Charging EF Delta Pros from 48V Batteries: How to ensure overcurrent protection?

[JamesTheCrow]

Hi!

Long time lurker, first time poster.

Context:
I have two Ecoflow Delta Pros that I connect to our house via the Double Voltage Hub (DVH) and a transfer switch.

I'd like to charge my Ecoflow Delta Pros from my 48V server rack batteries using each Delta Pro's PV input (XTi 60 connector). Given that the Delta Pro's SCC limits amperage to somewhere between 15A and 16A, I should be able to charge each Delta Pro with somewhere between 700W and 750W.

I've already browsed through related posts but couldn't find what I'm looking for.

Where I need help:
What stumps me is how to protect each Delta Pro from the potential 100A of each server rack battery. I'd like to connect 3x 48V 100 Ah server batteries in parallel. If I'm not mistaken (I'm a DIY solar beginner), that means that these batteries - when connected in parallel - can output up to 300A (3x 100A). And while each Delta Pro's SCC limits input current to about 16A, I want to put something between the batteries and each Delta Pro to make sure that the Delta Pros are protected in any case.

1) Do I need a T-Class fuse between batteries and each Delta Pro for this?
2) If so: would it have to be rated for 1.25 x 300A at least? Which rating should it have? 16A?
3) Is there an alternative to using T-Class fuses?
4) Do I need anything else in terms of overcurrent protection between the batteries and the Delta Pros?

Thanks for reading.

James

 

[Wakintx]

BATTERIES TO SCC? why,, not a solar panel. Its a battery. SORRY, this surface tablrt keeps going upper case.

OK, im goi to look at charging inputs for it

 

[JamesTheCrow]

BATTERIES TO SCC? why,, not a solar panel. Its a battery. SORRY, this surface tablrt keeps going upper case.

OK, im goi to look at charging inputs for it

Yeah, I know the feeling. I'm not much of a phone/tablet typer, myself.

As to your question:
I plan on charging my server rack batteries via solar. And use the server rack batteries to charge the Delta Pros to get around the 1800W PV input limitation per Delta Pro. Feel free to take a look at my "About" section where you can see where we're at in our transitioning to offgrid journey.

 

[Wakintx]

Yeah, I know the feeling. I'm not much of a phone/tablet typer, myself.

As to your question:
I plan on charging my server rack batteries via solar. And use the server rack batteries to charge the Delta Pros to get around the 1800W PV input limitation per Delta Pro. Feel free to take a look at my "About" section where you can see where we're at in our transitioning to offgrid journey.

So, i looked at the charging options of the delta pro and i frowned... a cigarette plug. UGH. For a portable thing i assumed better. Not my kind of equipment but i was interested to see the answer

 

[JamesTheCrow]

So, i looked at the charging options of the delta pro and i frowned... a cigarette plug. UGH. For a portable thing i assumed better. Not my kind of equipment but i was interested to see the answer

The cig plug is one of many options. In my original post, I was referring to the XTi 60 input, aka the Delta Pro's PV input. Depending on how you put your solar array strings together, it allows for quite a solid amount of input wattage given the overall system sizing. For the application I'm envisioning (see original post), that would amount to 15A x 48V = 720W per Delta Pro. Since both legs of my house's electricity usually pull between 500W and 700W (individual peaks notwithstanding), this is enough for my purposes, as long as the batteries start with full-ish SOC and are getting (re)charged by solar.

Clear as mud?

 

[Bud Martin]

Delta pro circuit will only allow it to draw 15A of input current from the power source even though the power source can supply more than 15A. which mean at 48V and with 15A limit you will only get 48V x 15A = 720W from your 48V source, to get more power you will need to raise the Voltage up but not to exceed the max input Voltage of the Delta, you can get boost converter that can deliver 15A and higher Voltage to get more power.

 

[DarrylG]

Bud is right. The Delta Pro will provide a limit. Depending on your wiring, having a fuse sized to your wire is still a good idea.

Charging with 48v through the DC Input will work well, just be sure to use an XT60i connector where the center pin is negative. Check out: https://diysolarforum.com/threads/ecoflow-delta-pro-charging-from-a-switching-power-supply.43369/ Or just use your solar charging cable from Ecoflow which has this connected already.

The Ecoflow Delta Pro can handle up to 150 volts on this input. You could connect two of these 48v batteries in parallel to charge even faster. I think three batteries in parallel would exceed the 150 volt limit as the 48v batteries are generally near 52 volts full charged.

 

[Bud Martin]

Bud is right. The Delta Pro will provide a limit. Depending on your wiring, having a fuse sized to your wire is still a good idea.

