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  1. #1
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    Default Advice on replacing batteries: offgrid system

    I think the time has almost come for me to replace my batteries and the question now really is what to get. The current setup is 8*200amh 12v solatron lead acid batteries connected in series and in parallel to get 48v. The system consists of a fairly old 5kw Microcare inverter and 60 amp Microcare charge controller and a total of (6*310W panels and 6*256W) panels. The house runs mainly off gas and low energy appliances and if push comes to shove we manage within our current limits. In winter it gets difficult of course. The challenge is that i do generate excess electricity as the batteries as a rule are full some time before the sun sets. So was thinking of going a single lithium iron battery route of say 7kw which allows far greater draw down than my current setup (which i operate within the discharge parameters of the default settings) and allows for the full utilisation of available sunlight.

    any ideas ?

  2. #2
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    Default Re: Advice on replacing batteries: offgrid system

    Speak to these guys for some good advice - https://rentech.co.za/

  3. #3
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    Default Re: Advice on replacing batteries: offgrid system

    I think you need to make sure your inverter is lithium compatible first...
    BUT, if you can, Lithium is definitely the way to go
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  5. #4
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    Default Re: Advice on replacing batteries: offgrid system

    Quote Originally Posted by BobMabena View Post
    I think you need to make sure your inverter is lithium compatible first...
    BUT, if you can, Lithium is definitely the way to go
    Good advise - will ask microcare

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  7. #5
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    Default Re: Advice on replacing batteries: offgrid system

    About 10kWh "48V" Lithium setup should give you a "similar" capacity as you had before. Efficiency and what you actually get out of your PV will however be much better with lithium.

    Consider modular batteries like BlueNova RacPower or PylonTech batteries to be able to easily add more capacity later without replacing anything.

    https://shop.energyon.co.za/shop/52v...ppower-battery
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  8. #6
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    Default Re: Advice on replacing batteries: offgrid system

    Ouch, that s R55k to replace with lithium,microcare do software upgrades on old units to make them compatable .

    Recently sent my 5kva 24v unit to PE and got the. Upgrade - 2014 model
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  9. #7
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    Default Re: Advice on replacing batteries: offgrid system

    Blue Nova yes, Pylontech no no No!
    Quote Originally Posted by Monkey-D View Post
    About 10kWh "48V" Lithium setup should give you a "similar" capacity as you had before. Efficiency and what you actually get out of your PV will however be much better with lithium.

    Consider modular batteries like BlueNova RacPower or PylonTech batteries to be able to easily add more capacity later without replacing anything.

    https://shop.energyon.co.za/shop/52v...ppower-battery

  10. #8
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    Default Re: Advice on replacing batteries: offgrid system

    Quote Originally Posted by Kamakazi View Post
    Ouch, that s R55k to replace with lithium ...
    On another forum me and a few others have recently pooled our monies and ordered 124 x 280ah Grade A EVE cells from China in a group buy.

    Our thoughts are:
    Set volts per cell to 3.37v so 18 x 280ah Grade A cells = 60.66v which is well within Victron's max volts limits
    +-60.66v x 280ah = 17kWh bank
    Cost: R50 400 (R/$ dependent) including a BMS that can interfaces with the Venus

    Vs https://shop.energyon.co.za/shop/52v...r-battery/#top m their Bluenova, a +-15.6kwh bank probably coming in at +-R 82 179.00

    This idea was born between existing solar DIY users, people who are upgrading banks not prepared to pay brand name prices, who are prepared to mitigate some of the risks themselves.

    The idea behind the lower voltage setting is to ensure the cells last their maximum cycles, capacity topped by adding 2 extra cells.
    And 18 cells is also a form of "warranty" security as one can use as little as 15 cells at 3.45v, whilst one waits for the 3 year warranty replacement cell to be sent. Although there will be spare cells in SA for urgent replacements.

    Just thought I throw this titbit in here.
    Last edited by the_terrible_triplett; 2021/05/27 at 07:38 AM.
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  12. #9
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    Default Re: Advice on replacing batteries: offgrid system

    Quote Originally Posted by Monkey-D View Post
    About 10kWh "48V" Lithium setup should give you a "similar" capacity as you had before. Efficiency and what you actually get out of your PV will however be much better with lithium.

