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Al avatar image
Al asked

What's Your Battery Round Trip Efficiency?

I've always wondered how we fared compared to others, either Pb or Li etc with our second hand Hoppekke 2v Flooded lead acid cells, this will not be very scientific and quite a few factors will skew the results, but it would still be interesting to compare for fun.

We have:

Hoppekke 930Ah (C5) x 24 = 1,860Ah (C5) @ 24v / Quattro 8k (batteries probably 4-5years old)

VRM / Connect Battery History:

round-trip-efficiency.jpgFor the lazy maths calculation: https://percentagecalculator.net/

percentage.jpg

So for my 5 year old-ish FLA's roughly 85%


That's mine, what's yours!? Imaginary prizes for the most efficient and the least efficient :)

battery
round-trip-efficiency.jpg (15.5 KiB)
percentage.jpg (18.2 KiB)
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Al avatar image Al commented ·

I was interested in starting this after @JohnC posted his RTE https://community.victronenergy.com/questions/112125/what-goes-into-the-battery-and-what-did-i-take-out.html

I think we have similar banks and there aren't many real world comparisons that I've seen. My old ex 420Ah forklift bank was averaging 76% before I gave it away as scrap to a friend but that's still working perfectly for his much smaller needs. That really doesn't compare to the dream of closer to 98% for Alexandra's though!

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Alexandra avatar image
Alexandra answered ·

@Al

An interesting comparison for sure. The FLAs are on point.

We are running 12v Blue Novas BN108ah lifepo4 and have cycled/experimented with them between 24v and 12v systems over about 2 years now same bmv though.


screenshot-20211217-210204.jpg


using the lazy calculator ....

screenshot-20211217-210204.jpg


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screenshot-20211217-205925.jpg (31.1 KiB)
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Al avatar image Al commented ·
You're Currently winning @Alexandra! :) It would be great to see more people with similar systems, it's already looking like it will be quite varied.
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klim8skeptic avatar image
klim8skeptic answered ·

4 Winston 300ah cells, 34 months use off grid.

battery-history.png

battery-efficiency.png



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battery-efficiency.png (15.8 KiB)
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multivictor avatar image
multivictor answered ·

MultiPlus-II 48/5000/70-50 + 1 LiFePo4 BYD LVL 15.36 kWh + Solarsystem SMA 5000 TL /5.6 kWp .
Monfofase 40A + N grid connection.

System started on 01 october 2021.

Disapointing results so far:

Oktober: RTE 69.78% - November: RTE 73,13 %.
01-10-2021 => 17/12/2021: 241.5 kWh charged - 171.2 kWh discharged. RTE 70.89 %

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Al avatar image Al commented ·
Hi @MultiVictor have you been manually writing down monthly your results to check your RTE? - It does seem low for LiFePo4?
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multivictor avatar image multivictor Al commented ·

Ik know it's low. :-( System is only three months old.

I didn't take notes manually. I used the real time data shown in the VRM dashboard.

To battery 259 kWh - from battery 180 kWh => 69.5%.

Did I calculate something wrong?
Can't I use the VRM data?

data-consumption.jpg

data-solar.jpg


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Al avatar image Al multivictor commented ·

Ahh, @MultiVictor do you have a smartshunt / BMV? Look at battery history in VictronConnect or in advanced on VRM to get the totals. I think you'll then be happier ;)


The dashboard of VRM doesn't add everything up, it doesn't currently show how many kWh from a generator have charged the batteries for example, but the accurate totals are shown in battery history.

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peter1 avatar image peter1 multivictor commented ·

You also have to take into account the SOC at the beginning and the SOC at the end of the period you are calculating.

Also Ivo you are calculating RTE on the AC side, others here are calculating the RTE on the DC side. That is a big difference.

Normaly you should get around 75% RTE on the AC side with your system.

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multivictor avatar image multivictor commented ·
Now I used the "History" data shown in the remote console of the ESS system:

- PV output: 431,2 kWh
- Battery input: 238,3 kWh
- Battery output: 230,1 kWh
RTE result: 96,5 %
-------------------------------------------------------------
On VRM dasboard:
- PV output: 434 kWh
- To Grid: 37 kWh
- Direct AC use: 143 kWh
- Battery input: 261 kWh
- Battery output: 181 kWh


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marekp avatar image
marekp answered ·

@Al

400Ah LiFeYPo4 Winston 48V

screen-shot-2021-12-18-at-51015-pm.png


95.82%


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ianddindustries avatar image
ianddindustries answered ·

Hi. We have a system in a coffee van that consists of a 300 amp victron lithium and a 3k multiplus. It is 3 years old and runs at about 95%. Uses about 50% of the battery 5 days a week
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Al avatar image Al commented ·

95% :)

iandd.jpg

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taavij avatar image
taavij answered ·


screenshot-20211218-0903582.png4 Pylontech US2000b offgrid use and 2,5 years old. BMV 702 is doing measuring work, but I have doubts its accuracy.screenshot-20211218-0858562.png


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soky avatar image
soky answered ·

Hoppecke 200 Sun Power VRM 6V in 48V system, during 4 years -> 84.6 %

vrm-data2.png


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Marco Nijholt avatar image
Marco Nijholt answered ·

6x Victron Lfpo4 200Ah 25v Smart batteries (30kwh)

96.31% based on this, its currently 100% SoC, i believe i got it with 50% SoC (30kwh bank). Then we'd get to 97%

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