Current Surge Limiters, 4kw Inverters, and LFP Batteries...

Sorry if this has already been discussed (I tried my best at searching this forum but didn't really find anything yet), and if so please direct me to the proper post  :smile:

Today I had delivered an AIMS 4000 watt inverter (24v to 120v, and yeah I know it's no Magnasine, but I'm saving up for one two or three! lol), however before I hooked it up to my Battle Born battery bank, I noticed that BB now is selling a Current Surge Limiter (CSL500) for large inverters.  For what I found earlier, it is meant for inverters greater than 4kw.  At first I thought I was free and clear to go ahead and install the AIMS 4kw.  But then I found a YouTube series of a 24v upgrade where they installed two Victron 3kw inverters and both had these CSL500's on them and was curious why if the inverters are only 3kw.

My first hunch were the Victrons were paralleled... 6kw total so maybe they need the CSL500's.  But I can't seem to find another system out there that was using BB batteries and a 4kw+ inverter to see if they had any trouble.

I contacted Battle Born and they said that yes I definitely need the CSL500 for my new inverter.  And in fact, they were awesome enough to send me pdf's of the CSL500 that appear to be updated from what I could find online.  (I attached them to this post)

So I'm basically looking for insight/experience of anyone either using the CSL500's or if someone has used a 4kw inverter without the CSL500's... there is so little info on this out on the intertubes that as of right now, with the new data sheets Battle Born provided me today, I will likely need to get a CSL500 to install the new inverter.  I love my Battle Born batteries, they've been absolutely great and in fact I intend to get four more to double my current bank next month.  So spending $280 to protect almost $10k of batteries is really a no-brainer.

Just curious to what others have found/experienced.

Many thanks in advance!!!
6.4kw solar, 3x MidniteSolar 150, 200ah LFP @ 24v off-grid

Comments

  • mcgivormcgivor Solar Expert Posts: 2,506 ✭✭✭✭✭
    The surge occurs during the initial connection or after a disconnect by the BMS and subsequent reconnect of the inverter due to capacitor inrush. The larger the inverter, the larger the capacitors, this inrush can overwhelm cells in the battery causing a reverse in polarity, if the battery capacity is small in relationship to the inverter this becomes more of an issue. There may be more potential for damage due to the Battle Borne's use of hundreds small cells (a speculation ), so their BMS is calibrated to restrict discharge currents to a lower threshold than the capacitors require.The questions to ask Battle Born is, if the battery capacity is much greater, say 800Ah, would there still be a need for this device and how much energy the device actually uses itself because it will continue some.
        

    Out of curiosity do you have 24V 50Ah , or 12v in series, why I ask is because you cannot series connect this type of battery.

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
  • BB.BB. Super Moderators, Administrators Posts: 28,315 admin
    I was wondering about series connected Battle Borne Batteries too... Because the CLS 500 documentation shows them being used in a 48 VDC bank.

    https://www.solar-electric.com/lib/wind-sun/Battle_Born_Manual.pdf
    Series

    Up to four BB10012 batteries may be connected in series to increase the voltage of the system up to a 48V system. When batteries are mounted in series, current capacities remain the same, but the system voltage is additive. Two BB10012 batteries mounted in series to form a nominally 24V system should be charged using a bulk and absorption voltage of 28.8V, and a float voltage of 27.2V. Four BB10012 batteries mounted in series to form a nominally 48V system should be charged using a bulk and absorption voltage of 57.6V, and a float voltage below 54.4V. Batteries to be connected in series should be at the same state-of-charge before they are connected. For best results, fully charge each BB10012 battery using a 12V charger prior to connecting them in series, in order to ensure that they are at the same state-of-charge.
    ...
    Maintenance 

    Battle Born Batteries require very little maintenance if any at all. If your batteries are in series and not being charged by a multi-bank charger it is recommended that you fully charge the batteries individually once a year. This will balance out the entire battery bank to ensure the batteries will reach its expected life span. If your batteries are in parallel this is not necessary. Our BMS has a built in passive balancing system that will take care of this for you.

