Page 14 of 20 FirstFirst ... 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 LastLast
Results 261 to 280 of 394
  1. #261
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    64
    Posts
    2,701
    Thanked: 1114

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by grantt View Post
    Awesome thread

    Does anybody have any experience with Hoselect?

    https://www.electromannsa.com/produc...ifepo4-battery

    Seems like a really good deal?

    Or would I be better of building my own with the DIY kits from https://lithiumbatteriessa.co.za?

    Regards,

    Grant
    What struct me is that these units weigh about what a lead acid would. Further Electromann give a 22kg value while the battery label shows approximate 12kg.

  2. The Following User Says Thank You to ekkekan For This Useful Post:


  3. #262
    Join Date
    Mar 2018
    Location
    Ellisras
    Posts
    104
    Thanked: 69

    Default Re: Lithium vs Lead Acid

    Any reviews on these, they look reasonably priced(R6,438.00 shipping Inc) , but 1500 cycles seems a bit low.

    https://mhn.co.za/shop/mecer-lifepo4...attery-200-ah/

  4. #263
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    64
    Posts
    2,701
    Thanked: 1114

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by WantOnsKan View Post
    Any reviews on these, they look reasonably priced(R6,438.00 shipping Inc) , but 1500 cycles seems a bit low.

    https://mhn.co.za/shop/mecer-lifepo4...attery-200-ah/
    Price seems good. Bear in mind the cycles are to 100% DOD. If you use 90% as a lot of sellers indicate more cycles should be on offer.
    Some members had problems with these if used in series or parallel. Can't remember.

  5. #264
    Join Date
    Mar 2018
    Location
    Ellisras
    Posts
    104
    Thanked: 69

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by ekkekan View Post
    Price seems good. Bear in mind the cycles are to 100% DOD. If you use 90% as a lot of sellers indicate more cycles should be on offer.
    Some members had problems with these if used in series or parallel. Can't remember.

    Thanks, I missed that, then it should be much more at 80%DOD.
    Last edited by WantOnsKan; 2021/04/15 at 03:24 PM. Reason: Typo

  6. #265
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    64
    Posts
    2,701
    Thanked: 1114

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by WantOnsKan View Post
    Thanks, I missed that, then it should be much more at 80%DOD.
    80% DOD can give 2 times more cycles. You also need to compare the retention % after the said cycles. Both variables MUST be taken into account.

  7. The Following User Says Thank You to ekkekan For This Useful Post:


  8. #266
    Join Date
    May 2007
    Location
    Durbanville Cape Town
    Age
    38
    Posts
    328
    Thanked: 190

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by ekkekan View Post
    Some members had problems with these if used in series or parallel. Can't remember.
    Can connect up to 4x in series, but not parallel. This according to the spec sheets

  9. #267
    Join Date
    Aug 2019
    Location
    Roodepoort
    Posts
    398
    Thanked: 399

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by bees View Post
    Can connect up to 4x in series, but not parallel. This according to the spec sheets
    I have been racking my brain the whole day trying to understand why their BMS doesn't allow parallel connection. The first time in my life I have come across a battery that doesn't allow parallel connection.

    I could probably come up with a few reasons why series connection could pose an issue, but here it's allowed 🤣

    I give up

  10. #268
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    64
    Posts
    2,701
    Thanked: 1114

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by bees View Post
    Can connect up to 4x in series, but not parallel. This according to the spec sheets
    That is correct as per the specs. Member Gerlach reported on batteries that failed when connected in series so one has to be careful and check in use.

    When I read specs listed for say 24V and they list information related to 48V I get worried.....
    Last edited by ekkekan; 2021/04/16 at 11:26 AM.

