thru your home wiring. My charge controller ground is hooked to the same ground - basically the metal case I believe. So is the inverter. *I do NOT ground the battery side and for 24vdc I don't think you need that.

Batteries are diy. 8s 24v @100ah. Deligreen bms.
Have only 1 cycle on batteries with bms and might add another set for 24v 200ah before I put them to use.

Just trying to run the necessities when things go south. Charge with both panels and/or generator if need be.

Maybe buy another mppt? Would that be idiot proof? Lol

The charge controller you selected doesn't show a ground in their wiring diagram. Personally, I wouldn't hook the Solar Panel pos or neg to house ground and on the battery side for 24vdc you not at much risk.

So get the solar panels grounded properly and you'll be at least partly there. Maybe others will comment on this specific controller.

 

[12VoltInstalls]

I wouldn't hook the Solar Panel pos or neg to house ground and on the battery side for 24vdc you not at much risk.

However, in my case the batt(-) is grounded to the frame of my rv/camper. So a chafing of the 2/0 cables could create a DC fault, no?
Likewise for the SCC output to batteries where neg(-) is of course a circuit looking for a way to short. Manufacturer sigineer says to let it float.

 

[12VoltInstalls]

This thread is about using “positive ground” SCCs

I am researching buying a PowrMR 60A SCC but it’s “positive ground” which according to some sources it will damage equipment (sounds ludicrous on one and confusing elsewhere) and it’s not covered here on diysolarforum very much at all.

My prior understanding is that “positive ground” merely refers to which terminal is bonded and/or which polarity is “switched” to control voltage. The assumption being that you would install an SCC such as this PowrMR floating and not install its chassis/equipment ’ground’ to the “common negative” of a battery/vehicle chassis.​

Is this^^^ true, or am I wrong?

The following quote seems to be about ‘dirt’ grounding:

Let's step back a bit. A PV array (1 or more panels) should be bonded / grounded - e.g. the panel frames and metal they are fastened to. This has nothing to do with pos and neg coming from the panel. For that, you should have a lightning arrestor (typically before the wires enter the house) that blocks surges down the pos + neg wires and shunts to the ground (a 3rd, separate wire).

Then you have PV pos and neg and a separate ground wire coming to the Charge Controller. On my charge controller, the pos and neg and ground are 3 separate things - so I don't ground pos or neg but rather hook the Charge Controller's ground to the overall ground. If you have 12v panels then not a big deal - but mine is 90v (MPPT) to 120v (VoC) and at that level shock is a real risk

2) Can I use the PowrMR safely “floating?”​

3) the “load” terminals should not be used other than a ‘signal’ to operate a relay?​

4) what if anything am I missing?​

(It bothers my head to not ground the chassis)

Context if you want it, skip if you don’t:
- not flush with cash right now, hence not just buying victron
- my Epevers all seem to be consistent in randomly exhibiting the “high voltage cutout ’bug’” and I need a quick cheap solution
- running eight 100W 4S2P panels, wanting to finally add in my six 315W panels without having the ‘cutout bug’ keep biting me because I’ll be 100% offgrid for most of the next 5 months (summer). I’ve got all the parts now but want to solve the bug to get actual performance indicators instead of beating my head against a wall.

 

[Solarismaximus]

This thread is about using “positive ground” SCCs

I am researching buying a PowrMR 60A SCC but it’s “positive ground” which according to some sources it will damage equipment (sounds ludicrous on one and confusing elsewhere) and it’s not covered here on diysolarforum very much at all.

My prior understanding is that “positive ground” merely refers to which terminal is bonded and/or which polarity is “switched” to control voltage. The assumption being that you would install an SCC such as this PowrMR floating and not install its chassis/equipment ’ground’ to the “common negative” of a battery/vehicle chassis.​

Is this^^^ true, or am I wrong?

The following quote seems to be about ‘dirt’ grounding:

2) Can I use the PowrMR safely “floating?”​

3) the “load” terminals should not be used other than a ‘signal’ to operate a relay?​

4) what if anything am I missing?​

(It bothers my head to not ground the chassis)

Context if you want it, skip if you don’t:
- not flush with cash right now, hence not just buying victron
- my Epevers all seem to be consistent in randomly exhibiting the “high voltage cutout ’bug’” and I need a quick cheap solution
- running eight 100W 4S2P panels, wanting to finally add in my six 315W panels without having the ‘cutout bug’ keep biting me because I’ll be 100% offgrid for most of the next 5 months (summer). I’ve got all the parts now but want to solve the bug to get actual performance indicators instead of beating my head against a wall.

Did ypu ever find an answer to this I have the same pow Mr unit from when I first order my house setup but bought an epever before installing anything and pow Mr just refunded me and said to keep it when I tried to send it back lol. Now installing solar in my van and have this one laying around. Figured i would leave it free floating but would like to know if you found anything out.

 

[12VoltInstalls]

Did ypu ever find an answer to this

It is pos(-) common.
I did answer your pm.

Now installing solar in my van and have this one laying around

As I stated in my pm: don’t load it heavy, don’t ground it, do mount to 5/8 gypsum or concrete wall.
Subjectively, the 630W currently feeding mine is at or slightly over what I’m comfortable driving it with.

For peace of mind take ~$150 ish and just buy an Epever or higher shelf stuff. Victron seems less money than they usedta be fwiw. The thing makes me nervous.
Epever/MPP Solar/Victron/QZRELB does not