Beware what batteries you buy to fight load-shedding

Jamie McKane

MyBroadband Journalist
Staff member
Super Moderator
Joined
Mar 2, 2016
Messages
5,732
Beware what batteries you buy to fight load-shedding

South Africans looking to purchase a backup power solution should be careful when considering suitable batteries.

The prevalence of load-shedding has led many to resort to battery-inverter systems that are able to charge when the power is on and then provide stored electricity for use during power cuts.
 

system32

Expert Member
Joined
Dec 29, 2009
Messages
3,252
"LiFeYPO4 as replacement for Lead-Acid"
Very good presentation from Blue Nova can be found here:

Summary:
For the same Price (2016)
• Same usable kWh
• LFP lasts 2 -4 times longer (10-15 years)
• 10 year warranty
• < 25% of the weight
• < 33% volume
• No gasses or acid
• 100% safe
• 100% environmentally friendly
• 26% less kWh to charge LiFePO4 (less panels)

123 Lead to Lithium:
• Ah (LiFeYPO4) = Ah (LA) x 50% x 75% x 95% = 36%
 

SlinkyMike

Executive Member
Joined
Jan 23, 2006
Messages
6,286
Judging batteries by Amp hours (Ah) is like judging a car by the size of the fuel tank. You need to educate yourself and understand the other parameters. It's not that difficult.
Any good sources? Keen to educate myself.
 

Gaz{M}

Executive Member
Joined
Feb 9, 2005
Messages
6,152

It's long but you will learn a LOT about batteries and inverters.
 

Suspect99

Executive Member
Joined
Aug 22, 2012
Messages
5,781
"LiFeYPO4 as replacement for Lead-Acid"
Very good presentation from Blue Nova can be found here:

Summary:
For the same Price (2016)
• Same usable kWh
• LFP lasts 2 -4 times longer (10-15 years)
• 10 year warranty
• < 25% of the weight
• < 33% volume
• No gasses or acid
• 100% safe
• 100% environmentally friendly
• 26% less kWh to charge LiFePO4 (less panels)

123 Lead to Lithium:
• Ah (LiFeYPO4) = Ah (LA) x 50% x 75% x 95% = 36%
It's not the same price though. The it's over 4 times more expensive than the equivalent lead acid
 

netstrider

Senior Member
Joined
Nov 1, 2006
Messages
995
It's not the same price though. The it's over 4 times more expensive than the equivalent lead acid
Is he basically saying a 100A Lead Acid battery has roughly 36% efficiency when all factors are taken into account? (I have the efficiency at 85% rather than 75% but anyway)

So +- 36A usable at roughly R2000 a battery, with SA's weather reducing the lifespan to probably about 500-1000 cycles even for a good LA battery if not less.

https://www.sustainable.co.za/freedom-auxillary-range-fw12-40-40ah-12v-lifepo4-battery.html Nearest equivalent to 36A

Roughly 3 times the price, but 2 to 3 times the cycles and lifespan as well, then we're not even talking about discharge rates.

Of course, the Wh rating for a 100A and 40A battery will differ vastly on the surface, but if you're only getting about 40A worth from said 100A then it is extremely inefficient, never mind bulky and heavy.

If I understand this correctly then:

  • 100A at 12V with LA = 1200Wh
  • Of which you can use 432W for an hour (1200 x 0.36) or 1200W for roughly 21 minutes (60 x 0.36) before you need to shut off and recharge? - IF you want to get the optimal cycles out of said battery. Otherwise you could probably run it at 1200W for a full hour and probably get like 200 cycles out of it?
  • Whereas with a 40A Lithium, assuming 100% DOD = 480Wh
  • Of which you can use the 480W for an hour ???
 

itsme2

Senior Member
Joined
Sep 25, 2018
Messages
519
We just put in 10,5kWh worth of LiFpo with a very nice Victron inverter and color control. Let me tell you this setup is a beast. We pull out about 2kWh during a loadshed, and it's over 50% once done. Charged and ready to slay again within a few hours. The peace of mind and freedom is worth every cent. F*** you Eskom
 

system32

Expert Member
Joined
Dec 29, 2009
Messages
3,252
It's not the same price though. The it's over 4 times more expensive than the equivalent lead acid
Please read the PDF,
You only need 36% the capacity for lithium.
Lithium last 2 to 4x years longer.
Lithium charges with 96% efficiently.