  11. #269
    Join Date
    Nov 2008
    Location
    Ellisras
    Age
    58
    Posts
    1,484
    Thanked: 1350

    Default Re: Lithium vs Lead Acid

    My take:
    Those cheap 12V LifePO4 batteries have very cheap BMS's fitted. They have very low cell balancing current capability. Meaning they balance cells very very slowly and only when a particular cell is above 3.5V or when the battery is around 14V. In parallel a particular battery might not reach those balancing voltages or stay there long enough for the BMS to be effective. It will therefore have cells lagging more and more behind causing overcharging of the one cell that is above the rest. The BMS will try to protect that cell and disconnect the battery. Then another battery will do the same....So you then have a bank with batteries being randomly disconnected from the parallel set. Chaos from then onwards......

    By disconnect above I mean the BMS will halt current going into the battery....

    Then the worst...If a particular cell drops to 10V it WILL disconnect that battery completely during discharge, who knows what then onwards

    What I do deduct is that the battery will then never really catch up again and keep being a menace


    A solution for those that have such systems already is to remove the offending battery from the set. Charge it fully with any charger. Then connect it to a simple adjustable power supply set at exactly 14.2V, not 14.4V. Leave it for a a few hours to allow the BMS to do its work. Install again. Problem is you will have to do that regularly, maybe to all of them turn by turn.

    For those that want the capacity of 2 batt one could install a simple switching system where you alternate charging and loads from one batt to the other, meaning charge one while draining the other - in this you allow the battery being charged to full charge and give the BMS some chance to work.

    (With LifePO4 batteries you do not have the option to put the bank through a high voltage equalization charge as with Flooded Lead Acid Deep Cycles that are servicable....Dixon DT105DC and Trojan as examples)

    Having said all of this wrt parallel, I also do not believe they will work well in series. Despite the suppliers saying so - I say they do not know what they are saying. If you want a 48V system from LifePO4 cells you should build 16 cells in series and install a BMS that balance all 16...preferably a high current active balancer, not top balancer only.

    And beware, I say the so called top notch Drop in Lead Acid replacements (such as Blue Nova Mobile Series, Relion etc) will probably suffer the same fate....just a more expensive one.
    Last edited by Dungbeetle; 2021/04/19 at 05:13 AM.
    Donít blame yourself over past mistakes. Itís like driving down the N1 while looking in the rear view mirror only.

    2000 Patrol GU 4.2D(onkey) "old-timer" chugging along towards 900 000 km.
    2014 Patrol GU 3.0CRD "teenager" in puberty - 126 000 km
    2007 Echo3 Trailer "the nest" with Braked Axle fitted >60 000 km
    2012 NP300 YD2.5 D/C 2x4 High Rider "platkar" - 125 000 km

  12. The Following User Says Thank You to Dungbeetle For This Useful Post:


  13. #270
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    64
    Posts
    2,701
    Thanked: 1114

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by Dungbeetle View Post
    My take:


    If you want a 48V system from LifePO4 cells you should build 16 cells in parallel and install a BMS that balance all 16...preferably a high current active balancer, not top balancer only.
    Thanks for giving the reasons why lithium can give problems when in series or parallel.

    Just a slip - 16 in series to get 48V
    Last edited by ekkekan; 2021/04/18 at 06:20 PM.

  14. The Following User Says Thank You to ekkekan For This Useful Post:


  15. #271
    Join Date
    May 2009
    Location
    Pretoria
    Age
    57
    Posts
    3,493
    Thanked: 281

    Default Re: Lithium vs Lead Acid

    Dungbeetle

    a long rambling post

    i assume you have empherical data to backup your fairly wild claims regarding the bms involved

    either understand a bms or stick to your ford thingy

    nee boet
    i had a higher bar set for you

  16. #272
    Join Date
    Nov 2008
    Location
    Ellisras
    Age
    58
    Posts
    1,484
    Thanked: 1350

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by ekkekan View Post
    Thanks for giving the reasons why lithium can give problems when in series or parallel.

    Just a slip - 16 in series to get 48V
    Typo fixed now, thanks
    Last edited by Dungbeetle; 2021/04/19 at 05:14 AM.
    Donít blame yourself over past mistakes. Itís like driving down the N1 while looking in the rear view mirror only.

