24 volt van build

sutton · Feb 13, 2024

Hello,

Would this system work for my van (hightop econoline)?

2-SOK 24 volt, 100 AH batteries
rec charge- 20 amp
max charge -70 amp
rec charge- 28.8v-29.2v

3-200 watt, 24 volt solar panels (newpowa) (600 watts total)
pmax 37.2 volts
vmp 5.38 amps

1-Ep Ever MPPT

at 24 volts, rated charge 40a
rated load. 20a
max pv open 138 volts
max pv input 1040 watts

1-Lvyuan 24 volt 4000 w inverter

50 amp fuse from battery to solar charger.

300 amp fuse from battery to inverter

The solar panels would be hooked in parallel.

I think everything will work but I'm not sure about the 300 amp fuse, Should it be 200 amp since the max battery discharge is 200 amps?

I thought of getting an EG4, 24 volt 100 AH battery instead of the SOK because they have a sale right now.

Thank you!

RV8R · Feb 13, 2024

Assuming the 300A fuse is to protect the wire not the battery as it has a BMS.

Also note 175A peak.

330A BMS cut off current.

Without the specs on the inverter, looks like you are right on the edge of demanding 100% current, if not a little more

. What do you expect the inverter to draw from the batteries?

seneysolar · Feb 13, 2024

4000 watts is alot for a van! What are you running off it?

sutton · Feb 13, 2024

RV8R said:
View attachment 195359

Assuming the 300A fuse is to protect the wire not the battery as it has a BMS.

Also note 175A peak.

330A BMS cut off current.

Without the specs on the inverter, looks like you are right on the edge of demanding 100% current, if not a little more . What do you expect the inverter to draw from the batteries?

I could use a 3000 watt inverter, or even a 2000 watt. I am using tools for sharpening and lights. One machine might use 3.5 amps at 120v, some might use more but I only use one at a time. However I want to be able to run a small window unit or mini split air conditioner for about up to an hour or two. If I need air conditioning for longer I will have a gas generator to run the air conditioning.
The 300 Amp fuse would be right off the battery, I heard Will Prowse talk about it. I guess it would be for the wire. Would a 175 or 200 amp fuse be a better pick?

sutton · Feb 13, 2024

seneysolar said:
4000 watts is alot for a van! What are you running off it?

The 4000 watt 24 volt inverter was less expensive than the 3000 watt Giandel inverter. The 3000 watt would be fine. I sharpen out of my van and will be running lights and grinding machines that use 3.5-4 amps at 120v, but I only use one machine at a time. I would like to run a small window air conditioner for an hour during the summer. If I need it longer than that I will have a gas generator to run the air conditioner.

Rocketman · Feb 13, 2024

A couple of things…

If three+ solar panels in parallel, you need a fuse on each panel- there are mc4 fuse holders for this, plus a set of 3-1 mc4 splitters. Use 10awg wire down to the mppt.

Also, consider a shunt based battery monitor. (I use a Victron BMV712). Some bms’s don’t do a good job at tracking low amp loads and charging…. In a van you want to know the status of the state of charge. You may(or may not) want an external display so you don’t need to grab your phone every time you want to check.

Also, I would highly recommend making a drawing with all the equipment, fuses, wire size and length and posting it. Sometimes assumptions get made (on both ends) that would be cleared up with a drawing- plus then you have the drawing for installation and keep it for future troubleshooting.

sutton · Feb 13, 2024

Rocketman said:
A couple of things…

If three+ solar panels in parallel, you need a fuse on each panel- there are mc4 fuse holders for this, plus a set of 3-1 mc4 splitters. Use 10awg wire down to the mppt.

Also, consider a shunt based battery monitor. (I use a Victron BMV712). Some bms’s don’t do a good job at tracking low amp loads and charging…. In a van you want to know the status of the state of charge. You may(or may not) want an external display so you don’t need to grab your phone every time you want to check.

Also, I would highly recommend making a drawing with all the equipment, fuses, wire size and length and posting it. Sometimes assumptions get made (on both ends) that would be cleared up with a drawing- plus then you have the drawing for installation and keep it for future troubleshooting.

I meant to say I was going to put them in series. I was told putting them in series will give enough voltage on cloudy days to charge the batteries. The pmax on the panels I'm looking at is 37.2.

seneysolar · Feb 13, 2024

sutton said:
I meant to say I was going to put them in series. I was told putting them in series will give enough voltage on cloudy days to charge the batteries. The pmax on the panels I'm looking at is 37.2.

But thats only a 100v mppt, 37 x 3 = 111

Rocketman · Feb 13, 2024

Often on RV’s because we park under various shade, it is usually better to wire panels in parallel than series.

