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What happens if you parallel two identical cells but with different unmatched voltages? How close should the voltages be before putting two cells in parallel? Can a really high voltage cell be added to a balanced bank of much lower voltage paralleled cells(say a 7P config), for example, 7P cells...

I simply slide the switch from external power to being powered through the sense wires.... you get an instant reading of all the cell voltages. You are correct, i'm talking from the perspective of an RV which gets basically shut down for the winter. If the pack is around 50 - 60% when the main...

Having problems trying to get the Victron connect program to find my 24/3000/70 unit. Drivers installed. Connect software installed. UTP cable tried in both ports of multi. Have the MK3-USB connector connected up, with UTP cable going to UTP port on multi. Tried scanning on the victron connect...

It is 8 x 280Ah/3.2v eve cells as a straight 8 in series. (this is a DIY pack build, not a prebuilt battery.) The BMS was a completely seperate entity that i had to purchase for protection....think maybe we are comparing apples and oranges :)) On a properly configured pack, the BMS should never...

wow...i always thought damage was done below 2.5v. Did they attempt to explain the technicalities behind this....that would be good info to know.

Thanks Joey, I'm not particularly keen on Megafuses, but open to your suggestions. The inverter output can peak at 6000W (for a few seconds) and with the 24V setup, im estimating that it could draw 250A. I would prefer something that could be 'reset' rather than replaced if blown. I really dont...

What length would you think ok? I have these already on their way, so not keen to order others. Any other 'safe' fixes you can think of? Thanks for your input.

Thanks EllaBella, i have a good idea about the layout of the various components, it was simply if there was a conflict of code with regards to the inverter/charger, sometimes being grid powered thus earthed through grid supply connection but other times, there would be none. I'd be using a 48v...

Got word back from JasonWang, the 100mV shunt would not be ok....so at least that is clear. Too bad about your snowfall Steve....i dont envy you that.

Conundrum.... Powering down a RV for winter storage, ideally whereby the negative terminal on the house battery is disconnected, but the BMS is still connected/powered via the sense cables, could the BMS take a 280AH pack down below LVD over a six month period, more so if the pack was put to...

Still trying to figure, if the 'repeated absorption time' means the time between each successive absorption pulse or else is it the length of time that these subsequent pulses actually last for???

You could maybe look at these...not sure how suitable though... https://www.alibaba.com/product-detail/5A-Active-Equalizer-Balancer-3S-4S_62357932989.html?spm=a2700.7724838.2017115.48.43624527VDGQOE or...

Just for interest... I have taken a picture of the items i have sourced for my winter 'bus to camper conversion' project. I've still to to fund a Victron SCC, but i'm getting there. :) I also opted for 2x 370W longi HiMo4 Black Framed Split Cell Mono (white backsheet) from a UK supplier.

You are lucky to get three 370W panels onto your available roofspace. Because my VW crafter coach narrows at the top so much, the over hang is too much when these panels are mounted across the vehicle...i had to settle on just 2x 370 panels re orientated. :-( Thought for a long time at doing...

Anyone care to explain their recommendations for top balancing (16x)3.2v 400Ah cells, which will be configured as a 16s 48v lifepo4 battery bank? Lets assume one cell is out by a significant margin.....best method to deal with it?

Oh...im not saying your wrong....just bouncing about idea's and opinions...all just a learning curve to me. (y)

Cheers DZL. I'm not sure these are as readily available in UK, but i will cost out online.

Thanks snoobler. I had thought that so long as the middle terminal was getting the required voltage it would operate. What about going through an Inverting remote on-off cable then? Going by info on ( https://www.victronenergy.com/upload/documents/Inverting-remote-on-off-cable-EN.pdf ), in...

In a Lifepo4 battery pack system, whereby charging would be 0.1CA, discharging would be 0.4CA(10% of time)& 0.1CA (90%of time), running from 3.1V/cell to 3.4v/cell capacity wise....any reason to consider any balancing measures whatsoever? If pack is top balanced initially and then never taken...

Thanks gnubie Ok, changing train of thought, could the item listed below, be used to charge each individual lifepo4 cell to exactly 3.65v, seperately, before being paralleled together to top balance...

Thanks for the reply gazoo....only reason i thought the pack might be full at 3.4v if left for amps to tail off, was because of this chart below...

Moving RV. He envisions a short earth rod pounded in with a hammer and soaked with water. I dont fancy the idea myself, but everyone says that i must get the system 'checked out by a qualified electrician', but having done so, i'm now getting told frequently that he is wrong in his assertions...

