Victron 100/20 for 48-volt server rack batteries.

[Jmhai3]

Can't disagree. Manual written by Dutch speakers, so it's not always explicitly accurate without a little reading between the lines.

I kinda read things like a lawyer wrote it who might be trying to screw me...

Worth noting that the BT dongle does make the unit similar to the smartsolar version, it has some limitations:

• The VE.Direct Bluetooth Smart Dongle is not compatible with Windows PC*.
• Synchronised charging is not possible with VE.Smart Networking.
• Stored trends is not supported.
• “Keep SOC” option is not supported for the Battery SOC on reset setting.
• Bluetooth GATT service is not supported.

*NO BT devices work with Windows PC version of VictronConnect.

So the Smartsolar is a much better option all around.
That is what I get buying first and researching later...

Also if I got the BT would just use my phone for the Victron not worry about the laptop.

 

[Brucey]

So the Smartsolar is a much better option all around.
That is what I get buying first and researching later...

Also if I got the BT would just use my phone for the Victron not worry about the laptop.

Ultimately they both deliver the same electrical performance, ve.smart network can be nice for a small system where it talks to a smartshunt and smart battery sense for low temp charge protection but otherwise no biggie.

 

[sunshine_eggo]

So the Smartsolar is a much better option all around.
That is what I get buying first and researching later...

Also if I got the BT would just use my phone for the Victron not worry about the laptop.

Many of us, me included, have paid FAR greater tuition in these DIY solar endeavours.

 

[sunshine_eggo]

Could someone contribute to the questions below?


I read elsewhere that the panels in series could be expanded in parallel.

"If your panels have VOC of about 20, the Victron 100/20 would be quite happy with 4 of those panels in series. And you could do 3 strings of those."

Which would be 4S3P? That would be a total VOC of 80 and 1200 watts, correct?

So, say larger panels (200 watts) with a VOC of 36.5 (example, which I have seen) I could go with 2S2P and would be VOC 73 and 800 watts.

Like I said learning thank you for the help.

Also, can I wire the MPPT output directly to the batteries (as paralleled going to the inverter) or do I have add a busbar.
My cart is getting pretty full.

36.5Voc is potentially too low. These are 60 cell panels and will yield a STC Vmp of about 30V. Panel heating even in mild 20°C conditions can drive this down to the 27V range. Victron MPPT require PV +1V above battery, so it will not perform at its optimal Vmp, but at a higher voltage where current output/power will be reduced significantly.

 

[Jmhai3]

36.5Voc is potentially too low. These are 60 cell panels and will yield a STC Vmp of about 30V. Panel heating even in mild 20°C conditions can drive this down to the 27V range. Victron MPPT require PV +1V above battery, so it will not perform at its optimal Vmp, but at a higher voltage where current output/power will be reduced significantly.

Ok, so as close to optimum in cold temps I may see so in normal operation I am still in the range of the needs of the batteries. I see why you originally said it was a tight band to stay within as I need operation range to stay within the needs of the 48v battery.

You saying PV + 1 = 48v + 1 or the optimum charge voltage for the 48v battery + 1 ?

 

[Brucey]

A non rs450 victron scc needs +5V over battery voltage to start charging and then +1V to continue charging. If your battery is at say 54V, you'll need 59V out of the panels to start charging. That could be tricky in the heat of summer.

 

[sunshine_eggo]

A non rs450 victron scc needs +5V over battery voltage to start charging and then +1V to continue charging. If your battery is at say 54V, you'll need 59V out of the panels to start charging. That could be tricky in the heat of summer.

True, but it helps to distinguish that +5V is Voc and +1V is Vmp

 

[sunshine_eggo]

Ok, so as close to optimum in cold temps I may see so in normal operation I am still in the range of the needs of the batteries. I see why you originally said it was a tight band to stay within as I need operation range to stay within the needs of the 48v battery.

You saying PV + 1 = 48v + 1 or the optimum charge voltage for the 48v battery + 1 ?

If your absorption voltage is 55.2V (common for slow-charge LFP), Vmp needs to be 56.2V. Note that you will still get charging even if the Vmp is lower, but it will operate at 56.2V, which may not be at the maximum power point.



Forcing the panel to run at a higher voltage will produce less power and drops off quickly as you approach Voc.

 

[Jmhai3]

A non rs450 victron scc needs +5V over battery voltage to start charging and then +1V to continue charging. If your battery is at say 54V, you'll need 59V out of the panels to start charging. That could be tricky in the heat of summer.

That is going to be very tricky.
My original question raises it ugly head… Is this worth the effort or just a drop in the bucket even in the best conditions?

 

[Brucey]

That is going to be very tricky.
My original question raises it ugly head… Is this worth the effort or just a drop in the bucket even in the best conditions?

20A is 20A. Certainly for a standby ups system on a cart its prob fine.

 

[Jmhai3]

If your absorption voltage is 55.2V (common for slow-charge LFP), Vmp needs to be 56.2V. Note that you will still get charging even if the Vmp is lower, but it will operate at 56.2V, which may not be at the maximum power point.

View attachment 296012

Forcing the panel to run at a higher voltage will produce less power and drops off quickly as you approach Voc.

That does help to show the range and how it changes. The window of solar opportunity is very small.

 

[sunshine_eggo]

That is going to be very tricky.
My original question raises it ugly head… Is this worth the effort or just a drop in the bucket even in the best conditions?

Per @JoeHam it's do-able. If you can hit somewhere in the 80-88Voc range, you'll have some safety margin. Takes some google-fu, but you can get there.

