June 25, 20242 yr Hi I installed a 8kw Sunsynk inverter with 18 x 550 watt JA solar panels and 3 x BSLbatt 5 kW batteries My question is why will the Inverter throttle the charging of the batteries on a clear sunny day when I have no load - sun is shining flatout but by batteries only charge +- 3000 to 3500 watt If I then switch on the kettle or my heatpump the panels immediately gives more electricity I would like to charge my batteries quicker rather than later in the afternoon
June 25, 20242 yr @FransSmith, You need to check what the default charging Amps is on the inverter. A value of 60A (20A per battery) would be a safe/sensible number. If your batteries are charging @ 3500W, it means (3500/54) = 64 Amps, so that is OKish. You can set it higher (in 5A increments), but remember, the harder a battery is charged, it shortens the lifespan. So you pick your battles....I suppose the charge rate in every scenario is different, specially when there's lots of load shedding around. My preference is: No/little loadshedding/good sunshine => 20A per battery (no grid charge allowed) Med. loadshedding/intermittant => 30A per battery (maybe 1 timer interval Grid charge allowed) High Loadshedding/100% overcast => 40A per battery (2 timer intervals allowing Grid charge) Just a guideline, ramp up or down to suit your environment/requirement. The depth of discharge (SOC%) is also an factor, the lower your SOC at sunrise, one may need to adjust the charging rate accordingly.
June 25, 20242 yr Author Thank you - I am a total novice and don't touch the Inverter settings - what you say make sense and I will discuss with my installer At my previous house I had 3 x 5kw Sunsynk inverters with 4 x 5.5kw Hubble batteries and 11kw of panels - 11H00 in the mornings my batteries were fully charged In this case currently they are full only late in the afternoons and my Inverter throttle back the whole time
June 25, 20242 yr Different battery models have different recommended C values for charge/discharge - can you share the model numbers of your BSL's? 56 minutes ago, FransSmith said: 3 x BSLbatt 5 kW batteries
June 25, 20242 yr It's because the BSL's BMS sets a relatively low voltage for charging (55V), so the current will quickly taper off when the batteries go over 50-60%.
June 25, 20242 yr It could be that your installer set the battery charge amps to 60-65A in order to comply with this NRS restriction of limiting the charging power from Grid to 25% of NMD. He would have to confirm, though, I'm just speculating.
June 25, 20242 yr 4 minutes ago, GreenFields said: It could be that your installer set the battery charge amps to 60-65A in order to comply with this NRS restriction of limiting the charging power from Grid to 25% of NMD. He would have to confirm, though, I'm just speculating. Could very well be; however there are two different Battery Charge Amp settings - so it's still possible to have still set it to charge at full speed from Solar, whilst limiting Grid Charging current.
June 25, 20242 yr 6 hours ago, FransSmith said: If I then switch on the kettle or my heatpump the panels immediately gives more electricity Above statement is then a dead giveaway that your batteries bms's are limiting the charge current and not necessarily the inverter charge current setting. What was the batteries soc when the 3000~3500w was noticed. Like @P1000mentioned bms tapering the charge current. Would it be possible to post solar output curve vs battery soc.
June 25, 20242 yr 3000 - 3500 is the region of 5hr charge rate which is recommended for batteries so as some have said above your installer likely set it that way i also have 3 x 5kw FW eTowers. The bank is capable of insane amount of charge rate but i hardly do even 5hr charge rate. All depends on how much you discharge. You can still adjust to highier charge rate as recommended by your battery manufacturer. Slow charge is good for batteries.
June 25, 20242 yr Author 9 hours ago, FransSmith said: Hi I installed a 8kw Sunsynk inverter with 18 x 550 watt JA solar panels and 3 x BSLbatt 5 kW batteries My question is why will the Inverter throttle the charging of the batteries on a clear sunny day when I have no load - sun is shining flatout but by batteries only charge +- 3000 to 3500 watt If I then switch on the kettle or my heatpump the panels immediately gives more electricity I would like to charge my batteries quicker rather than later in the afternoon 8 hours ago, JayMardern said: Different battery models have different recommended C values for charge/discharge - can you share the model numbers of your BSL's? They are the BSLBATT Powerline 5 https://bslbatt.co.za/bsl-powerline-5/
June 26, 20242 yr 3 hours ago, FransSmith said: They are the BSLBATT Powerline 5 https://bslbatt.co.za/bsl-powerline-5/ Those are good specs. Recommended Continuous Charge is listed at 50A per battery; more than double what you're getting right now (you're currently at approx 20A charge current per battery based on your testing). As a sanity check to be safe, what's the "Charge Current Limit" reading you see on the "LI BMS" Screen when your batteries are at low SOC? Is it around 300A? We'd never want to go that high (because thats not for continuous charging and there's also no way to guarantee perfectly equal distribution of that current between the three batteries), but its still good to check this value to ensure comms is solid. I'm assuming the "Battery" --> "Batt Type" --> "Charge Amps" settting is set to just 60-ish? This is the global battery charge limit (for any source: grid or solar). I can't see any reason not to push this up a little - you'd still be well within manufacturer specifications. In contrast, the right-hand Amp setting on the "Bat Charge" tab (the text-box above the "Grid Charge" checkbox) can be used to limit charging from the grid.
