Van solar system - does this make sense?

[josequesado]

So... Here I am once again. After some thinking and research finally ended up buying a Jinergy 450W half cell PERC panel (it's the biggest I could get that would fit and still leave a little room to pass on the side in the roof without stepping on it!).
Also I bought 2 100Ah Lithium batteries from Renogy as they were a good deal and I informed about costumer service in Spain and I didn't find as bad opinions as in the USA. Still, I hope I don't need them of course!

So, I'm now on the hunt for the rest of my system. I've contacted several electricians in the nearby but no one has the smallest idea apparently...
After all the considerations expressed here, I was thinking about:
- Victron SmartSolar MPPT 100/50
- Giandel 2000W 12V inverter (I was trying to get a Xandrex, but everything is out of stock...)

My question remains de DC-DC and the shunt.

As for the DC-DC: A Victron Orion TR Smart can give me 30A for 220€. A Renogy DC-DC can give me 40A for 145€. I've read that the victron might be better at not putting too much stress on my alternator. Does someone have knowledge as why to lose 10amps and spend 75€ more?

As for the Shunt:
- Renogy as a battery monitor (with shunt) for 57€. What would be the advantages of having the Victron Smartshunt over this one?
- Renogy also has a screen that connects directly to the BMS of their batteries for 45€.
I'm no expert as you can tell by my questions... Is there a good reason to spend those extra euros on a smartshunt? I want a durable system but I don't have infinite resources...


Thank you so much once again!

 

[Rocketman]

One reason for getting both the Victron mppt and Smartshunt is you can link a Bluetooth network between the two so the Smartshunt will pass battery temp, voltage and current back to the mppt. If the batteries will be in a different temperature zone as the mppt - this would be critical. (My guess is they will both be in the same temperature for you). The voltage pass back is very nice because it will account for line losses along the way.

With the Victron you can easily set a Lithium temp cut-off in the mppt - so you don’t charge when the batteries are too cold. (That will ruin them).

With the Orion B to B charger, it has a spot to setup a on/off charging switch - you may want to setup that switch and then if you ever start driving when the batteries are cold (below freezing) - switch that switch before starting the van.

I can’t speak to the difference between the two shunts (I have the Victron one - and love it).

If you want to see all the screens and settings for any Victron item - download the Victron Connect app (on android or apple). There is a demo library- select the device you are interested in and you will get some data of a setup - plus you can see all the settings and screens and change any settings you want.

 

[HRTKD]

Victron equipment can work well together - most of it. Some items have no ability to communicate outside themselves so they'll never work well together.

Access to your BMS through a screen isn't all it's cracked up to be. After the first month or so, I rarely look at my BMS. Maybe once every couple of months, just to check the cell balance.

The Victron MPPT 100/50 should work well with that solar panel.

For your DC-DC charger, I would stick with the 30 amp. The higher amp charger may require much larger cabling, which is more expensive and slightly more difficult to install.

 

[Rocketman]

For a van (flat mounted solar panel) I would use the Victron mppt 100/30. In 12v it can handle 440 watts. With your 450 watt panel I doubt you will ever see those last 10 watts - save the money over the 100/50.

 

[josequesado]

One reason for getting both the Victron mppt and Smartshunt is you can link a Bluetooth network between the two so the Smartshunt will pass battery temp, voltage and current back to the mppt. If the batteries will be in a different temperature zone as the mppt - this would be critical. (My guess is they will both be in the same temperature for you). The voltage pass back is very nice because it will account for line losses along the way.

With the Victron you can easily set a Lithium temp cut-off in the mppt - so you don’t charge when the batteries are too cold. (That will ruin them).

With the Orion B to B charger, it has a spot to setup a on/off charging switch - you may want to setup that switch and then if you ever start driving when the batteries are cold (below freezing) - switch that switch before starting the van.

I can’t speak to the difference between the two shunts (I have the Victron one - and love it).

If you want to see all the screens and settings for any Victron item - download the Victron Connect app (on android or apple). There is a demo library- select the device you are interested in and you will get some data of a setup - plus you can see all the settings and screens and change any settings you want.