If I found the same panels you are looking at they have the following specs:
Voc 46.6v
Vmp 37.2v
Imp 5.32a

With a Voc of 46.6*3 = 139.8 at 25degreesC. You will need a mppt that can handle at least 175v or 200v for max voltage (depending on how cold it is where you live and camp).

I don’t know that line of solar charge controllers but @seneysolar says it is only a 100v controller - but even if it is a 150v one it will die on a cold winter morning.

I see your choices as:
1. Wire panels in parallel. (Yes they will produce power on cloudy days).
2. Change to a 12v panel of the same size - then you must run it in series.
3. Get a different, bigger and more expensive solar charge controller.

Any questions?

Good Luck

Rocketman · Feb 13, 2024

On cloudy days you will often only get 7 to 10% of rated power - thus you will be lucky to get 60watts from a 600w array. Series might gain a few watts over parallel in this situation- but if a tree or a power line casts a shadow on your panels- parallel will be better.

sutton · Feb 13, 2024

seneysolar said:
But thats only a 100v mppt, 37 x 3 = 111

The EPEver MPPT at 24 volts has a voltage range of 26v-108v and a max pv open circuit of 138volts. If I'm reading things right, that should work but I'm still learning.

sutton · Feb 13, 2024

Rocketman said:
On cloudy days you will often only get 7 to 10% of rated power - thus you will be lucky to get 60watts from a 600w array. Series might gain a few watts over parallel in this situation- but if a tree or a power line casts a shadow on your panels- parallel will be better.

ok, thank you!

Bop · Feb 13, 2024

Rocketman said:
A couple of things…

If three+ solar panels in parallel, you need a fuse on each panel- there are mc4 fuse holders for this, plus a set of 3-1 mc4 splitters. Use 10awg wire down to the mppt.

Also, consider a shunt based battery monitor. (I use a Victron BMV712). Some bms’s don’t do a good job at tracking low amp loads and charging…. In a van you want to know the status of the state of charge. You may(or may not) want an external display so you don’t need to grab your phone every time you want to check.

Also, I would highly recommend making a drawing with all the equipment, fuses, wire size and length and posting it. Sometimes assumptions get made (on both ends) that would be cleared up with a drawing- plus then you have the drawing for installation and keep it for future troubleshooting.

Would never recommend running in parallel- you lose a lot of 'poor generating' conditions power doing that (up to 30% more daily total generated power in series than in parallel) but Senysolar is correct, it is rated at 100v PVmax at up to 1040w total output
So 2 or 4 of your 38v Voc panels (2S or 2S2P) would be a better solution if space allows...
Plus with 38v Voc panels, the Vmp is likely around 30-31v, and thats horribly low for a MPPT charge controller most prefer a panel voltage 5v or higher above the charging voltage, on a 24v nominal system, that puts your panels Vmp voltage well under that...

seneysolar · Feb 13, 2024

sutton said:
The EPEver MPPT at 24 volts has a voltage range of 26v-108v and a max pv open circuit of 138volts. If I'm reading things right, that should work but I'm still learning.

Sorry i see now there are 2 versions in the "Extra" line The 4210 and the 4215. Which one do you have?

Rocketman · Feb 13, 2024

sutton said:
The EPEver MPPT at 24 volts has a voltage range of 26v-108v and a max pv open circuit of 138volts. If I'm reading things right, that should work but I'm still learning.

Nope! You will have a dead mppt.

For the max voltage you look at the Voc (Voltage open circuit), With a Voc of 46.6 * 3 panels = 139.8v - you are already over the max range. Plus as solar panels get colder the Voc goes up. That number of 139.8v is at standard conditions 25C or 77F. As it gets colder than that - the voltage rises - if it is warmer the voltage falls.

The max voltage is a never to exceed number or you have a dead piece of equipment.

sutton · Feb 13, 2024

Rocketman said:
Often on RV’s because we park under various shade, it is usually better to wire panels in parallel than series.

If I found the same panels you are looking at they have the following specs:
Voc 46.6v
Vmp 37.2v
Imp 5.32a

With a Voc of 46.6*3 = 139.8 at 25degreesC. You will need a mppt that can handle at least 175v or 200v for max voltage (depending on how cold it is where you live and camp).

I don’t know that line of solar charge controllers but @seneysolar says it is only a 100v controller - but even if it is a 150v one it will die on a cold winter morning.

I see your choices as:
1. Wire panels in parallel. (Yes they will produce power on cloudy days).
2. Change to a 12v panel of the same size - then you must run it in series.
3. Get a different, bigger and more expensive solar charge controller.

Any questions?

Good Luck

yes, the max pv open circuit is 138 volts at 25 degrees C for the EPEver Mppt at 24 volts. I was using VMP instead of VOC. I'm still learning, thank you for the help. It looks like I'll be ok if I wire them in parallel and add a Victron Battery monitor and a battery on/off switch.

sutton · Feb 13, 2024

seneysolar said:
Sorry i see now there are 2 versions in the "Extra" line The 4210 and the 4215. Which one do you have?
View attachment 195375

I was going to get the 40 amp, 4215 and it sounds like parallel will be better for the solar panels.