June 26, 20242 yr Yeah, the fact that the battery voltage is 54.3 probably means the inverter is outputting 55V, so it is limiting the voltage.
June 26, 20242 yr @FransSmith, Seeing you've got Solar Assistant, just post a pic of the Battery Settings there. Steps: Click on Configurations Scroll down to Inverter and find a clickable (blue) link named "Settings" Then look for "Battery Charging - Edit" portion (to the right & middle of the page). It will tell you what Discharge and Charging parameters are set. To change: Press on blue "Edit" as in the "Battery Charging - Edit" title Rectangular blocks will appear Hover mouse to the right hand side of the rectangle (Max Charge Current) - a "up and down" icon will appear. Click on the top portion to increase the value by 1 (A). Repeat till you reach your desired new Charging Amps Click "Save" Wait to ensure the green Wait message disappears and the new value is reflected Repeat if necessary Edited June 26, 20242 yr by Sidewinder
June 26, 20242 yr Author Hi - both charge and discharge of the Battery already set at 155A - I followed your steps Edited June 26, 20242 yr by FransSmith
June 26, 20242 yr Hi @FransSmith, Just want to clarify something.... Initially, you mentioned you have BSL slimline batteries. I see your signature says Hubble. Hopefully just a bit of update forgetfulness, I hope! Ok, with charge settings that high, it only leave three options (or more that other people can think of) 1) You do not have enough solar PV to cover that high a charge current. The best way to confirm this is to post a pic from Solar Assistant home page of the: - Battery Power - Battery SOC - Overview 2) As mention earlier in one of the posts, the BMS itself may be limiting charging. Personally I have not seen this happen, as the spec's for you battery is 50A continues, with 100A peak, so should not warrant any investigation. I'm putting my money on not enough solar, as 11200W of PV will give you no more that 7500 - 8000W this time of year. And that happens at +-11h30 here in Gauteng. 3) You may also want to check that your Inverter setting is set to "Battery First" (same procedure as before, just look for "Work Mode Detail" section, then look for "Energy Pattern" and change it. Don't forget to "Save"
June 26, 20242 yr Could you confirm the PV Voltage on the panels while charging, both before, during and after you add an additional load? Just wondering out loud whether your 18x550W panels could be installed 9 in series per MPPT, and what impact it could have at lower morning temps and lower power levels, like while ramping up charging. Again, all just speculation.
June 26, 20242 yr this is from the manual for the BSL batteries. Charge voltage on inverter should be 58.4v. charge amperage 50amps. as P1000 mentioned. i think the charge voltage is too low at 54.3v. Edited June 26, 20242 yr by razzor13bt
June 26, 20242 yr 9 minutes ago, razzor13bt said: i think the charge voltage is too low at 54.3v. The charge voltage is set by the BMS. The voltage that the BMS sets is regulated at the inverter, so naturally it will be lower at the battery when charging.
June 26, 20242 yr Author Thank you - I updated my profile - the 3 x 5kw Sunsynks and 11400 watts of solar panels was at my previous house - I mentioned earlier that I had 4 x Hubbles and they were fully charged by 11H00 in the mornings Currently I have 2 strings of 9 x 550watt panels - One facing North and one facing West (not enough room on my roof to allow all 18 facing north) The panels West start producing at around 09H00 and then pick up - I can see it when I switch on appliances Edited June 27, 20242 yr by FransSmith
June 28, 20242 yr On 2024/06/26 at 4:02 PM, P1000 said: The charge voltage is set by the BMS. The voltage that the BMS sets is regulated at the inverter, so naturally it will be lower at the battery when charging. Had the same issue with my new batteries and the manual specifically says the inverter must be set to 58.4v bulk and float charge voltage. the BMS then has its own settings to monitor and control the battery input and output but it still needs that higher input voltage setting on the inverter. the lithium chemistry batteries charge in 2 stages : CC - constant current and switches over to CV - Constant Voltage . depending on bms voltage and inverter voltage settings if set too low then the battery does not fully charge to capacity. the pic i posted is from the BSL manual that has the recommended settings. https://bslbatt.com/wp-content/uploads/2023/02/PowerLine-OPERATING-INSTRUCTION.pdf https://bslbatt.co.za/wp-content/uploads/2023/03/PowerLine-5-230202.pdf Edited June 28, 20242 yr by razzor13bt
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