Arthur
Honorary Master
No. Regular "solar" 12V x 105Ah. All things considered, they were the better financial decision at the time.
-
Join the MyBroadband community
South Africa’s biggest forum. Discuss, discover, and connect with thousands of members.
-
Question of the Day: Do you think Bafana Bafana will win tonight?
Does battery weight matter?
- Thread starter DTBA
- Start date
itareanlnotani
Executive Member
Agreed. At the time, being the key point. Things have moved on, and Op shouldn't even look at Lead Acid.
Our systems are of a similar age. You gave me your docs at the time, too
In 2015 I had 24 x 12 volt 105 a/h batteries in series/parallel to get 48 volts. Cost was R49k
(6 banks of 4 in series)
The charging value was set to 52 volts at 20 amps
Draw during load-shedding never exceeded 350 watts
The first 2 batteries started failing within 18 months. Instead of measuring 13.45V, they were 10V or less
Within 3 years, the load-shedding power was down to 20 mins
Three of the batteries exploded, sending acid over the room
Got a 5Kw lithium-ion battery for R23k in 2019. It works superbly
(6 banks of 4 in series)
The charging value was set to 52 volts at 20 amps
Draw during load-shedding never exceeded 350 watts
The first 2 batteries started failing within 18 months. Instead of measuring 13.45V, they were 10V or less
Within 3 years, the load-shedding power was down to 20 mins
Three of the batteries exploded, sending acid over the room
Got a 5Kw lithium-ion battery for R23k in 2019. It works superbly
Arthur
Honorary Master
Yeah, I remember well. Hope all is still working well.Agreed. At the time, being the key point. Things have moved on, and Op shouldn't even look at Lead Acid.
Our systems are of a similar age. You gave me your docs at the time, too
Btw, I replaced the 12kW PowerStar and Outback MPPTs with something more smoothly compatible with the new batteries.
itareanlnotani
Executive Member
Yeah, mine has morphed and moved over the years.
Current setup is 13KW of panels, and 2 interlinked systems - Sunsynk 8KW with 9.5KW, and the venerable old Victron, with 3.6KW.
10KW of Lithium storage (35k Revov special!), and the old dead acid on the Sunsynk so it can do its feeding.
When I have the cash will stick another 20kw of battery on the Sunsynk.
My outback, growatt grid tied, and 24v victrons are sitting in the garage. I should probably setup another system with them for shits n giggles in the wendy at some point, as i have another 2 dead acid i can throw at that.
PaulGherkin
Honorary Master
- Joined
- Jan 31, 2020
- Messages
- 10,294
- Reaction score
- 10,325
Lead acid is a proven technology that predates Lithium-ion by decades.
If you treat lead acid batteries with respect they will last long.
The reason why people have issues with them is because they don't know what the fark they are doing and run the things into deep discharge or worse.
If you treat lead acid batteries with respect they will last long.
The reason why people have issues with them is because they don't know what the fark they are doing and run the things into deep discharge or worse.
AchmatK
Honorary Master
They are at the point of being obsolete and has no place in any battery backup system, from 7Ah 12v garage and alarm batteries to over 100Ah 48v whole house backup systems. At least not when they are going to be used on a daily basis.
Many technology items has gone through this phase and you will get die hard fans that refuse to move on.
We moved from incandescent lights to cfl and now to led lights and you will still find people insisting on using incandescent lights.
To me a battery needs to be measured by the number of kWh you can extract from it over its lifetime. I'm sure you could extract 1kWh from a 5kwh lead acid battery and it will last a very long time. Extracting 1kWh from a 1.1kWh lithium battery would still end up with a battery that lasts longer.
I've extracted nearly 6 900kWh(6.9MWh) from my lithium batteries in just over 2 years and it's still at 97% of its original capacity. I'm yet to see a comparison where lead acid comes out on top when it comes to R/kWh over the lifetime of the battery.
AchmatK
Honorary Master
KWh of the battery or KWh that can be extracted over the lifetime of the battery?
Lithium can also be scaled easier and in stages.
Try and add a new lead acid battery to a 2 year old lead acid battery bank to increase your storage capacity. Everyone will tell you not mix new batteries with old when it comes to lead acid
I've added 2 new lithium iron batteries to my existing bank at different times so I can just increase my storage capacity as funds become available instead of having to replace the entire battery bank.
DTBA
Executive Member
- Joined
- Nov 27, 2011
- Messages
- 5,444
- Reaction score
- 840
Over the life of the battery. What batteries are you using?
Speedster
Honorary Master
What would you consider an accurate equivalency ratio between LA and lithium (LiFePO4)? Also, are you genuinely expecting to get around 6000 cycles (i.e. 6000 x nameplate rated Ah) out of your LA batteries?
Ianf1
Expert Member
TheChamp
Honorary Master
Yeah, hauling two of my 100Ah Oliters up the stairs to the first floor almost killed me.
TheChamp
Honorary Master
That's like buying a car and treating it with respect by just driving it to the shops, then parking it in the garage and taking a taxi or a bus when you have to travel longer distances because your car won't last for long if driven for longer distances, it's silly.
I have done a few of these kinds of set up, and from what you say it seems to me that the batteries where not maintained. It also seems like they where not balanced properly. There would have been a sulfur smell long before those batteries exploded.
What BMS where you using? Managing such a big bank of batteries in 2015 would require rotation, filling and balancing over the course of their life.
AchmatK
Honorary Master
I'm using pylontech batteries.
3 x US3000B added when system was installed in 2019
1 x US3000C added in 2020
1 x UP5000 added this year
Planning to add at least another two more UP5000 batteries to them.
Adding new lithium to old ones does not matter because each battery has a built in BMS. Lead acid is connected directly to other batteries so you can't mix old and new.
Also with lithium it should be easy for you to see how many cycles the battery has done and compare that with the spec sheet. That should tell you at what point you need to start saving to replace the battery.
Speedster
Honorary Master
Correct. I think Achmat knows about as much about lithium batteries (specifically Pylontech) as anyone on this forum.
AchmatK
Honorary Master
The question is when to replace.
Lithium ion batteries don't just go dead. Even a US3000 battery capacity doesn't just fall off a cliff at x number of cycles.
Due to each battery having its own bms I could have the first 3 batteries at 50% of original capacity and still functioning and contributing to the battery bank.
AchmatK
Honorary Master
Coming back to this question.
If you had to go LA and you want it to last a significant amount of time and extract the most from it you need to look at using only up to 25% off its rated capacity. Even then it might not give the same output. This means you need to size it at a minimum of 4 times bigger than an equivalent lithium battery.
I have ±400Ah @ 48v lithium that takes up just over 1m of cupboard space.
An equivalent LA battery would need to be at least 1 600Ah @ 48v. Random Google gives me a price of R5k for 200Ah @ 12v.
4 of these would get to 48v x 8 to get 1 600Ah. That's 32 of these batteries coming in at R160k. You need to start off at what you need as you cannot only start with 4 and add later as you can with lithium.
4 x UP5000 pylontech batteries will be R120k at the most and take up significant less space and require zero maintenance or load management.
Even sizing it at half or quarter that size, lithium still comes out on top.