Bop · Feb 13, 2024

Rocketman said:
On cloudy days you will often only get 7 to 10% of rated power - thus you will be lucky to get 60watts from a 600w array. Series might gain a few watts over parallel in this situation- but if a tree or a power line casts a shadow on your panels- parallel will be better.

Incorrect sorry....
In either case, the panel with the shadow will produce less, but I haven't seen any quality panels this applied for for decades..
I actually did this with my own panels a while back after someone claimed that a single shadow would 'shut down' the entire series array...
This is 3 series panels (the three on the right) being deliberately shadowed and the end results from that arrays controller...

The other disadvantage of using 'low voltage/matched' panels in parallel is your 'bad weather' generation ability drops markedly- yes often down to that 7-10%, while my high voltage array in 'grey 100% overcast will drop down to about 50%, and it takes 'black cloud' 100% overcast with heavy rain before I drop down to 30%... (a low voltage parallel array on either PWM or MPPT will likely not generate anything at all in these conditions)
This was from the old 'campsite' when I was still building the shed- 8AM, 100% grey overcast and showers, with the sun down in the treetops still (look just to the left of the tree by itself- you can see a 'bright circle' with an arrow pointing at it- and my system was already up to 4.4A into the battery bank by that stage...

Series always works better than parallel for total generated daily power... and on small arrays, you want every watt you can suck out of those panels...
(those 3 series panels on my controller will actually start putting 'pulses' of power (about 0.5A about once a second) into the battery bank before the sun is even visible above the horizon... I got a short 1 minute video of it uploaded of it doing just that... no visible disc of the sun visible at all- just running off the 'skyglow' you see just before dawn... A low voltage parallel array won't be generating for an hour or two under the same conditions...)

sutton · Feb 14, 2024

Bop said:
Incorrect sorry....
In either case, the panel with the shadow will produce less, but I haven't seen any quality panels this applied for for decades..
I actually did this with my own panels a while back after someone claimed that a single shadow would 'shut down' the entire series array...
This is 3 series panels (the three on the right) being deliberately shadowed and the end results from that arrays controller...
View attachment 195379
View attachment 195381
View attachment 195385
The other disadvantage of using 'low voltage/matched' panels in parallel is your 'bad weather' generation ability drops markedly- yes often down to that 7-10%, while my high voltage array in 'grey 100% overcast will drop down to about 50%, and it takes 'black cloud' 100% overcast with heavy rain before I drop down to 30%... (a low voltage parallel array on either PWM or MPPT will likely not generate anything at all in these conditions)
This was from the old 'campsite' when I was still building the shed- 8AM, 100% grey overcast and showers, with the sun down in the treetops still (look just to the left of the tree by itself- you can see a 'bright circle' with an arrow pointing at it- and my system was already up to 4.4A into the battery bank by that stage...

View attachment 195386
Series always works better than parallel for total generated daily power... and on small arrays, you want every watt you can suck out of those panels...
(those 3 series panels on my controller will actually start putting 'pulses' of power (about 0.5A about once a second) into the battery bank before the sun is even visible above the horizon... I got a short 1 minute video of it uploaded of it doing just that... no visible disc of the sun visible at all- just running off the 'skyglow' you see just before dawn... A low voltage parallel array won't be generating for an hour or two under the same conditions...)

ok, great. So instead of the EPEver mppt at 40 amps, I should get something like the Victron 250v/60a mppt solar charger which has a max pv open circuit voltage of 250v. My 3, 24 volt, 200 watt solar panels in series are rated at 139.8 @ 25 degreesC (46.6v per panel). Does that sound correct?

sutton · Feb 14, 2024

Rocketman said:
Often on RV’s because we park under various shade, it is usually better to wire panels in parallel than series.

If I found the same panels you are looking at they have the following specs:
Voc 46.6v
Vmp 37.2v
Imp 5.32a

With a Voc of 46.6*3 = 139.8 at 25degreesC. You will need a mppt that can handle at least 175v or 200v for max voltage (depending on how cold it is where you live and camp).

I don’t know that line of solar charge controllers but @seneysolar says it is only a 100v controller - but even if it is a 150v one it will die on a cold winter morning.

I see your choices as:
1. Wire panels in parallel. (Yes they will produce power on cloudy days).
2. Change to a 12v panel of the same size - then you must run it in series.
3. Get a different, bigger and more expensive solar charge controller.

Any questions?

Good Luck

ok, makes sense. So I should upgrade to a Victron 250/60 solar charge controller to be on the safe side. Does that sound right? Thank you!

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