Testing Delta 2 efficiency under constand load

[Mirai]

Every solution has it's pros and cons, the pps has the portability advantage to power certain stuff and specifically the ecoflow has the fast charging and user friendly updating of frequent firmware updates.

There is 2 important factors, price how much wh is required

Those are nice features too. They are a bit scummy though in how they push the 2KWh battery as an extra where it's a Li NCM 800 cycle battery.

 

[KOPITE]

Those are nice features too. They are a bit scummy though in how they push the 2KWh battery as an extra where it's a Li NCM 800 cycle battery.

why would you want to buy the older NCM unit when the new LiFePo are available, budget and needs takes preference irrespective if pps, trolley or home system with solar panels

 

[Mirai]

why would you want to buy the older NCM unit when the new LiFePo are available, budget and needs takes preference irrespective if pps, trolley or home system with solar panels

If you look at the Ecoflow promo material they push the Max battery for a total of 3KWh. Except that battery is old tech.The 2KWh model is mentioned at least twice in the actual listing for the device. Unless you're diligent and check that the battery is old tech you may buy the combo and think you're getting 3000 cycles minimum on both.

The Delta 2 can take an extra battery. Either the new LFP Delta 2 extra battery (1KWh) or the Delta Max battery which is 2KWh but is NCM and 800 cycles.

 

[Valaskjalf]

If you look at the Ecoflow promo material they push the Max battery for a total of 3KWh. Except that battery is old tech.The 2KWh model is mentioned at least twice in the actual listing for the device. Unless you're diligent and check that the battery is old tech you may buy the combo and think you're getting 3000 cycles minimum on both.

The Delta 2 can take an extra battery. Either the new LFP Delta 2 extra battery (1KWh) or the Delta Max battery which is 2KWh but is NCM and 800 cycles.

I Also dont get this...so the extra battery has almost a 1/4 of the cycles of the main unit and really expensive. Also see the Delta max 2000w is still going for an exorbitant amount with its NMC. Delta 2 + LifePO 1kw battery is way cheaper...still expensive but cheaper.

 

[Valaskjalf]

For me the LFP and fast charge was the main selling point. Pity about the weak efficiency but thats the toss up - when stage 6 hits and you have 2hrs to recharge then having one of those big ass trolleys wont help you much when they take 5+ hours to recharge. Im still going to get a watt meter like one of the posters mentioned to see total wh draw from 100-0%. Thanks for the advice.

 

[Mirai]

I Also dont get this...so the extra battery has almost a 1/4 of the cycles of the main unit and really expensive. Also see the Delta max 2000w is still going for an exorbitant amount with its NMC. Delta 2 + LifePO 1kw battery is way cheaper...still expensive but cheaper.

They haven't produced a Delta 2 Max and Delta 2 Max Battery model yet. They have old stock of Delta 1 Max. So what better way than through obfuscation dump that old tech on people who assume that because these are together and the promo for Delta 2 claims 3,000 cycles, then surely the combo is the same. Slimy and greedy.

 

[Valaskjalf]

I'm not sure what exactly is meant by efficiency in this context but I wouldn't assume the battery capacity is a known quantity in the first place - so yes I would run the unit down to zero, measure the energy extracted (with an external meter on the output) and call that the "effective capacity" for a given load.

Then do the same with the meter on the input side for a recharge from zero to 100%.

The difference is the "end-to-end" loss. But you can't really isolate the inverter output and charging input losses unless you know the "raw" battery capacity, which would need to be tested directly.

Im no expert in any of this, clearly, but I wonder whether the YT videos that scored 90% efficiency (usable wh compared to 1024wh) are a little misleading in the sense that they use high-powered devices which drain the thing in an hour or so. So the real-world usecase where you want the battery to last longer is averted, and thereby also the self-discharge the unit will experience over 8hrs for instance compared to 1hr. I would assume the longer you try to run this thing, the less efficient it will be?

 

[Mirai]

For me the LFP and fast charge was the main selling point. Pity about the weak efficiency but thats the toss up - when stage 6 hits and you have 2hrs to recharge then having one of those big ass trolleys wont help you much when they take 5+ hours to recharge. Im still going to get a watt meter like one of the posters mentioned to see total wh draw from 100-0%. Thanks for the advice.

I'm going to be an ahole now and ask, who will calibrate your Watt meter?

 

[Valaskjalf]

I'm going to be an ahole now and ask, who will calibrate your Watt meter?

Lol well it will certainly be closer to the truth than me sitting with a calculator and guess whether it pulled 75w or 100w for 7 hours

 

[Mirai]

Lol well it will certainly be closer to the truth than me sitting with a calculator and guess whether it pulled 75w or 100w for 7 hours

Plug in a 100w incandescent bulb and run with that with a stopwatch?

 

[Valaskjalf]

Plug in a 100w incandescent bulb and run with that with a stopwatch?

Ja thats the other option, thanks. I just wanted a constant load so whatever can give me that I will use.

