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Chris Hobson

Which batteries should I buy (rhetorical question)

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Having done some reading the discharge rate of LiFePO4 is based the thickness of the layer of active material on the anode and cathode. A thin layer leads to a thinner separator and a shorter distance between the Anode and cathode for the diffusion of Li+. Engineering thin layers of active material is expensive. We can see this in Plonky's Victron LiFePO4 batteries which are much more expensive but have discharge capability of C½. It also seems that the capacity of a LiFePO4 is based on 140mAh/g of active material.

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Bit the bullet and ordered the 15/11 battery from Freedomwon. Install will be next week hopefully. Works out to R6413/kW ex VAT.  

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Hi all

I've been reading this topic with a lot of interest as I sit with a situation where all 8 my batteries have gone bellyup - just over 2 years of use and R24K down the toilet.

I need to get new batteries as my system is down at the moment and it seems the  Pylon Tech Lithium Ion batteries are the way to go.

Where is the best place to buy in GP - cost wise?

What would the cost be for 2 units plus a cabinet?

A big thank you to the experts that make life easier for non-techs like me :)

Thanks

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1 hour ago, Henkt said:

Hi all

I've been reading this topic with a lot of interest as I sit with a situation where all 8 my batteries have gone bellyup - just over 2 years of use and R24K down the toilet.

I need to get new batteries as my system is down at the moment and it seems the  Pylon Tech Lithium Ion batteries are the way to go.

Where is the best place to buy in GP - cost wise?

What would the cost be for 2 units plus a cabinet?

A big thank you to the experts that make life easier for non-techs like me :)

Thanks

Which inverter do you have? I can source you some batteries in Johannesburg 

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I bought the Pylontech batteries for R15 000 per battery and the Full Circle Solar combined cabinet for R4 200 on a special in Dec.

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1 hour ago, SilverNodashi said:

Which inverter do you have? I can source you some batteries in Johannesburg 

I have 2 x Axpert MKS 5KVA converters.

12 Renesola 305W panels - 3x3 on the one inverter and 3 on the other (west facing).

The batteries I had - 8 x Monbat 12MVR180 in two banks

They are punted as deep cycle but are not :(

 

 

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On 1/17/2018 at 12:11 PM, Tersius said:

Bit the bullet and ordered the 15/11 battery from Freedomwon

Had to fix a bug today for a FW customer who complained that he can't set the inverter power limit to more than 100kw. (yes... kilowatt). 'twas a case of "640k ought to be enough for anyone". You can build some seriously big setups with lithium batteries and enough inverters in parallel.

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7 hours ago, plonkster said:

Had to fix a bug today for a FW customer who complained that he can't set the inverter power limit to more than 100kw. (yes... kilowatt). 'twas a case of "640k ought to be enough for anyone". You can build some seriously big setups with lithium batteries and enough inverters in parallel.

Crazy, is this for private use?

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19 hours ago, Henkt said:

I have 2 x Axpert MKS 5KVA converters.

12 Renesola 305W panels - 3x3 on the one inverter and 3 on the other (west facing).

The batteries I had - 8 x Monbat 12MVR180 in two banks

They are punted as deep cycle but are not :(

 

 

My batteries also started failing after two years, while they were punted to last 10-15 years on floating. I just hope the lithium lasts the claimed 10 years. Makes me wonder how one should maintain these deep cycle sealed battery types so that they last. Seems the only lead acid that lasts are the un-sealed ones you have to vigorously maintain and baby.

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23 minutes ago, Tersius said:

My batteries also started failing after two years, while they were punted to last 10-15 years on floating. I just hope the lithium lasts the claimed 10 years. Makes me wonder how one should maintain these deep cycle sealed battery types so that they last. Seems the only lead acid that lasts are the un-sealed ones you have to vigorously maintain and baby.

Its this case that was enough for me to go Lithium. I hope i get 10 years out of them as well.

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2 hours ago, Tersius said:

My batteries also started failing after two years, while they were punted to last 10-15 years on floating.

Makes me wonder how one should maintain these deep cycle sealed battery types so that they last. Seems the only lead acid that lasts are the un-sealed ones you have to vigorously maintain and baby.

The 10-15 years is on standby, not when used to say 50%, then maybe 2 years. Therein the effort we put in with BMV's.

Vented lead acid, like Trojans T105RE's can last 10 years if they are not used below 20% DOD. BUT, if use hard, they will give you 1600 cycles, about +-5 years. Good thing with them they are tried and tested, and you get what you paid for. Lithium obviously is better new tech.

Depending on use, temperature etc, they may need water every month, or even 6 months. It is also good to check batteries regularly in any event. In my case, every 30 days my controller auto equalise them batteries, and every 2-3 months I add more water. Batts are in a hot braai room inside a wooden box on wheels.