    It does appear that (at least) one model does support 48 volt battery banks

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mcgivormcgivor Solar Expert Posts: 2,506 ✭✭✭✭✭
    BB. said:
    I was wondering about series connected Battle Borne Batteries too... Because the CLS 500 documentation shows them being used in a 48 VDC bank.

    https://www.solar-electric.com/lib/wind-sun/Battle_Born_Manual.pdf
    Series

    Up to four BB10012 batteries may be connected in series to increase the voltage of the system up to a 48V system. When batteries are mounted in series, current capacities remain the same, but the system voltage is additive. Two BB10012 batteries mounted in series to form a nominally 24V system should be charged using a bulk and absorption voltage of 28.8V, and a float voltage of 27.2V. Four BB10012 batteries mounted in series to form a nominally 48V system should be charged using a bulk and absorption voltage of 57.6V, and a float voltage below 54.4V. Batteries to be connected in series should be at the same state-of-charge before they are connected. For best results, fully charge each BB10012 battery using a 12V charger prior to connecting them in series, in order to ensure that they are at the same state-of-charge.
    ...
    Maintenance 

    Battle Born Batteries require very little maintenance if any at all. If your batteries are in series and not being charged by a multi-bank charger it is recommended that you fully charge the batteries individually once a year. This will balance out the entire battery bank to ensure the batteries will reach its expected life span. If your batteries are in parallel this is not necessary. Our BMS has a built in passive balancing system that will take care of this for you.

    It does appear that (at least) one model does support 48 volt battery banks

    -Bill


    Thats interesting, all the manufacturers I contacted said no to series connected but could make any nominal voltage required. Never asked Battle Born as I had decided on prysmatic cells, which they are not, learn something new every day.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
  • ShadowWolf180ShadowWolf180 Registered Users Posts: 4
    Hi All and thanks for the replies.  :smile:

    Mcgivor, you are right about the inrush, I guess I was led to believe that if these batteries could do a constant 1C discharge, and even a momentary 2C+ discharge, then I wouldn't have to worry about using the CSL500.  But then again, maybe these large inverters do draw so much current when first connected to charge the capacitors that even on a moderate Battle Born bank there could be some worry with the safety cutoff of the BMS.

    As for my BB's, I currently have four 12v 100ah versions, wired in 24v.  So it gives me 200ah and according to documentation should be able to give up more than 400 amps for a moment if need be.  I tried out two of these in series a year ago and loved them so much I bought two more.  Next month I plan to double the bank to eight.  I have put the four I have to decent real-world testing, and have drawn over 120 amps from these four at times.  

    When the BB's came out, they initially said they could be wired in series up to 48v, then I noticed a few months later that 24v was still ok, but to hold off on 48v until further testing was done, and now Battle Born says 48v is fine again.

    I guess every new technology goes thru its growing stages, but it certainly seems like they are definitely proving the LiFePO4 tech to be solid so far, albeit now with a small caveat or two.  Heck, it seems the field of manufacturers is steadily growing, Battle Born wasn't the first but they're joined with ReLion, AIMS, Renogy, Simpliphi, KiloVault, Iron Edison, not to mention other new comers.  

    So unlike many other Battle Born customers who run maybe 4, 5, or 6 in an RV, I have lots of room to grow in my house and would love to eventually have 12 or 14 of these batteries wired in 24v to run everything my heart desires off-grid.  And I'm not knocking Battle Born in the least, but it seems the usage of the CSL500 could mean that they need to tweak their BMS' some?  I dunno.  Also lures my curiosity to the other manufacturers of LFP batteries, and how their BMS stacks up to large inverters.  :smiley:

    So your question about an 800ah bank (or in my case next month, 400ah @ 24v) is one I've been thinking about too, would a CSL500 even be necessary?


    6.4kw solar, 3x MidniteSolar 150, 200ah LFP @ 24v off-grid
  • jonrjonr Solar Expert Posts: 1,188 ✭✭✭✭
    The CSL500 protects the BMS from damage or limiter activation -  not the batteries.

    Alternatively, you can use a resistor to get inverter capacitors charged.
  • ShadowWolf180ShadowWolf180 Registered Users Posts: 4
    I did take a set of two 200ah SLA batteries I had and hooked the new 4kw inverter up to them instead of my LFP's.  I know the inverter is in good working order.  So now it's a matter of patience to get the CSL500.  :smiley:

    I could probably "cheat" now that the capacitors are charged from my SLA's and connect it to my LFP bank without much inrush risk, but I would rather wait and play it safe with my LFP investment.  I'll be placing an order with NAWS soon for a CSL500.
    6.4kw solar, 3x MidniteSolar 150, 200ah LFP @ 24v off-grid
  • mcgivormcgivor Solar Expert Posts: 2,506 ✭✭✭✭✭
    Probably a wise decision to follow manufacturers recommendations, as the warranty may/would be dependent on the use of recommend  equipment. There are many unanswered questions  which I will ask BB, for my personal curiosity, which I will share, they are very forthcoming and look forward to their replies 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
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