Yes, it's a van, so the batteries wil have roughly the same temperature. And I read the MPPT also has an internal temperature sensor. Is it not programable based on that temperature?

Thank you so much!

 

[josequesado]

For a van (flat mounted solar panel) I would use the Victron mppt 100/30. In 12v it can handle 440 watts. With your 450 watt panel I doubt you will ever see those last 10 watts - save the money over the 100/50.

I was going for the 50 as there is no 40 amp from Victron... And on the supposition that if ever my panels are short I could expand it later and not buy another MPPT as they last a long time from my understanding, no?

If the MPPT receives more than the 30amp nothing bad happens I understand?

Thank you!

 

[HRTKD]

Yes, it's a van, so the batteries wil have roughly the same temperature. And I read the MPPT also has an internal temperature sensor. Is it not programable based on that temperature?

Thank you so much!

The Victron MPPT will use its internal temperature sensor. If you have the BMV-712 and link the MPPT to the BMV-712 then the MPPT will use the BMV-712's temperature sensor, which is located right on the battery.

If the MPPT is located closely to the battery then maybe it won't matter. But if there is enough distance where the temperatures could vary quite a bit then basing the charging off of the battery temperature, not the MPPT temperature, is the way to go.

 

[josequesado]

The Victron MPPT will use its internal temperature sensor. If you have the BMV-712 and link the MPPT to the BMV-712 then the MPPT will use the BMV-712's temperature sensor, which is located right on the battery.

If the MPPT is located closely to the battery then maybe it won't matter. But if there is enough distance where the temperatures could vary quite a bit then basing the charging off of the battery temperature, not the MPPT temperature, is the way to go.

I understand. There will be like 60 cms apart from each other... So I don't think that'll be the reason.

Woud you opt for a SmartShunt or a BMV-712? Because the 712 gives the same info, no? The difference is the screen and the alarm sound?

 

[HRTKD]

Woud you opt for a SmartShunt or a BMV-712?

It depends on if you want a display on the wall or not. Both can be accessed by Bluetooth from your phone.

 

[Rocketman]

Yes, it's a van, so the batteries wil have roughly the same temperature. And I read the MPPT also has an internal temperature sensor. Is it not programable based on that temperature?

Thank you so much!

Yes the mppt also has an internal temp and will use that if it doesn’t have “better” data.

If you ever decide to expand your panel - you need to match either the current or the voltage- one is for series and one is for parallel (I don’t remember which goes with which right now). That may be hard to do with your one large panel.

As for being over paneled (more solar than the mppt can produce) it will not matter. On my MotorHome I have 800watts of solar (flat mounted) going into a 100/50. The 100/50 can only output 700watts. It’s not a problem- on the rare occasion the panels can produce over 700 watts - the controller just clips the power at 700.
I have only seen it happen once. For it to happen my battery needs to be in bulk mode between 11am and 1pm on a really bright summer day. Usually if the conditions are right to do it the battery has already been charged up by that time.

The screen on the BMV712 is ok - but I found I never used it - I always used my phone. The BMV712 does have a relay that can be used and will beep on certain errors (low battery is one - probably more). No relay on the Smartshunt. I prefer the Smartshunt (no extra wire and display panel).

Good luck

 

[josequesado]

It depends on if you want a display on the wall or not. Both can be accessed by Bluetooth from your phone.

That's a hell of an expensive display for so little pixels! xD

 

[josequesado]

Yes the mppt also has an internal temp and will use that if it doesn’t have “better” data.

If you ever decide to expand your panel - you need to match either the current or the voltage- one is for series and one is for parallel (I don’t remember which goes with which right now). That may be hard to do with your one large panel.

As for being over paneled (more solar than the mppt can produce) it will not matter. On my MotorHome I have 800watts of solar (flat mounted) going into a 100/50. The 100/50 can only output 700watts. It’s not a problem- on the rare occasion the panels can produce over 700 watts - the controller just clips the power at 700.
I have only seen it happen once. For it to happen my battery needs to be in bulk mode between 11am and 1pm on a really bright summer day. Usually if the conditions are right to do it the battery has already been charged up by that time.

