Mecer 2400VA Inverter (Community Support)

[AlphaJohn]

That's probably the crux. They are all the same if you consider price versus life cycle, and don't discharge the LA beyond 50% or the Lithium beyond 80%.

There is too much fuss about battery type. Lithium has its own issues which is why sodium ion is the new kid on the block, and research continues into many other battery variants.

Rather focus on load management. Calculate your load, multiply that by 4 and get a battery of twice that capacity. Then get a charger that can recharge the load capacity in 4 hours without exceeding the safety guidelines for the battery.

The cost of either solution will render a roi, in terms of losses resulting from loadshedding, electricity arbitrage, and kwh cost.

As of 2020, sodium ion batteries have very little share of the battery market. The technology is unmentioned in a United States Energy Information Administration report on battery storage technologies.[3] No electric vehicles use sodium ion batteries. Challenges to adoption include low energy density and a limited number of charge-discharge cycles

Source

Also:



Yeah no, I'll bank on something I can use now. Not something that might some day be something.....

 

[BrandonJ]

Source

Also:

View attachment 1396083

Yeah no, I'll bank on something I can use now. Not something that might some day be something.....

Perhaps we should rephrase this as we were not recommending anybody buy or can buy Sodium Ion.

The intent was simply to mention that due to issues with lithium ion, researchers continously search alternatives. Lithium is not the end game. For one lithium is a finite resource that has to be mined.

The entire point was. Calculate your load, and make sure whatever battery you have can handle that load without exceeding it's effective DOD. If you do that it doesn't really matter what battery you get. (without getting into the scientific advantages of lithium)

For the average consumer. If you have a 7AH SLA battery in your alarm system, and the load on that alarm system is 0.4A, you don't need anything more than the SLA. If the load is higher than that, you won't make it through stage 6 loadshedding, and the battery life will deteriorate. Even if you put in a bigger battery, or the same capacity Lithium battery, you won't make it through stage 6 loadshedding.

 

[wingnut771]

Perhaps we should rephrase this as we were not recommending anybody buy or can buy Sodium Ion.

The intent was simply to mention that due to issues with lithium ion, researchers continously search alternatives. Lithium is not the end game. For one lithium is a finite resource that has to be mined.

The entire point was. Calculate your load, and make sure whatever battery you have can handle that load without exceeding it's effective DOD. If you do that it doesn't really matter what battery you get. (without getting into the scientific advantages of lithium)

For the average consumer. If you have a 7AH SLA battery in your alarm system, and the load on that alarm system is 0.4A, you don't need anything more than the SLA. If the load is higher than that, you won't make it through stage 6 loadshedding, and the battery life will deteriorate. Even if you put in a bigger battery, or the same capacity Lithium battery, you won't make it through stage 6 loadshedding.

300 cycles vs 3000++++ cycles.

 

[BrandonJ]

300 cycles vs 3000++++ cycles.

130% higher initial cost (Yes it balances out over the 5 year, 10 year life cycle of the lithium battery for those who have the budget)

Average lifespan of a lithium battery is 5 Years at 2000 Cycles - 3000 if everything is idela. Lead acid has a similar lifespan at 500 to 700 cycles - 1000 under ideal circumstances.

If you don't discharge your SLA battery below 50% DOD and other factors are ideal the battery could last 3 years or longer.

All the problems under discussion here relate to exceeding the efficient capacity of the battery.

 

[AlphaJohn]

The entire point was. Calculate your load, and make sure whatever battery you have can handle that load without exceeding it's effective DOD. If you do that it doesn't really matter what battery you get.

Also very wrong advice

If you look over the lifetime of a product LFP works out waaaaay cheaper



Edit: Not to mention looking at last 2 years history you gonna have to fork out that R3K every year vs R7k every 7 to 8 years.

 

[BrandonJ]

Also very wrong advice

If you look over the lifetime of a product LFP works out waaaaay cheaper

View attachment 1396207

I did not dispute that LFP has a lower cost per Kwh over the lifespan of the battery.