    Consider modular batteries like BlueNova RacPower or PylonTech batteries to be able to easily add more capacity later without replacing anything.

    https://shop.energyon.co.za/shop/52v...ppower-battery
    Ja I guess the way my current setup is structured I probably come out at around 9,6Kwh for my existing pack - but as you said the lithium will certainly give me more put in and take out than the lead acid. I have asked microcare and the solar control battery run to range for the 48v system of between 42 and 50 v would allow (from first take) the parameters of the BlueNova lithium

  13. #10
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    Default Re: Advice on replacing batteries: offgrid system

    Quote Originally Posted by coala View Post
    I think the time has almost come for me to replace my batteries and the question now really is what to get. The current setup is 8*200amh 12v solatron lead acid batteries connected in series and in parallel to get 48v. The system consists of a fairly old 5kw Microcare inverter and 60 amp Microcare charge controller and a total of (6*310W panels and 6*256W) panels. The house runs mainly off gas and low energy appliances and if push comes to shove we manage within our current limits. In winter it gets difficult of course. The challenge is that i do generate excess electricity as the batteries as a rule are full some time before the sun sets. So was thinking of going a single lithium iron battery route of say 7kw which allows far greater draw down than my current setup (which i operate within the discharge parameters of the default settings) and allows for the full utilisation of available sunlight.

    any ideas ?

    I would get a Freedomwon Lite 10/8. You have the ability if you ever wanted to add more as they can be chained.
    10year guarantee, and we have packs that are 7-8 years old that are still working perfectly. Excellent customer service.

    They are going for 65 - 70k depending supplier.

  14. #11
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    Default Re: Advice on replacing batteries: offgrid system

    Quote Originally Posted by HarleyD View Post
    Blue Nova yes, Pylontech no no No!
    Explain a bit more please. Im looking at getting a system. Family member just received his pylontech batteries on Friday. What is the problem there?

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  16. #12
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    Default Re: Advice on replacing batteries: offgrid system

    Compare the specs, especially the battery V and discharge current. Talk to independent installers about issues (comms errors in particular) and look carefully at the warranty.

  17. #13
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    Default Re: Advice on replacing batteries: offgrid system

    Quote Originally Posted by HarleyD View Post
    Compare the specs, especially the battery V and discharge current. Talk to independent installers about issues (comms errors in particular) and look carefully at the warranty.
    I haven't had any comms errors, use CAN BUS with a victron system. No problems.
    You do have to size the battery correctly tho, as you mentioned the charge at discharge currents are a lot lower than other batteries. For the 48V units it is 25A max, so 4 units min for a 5kW inverter ideally 5.
    I have seen installs don't size the batteries correctly and then the batteries have all kinds of balancing iusses.
    Other thing to note is that the are 15S packs not 16S like other brands. You don't want to charge them above 52V.

  18. #14
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    Default Re: Advice on replacing batteries: offgrid system

    Quote Originally Posted by the_terrible_triplett View Post
    On another forum me and a few others have recently pooled our monies and ordered 124 x 280ah Grade A EVE cells from China in a group buy.

    Our thoughts are:
    Set volts per cell to 3.37v so 18 x 280ah Grade A cells = 60.66v which is well within Victron's max volts limits
    +-60.66v x 280ah = 17kWh bank
    Cost: R50 400 (R/$ dependent) including a BMS that can interfaces with the Venus

    Vs https://shop.energyon.co.za/shop/52v...r-battery/#top m their Bluenova, a +-15.6kwh bank probably coming in at +-R 82 179.00

    This idea was born between existing solar DIY users, people who are upgrading banks not prepared to pay brand name prices, who are prepared to mitigate some of the risks themselves.

    The idea behind the lower voltage setting is to ensure the cells last their maximum cycles, capacity topped by adding 2 extra cells.
    And 18 cells is also a form of "warranty" security as one can use as little as 15 cells at 3.45v, whilst one waits for the 3 year warranty replacement cell to be sent. Although there will be spare cells in SA for urgent replacements.

    Just thought I throw this titbit in here.
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  20. #15
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    Default Re: Advice on replacing batteries: offgrid system

    I think it really depends on how you would like to use your system.

    If you just looking for backup power during load shedding, using gel batteries should not be a problem.
    If however, you charge and discharge on a daily basis, then Lithium is the way to go.

    Due to advances in technology, it think it might be better to upgrade the complete system?
    Yes, Lithium can work with just programming voltages, but using the communication interface is just so much better.
    All the parts in the system is then "talking" to each other.

    As mentioned, look very closely at Lithium specs.
    Things like 2nd life, discharge curves, life cycles and C ratings is extremely important.

    Make sure you get a decent price for your old batteries.
    Battery shops offer R50 per unit but you can get up to R10 per kg!!!


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