    2000 Patrol GU 4.2D(onkey) "old-timer" chugging along towards 900 000 km.
    2014 Patrol GU 3.0CRD "teenager" in puberty - 126 000 km
    2007 Echo3 Trailer "the nest" with Braked Axle fitted >60 000 km
    2012 NP300 YD2.5 D/C 2x4 High Rider "platkar" - 125 000 km

  17. #273
    Join Date
    Nov 2008
    Location
    Ellisras
    Age
    58
    Posts
    1,484
    Thanked: 1350

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by RossJ View Post

    ...I assume you have empherical data to backup your fairly wild claims regarding the bms involved
    ...
    Please give us your take then.....at least something we can read and get insight from.

    (P.S. I have 2 T-shirts, 1 full of holes burnt by Lead Acid Electrolyte and 1 full of holes burnt by molten solder while building quite a few LifePO4 sets and charging systems.)
    Last edited by Dungbeetle; 2021/04/19 at 05:52 AM.
    Donít blame yourself over past mistakes. Itís like driving down the N1 while looking in the rear view mirror only.

    2000 Patrol GU 4.2D(onkey) "old-timer" chugging along towards 900 000 km.
    2014 Patrol GU 3.0CRD "teenager" in puberty - 126 000 km
    2007 Echo3 Trailer "the nest" with Braked Axle fitted >60 000 km
    2012 NP300 YD2.5 D/C 2x4 High Rider "platkar" - 125 000 km

  18. #274
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    1,004
    Thanked: 1367

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by RossJ View Post
    Dungbeetle

    a long rambling post

    i assume you have empherical data to backup your fairly wild claims regarding the bms involved

    either understand a bms or stick to your ford thingy

    nee boet
    i had a higher bar set for you
    Bugger me, that was uncalled for!?


    Quote Originally Posted by Dungbeetle View Post
    My take:
    Those cheap 12V LifePO4 batteries have very cheap BMS's fitted. They have very low cell balancing current capability. Meaning they balance cells very very slowly and only when a particular cell is above 3.5V or when the battery is around 14V. In parallel a particular battery might not reach those balancing voltages or stay there long enough for the BMS to be effective. It will therefore have cells lagging more and more behind causing overcharging of the one cell that is above the rest. The BMS will try to protect that cell and disconnect the battery. Then another battery will do the same....So you then have a bank with batteries being randomly disconnected from the parallel set. Chaos from then onwards......

    By disconnect above I mean the BMS will halt current going into the battery....

    Then the worst...If a particular cell drops to 10V it WILL disconnect that battery completely during discharge, who knows what then onwards

    What I do deduct is that the battery will then never really catch up again and keep being a menace
    Jip, have seen that on a Daly BMS (16 cells), could not balance the cells over months resulting in DC Ripple each time the BMS decides to disconnect due to 1 cell shooting above 3.65v.
    If this continued I could have lost the inverter.
    Have seen a 250/100 blow because of same, as the BMS disconnecting due to same, and ALL of this happening on like 300w being powered from inverter, with full batteries.

    Found the problem when I got a BMS that had Bluetooth capabilities, could then see the offending cell/s and help them balance faster. Took a few days and it was sorted. Daly BMS I had could NEVER do that. And the Daly I had could not be connected in parallel nor series.

    Reason it can take weeks for a unbalance bank to get balanced is because I've heard the balancing currents are like 30mA.

    Most brand names run at like 3.45v per cell, even 3.4v, to steer well clear of cells overshooting. Less support required.

    What I have seen is some people connecting multiple banks to same busbar, each BMS being a separate unit BUT, as Dungbeatle has said, if one bank disconnects at high charge amps, that would be a dramatic experience when the inverter protects itself due to a high DC Ripple, and switches off, because the rest of the banks also "duck out". That is, IF the inverter can protect itself from a high DC Ripple and not just blow the caps.

    Unbalances cells in a lithium bank is a serious issue, running such a bank at 3.5v per cell (14v on 12v bank, or 56v for 48v) is quite a challenge.

