Van solar system - does this make sense?

[josequesado]

Hi there!

First time posting here... I'm building a van with my partner and the electrics are our biggest headache so far. We are noobs on the subject and so, we would much appreciate if someone could check if our solar setup makes sense or if you would change something.

Our system should be:
- 1x 450W; 24v Solar Panel (Vmp: 41,5V / Cmp: 10,85A) (Link)
- 1x MPPT charger: 20A (Link)
- 2x Lithium batteries 100Ah; 12v (Link) (thinking of expanding it to 300Ah when the budget is available and if needed).
- 1x DC-DC charger to use our alternator (we have a 2017 Mercedes Sprinter) (Link)
- 1x Inverter/charger 2000W; 12v (we are at the moment searching for one that is available in Spain that is Lithium compatible so that we can also charge from shore power).


Is there something that does not fit or that you would do differently?
We saw the DC-DC charger from Renogy but ditched it as it did not look like it would be as efficient as having 2 separete components for solar and alternator.


Thanks for any input!

 

[sunshine_eggo]

Hi there!

First time posting here... I'm building a van with my partner and the electrics are our biggest headache so far. We are noobs on the subject and so, we would much appreciate if someone could check if our solar setup makes sense or if you would change something.

Our system should be:
- 1x 450W; 24v Solar Panel (Vmp: 41,5V / Cmp: 10,85A) (Link)
- 1x MPPT charger: 20A (Link)

The 20A on a MPPT is the CHARGE current, not the current from the panel:
12V * 20A = 240W

If you want to be able to capture all the potential from the 450W panel, you'll want a charge controller with:

450/12 = 37.5A charge current

- 2x Lithium batteries 100Ah; 12v (Link) (thinking of expanding it to 300Ah when the budget is available and if needed).
- 1x DC-DC charger to use our alternator (we have a 2017 Mercedes Sprinter) (Link)
- 1x Inverter/charger 2000W; 12v (we are at the moment searching for one that is available in Spain that is Lithium compatible so that we can also charge from shore power).

Don't get hung up on "lithium compatible." If the charger can be configured for 14.2-14.4V absorption and 13.6V float, you're good.

One thing to watch for is the absorption period. Some units like AIMS or Sigineer have an absurdly long absorption time based on 10X of some portion of the bulk charge.

Something to consider is how much idle power do they use, i.e., even if you're not using AC power, if the unit is on, it's burning power. Let's say a 2000W unit uses 20W:

20W * 24hr = 480Wh

Your 200Ah@12.8V = 2560Wh

Just having the inverter on 24/7 burns:

480/2560 = 19% of your battery capacity.

Some have low power modes that reduce this a notable amount, BUT that is only if you have no AC loads of any kind. If you have any loads at all, low power mode won't work.

Another thing to consider is noise. If the fans run all the time even under low power conditions, you will likely be dissatisfied.

Is there something that does not fit or that you would do differently?

Only as mentioned above.

We saw the DC-DC charger from Renogy but ditched it as it did not look like it would be as efficient as having 2 separete components for solar and alternator.

You have done well, grasshoppa.

The Renogy combo unit has some pretty big limitations and wouldn't even work with your selected panel (25Voc max).

 

[rmaddy]

The 20A MPPT is too small. With a 450W panel at 12V you can get up to 450W / 12V = 37.5A. But with the panel mounted flat on the roof of the van you won't get 100% so a 30A MPPT would be a good choice. The 20A would only support a maximum of about 280W when the battery is full.

While I have no experience with Renogy, a lot of people on this forum have reported a lot of support issues recently. You may want to consider other options.

Since you are looking at a Victron DC-DC charger, you may want to consider one of their Smart charge controllers. The 100/30 would work well for you with that solar panel.

While there are many choices for a 12V 2000W inverter, something like the Victron MultiPlus Compact 12V/2000W would be a great choice. It is an inverter/charger with built in automatic transfer switch which makes it simple to setup with shore power charging.

Buena suerte

 

[josequesado]

Just to signal that the panel is a 24 volt even though the batteries are 12 volt.

I thought that having a 24 volt panel with an MPPT charger would give me more Amps at 12 volt after the charger. This does not work this way? And is my charger under dimensioned even if my panel is 24 volt?