In the scenario of a drop in replacement lithium battery, for a Lead Acid battery which is exceeding it's depth of charge though, it's a different ball game, since the higher cost replacement won't solve the problem unless the device has a capable charger.

In your example , obviously the lithium battery is going to be cheaper in the long run, but the lead acid battery will work for 3 to 5 years under ideal conditions. That's why you need to match the battery to your load. If the load on your lead acid is such that the battery will complete 300 cycles in 5 years, why would you need the lithium battery? If the load is heavier then you need a bigger battery or a better battery.

Keep in mind that the dependance of cycle life in a LFP battery on DOD is much higher than for a lead acid battery. Thus at all times you want to maxmize efficiency of whatever battery you have by examining the applied load, and the result cycle periods to be expected.

What this means is that pushing a LFP battery to 100% DOD will affect the Cycle Life far more than Pushing a Lead Acid battery to 100% DOD

 

[xumwun]

The real problem with LFP is actually finding them.

 

[AlphaJohn]

For the average consumer. If you have a 7AH SLA battery in your alarm system, and the load on that alarm system is 0.4A, you don't need anything more than the SLA. If the load is higher than that, you won't make it through stage 6 loadshedding, and the battery life will deteriorate. Even if you put in a bigger battery, or the same capacity Lithium battery, you won't make it through stage 6 loadshedding.

What you on about 7AH

This is a Mecer inverter thread, no one in his right mind gonna hook up 7ah's onto a Mecer.

 

[Gazbal]

I did not dispute that LFP has a lower cost per Kwh over the lifespan of the battery.

In the scenario of a drop in replacement lithium battery, for a Lead Acid battery which is exceeding it's depth of charge though, it's a different ball game, since the higher cost replacement won't solve the problem unless the device has a capable charger.

In your example , obviously the lithium battery is going to be cheaper in the long run, but the lead acid battery will work for 3 to 5 years under ideal conditions. That's why you need to match the battery to your load. If the load on your lead acid is such that the battery will complete 300 cycles in 5 years, why would you need the lithium battery? If the load is heavier then you need a bigger battery or a better battery.

I've come across a lot of your posts in the various threads. I think the point your are missing is that we are not in ideal situations! Obviously match your batteries to your load BUT loadshedding is lot allowing these batteries to be fully recharged again before use. This kills the LA batteries. Hence using lithium which do not need to be fully recharged again before the next loadshedding cycle.

 

[AlphaJohn]

On the subject of LFP's

I see an interesting pattern emerge this last week when bulking. (See attached)

There is a break in the bulk phase during the day vs none at night so must be temp related.... Just wondering if its my BMS that is limiting uptake on the inverter. Esp seeing that its not a total cut, just lower.

 

[BrandonJ]

I've come across a lot of your posts in the various threads. I think the point your are missing is that we are not in ideal situations! Obviously match your batteries to your load BUT loadshedding is lot allowing these batteries to be fully recharged again before use. This kills the LA batteries. Hence using lithium which do not need to be fully recharged again before the next loadshedding cycle.

I think I have stated in all my posts - the load and the charge rate of the device are critical.

Putting a lithium battery onto a 0.5A charger isn't going to give to you any different result than a lead acid battery on the same charger. Sure it might last a bit longer through the first few cycles, but soon thereafter will end up with the same situation. The issue is not about recharging to 100% capacity. It's about replacing the consumed load in the time between load shedding.

What will happen to a lead acid battery if you keep replacing less capacity than you are using?
What will happen to a lithium battery if you keep replacing less capacity than you are using?

Can your charger replace the used capacity in the allotted time between load shed cycles - that's the question, regardless of battery type.

 

[wingnut771]

130% higher initial cost (Yes it balances out over the 5 year, 10 year life cycle of the lithium battery for those who have the budget)

Average lifespan of a lithium battery is 5 Years at 2000 Cycles - 3000 if everything is idela. Lead acid has a similar lifespan at 500 to 700 cycles - 1000 under ideal circumstances.