    So with those Mecer drop in's, as with all lithium banks, the core is the charge voltages and quality of BMS, must be able to handle all and sundry throw at them or a cell gets out of balance.

    Can take week or more to balance a bank properly, if you can see each cells volts, can take days, via either Top or Bottom balancing. I do both on 2nd life cells ... a pet project of mine.


    EDIT:
    Most brand names use 15 cells. 16 for some.
    Default advised charge voltages are like 3.45v per cell.
    Me, I'm going to see how 18 cells work with a programmable BMS that can take 20 cells on a system that can handle up to 66v on the DC side. ;-)
    Last edited by the_terrible_triplett; 2021/04/19 at 10:51 AM.
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  19. The Following User Says Thank You to the_terrible_triplett For This Useful Post:


  20. #275
    Join Date
    Jan 2013
    Location
    Friemersheim, Southern Cape
    Age
    59
    Posts
    4,983
    Thanked: 5088

    Default Re: Lithium vs Lead Acid

    After reading all this I think I'll stick to Lead Acids.

    At least I understand them
    Robert van den Berg...(fully vaccinated with two Pfizer jabs)

    '98 Daihatsu Rocky 'The Kitty' (jabbed with 50ppm)
    '02 Daihatsu Rocky 'The Bully' (jabbed with 50ppm)

  21. The Following User Says Thank You to Prof For This Useful Post:


  22. #276
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    1,004
    Thanked: 1367

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by Prof View Post
    After reading all this I think I'll stick to Lead Acids.

    At least I understand them
    There is a lot to be said for lead acid and simplicity.
    But here is the thing, once you delve down into ones particular brand of lead acid cells, study the particular make's documentation, there are caveats in there to make them last longer.

    The bottom line I've seen the last few months with DIY lithium banks, if one does not buy a brand name like Pylontech, BlueNova etc, is that the DIY bank's BMS must:
    1) Have Bluetooth capabilities, to see each cell and be able to program the BMS to ones particular cells bought.
    2) BMS must interface with the system to further mitigate cells "running away".
    3) MPPT, inverter, charger MUST have adjustable charge voltages.

    Victron recently introduced "Limit Charge Voltages" for new lithium banks, even brand names, can sometimes have "issues".
    By dropping the charge volts one can "help" the BMS balance the banks faster.
    Last edited by the_terrible_triplett; 2021/04/19 at 09:49 AM.
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  23. #277
    Join Date
    Feb 2018
    Location
    Pretoria
    Posts
    892
    Thanked: 3114

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by the_terrible_triplett View Post
    Bugger me, that was uncalled for!?




    Jip, have seen that on a Daly BMS (16 cells), could not balance the cells over months resulting in DC Ripple each time the BMS decides to disconnect due to 1 cell shooting above 3.65v.
    If this continued I could have lost the inverter.
    Have seen a 250/100 blow because of same, as the BMS disconnecting due to same, and ALL of this happening on like 300w being powered from inverter, with full batteries.

    Found the problem when I got a BMS that had Bluetooth capabilities, could then see the offending cell/s and help them balance faster. Took a few days and it was sorted. Daly BMS I had could NEVER do that. And the Daly I had could not be connected in parallel nor series.

    Reason it can take weeks for a unbalance bank to get balanced is because I've heard the balancing currents are like 30mV.

    Most brand names run at like 3.45v per cell, even 3.4v, to steer well clear of cells overshooting. Less support required.

    What I have seen is some people connecting multiple banks to same busbar, each BMS being a separate unit BUT, as Dungbeatle has said, if one bank disconnects at high charge amps, that would be a dramatic experience when the inverter protects itself due to a high DC Ripple, and switches off, because the rest of the banks also "duck out". That is, IF the inverter can protect itself from a high DC Ripple and not just blow the caps.

    Unbalances cells in a iithium bank is a serious issue, running such a bank at 3.5v per cell (14v on 12v bank, or 56v for 48v) is quite a challenge.

    So with those Mecer drop in's, as with all lithium banks, the core is the charge voltages and quality of BMS, must be able to handle all and sundry throw at them or a cell gets out of balance.