Thanks a lot! I'm reviewing the rest of the feedbak!

 

[josequesado]

I was not clear enough I guess...

Everything would be 12 volt except for some kitchen appliance and the laptop charger. So the inverter would be off most of the time, meaning the idle consumption is not as important!

 

[rmaddy]

Your panel isn't 12V or 24V. With an MPPT charge controller that's irrelevant. The panel Voc and Vmp matter. As long as the Vmp is 5V higher than your battery voltage then the MPPT can charge the battery. Your panel Vmp is well over 17V.

The MPPT will take the current panel wattage (Vmp x Imp) and convert that to the battery voltage giving you the corresponding charging current.

Let's say you are getting 375W at the moment and your battery is currently at 13.4V. The charge current will be 375W / 13.4V = 28A. If you bought a charge controller with a max charge current of 20A then you would be losing out on 8 of those 28A in that example.

 

[josequesado]

The 20A MPPT is too small. With a 450W panel at 12V you can get up to 450W / 12V = 37.5A. But with the panel mounted flat on the roof of the van you won't get 100% so a 30A MPPT would be a good choice. The 20A would only support a maximum of about 280W when the battery is full.

While I have no experience with Renogy, a lot of people on this forum have reported a lot of support issues recently. You may want to consider other options.

Since you are looking at a Victron DC-DC charger, you may want to consider one of their Smart charge controllers. The 100/30 would work well for you with that solar panel.

While there are many choices for a 12V 2000W inverter, something like the Victron MultiPlus Compact 12V/2000W would be a great choice. It is an inverter/charger with built in automatic transfer switch which makes it simple to setup with shore power charging.

Buena suerte

Yep... Victron is regarded as the best, and without a doubt the most expensive. THat's why I was looking for reliable solutions elsewhere!

 

[John Frum]

I was not clear enough I guess...

Everything would be 12 volt except for some kitchen appliance and the laptop charger. So the inverter would be off most of the time, meaning the idle consumption is not as important!

To add to what @rmaddy said.
Renogy support is worse than their products and some of their products kinda suck.

 

[josequesado]

To add to what @rmaddy said.
Renogy support is worse than their products and some of their products kinda suck.

Oh my... Ditching Renogy by the experts opinion.

Even their batteries are bad?

Read somewhere a comparison with battleborn and they looked legit.

The MPPT we will get a victron one. As for the inverter/charger... Any brand recommendation that is not as expensive and that you consider reliable?

 

[John Frum]

The Renogy batteries are not popular on the forum so their is little feedback to go on.
The internet tells me that Spain uses 230VAC@50hz.
I'm not familiar with the inverter options for your side of the pond.
@rmaddy may be able to help here with battery and inverter options and in general.

 

[rmaddy]

@rmaddy may be able to help here with battery and inverter options.

Not really. I do know that Victron has a 12V/2000VA inverter with 230V output but I'm not up on any other, non-Victron, options. As for battery, again, I have no knowledge of European options since I'm in the States. I'm happy with my SOK batteries but I don't know if that's an option in Spain. It's tough to get them here.

 

[josequesado]

The Renogy batteries are not popular on the forum so their is little feedback to go on.
The internet tells me that Spain uses 230VAC@50hz.
I'm not familiar with the inverter options for your side of the pond.
@rmaddy may be able to help here with battery and inverter options.

Thanks a lot for your input! The plan is to circle the globe, so we might need some fancy input for shore power to be compatible with multiple configurations... Still a lot of books to read I guess!

Have a great day!

 

[John Frum]

Not really. I do know that Victron has a 12V/2000VA inverter with 230V output but I'm not up on any other, non-Victron, options. As for battery, again, I have no knowledge of European options since I'm in the States. I'm happy with my SOK batteries but I don't know if that's an option in Spain. It's tough to get them here.

Oops.

 

[John Frum]

Thanks a lot for your input! The plan is to circle the globe, so we might need some fancy input for shore power to be compatible with multiple configurations... Still a lot of books to read I guess!

Have a great day!

Ok, that is very cool and interesting problem.
Will start thinking about it.

Universal shore power... the hamster between my ears has gotten on the wheel.

 

[rmaddy]

Ok, that is very cool and interesting problem.
Will start thinking about it.

Universal shore power... the hamster between my ears has gotten on the wheel.

That's going to take the right kind of charger that can handle a range of input voltages and frequencies in addition to the various physical plug standards.

Not trying to push Victron but pointing it out as one example. Their 12V/2000VA MultiPlus inverter/charger with 230V output does support 187-265VAC input at 45-65Hz. That would cover European 230V/50Hz as well as US 240V/60Hz. The latter can be found at 50A campground hookups. 30A hookups wouldn't work since those are 120V.

 

[John Frum]

That's going to take the right kind of charger that can handle a range of input voltages and frequencies in addition to the various physical plug standards.

Not trying to push Victron but pointing it out as one example. Their 12V/2000VA MultiPlus inverter/charger with 230V output does support 187-265VAC input at 45-65Hz. That would cover European 230V/50Hz as well as US 240V/60Hz. The latter can be found at 50A campground hookups. 30A hookups wouldn't work since those are 120V.

Also wouldn't handle "moochdocking".
"moochdocking" is typically just parking in your friend's driveway and running a nema-5-15 extension cord from the house to the vehicle.

NEMA connector - Wikipedia

en.wikipedia.org

 

[rmaddy]

Also wouldn't handle "moochdocking".
"moochdocking" is typically just parking in your friend's driveway and running a nema-5-15 extension cord from the house to the vehicle.

NEMA connector - Wikipedia

en.wikipedia.org

I have support for 30A shore power at 120V. With two different plug adapters I can plug into 15A/120V or 50A/240V.

I don't know what would be needed to allow a 120V connection to work with something that needs more like 230 or 240V.

But, in the last three months of living in my trailer full-time I have yet to plug into shore power. My solar has been more than enough so far.

With sufficient battery capacity, good solar, and good power use management, you can avoid the whole issue.

 

[HRTKD]

Oh my... Ditching Renogy by the experts opinion.

Even their batteries are bad?

Read somewhere a comparison with battleborn and they looked legit.

The MPPT we will get a victron one. As for the inverter/charger... Any brand recommendation that is not as expensive and that you consider reliable?

Friends don't let friends buy Renogy.

I do mostly boondocking. A trip to a town where a replacement solar charge controller, inverter, etc. would be many hours. I need reliability and that's why I went with Victron.

 

[ianganderton]

Epever make well regarded cost effective solar charge controllers

Their inverters also seem decent quality but maybe not quite as cost effective.

I’m linking my epever SCC and inverter together with the MT75 monitor

Only problem you may have with one big panel is pooling of water and resulting dirt which = shade. You will just need to ensure you have an access ladder for cleaning.

Several smaller panels in parallel are more shade resistant but it certainly doesn’t eliminate the problem

With a good solar array (put as much up there as you can, it’s the best value component) and dc to dc charging you won’t need AC charging

If you do AC chargers aren’t expensive. You aren’t planning to run high AC loads. If you are plugging in AC it’s 24/7 so the charger can be relatively low amps/watts

If you did find you need AC most of the world uses 230/240v so just get a cheap charger for the location you are in. If you find yourself in the us or one of the very few other countries that uses 110 then sort that there then

And look at getting a dc laptop charger. Much more energy efficient ?

 

[Rocketman]

One other item that you may want to consider is adding a Victron Smartshunt to keep track of how full your batteries are. If you use the Victron SCC (solar charge controller) - use the Victron smart shunt. (There is a Bluetooth network that will transmit voltage and current and temperature back to the SCC).

I know on Victron’s Multiplus inverter/chargers they can go between 50 and 60 Hz (the larger ones) check to see if the size of ones you are looking at can do that.

When you get to the states, you could add an auto transformer. I believe that can take our 120v and convert it to 240v 60Hz. If your inverter/charger can handle that power - you would be good to go (after making the proper cord) or you may not be with the difference in the Hz.

You may be better off with a seperate inverter and a separate charger. That way you always have “your” proper voltage inside your rig, and at worst- you change the charger for the different powers.