Portable Solar Setup for 48 Volt System. Need voltage boost.

[bellevent]

We are building a portable 48 volt system (6000 watt output). We need 120 volts from the panels to charge the batteries. We want a small solar panel setup that travels well. Is there a booster that will boost a small panel setup (2 or 3 110 watt panels) up to the voltage we need? We have not purchase panels as of yet. Trickle charge is fine for our application. Pardon our ignorance. We are now to this.

 

[12VoltInstalls]

330W is like 20/25% of what you need, right? Just guessing re: the 6000W output statement.

Two 300W panels in series will be somewhere around 90V which will charge 48V just fine and be ~3000Wh a day in good sun.

 

[bellevent]

The manual says the input of an EG4 6000XP needs to see a minimum of 120 volts PV to wake up the charger when charging a 48 volt battery. That's around 1200 watts. Is there a booster that will raise voltage on panels?

 

[Ampster]

The manual says the input of an EG4 6000XP needs to see a minimum of 120 volts PV to wake up the charger when charging a 48 volt battery.

Larger panels will have more voltage but what ever you use, you will still need to string them in series. I would also figure on running more that the minimum to find a sweet spot on the MPPT charge controller. Voltage of panels drops as temperature increases so you should allow for that as well.

 

[mattleonard]

I have a similar situation - my hesitation on buying a 6000xp is that 120v voltage minimum for the MPPT. I would like to be able to have a single portable panel (meaning, easily moved by one person) to recharge, even if it takes several days at a slower rate. Here are the options I've found:

1. Rich Solar makes 200 watt rigid "24v" panels - with a Voc of ~45 volts. 3 of those in series will get you solidly over the 120v minimum MPPT voltage. They panels are reasonably portable (~26 lbs), but you'll still need to set up 3 of them. I have built little PVC kick-back frames for them, and they can be deployed very quickly.
   
   
2. There are various flexible panels that have ~35 Voc. You could get 4 of those, pair up two each with some hinged frames (PVC or similar), and then be at ~140 Voc, with 2 deployable frames under 25lbs each.
   
   
3. Get a separate MPPT wired to your battery bank - Victron units only need 5 volts above your battery/system voltage (so, a 48v system would need 53v Voc). This could let you use just 2 of those panels (or just 1 if you are on a 12/24v system). This is likely what I'll do - with an Anderson SB50 cable from the battery, so I don't have to bring the MPPT if I'm not planning to be charging (keeps the whole system more portable)
   
   
4. Renogy makes a voltage booster MPPT - that is more akin to option 2, but would allow even smaller panels / lower Voc.

 

[Ampster]

If the OP is going to go with a separate MPPT controller, is there any advantage of spending the money on an All In One inverter unless he has already purchased it.

 

[12VoltInstalls]

There are various flexible panels that have

I’d never touch those with a 9-1/2 pole

Renogy makes a voltage booster

…nor that brand

input of an EG4 6000XP needs to see a minimum of 120 volts PV to wake up the charger

I’d just get an MPP or go to Victron or something. I’d still want more panels, too, but if you’re set on using so few watts that finding something better isn’t attractive I’d just change brands; lucky strike, chesterfield, benson&hedges….

 

[mattleonard]

If the OP is going to go with a separate MPPT controller, is there any advantage of spending the money on an All In One inverter unless he has already purchased it.

This is my debate - but in the end, a 6000xp along with a smaller Victron MPPT (I already own a few) is still a cheaper option than many other stand-alone inverter options that will get you 6,000 watts split-phase (if that's what you need). Sure, there are other factors to consider and balance too.

 

[A.Fenderson]

We are building a portable 48 volt system (6000 watt output).

I'm guessing OP is referring to 6kW of inverter output, not PV input, otherwise I really would like to know about their 6kW "small solar panel setup that travels well".

In my search for a voltage-boosting MPPT charge controller, I ran across this BougeRV model, which is actually a buck-boost controller with the widest "low-voltage" input range I've yet seen on an MPPT, with 25 Amp PV input and 20 Amp charging output. Unfortunately I can't yet find any reviews or even mentions of it anywhere, really. The manual also states that there is a 40 Amp version capable of handling 50 Amps of PV input, but Google has never heard of the 40 Amp version. The 20 Amp version is also sold on Amazon, but it's a multi-product listing and zero of the posted reviews apply to this buck-boost controller.

For OP or anyone wanting the ability to use from one to just a few panels to charge, this buck-boost MPPT would seem to be just the ticket, but that precludes the simplicity of routing everything into an all-in-one inverter like the EG4 6000XP that was mentioned, and would mean piecing together a custom setup with more components.

The manual says the input of an EG4 6000XP needs to see a minimum of 120 volts PV to wake up the charger when charging a 48 volt battery. That's around 1200 watts.

I'm not seeing where you got the 1200 Watts number, but as regards specifically the EG4 6000XP (to my understanding as a noob--someone please correct me if I'm wrong), at the minimum of 120 volts PV input, along with anything between greater-than-zero current all the way to the max current rating (17 Amps), the unit will charge the battery, albeit very slowly for low PV input current. The 6000XP would charge the battery at a maximum of 2040 Watts if you were somehow able to feed it the max 17 Amps of PV at the minimum 120V PV, but by my calculations that would look something like having between 3 and 4 strings of serial-connected typical (~24V Voc / ~5 Amp) 100 Watt panels with 5 panels per string, or in other words 15 to 20 panels @ 100W each.

The only thing I know of that might work to stick with something like the EG4 6000XP or similar and still charge with just a few ~100W typical panels would be to put a DC-DC boost converter on the PV line between the panels and the MPPT input of the all-in-one inverter, but for one thing I can't find any with the proper input and output ranges that look like they're not total junk, and for another thing I'm guessing other forum members could give me a thousand reasons why that's a bad idea.