    Can take week or more to balance a bank properly, if you can see each cells volts, can take days, via either Top or Bottom balancing. I do both on 2nd life cells ... a pet project of mine.


    EDIT:
    Most brand names use 15 cells. 16 for some.
    Default advised charge voltages are like 3.45v per cell.
    Me, I'm going to see how 18 cells work with a programmable BMS that can take 20 cells on a system that can handle up to 66v on the DC side. ;-)

    My experience bears this out my JBD BMS allows you to set the start voltage for top balancing via Bluetooth but the default is 3.45v and what happens is that by the time it kicks in some cells are already at 3.65v and the BMS stops all charging to protect that cell and no balancing can take place. I have seen the following values for the cells 2.8v, 3,1, 3,2 and 3.65v or 12.75v collectively with all charging stopped, you want to be around 14.2v to optimize capacity. When I set the balancing start parameter to 3.0 v it solves most of the problem but still not optimum because it needs bottom balancing as well, the whole performance of the battery has improved dramatically since I installed an active battery balancer. This sorts out most of the balancing issues and it's well worth the additional R500 cost but to Dungbeetle's point the problem starts with a substandard BMS.

  24. #278
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    1,004
    Thanked: 1367

    Default Re: Lithium vs Lead Acid

    It is reasoned that 3.45v, on another forum, being the ideal.
    Too high and the cells are "pushed". Too low and the cells are "pushed".

    One wants longer life, good performance, not very good performance and shorter life. ALL of this is new.

    My BMS balances at 160mA or some such, even it struggles at times.

    Quote Originally Posted by River Rat View Post
    My experience bears this out my JBD BMS allows you to set the start voltage for top balancing via Bluetooth but the default is 3.45v and what happens is that by the time it kicks in some cells are already at 3.65v and the BMS stops all charging to protect that cell and no balancing can take place. I have seen the following values for the cells 2.8v, 3,1, 3,2 and 3.65v or 12.75v collectively with all charging stopped, you want to be around 14.2v to optimize capacity. When I set the balancing start parameter to 3.0 v it solves most of the problem but still not optimum because it needs bottom balancing as well, the whole performance of the battery has improved dramatically since I installed an active battery balancer. This sorts out most of the balancing issues and it's well worth the additional R500 cost but to Dungbeetle's point the problem starts with a substandard BMS.
    I use this to force balance a "runaway" cell, after lowering the charge voltages to 3.4v cause at 3.5v charge per cell, that the Jaibaida BMS defaults on, can be a challenge if the bank is not balanced.

    Two x brake light bulbs with both filaments active per bulb.
    Attached Images Attached Images  
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  25. #279
    Join Date
    Mar 2009
    Location
    Florida
    Age
    69
    Posts
    2,966
    Thanked: 835

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by Dungbeetle View Post


    A solution for those that have such systems already is to remove the offending battery from the set. Charge it fully with any charger. Then connect it to a simple adjustable power supply set at exactly 14.2V, not 14.4V. Leave it for a a few hours to allow the BMS to do its work. Install again. Problem is you will have to do that regularly, maybe to all of them turn by turn.
    .
    Can anyone advise on a simple Voltage adjustable charger (and a supplier). I have a Moto-quip simple 6V/12V charger (not adjustable) but the 12V output at 17V is too high and a no-no for LiFePO batteries.

  26. #280
    Join Date
    Sep 2006
    Location
    Plett/Paulshof
    Age
    55
    Posts
    3,741
    Thanked: 1876

    Default Re: Lithium vs Lead Acid

    Quote Originally Posted by TRON View Post
    Can anyone advise on a simple Voltage adjustable charger (and a supplier). I have a Moto-quip simple 6V/12V charger (not adjustable) but the 12V output at 17V is too high and a no-no for LiFePO batteries.
    Victron 5A, has lifepo4 feature plus BT
    Bruce Hunter
    "your signature should not be used to judge you or your opinions"

Page 14 of 20 FirstFirst ... 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •