A true power hog's ULTIMATE power wall...?


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F9Solar

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Joined
Mar 17, 2022
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8
Well folks...

Brainstorming moment & gut check for a true off-grid power hog's ULTIMATE power wall (BESS).

Real-world users are being sought out.

This is about cells, BMS and overall systems.

Looking at LFP, LYP, & LTO options.

The LFP is a hi-voltage all-in-one solution
(with Inverter/charger, BMS.. & MPP pv charger, etc).
I believe nominal over 300vdc(?) and with about 92kwh storage.
1p,92s P (Lishen 202ah... total 92 cells)

------

The LYP is Winston in a 48vdc configuration using the normal bi-directional off-the shelf common inverter/ charger (Magnum or Victron).
Would need BMS to complete it (Batrium, REC, eLithion, etc).
Thirty-two 1,000ah cells used for a capacity of about 102kwh.
One 2p,16s or
Two strings of 1p 16s (fused/buss)
(Again... 32 cells regardless)

---------

The LTO is same as LYP for inverter options,
but half capacity storage.
Using Yinlong 40ah cells (total of 704 cells).
Two strings via fuse and buss... 16p,22s

-----

The curve ball interest/side-glance was the late Jack Rickard's hi-voltage oem full battery pack a high voltage system.... but don't know if they are even in business anymore.
------

Am interested in thoughts about those options from any users of such.

Primary charging is PV.

THANKS in advance!

All the best,
A true power hog
 
Last edited:

Oberfail

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Jun 22, 2021
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247
I'd go with the first, simply for the name of efficiency.
When the DC voltage is above the peak AC voltage (120V AC RMS = 170V AC Peak, 230V AC RMS = 325V AC Peak), it can be easily made directly from the DC source without any conversion, thus making it far more efficient than low voltage systems.
 

F9Solar

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Mar 17, 2022
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Thanks

The things that make me nervous about the hi-V. option are parts and customer service/tech support.

Anyone have any experiences with Sandi brand?
 

floydR

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Aug 23, 2017
Messages
1,466
The LFP is a hi-voltage all-in-one solution
(with Inverter/charger, BMS.. & MPP pv charger, etc).
I believe nominal over 300vdc(?) and with about 92kwh storage.
1p,92s P (Lishen 202ah... total 92 cells)
92s1p 294.4V x 202Ah =59.46kWh
The LTO is same as LYP for inverter options,
but half capacity storage.
Using Yinlong 40ah cells (total of 704 cells).
Two strings via fuse and buss... 16p,22s
22s16p 52.8V x 640Ah = 33.79kWh 2.4Vnominal
50.6V x 640Ah = 32.38kWh 2.3Vnominal
You got the LYP right. Don't think efficiency of the HV system can make up 40kWh
Later floyd
 

Redpacket

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Feb 28, 2018
Messages
1,414
If DIYing, nominal 48V systems are much safer to work on.
With more parallel battery strings, you have options to take part of the battery bank offline eg for maintenance, upgrades, etc.
(Same applies for PV, etc too)
48V gear is readily available, 300V(ish) gear not so.
1P strings = 1 cell fault = system off-line.
LiFePo4 at 48V (16S) works well & lasts.

It's true PV (DC) > AC (eg micro inverters) > DC storage (inherently DC in batteries) > AC > end use = considerable inefficiencies
But PV > DC > 48V batteries > AC > end use, efficiencies are much better

Best advice: minimize usage first, try & wean off the hog as best you can where possible.
Every watt less you use is less PV, less storage & easier inverter size.
 

F9Solar

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Mar 17, 2022
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8
Appreciate that.

Unfortunately there's more than one family here, some elderly; so, usage isn't going to change.
 

Oberfail

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Jun 22, 2021
Messages
247
You could try to tell them, to try moving their electricity usage habits to moments/days, when the sun shines a lot, but it isnt a must.
 
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