TheChamp

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Are the prices drastically dropping for the LiFePo batteries? Would it be worth it to get LA batteries now and then invest in a bigger LiFePo battery pack a few years down the line (5 years give or take).
No, it would be a massive waste of money, a 5kW Inverter takes 4 batteries for 48V, a cheap and nasty 105Ah battery cost around R2800, four of them is already R11 200, a basic lithium 2.4kWh battery is around the R12k mark. In all seriousness you don't want to buy a R2800 battery, close to R4k a battery is what you need, 4 of them are already at R16k.

Taking into consideration that your 4 lead acid will only be 105Ah, with 50Ah usable and the fact that they would need to be thrown away after a couple times of handling a few longer power cuts period you are better off going lithium right away.
 

TheChamp

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Looking for some sage advice here gents - we want to put in a starter inverter system for our home to get us through loadshedding. Initially just inverter and batteries with the option to add panels later as budget permits. Which, if any, of the options below makes sense and has anyone dealt with Freshtec before?

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Decent packages, I haven't bought anything from them but they say they are in Bryanston so if you are around take a drive one day and see.
 

Neuk_

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Are the prices drastically dropping for the LiFePo batteries? Would it be worth it to get LA batteries now and then invest in a bigger LiFePo battery pack a few years down the line (5 years give or take).

As @MidnightZA says, if all you want is backup then LA's will do the job but if you are looking at expanding your system with PV then LiFePo are a far better choice, they can be cycled daily to take up more of your daily load and recharged using the PV.
 

Mier

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Just consider the discharge rate of the Lithium batteries.
Too low C rating and you won't be able to use the full capacity of the inverter.
 

TheChamp

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Just consider the discharge rate of the Lithium batteries.
Too low C rating and you won't be able to use the full capacity of the inverter.
For a regular backup he doesn't really need all of the inverter, so the 37A from the 3.5kWh Pylontech should be more than adequate.
 

Tinuva

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This question deserves its own thread. I am also considering this exact approach.
Always start with your budget in my opinion. My current system was set out based on a budget I had available.

But if you do plan on adding solar later, make sure you get the correct inverter as that is the heart of the system unless you go with something different than a standard system.
 

MidnightZA

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For a regular backup he doesn't really need all of the inverter, so the 37A from the 3.5kWh Pylontech should be more than adequate.
I have no idea what the discharge rate means or the C rating. But what would that mean in the case of future proofing?

For example if I want to take my house fully off the grid.
I dont plan on doing that anytime soon, but the way this country is going it will seem like a smart idea to plan for it now.
 

Tinuva

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I have no idea what the discharge rate means or the C rating. But what would that mean in the case of future proofing?

For example if I want to take my house fully off the grid.
I dont plan on doing that anytime soon, but the way this country is going it will seem like a smart idea to plan for it now.
It just means there is a limit on the amount of Amps or Watts that can be discharged at a given time from the battery.

So simplistic example. If you run a single pylontech battery, the rating will be low at 0.5c, but imagine you can only do 36Amps or in other words limited to run appliances up to 1500watt. So if you turn on a 1000watt appliance while your house is already pulling 1000watt from the batteries, basically it will die or the cables will overheat.

From my own experience, I was able to pull up to 3900watt from 2x US3000b batteries, which is pretty much what I will ever peak. But in my case, the batteries BMS do communicate properly with the inverter, letting it know, to max pull at 74amps.

The problem come in, when you happily running of solar at 4000watt or more, then a cloud decide to ruin your day, throw a shadow on your panels, and boom the inverter throws the whole load instantly over to the batteries.

This is where you need to spec your system correctly.

Either overspec or enough, or make sure that the backup circuit will only have devices on that will never reach the limits on your batteries or solar etc.

That said, if you start with only lights and a select few plugs (hopefully you can do this at your house, I cant), then it is easy to prevent a problem of batteries with a too low C rating.

Generally speak, on Pylontechs, you just go with 2 or more batteries instead of 1. So think about this in your budget. Go with 2x US3000 or 1x US5000 battery. Actually, I think the US3000c fixed some of this over the US3000b batteries.

The hubbles which powerforum rave about, is fine too mostly I think, just select the correct one, I dont know which one that is haha.
 

signates

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I have no idea what the discharge rate means or the C rating. But what would that mean in the case of future proofing?

For example if I want to take my house fully off the grid.
I dont plan on doing that anytime soon, but the way this country is going it will seem like a smart idea to plan for it now.
C rating is more important with a smaller system but as the battery bank expands this becomes less of a consideration.

The C rating refers to the max discharge rate of the battery. A pylontech us3000 battery is rated at 0.5C so can only deliver up to 1.75kw at any time.

Having one of these on a 5kw inverter could result in the battery switching off if the inverter is pulling more than the C rating of the battery.

I had 3 pylontech us3000 batteries on my 8kw inverter and had on a couple of occasions have the the batteries disconnect as I exceeded the C rating of the batteries. I've since added another battery so the I can pull a mac off 7kw from the 4 batteries at anytime. I plan to eventually have 8 so then the C rating will be irrelevant as the inverter will never be able to pull that amount from the batteries.
 

TheChamp

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I have no idea what the discharge rate means or the C rating. But what would that mean in the case of future proofing?