Just found this:

QCELLS 340W Q.PEAK DUO BLK-G6+ All Black Solar Panel

The Q CELLS Q.PEAK DUO BLK-G6+ 340 is an ideal choice for high-efficiency solar installations, offering superior performance, durability.

ussolarsupplier.com

40.66Voc and 33.94Vmp

2S of these would be tits. They would work from -32°C to hot as shit.

Getting just two of them would be nearly impossible, but it shows that there's stuff out there.

 

[Jmhai3]

Per @JoeHam it's do-able. If you can hit somewhere in the 80-88Voc range, you'll have some safety margin. Takes some google-fu, but you can get there.

Just found this:

QCELLS 340W Q.PEAK DUO BLK-G6+ All Black Solar Panel

The Q CELLS Q.PEAK DUO BLK-G6+ 340 is an ideal choice for high-efficiency solar installations, offering superior performance, durability.

ussolarsupplier.com

40.66Voc and 33.94Vmp

2S of these would be tits. They would work from -32°C to hot as shit.

Getting just two of them would be nearly impossible, but it shows that there's stuff out there.

Larger panels than I would want to mount on the EW rack to roll around, but did find these are a good size and right in the sweet spot you recommended and fit the rack without issue.
Total for 4 would be 83.2 VOC and 70 VMP and if I wanted to add could go two racks (I bought 2 racks on that sale) of 4 with 4S2P.

Do I need to stay within the 20A (of the 100/20) which from what I read 480-watts = 10a so would not want to exceed 960-watts? This part is still fuzzy on the requirement since the EG4-3k AIO gives voltage MIN/MAX need and watt MAX requirement not to exceed.

I don't understand why to buy two with the discount offer of $30 dollars coupon would be more per panel than just buying one with the $24 coupon. shipping is free. for the best deal I will need to buy it four times. I wonder if the coupon is one use and if I try to purchase another it will not allow the coupon.

 

[JoeHam]

My original question raises it ugly head… Is this worth the effort or just a drop in the bucket even in the best conditions?

I would say it’s completely worth it for your use case of what I assume is intermittent useage.

I have a system like that set up for a boat house that requires power to run a 12,000 pound boat lift. That’s a big power draw but since it’s intermittent my 100/20 and 4 100W panels handle the whole thing fine.

The SmartSolar holds all the data until I show up with my phone and remember to check it out. I think it store’s about a month worth of data but I’m too lazy to look it up.

At $82 for the SmartSolar (they used to be more) you get the Bluetooth functionality and Victron quality. I’ve wasted much more money on crappy MPPT’s in the past that aren’t as capable.

At $200 for the original panels you were looking at, plus the Victron it’s far, far cheaper than the crappy stuff I paid ridiculous money for a decade ago.

It’s a great “starter setup” that should last for a decade or more. That’s sufficient value in my book. YMMV.

 

[Jmhai3]

I would say it’s completely worth it for your use case of what I assume is intermittent useage.

I have a system like that set up for a boat house that requires power to run a 12,000 pound boat lift. That’s a big power draw but since it’s intermittent my 100/20 and 4 100W panels handle the whole thing fine.

The SmartSolar holds all the data until I show up with my phone and remember to check it out. I think it store’s about a month worth of data but I’m too lazy to look it up.

At $82 for the SmartSolar (they used to be more) you get the Bluetooth functionality and Victron quality. I’ve wasted much more money on crappy MPPT’s in the past that aren’t as capable.

At $200 for the original panels you were looking at, plus the Victron it’s far, far cheaper than the crappy stuff I paid ridiculous money for a decade ago.

It’s a great “starter setup” that should last for a decade or more. That’s sufficient value in my book. YMMV.

Correct, intermittent use in back yard when weather nice it will be out (day and night) but in bad or a lot of rain/overcast in the forecast will roll under the deck to keep them safe.

I agree that the EW panels (4 for $200) look like a great choice (and price) since I have the racks.

 

[Jmhai3]

Now the question is do I go with 14 (goggle recommended), 12, or 10 AWG wire?
Goggle says the four panels in series would be fine with 14 AWG up to 100 feet with minimum loss.
I don't think I will need more than 50 feet but will need to measure the 2 potential spots this could be located and make sure it can reach both.

 

[sunshine_eggo]

Now the question is do I go with 14 (goggle recommended), 12, or 10 AWG wire?
Goggle says the four panels in series would be fine with 14 AWG up to 100 feet with minimum loss.
I don't think I will need more than 50 feet but will need to measure the 2 potential spots this could be located and make sure it can reach both.

Fuck Google.

6.42A * 1.56 (a safety factor for sizing PV wire) = 10A

14awg will handle 10A, and a voltage drop calculation shows 2.3% drop over 50 ft:

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

If you go over 50 feet, I go with 12awg.

 

[JoeHam]

Agreed.

Don’t try to save money on wiring or OCP (over current protection) devices.

It can be very expensive saving money that way .

 

[Jmhai3]

I went with these panels they had a $25.00 coupon when I ordered, 12awg 50' PV wire (in case I build another rack), and the BT for the Bluesolar SCC.
Already have the breaker/switch, rack, and will build the frame with wheels.

Question... If I build the second rack as the first and connect in parallel it will double the amps 5.68 x 2 = 11.36 x 1.56 = 17.72 amps which would be fine for the 12awg wire, but will I see a true double output at the batteries? up to 20 amps, correct? Is it worth the effort or would it only make sense to do it with a 100/30 SCC?