My Lead Acid setup requires 2kWh in to charge for evey 1kWh out.
Lead Acid is OK for occasional UPS (and even that is debatable)
Lead Acid is not good for daily discharge/charge.
 

Steamy Tom

Executive Member
Joined
Jan 23, 2019
Messages
5,315
We just put in 10,5kWh worth of LiFpo with a very nice Victron inverter and color control. Let me tell you this setup is a beast. We pull out about 2kWh during a loadshed, and it's over 50% once done. Charged and ready to slay again within a few hours. The peace of mind and freedom is worth every cent. F*** you Eskom
It should be like 80% when loadshedding is done?
 

itsme2

Senior Member
Joined
Sep 25, 2018
Messages
519
It should be like 80% when loadshedding is done?
No, my post wasn't that clear. Our load is 2kW with all of our aircons and equipment. For 2.5 hours of "Failure to supply a basic service by a corrupt, poorly run monopoly" is +-5kWh. 10,5kWh stored in the cells. 10,5 less 5 = 5,5 left = about 53%
 

eye_suc

Expert Member
Joined
Feb 14, 2005
Messages
3,752
We just put in 10,5kWh worth of LiFpo with a very nice Victron inverter and color control. Let me tell you this setup is a beast. We pull out about 2kWh during a loadshed, and it's over 50% once done. Charged and ready to slay again within a few hours. The peace of mind and freedom is worth every cent. F*** you Eskom
Heya! Tried to PM you, but was unable to. Would you be able to send me some details about your system? :)
 

RonSwanson

Expert Member
Joined
May 21, 2018
Messages
2,317
We just put in 10,5kWh worth of LiFpo with a very nice Victron inverter and color control. Let me tell you this setup is a beast. We pull out about 2kWh during a loadshed, and it's over 50% once done. Charged and ready to slay again within a few hours. The peace of mind and freedom is worth every cent. F*** you Eskom
Well done, but I need to point out that if you are paying Eskom to charge it up again, then it's not exactly F*** you time yet. Are you going to couple it with a few solar panels in the future?
 

itsme2

Senior Member
Joined
Sep 25, 2018
Messages
519
Well done, but I need to point out that if you are paying Eskom to charge it up again, then it's not exactly F*** you time yet. Are you going to couple it with a few solar panels in the future?
Not a Raaa Raaa F*** you. More still a normal F*** you. Will be adding panels too but this base system was needed just survive the current project workflow.
 

CB40

Senior Member
Joined
Jun 20, 2009
Messages
875
What sort of price range are we looking at for "LiFeYPO4 "batteries
I only need to run wifi router,ONS and a laptop.I have a Hawkins 1000w inverter.
We sell chargers so I get them at cost
 

Yster21

Senior Member
Joined
Feb 3, 2009
Messages
779
We just put in 10,5kWh worth of LiFpo with a very nice Victron inverter and color control. Let me tell you this setup is a beast. We pull out about 2kWh during a loadshed, and it's over 50% once done. Charged and ready to slay again within a few hours. The peace of mind and freedom is worth every cent. F*** you Eskom
I did the same. Got 3x3.5kWh Pylontechs and a Victron Multiplus-II 5kVA inverter with the Victron Venux GX for remote monitoring. We live in Jhb, so our loadshedding is 4.5 hours. Even during peak hours with two aircons running, all my network equipment, outside floodlights (we live next to a nature reserve), gaming PC and one TV, the draw is no more than 1.2kW. After loadshedding my batteries are still at >65% state of charge (SoC).
 
Top