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igg

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  1. It's the standard unit as linked in the OP. Marked as 200A charge/discharge, but general opinion is that you should halve that. No bluetooth. Pictured below when it was still in use:
  2. Over the last week or so I've been noticing my solar yield has dropped off sharply. I have a 2x2 array of 405w CS panels. It looks like at some point in the day, one of the strings will stop producing. I've just pulled the fuses on the string 2 with no drop in solar yield. All 4 panels are currently in full sun; string 1 is measuring a 68-70v, while string 2 is all over the place from 22-38v. What would be my next diagnostic step here? I'm assuming one of the panels in string 2 is faulty. Also, does anyone know the warranty duration on CS panels; this install isn't even a year old with the panels being extremely difficult to access :(.
  3. Daly 200A48V Common Port BMS (https://www.aliexpress.com/item/32888385718.html?spm=a2g0s.9042311.0.0.212c4c4ds4sskw) R1900 Originally installed in March 2020, removed in Jan 2021. I pinched one of the balance leads at some point, but it only broke a few strands and not all the way through. Added a blob of solder to rejoin all the strands and ensure balance leads remained same length. Otherwise in perfect condition. Available for collection in Weltevreden Park, otherwise shipping can be arranged at buyer's cost (Postnet preferred).
  4. I assume it's this one: https://www.aliexpress.com/item/32997552090.html?spm=a2g0o.productlist.0.0.98612689xH5UV9&algo_pvid=9c57c7d2-d767-49c6-88f7-452a1dc47064&algo_expid=9c57c7d2-d767-49c6-88f7-452a1dc47064-5&btsid=0ab6f83115944754191536779e56d5&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_ I looked at that and then went and got the Daly instead... oh well, hindsight and all that. I actually had the batteries resting for a month on the Daly BMS, but I guess since they do voltage balancing and my cells all like to rest around 3.3v the balancing function would never have worked for SoC. The 20ma balance is way too small to do anything during charge. Hence the process of putting them all in parallel and slow charging them with a bench PSU for a few days. So now the Daly is just relegated to doing the high/low voltage cell protection.
  5. Thanks for this. Are you sure that the dynamic cutoff is only used in when grid connected, the ESS docs seem to imply otherwise (https://www.victronenergy.com/live/ess:design-installation-manual#dynamic_cut-off) The Dynamic cut-off mechanism effective both when mains is available and during a mains-failure (system is in Inverter mode). The primary scenario I'm trying to avoid is having the battery sitting at 40%. Then turning on a microwave for 2 minutes resulting in a cut-off due to a voltage droop. If this happens during no grid supply, I assume I'll unnecessarily lose power to everything. The BMS I'm using is a Daly, so it will only disconnect the DC bus when a cell hits 2.5v, which I believe is too low for typical operation. So I assume a flat curve from 49 down to 48 should be good for my needs to get rid of the pre-alarms and have it cutoff at safe levels.
  6. Thanks, yea; I went through a similar trial phase that resulted in me buying a bench PSU so I could top balancing all my cells. The cells were all resting at the same voltage, but most definitely did not have the same SoC, so I had some cells spiking to 3.7v while the rest were at 3.3v during charge. I settled on 54.5v bulk/absorb and 53.7v float after that, so almost the same as your numbers, and have been running without issue like this. Also yes, using a Daly BMS, which I'm really not happy with... :(. It's a really expensive black box that has given me quite a lot of grief figuring out why it would just randomly disconnect the battery. It also causes the inverter to misread the voltage by +-1.5v during charge, so I ended up sticking the BMV between it and the battery to get accurate readings. I only added the PV array with ESS this weekend, so still trying to figure out how to ensure the MP2 won't just randomly disconnect me under normal operation. If I understand correctly, that means Pylontech recommends not using the dynamic curve and just set everything the same. So for a 16s the equivalent would be 49v?
  7. So I've finally finished installing my backup system (just in time for load shedding it seems), and I've configured the ESS assistant. My question is this, are the voltages Victron have for the dynamic voltage cut-off extremely conservative? I've left them at defaults, but I feel like I should be lowering them quite a bit: 0.005C = 52V, 0.25C = 50V, 0.7C = 49.2V, 2C = 48V. With the standard 1.2V delta, and 50V sustain. My setup is a 48v system with the following components: Victron MP2 3000, 16x 120ah LifePo4 (https://lithiumbatteriessa.co.za/collections/cells/products/3-2v-120ah-lifepo4-lithium-ion-phosphate-battery-cell?variant=31983589359706), SmartSolar 150/35, 1640w PV array, BMV712. Now my basic understanding is that the MP2 can't even pull more than around 55A (0.46C) from the battery at full load, and my typical load is only around 7-9A (0.05 - 0.08C). The defaults give me low battery warnings from as high as 85% due to this. Does anyone have a suggestion as to what would be a more reasonable curve for my setup? Before I installed ESS I just had a the hard cutoff at 48V. I'm thinking 0.005C = 50V, 0.25C = 48.8V, 0.7C = 48V, 2C = 47V, with a sustain at 49V.
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