If you don't discharge your SLA battery below 50% DOD and other factors are ideal the battery could last 3 years or longer.

All the problems under discussion here relate to exceeding the efficient capacity of the battery.

Okay but you need double the amount of LA batteries to get to your 50% DOD, so 2 LA's vs 1 LFP. That should factor into the costs aswell. You're also forgetting about this characteristic when it comes to LA:

 

[AlphaJohn]

What will happen to a lead acid battery if you keep replacing less capacity than you are using?

Lead dont like being bellow 100% else damage set in

What will happen to a lithium battery if you keep replacing less capacity than you are using?

LFP dont wanna be full in the 1st place so will be happy not going to 100% in the 1st place

That said on the 0.5A charge you will get more WH back into LFP vs LA cause its uptake is faster.


I want this shirt

 

[wingnut771]

I did not dispute that LFP has a lower cost per Kwh over the lifespan of the battery.

In the scenario of a drop in replacement lithium battery, for a Lead Acid battery which is exceeding it's depth of charge though, it's a different ball game, since the higher cost replacement won't solve the problem unless the device has a capable charger.

In your example , obviously the lithium battery is going to be cheaper in the long run, but the lead acid battery will work for 3 to 5 years under ideal conditions. That's why you need to match the battery to your load. If the load on your lead acid is such that the battery will complete 300 cycles in 5 years, why would you need the lithium battery? If the load is heavier then you need a bigger battery or a better battery.

Keep in mind that the dependance of cycle life in a LFP battery on DOD is much higher than for a lead acid battery. Thus at all times you want to maxmize efficiency of whatever battery you have by examining the applied load, and the result cycle periods to be expected.

What this means is that pushing a LFP battery to 100% DOD will affect the Cycle Life far more than Pushing a Lead Acid battery to 100% DOD

You can get 3000 cycles at 100% DOD, then still have 60-80% capacity remaining.

LA has 0% capacity remaining after 300 or whatever cycles.

 

[BrandonJ]

Lead dont like being bellow 100% else damage set in


LFP dont wanna be full in the 1st place so will be happy not going to 100% in the 1st place

That said on the 0.5A charge you will get more WH back into LFP vs LA cause its uptake is faster.

View attachment 1396243

Ok, So you are saying that I will get through stage 6 load shedding on my alarm system if I simply replace the 7AH lead acid battery with a 7A Lithium Battery?

Thank you for your contribution.

 

[wingnut771]

On the subject of LFP's

I see an interesting pattern emerge this last week when bulking. (See attached)

There is a break in the bulk phase during the day vs none at night so must be temp related.... Just wondering if its my BMS that is limiting uptake on the inverter. Esp seeing that its not a total cut, just lower.

It would be the BMS yes.

 

[AlphaJohn]

Ok, So you are saying that I will get through stage 6 load shedding on my alarm system if I simply replace the 7AH lead acid battery with a 7A Lithium Battery?

Thank you for your contribution.

Not saying it will get through, saying it has a better chance of surviving.

 

[wingnut771]

I think I have stated in all my posts - the load and the charge rate of the device are critical.

Putting a lithium battery onto a 0.5A charger isn't going to give to you any different result than a lead acid battery on the same charger. Sure it might last a bit longer through the first few cycles, but soon thereafter will end up with the same situation. The issue is not about recharging to 100% capacity. It's about replacing the consumed load in the time between load shedding.

What will happen to a lead acid battery if you keep replacing less capacity than you are using?
What will happen to a lithium battery if you keep replacing less capacity than you are using?

Can your charger replace the used capacity in the allotted time between load shed cycles - that's the question, regardless of battery type.

It would be able to catch up during the long patches when there is power and not get damaged in the process.

 

[BrandonJ]

Lead dont like being bellow 100% else damage set in

LFP even less so, and more damage will set in.

 

[AlphaJohn]

Erm Not what I said Here

And if that is your argument see:



Source: https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries

Best performance was to keep bellow 75% and above 65%, followed by 45% and 25% above empty. They really dont like being full.