Charging with 48v through the DC Input will work well, just be sure to use an XT60i connector where the center pin is negative. Check out: https://diysolarforum.com/threads/ecoflow-delta-pro-charging-from-a-switching-power-supply.43369/ Or just use your solar charging cable from Ecoflow which has this connected already.

The Ecoflow Delta Pro can handle up to 150 volts on this input. You could connect two of these 48v batteries in parallel to charge even faster. I think three batteries in parallel would exceed the 150 volt limit as the 48v batteries are generally near 52 volts full charged.

Must be a typo, you mean series connections.

 

[DarrylG]

Must be a typo, you mean series connections.

Oops. Not typo, but Brain-farto. ? I edited the original. Thanks!

 

[JamesTheCrow]

Thank you, guys, much appreciated.

 

[farmhand]

Delta pro circuit will only allow it to draw 15A of input current from the power source even though the power source can supply more than 15A. which mean at 48V and with 15A limit you will only get 48V x 15A = 720W from your 48V source, to get more power you will need to raise the Voltage up but not to exceed the max input Voltage of the Delta, you can get boost converter that can deliver 15A and higher Voltage to get more power.

In all my research on my project overpanelling an Eco Max, indeed it caps at 800w on a 2400w array. However, I remember many comments in posts where folks basically say that panels don't push current so operpaneling a MPPT is ok, but that batteries do push current and could fry a MPPT is over the rated input. I didn't go down that rabbit hole on the batteries as it's N/A in our setup, just wanted to let you know there is such a hole out there

 

[Bud Martin]

In all my research on my project overpanelling an Eco Max, indeed it caps at 800w on a 2400w array. However, I remember many comments in posts where folks basically say that panels don't push current so operpaneling a MPPT is ok, but that batteries do push current and could fry a MPPT is over the rated input. I didn't go down that rabbit hole on the batteries as it's N/A in our setup, just wanted to let you know there is such a hole out there

I am sure what you mean by 'could fry a MPPT is over the rated input.', the load dictates how much current it will draw from power source, I.E. house AC outlet can supply 120V 15A (1800W of power), so if you plug in 100W bulb, it will only draw 0.83A (100W) from the outlet.
The ECo will not draw more than its input current limit.
I have Bluetti that has 8A of input current limit, I charge it with 12V 100Ah LiFePO4 battery through boost converter to around 24V to get close to 200W charging from 12V battery, without booster I can only charge to a little over 90W.

 

[farmhand]

The internal battery is charged by the MPPT Solar charger controller, the inverter draws current from the battery, so I am sure what you mean by 'could fry a MPPT is over the rated input.', the load dictates how much current it will draw from power source, I.E. house AC outlet can supply 120V 15A (1800W of power), so if you plug in 100W bulb, it will only draw 0.83A (100W) from the outlet.

Bud,
Are you saying running batteries to the DC input of a MPPT shouldn't damage it? If so this will make my life easier as I need to add a few batteries in the outhouse where the PV line routes thru, so to give some extra power in the evenings. It would save a ton of money (and noise from those dang fans) if I can add batteries inline and not smart Eco batteries. I have a charge controller for the outhouse, and can split the PV array output at the outhouse (1200w for the ECO, 1200w for the outhouse battery bank). I would just have to put a photocell controller to close the relay for those outhouse batteries once it's dark.....

 

[Bud Martin]

Bud,
Are you saying running batteries to the DC input of a MPPT shouldn't damage it? If so this will make my life easier as I need to add a few batteries in the outhouse where the PV line routes thru, so to give some extra power in the evenings. It would save a ton of money (and noise from those dang fans) if I can add batteries inline and not smart Eco batteries. I have a charge controller for the outhouse, and can split the PV array output at the outhouse (1200w for the ECO, 1200w for the outhouse battery bank). I would just have to put a photocell controller to close the relay for those outhouse batteries once it's dark.....

I have Bluetti that has 8A of input current limit, I charge it with 12V 100Ah LiFePO4 battery through boost converter to around 24V to get close to 200W charging from 12V battery, without booster I can only charge to a little over 90W, with this setup I can run my Bluetti at longer run time due to the added external battery.

 

[Bud Martin]

Charging with boost converter.