 

[DrJohnZoidberg]

Just be aware that the remaining battery percentage indicated may not always be accurate. If it's not calibrated quite right it will drain down to 1% and shutdown but still have a lot of runtime left on that 1%. See this video:

 

[Mirai]

Just be aware that the remaining battery percentage indicated may not always be accurate. If it's not calibrated quite right it will drain down to 1% and shutdown but still have a lot of runtime left on that 1%. See this video:

If that's what's usable, that's what's usable. It will charge up faster, next time, it's recharged.

 

[soulie]

if you have a double 5 ft flourecent lamp that will give a stable load as its controlled by the ballast inside it would be around 112 watts

 

[Tomtomtom]

I would assume the longer you try to run this thing, the less efficient it will be?

Im still going to get a watt meter

Yip given multiple variables there will be no single figure, just the one you get in your application with your particular unit.

Top tip, you can get a smart plug that has an energy monitoring feature e.g. this one or this one (these both use the Tuya platform) and when you're done with the experiment you still have a smart switch to keep. And they can be cheaper than dedicated power meters. (The catch is you have a slightly fiddly app instead of an LCD.)

 

[Tomtomtom]

I'm going to be an ahole now and ask, who will calibrate your Watt meter?

Well at least it wasn't the manufacturer of the system under test, so the error has more likelihood of being symmetrical around the true value, and not biased to the side favourable to their product.

I do wonder about this "efficiency" thing in the first place though. Is it standard for an integrated PPS?

When you're spending in the region of R 10-30/Wh, being 10% short is thousands of bucks. And if there's no load at which you get your rated energy, what is the spec actually telling you? It's like giving an engine's thermal power output instead of horsepower at the wheels. Shouldn't they specify the unit's effective energy (at some reasonable load, like a battery itself is rated)?

On my PPS rated 1280 Wh, I did a ~130W load test and got 10 hours -- bang on -- and I assumed that was by design... but maybe I just got lucky?

 

[Valaskjalf]

One of the strangest things Im realising with all these batteries/systems is that essentially the advertised wh is all bogus. Let's say you have a unit rated at 1000wh...well firstly the bigger the inverter the bigger the efficiency loss so lets say on a good day you're getting 850wh. But then the battery chemistry comes in and you read the manual where it states its probably best to maintain a charge/discharge rate of 20-80%. So now your 850wh usable power goes down by another 40% since you shouldn't really access the extreme ends of the battery capacity as it hates it and will reduce the lifespan.
Your 1000wh on paper is now actually only 510wh.

 

[Bundu]

One of the strangest things Im realising with all these batteries/systems is that essentially the advertised wh is all bogus. Let's say you have a unit rated at 1000wh...well firstly the bigger the inverter the bigger the efficiency loss so lets say on a good day you're getting 850wh. But then the battery chemistry comes in and you read the manual where it states its probably best to maintain a charge/discharge rate of 20-80%. So now your 850wh usable power goes down by another 40% since you shouldn't really access the extreme ends of the battery capacity as it hates it and will reduce the lifespan.
Your 1000wh on paper is now actually only 510wh.

exactly, quoting battery capacity is simply an indication (obviously higher than one will ever get out)

 

[Mirai]

Well at least it wasn't the manufacturer of the system under test, so the error has more likelihood of being symmetrical around the true value, and not biased to the side favourable to their product.

I do wonder about this "efficiency" thing in the first place though. Is it standard for an integrated PPS?

When you're spending in the region of R 10-30/Wh, being 10% short is thousands of bucks. And if there's no load at which you get your rated energy, what is the spec actually telling you? It's like giving an engine's thermal power output instead of horsepower at the wheels. Shouldn't they specify the unit's effective energy (at some reasonable load, like a battery itself is rated)?

On my PPS rated 1280 Wh, I did a ~130W load test and got 10 hours -- bang on -- and I assumed that was by design... but maybe I just got lucky?

I again have to ask about the bias since you're not looking at the device display but using your own load and your own timer. You charge it up fully, then dischagre under known load fully, and you can more or less know how much effective capacity the box has. Your 100W incandescent should pull 100W per hour give or take a small percentage. If the Ecoflow lets it burn for 8hours from full charge to discharge you know you have 800Wh capacity. As a bonus you can also look on the display and see if it shows about 100W output.

 

[Mirai]

One of the strangest things Im realising with all these batteries/systems is that essentially the advertised wh is all bogus. Let's say you have a unit rated at 1000wh...well firstly the bigger the inverter the bigger the efficiency loss so lets say on a good day you're getting 850wh. But then the battery chemistry comes in and you read the manual where it states its probably best to maintain a charge/discharge rate of 20-80%. So now your 850wh usable power goes down by another 40% since you shouldn't really access the extreme ends of the battery capacity as it hates it and will reduce the lifespan.
Your 1000wh on paper is now actually only 510wh.

This is true but it's true for all batteries and inverters. All batteries should not be run down to 0 and ideally not always charged to 100% and all inverters have heat losses.