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5 hours ago, Tersius said:

Crazy, is this for private use?

I seriously doubt it!

Unofficially the blue kit can build systems up to 270kw. If you use 18 x 15kva Quattro inverters, and build a 3-phase system with 6 units in parallel on each phase. This is however the largest one I've heard of so far. The customer wanted to cap it at 100kw... which means that the equipment he has installed can do more than that! ;-)

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Just an update the battery was installed last Friday and most of the house has been running "off-grid" for an average 50% DoD. Solar panels are now finally showing their full potential instead of the instantaneous use which used to give about 7-10kW per day the array is now doing 15-20kW per day to charge up the battery.

Ovens, stove and solar geyser and one kitchen plug still on Eskom.

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2 hours ago, Tersius said:

Just an update the battery was installed last Friday and most of the house has been running "off-grid" for an average 50% DoD. Solar panels are now finally showing their full potential instead of the instantaneous use which used to give about 7-10kW per day the array is now doing 15-20kW per day to charge up the battery.

Ovens, stove and solar geyser and one kitchen plug still on Eskom.

Hi Tersius

Once you have ironed out your install perhaps we could ask you to give us your opinion on the FreedomWon modules. There are lots of folk who are looking to make the change and the lithium market is nearly as diverse as the lead acid market.

 

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On 2/9/2018 at 11:47 AM, Chris Hobson said:

Hi Tersius

Once you have ironed out your install perhaps we could ask you to give us your opinion on the FreedomWon modules. There are lots of folk who are looking to make the change and the lithium market is nearly as diverse as the lead acid market.

 

So been running the system for about two weeks now and got most of the settings sorted out.

My current setup thus is an untidy bunch consisting of:

3600W Array of 12x300W Panels

Outback Flexmax 80 Charge Controller

MLT 8KVA Powerstar Inverter

Freedomwon 15/11 battery. 

A battery controlled 100A contactor that disconnects the solar panels if the battery disconnects, required because the MPPT does not turn off quick enough and might damage inverter if battery is not present to provide voltage reference.

The battery provides canbus and several analog outputs of which two provides SOC % and max charge current % because the powerstar does not have canbus. Inverter is setup to allow draw from battery until 45% SOC after which it floats the battery and switches over to eskom to power the load. If power goes off it will allow it to run down to 30% SOC before it will shutdown. The battery self will isolate by 15% SOC.

The battery uses an Orion BMS Jr. I can interface with it via a USB to Serial cable and the provided utility to see lots of different battery details such as SOC, Cell Voltages, Avg Temp etc. Can also modify the settings. (Probably means voiding your warranty though).

The battery was delivered in a wooden crate and it took 4 men to carry it inside the room since it weighs about 154kg, it was hanged on the wall after some effort. It has a SOC bar display, reset and breaker on the front, serial connector on the left, DC, CAN and Analog out in the right. 

In the last two weeks we averaged about 35-45% DoD which is about 6kw during the evening, the array quickly recharges the batteries and on sunny days the battery is 100% around mid day.

Price wise I was lucky to have gotten dealer prices and I was able to claim back VAT, so it came in at +-R6500/kW ex or R8900@70% DoD ex. So one major CON for the battery is price. For a normal home user the price would have been R8,664/kW incl. or R11800@70% DoD incl.. At that price point the Bluenova and Pylontechs batteries blow it out of the water, but I was lucky. Also their factory is 5km away from me.

They warrant the battery for 10 Years or 3500 cycles at 70% DoD. At the end of life it will then have 70% capacity left i.e. about 11kw. I'm cycling it at less than 50% so it should do about 20 years and 7000 cycles. What is quite nice is that I can later trade in the battery and Freedomwon will give you discount on a larger battery based on the pack age and cycles done. So it opens up an upgrade avenue. It can also parallel with 3 more for a total of 4 batteries or 60/44 capacity, recommended to rather upgrade after 3/4 years instead of adding more batteries.

All in all I'm happy with what I got and time will tell how it performs after 10/20 years.

Specs  :http://www.freedomwon.co.za/images/pdf/litebatteryspecsheet.pdf

.5a86c1250452c_WhatsAppImage2018-02-03at5_24_55PM.thumb.jpeg.f5afb40d74100ebac0b640d3d03bff4d.jpeg 

Freedom Lite Installation Manual Rev 5 (1).pdf

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I was led to believe that the BMS uses the same (CAN) protocol as the BYD battery, which is also used by LG-Resu, and also used by Pylontech. Though it seems there are tiny differences between them.

But their website seems to suggest they are using ODB2 (aka SAE J1939). It probably does not matter. These things all work the same way, they stuff all the data end to end into 8-byte packets with either the 11-bit ID in front or the extended 29-bit one, and chuck it onto the can bus. All you have to do is read them, chop it up in the right spots, potentially swap for endianness, and you're done :-)

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