 

[farmhand]

I have Bluetti that has 8A of input current limit, I charge it with 12V 100Ah LiFePO4 battery through boost converter to around 24V to get close to 200W charging from 12V battery, without booster I can only charge to a little over 90W, with this setup I can run my Bluetti at longer run time due to the added external battery.
View attachment 135902

You're my hero Bud, awesome!
My charge controller is 12/24v for the outhouse battery bank. So I plan to go with 24v, and now hope I can from the 10Amp rated "load" output terminals on the controller itself. Below is a link to the controller FYI. I plan to change the PV box for 12panels feed the Eco & 12 feed the outhouse battery bank.

https://www.amazon.com/gp/product/B08BC567VZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[Bud Martin]

You're my hero Bud, awesome!
My charge controller is 12/24v for the outhouse battery bank. So I plan to go with 24v, and now hope I can from the 10Amp rated "load" output terminals on the controller itself. Below is a link to the controller FYI. I plan to change the PV box for 12panels feed the Eco & 12 feed the outhouse battery bank.

https://www.amazon.com/gp/product/B08BC567VZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Sorry i do not understand what you mean on this statement "now hope I can from the 10Amp rated "load" output terminals on the controller itself."

Also "FYI. I plan to change the PV box for 12panels feed the Eco & 12 feed the outhouse battery bank." So you have EcoFlow and now you are going to get another MPPT from Amazon?
I do not quite understand your statement and the setup.

 

[farmhand]

Sorry i do not understand what you mean on this statement "now hope I can from the 10Amp rated "load" output terminals on the controller itself."

Also "FYI. I plan to change the PV box for 12panels feed the Eco & 12 feed the outhouse battery bank." So you have EcoFlow and now you are going to get another MPPT from Amazon?
I do not quite understand your statement and the setup.

Sorry for the misunderstanding.

now hope I can from the 10Amp rated "load" output terminals on the controller itself

Rephase; After learning I am able to add batteries to charge the Eco after dark, I now hope I can use the outhouse-battery-bank's charge controller's 10A rated "load" output directly to the Eco.

I bought this above noted charge controller for my initial idea for my whole DIY system to be in the Outhouse. Now that we have the ECO, I might as well use this previously purchased controller for the battery bank I plan to put out there.
Currently, the 2400w is feeding the Eco which is wasting a lot of power mid-day. So I will plan to change this setup to feed 1200w to the Eco & 1200w to the outhouse eco-recharge-battery-bank, once it's built.

 

[Bud Martin]

Sorry for the misunderstanding.

Rephase; After learning I am able to add batteries to charge the Eco after dark, I now hope I can use the outhouse-battery-bank's charge controller's 10A rated "load" output directly to the Eco.

I bought this above noted charge controller for my initial idea for my whole DIY system to be in the Outhouse. Now that we have the ECO, I might as well use this previously purchased controller for the battery bank I plan to put out there.
Currently, the 2400w is feeding the Eco which is wasting a lot of power mid-day. So I will plan to change this setup to feed 1200w to the Eco & 1200w to the outhouse eco-recharge-battery-bank, once it's built.

You have lots panel power.
I see, the OOYCYOO Load output is rated at 10A (not sure it can sustain 10A continuous or not), the EcoFlow can draw up to 15A (the limit) so it may overload it, 24V x 15A = 360W of charging.
Are you going to use the OOYCYOO to run anything else beside charging its battery? 1200W is lots of power. Will 1200W for ECO be enough to keep the ECO's battery full while using the loads on the ECO at the same time during the day?

 

[farmhand]

You have lots panel power.
I see, the OOYCYOO Load output is rated at 10A (not sure it can sustain 10A continuous or not), the EcoFlow can draw up to 15A (the limit) so it may overload it, 24V x 15A = 360W of charging.
Are you going to use the OOYCYOO to run anything else beside charging its battery? 1200W is lots of power. Will 1200W for ECO be enough to keep the ECO's battery full while using the loads on the ECO at the same time during the day?

I could go with the OOYCYOO load output closing a relay - but use a step-up transformer. The Eco Max is 100v max, and will draw up to 800w. I figure at 50% drain, I would only need 4 AMG deep cycles ($400) compared to a LIFEPO4 which wouldn't work in the winter in an outhouse in Ohio.
Our whole cabin, less the mini split averages 250w, peaking at 450w under idle. Of course a microwave & what not add up, but 99% of the day we are <450w. The minisplit is 300w, 240v and not tied in yet. I have a 2kvA & 5 kvA 120/240v transformer sitting around I can use for that someday.

As to your last question, I should go pull the fuses for half the array (3-strings) and see what the eco does under these not-so-great winter days. Currently I'm charging 250w 20-30mins past sunrise, and it drops out over two hours prior to dark, hitting down to 20watts before sunset. So far 800w steady gives us an 80% charge by the end of the day, on partly cloudy days including the cabins' pull. - It's a complex question to answer being less than a week of full-time cabin powering....

Overall, we need another 6-7hrs (2000wh) of capacity to get us thru the night (without the minisplit).