For example if I want to take my house fully off the grid.
I dont plan on doing that anytime soon, but the way this country is going it will seem like a smart idea to plan for it now.
I would say going with most 48V systems means you won't ever have to worry about the C rating, it simply gives you the amount of continuous current you can draw from.the battery as well as the current you need to charge the battery.

Going with the popular 5kVA inverter and 3.5kWh Pylontech example, the continuous current you can draw from.the battery is 37A, that implies only being able to use 1.7kW out of your 5kW inverter, which is what Mier was talking about.

This is not a problem for your future proofing because adding a similar battery in future now means you can draw 74A from your batteries, giving you 3.5kW, meaning you can still add another battery to make full use of the inverter.
 

Mier

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It's daunting subject when you start from zero, and unfortunately some of these bundled ads don't make it any easier for someone not that clued up on the subject. People don't always know the right questions to ask and end up buying systems without knowing it's limitations. (Especially with those power trolleys.)
The fortunate ones ask questions on places like MyBB and can make an informed choice, but sadly many will never understand why their batteries only lasted 6 months.
 

RonSwanson

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It's daunting subject when you start from zero, and unfortunately some of these bundled ads don't make it any easier for someone not that clued up on the subject. People don't always know the right questions to ask and end up buying systems without knowing it's limitations. (Especially with those power trolleys.)
The fortunate ones ask questions on places like MyBB and can make an informed choice, but sadly many will never understand why their batteries only lasted 6 months.
That's also why boards like powerforum.co.za exist.
 

Neuk_

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I would say going with most 48V systems means you won't ever have to worry about the C rating, it simply gives you the amount of continuous current you can draw from.the battery as well as the current you need to charge the battery.

Going with the popular 5kVA inverter and 3.5kWh Pylontech example, the continuous current you can draw from.the battery is 37A, that implies only being able to use 1.7kW out of your 5kW inverter, which is what Mier was talking about.

This is not a problem for your future proofing because adding a similar battery in future now means you can draw 74A from your batteries, giving you 3.5kW, meaning you can still add another battery to make full use of the inverter.

Either way, unless you go for a very large system intended to get you off grid that you can install and largely forget about, you should be managing loads especially when only battery is available. We have a small 3kVa inverter but still manage to run 'large' loads like a microwave, washing machine, dishwasher, etc. by actively managing the loads based on available supply and supply type. If we get load shed at night and only have battery available I make sure our load is as light as possible to limit drawing too much from the batteries, both to insure they aren't hit to hard and as well as to make sure they last as long as possible.
 

Tariqe

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I have two 2.4 Pylontech batteries on a 5 kW Sunsynk, never had a problem if grid is available, have gone up to 7.65 kW load, we just don’t run heavy loads when grid is not available, I have one socket in the kitchen on the essential circuit and use an extension cord to run the microwave or kettle ( which are used for short periods anyway ), using an extension cord makes you conscious of the loads on the battery
I would start with a Pylontech 5000
 

powermzii

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Can you mix Pylon 5000 and 3000 series batteries? If I do go with one of those bundles with a single 3000 then I could add a 5000 in 2 or so months?
 

signates

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Can you mix Pylon 5000 and 3000 series batteries? If I do go with one of those bundles with a single 3000 then I could add a 5000 in 2 or so months?
UP5000 can be mixed with US3000 and US2000 batteries as long as the UP5000 is set as the master battery.
 

powermzii

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UP5000 can be mixed with US3000 and US2000 batteries as long as the UP5000 is set as the master battery.
Then the roadmap is set so ideally get one of those packs to start, then in 2 or so months get a second battery then a few months later get panels
 

signates

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Then the roadmap is set so ideally get one of those packs to start, then in 2 or so months get a second battery then a few months later get panels
The sooner you can add the panels, the better. If you just need the batteries for loadshedding, then start with the smallest amount you need to get through the loadshedding slot.

Savings are from panels and generating your own electricity.

If I could start over i would first max my panels and go with one less battery. The savings from generating electricity adds up quickly to allow for additional batteries to be added quicker.
 

RonSwanson

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Then the roadmap is set so ideally get one of those packs to start, then in 2 or so months get a second battery then a few months later get panels
As @signates has suggested, if you have limited budget then the easiest (most economical) way to build your system is with panels. Batteries are expensive and best left for later on a tight budget. Use the savings from solar generation to pay for them. Not everyone has the capital to do a "big bang" install, and even then, adjustments are made.
If it means buying something like a Ratel for backup comms during loadshedding, then that's cool, it's a stopgap that will serve you well, and it's a commodity that you can sell secondhand once you are ready and strong enough to go for some Hubble lithium batteries. Keep your eye on the main objective, and your hand on your wallet.
 

Tinuva

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I started with 2x US3000b batteries + inverter. Technically I only needed 1x battery to do loadshedding. The inverter charges slow from Eskom in backup mode.

Then when the CoCT application was accepted, I installed the panels. Now the 2x batteries only last from 8pm to 6am (if DoD gets set to 65% by automation) if we don't run the dishwasher over night. This was a mission to get my wife to change habit. Will only work while we work from home. I would need a 3rd battery to run that too during the night.

The panels, 3300w easily charges the betteries before 1pm currently while running the dishwahser from around 11:30 when we reach enough solar input to run the load. geysers turn on around 1:30pm. problem is they use more than the panels at 3kW and 4kW geysers. So it will be a new smaller element or I need to redo the 4kW 300L geyser. Pain in the but.
 
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