The screen on the BMV712 is ok - but I found I never used it - I always used my phone. The BMV712 does have a relay that can be used and will beep on certain errors (low battery is one - probably more). No relay on the Smartshunt. I prefer the Smartshunt (no extra wire and display panel).

Good luck

Yep, my thought was more of if the panel stops working for whatever reason (it's a big panel, I'm not sure how it'll handle vibration and so on...) I can later research for a different combination and who knows find a better combination that gives me more than 500 watts. You think it's pointless?
I have more questions now than this morning now! eheheh!

 

[HRTKD]

That's a hell of an expensive display for so little pixels! xD

If you're the only one that would ever need to know the system statistics and you're fine with connecting your phone then the Smartshunt is a better option.

 

[sunshine_eggo]

BMV can also be programmed via the display in the event that bluetooth is unavailable or inop.

Caution with Victron MPPT. Yes, they have low temp charge protection, but their function is limited. When the unit is first powered on for the day, it takes a snapshot of the temp and then behaves that way for the rest of the day. It must behave this way as internal heating of the unit would influence temp in the unit. If below freezing, it will just wait until it raises to the specified point.

If the temp was +5 above freezing in the morning, but somehow the battery temperature dropped below freezing during the day, the MPPT would NOT stop charging the battery.

MPPT needs live temp data from:
VE.smart networked smart battery sense, BMV-712 or smartshunt
Temp from GX connected BMV-7XX.

 

[josequesado]

BMV can also be programmed via the display in the event that bluetooth is unavailable or inop.

Caution with Victron MPPT. Yes, they have low temp charge protection, but their function is limited. When the unit is first powered on for the day, it takes a snapshot of the temp and then behaves that way for the rest of the day. It must behave this way as internal heating of the unit would influence temp in the unit. If below freezing, it will just wait until it raises to the specified point.

If the temp was +5 above freezing in the morning, but somehow the battery temperature dropped below freezing during the day, the MPPT would NOT stop charging the battery.

MPPT needs live temp data from:
VE.smart networked smart battery sense, BMV-712 or smartshunt
Temp from GX connected BMV-7XX.

So, a Smart Battery Sense would be "enough" to prevent this from happening, right?

 

[sunshine_eggo]

SmartSolar MPPT + SmartBattery Sense in a VE.Smart network provides the MPPT with accurate/live voltage/temperature data.

 

[josequesado]

So, after many comes and goes I came up with a sketch of the system. If any good hearted is willing to take a look at it, I would much appreciate it.
The mm are in fact mm^2, I don't know if most of you are american... Maybe this is a weird representation for you. I can remake it with AWG!
As for the 12 volt loads, I don't have all of them, that's why some are blank; as for the heater, it comes with a fused cable, so nothing to do or check there.

Where would I need breaks on this circuit?
Do you need to ground this circuit? If so, how do you size the grounding? I read some people say it's pointless grounding, and some others say you must do it, so I'm quite lost.
Another stupid question, how do you calculate the fuse for the batteries? I went with 60A as a faith guess, but I can't find a way of being sure of the math.


Thanks again!!

 

[HRTKD]

A 60 amp fuse is not going to cut it. The 2000 watt inverter will blow right through that fuse.

2000 watt / 12 volts / .85 (inverter efficiency) * 1.25 (fudge factor to prevent nuisance trips) = 245 amps.

 

[12VoltInstalls]

how do you size the grounding? I read some people say it's pointless grounding, and some others say you must do it, so I'm quite lost.

You are confusing “neg(-)” aka “ground,” versus a ground rod driven into the ground, or perhaps versus an equipment chassis ground.
One it won’t operate without, one is necessary in certain circumstances, and the latter is not part of your load circuits but is nearly always required.

Which are you referring to?

Do you need to ground this circuit?

the negative connection to the battery is a “ground.” The case of the 2000W inverter should usually be “grounded” to the battery neg(-) but you should review the documentation from the manufacturer for guidance. You also didn’t include any distribution of the 120VAC from the inverter- but that may not be needed for your use.

 

[sunshine_eggo]