Knowing that bottom balanced pairs of paralled cells 'self balance' , would a single 16s BMS protect all 32 cells in a 2P16S configuration? Any downsides?

@FilterGuy OK, my theory is, that you need the highest possible PD(v) to drive the electrons for the quickest charge rate. With solar input being minimal, you want to capture it as quick as possible. You dont however want to terminate your charging at that high voltage end point. So, you set the...

Yes im aware of that function, but if connected through the sense wires, even at a very low draw in storage mode, you are still in reality unprotected in a low voltage situation? Take for example a situation where you think you are putting pack into storage at 50% capacity, but in reality it has...

Hope you haven't just been Riden :ROFLMAO:

How can you tell if the following item is suitable for continuous duty......i'm assuming so long as the DC side is powered up, then the 240vac can flow through the other side??? As soon as the DC is disconnected from BMS, the the AC switch breaks? Is that correct and could this be left powered...

@Steve_S Can you offer any guidance on good quality resistors, plus how do you calculate exactly what resistor you need? Is it based on the ratting of the two relays or the expected max continuous amperage or peak amperage? Picasso mentioned in another post that NTC resistors were thermistors...

Cheers justin. I knew where the edit button was, just didnt think i could edit the title....now done. I seen that portion of the spec, but on the competitors datasheet, it gives a range. No big deal really. Thanks for trying. (y) I would love to go with the victron product for reliability...

yeah....but nothing for a 600 shunt. :-(

I read, that so long as you dont flatten them, they spring back. I suppose a lot will depend on the thickness and quality as to how robust they will be??? Would you mind clarifying a basic engineering point for me(need confirmation of my thinking) If the load is 300kgf, and you have six threaded...

I have an obsolete aquarium undertank mat heater that gently pulses heat to maintain a steady 25degC ....i assume i could make use of that to keep the battery at the preferred temp??? It runs off 240vac but the wattage is low. Should work so long as battery containment is insulated and not...

My AH didnt change, because the 'BMS load' is less than 1A, so not recognised.(im still on ver4.0). The bit i dont understand, is, why does the WH value change when the system doesnt change the AH?

Delta at top of charge cycle 201mv ...cell average of 3.535 when the runner hit 3.65v(no bms balancing). Noticed the divergence starting at 27.36v(3.42v/cell) Delta a bottom of discharge cycle 383mv...cell average of 2.75v when the runner hit 2.5v(same cell) Point to note on my previous last...

Yeah, your promaster is much better in that respect.... much squarer shaped vehicle....mine curves in a lot at the top. As regards weight, i tend toward over engineer everything for safety, and thus by the time i allowed for substantial 'c-section' runners etc, it just didn't seem worth the...

Just started my first ever top balance of a battery bank...nerves jangling a bit....lol (8x280ah in parallel) Is there any harm in leaving a digital multimeter connected across the pack for hours at a time? Also, i noticed that after having set my bench top power supply to 3.63v it has crept up...

Got a reply from Jason.... "Power BMS using the sensing wires don't affect the BMS work normally. It is isolated internal of BMS, if power by bms by 24V battery but using separate cable, it has same result. need not do this as you suggested." I've made Jason aware of this conversation....he...

To be honest, i'm not overly concerned as i'm really only dedicating my chargery to the task of measuring voltage and providing protections. I'm not relying on it for SOC calcs or balancing function.

What is RTFM? What the document states is "Please use correct current shunt according to actual maximal charge and discharge current, singe shunt is enough for BMS16T, 75mV or less shunt is suggested" That does not specify a maximum in my english.

I cant. I've tried already using an old laptop running vista and it was a complete no go. :-(

Maybe my understanding of 'active' balancers is wrong, but i thought that they 'actively' balanced all the time on both charging and discharging, ensuring that the cells stayed balanced all the time. I didnt think it was something that was 'triggered' at set points etc. So i'm thinking, the pack...

Thanks Gazoo, When i was parallel charging the first time, i turns the voltage to 3.65v and had the current dialed up to maximum. Then i connected the load/battery pack. The unit stayed in CV mode and the current did not stay level until it reached 3.65v. In fact by the time i got it to 3.64v...

Thanks snoobler, but this was not my experience. On my top balance, the CV light was lit right at the start and the current did not stay level, but continually dropped.

I think one point to note about these cells, is that the statements on capacity of 280Ah is independant of the statement of using at a 0.5C discharge rate. Yes you can discharge at 0.5C, preferably 0.2C, but to get a full 280Ah out of a cell, you might well have to discharge at 0.001C. Do you...

Bumping thread back to the top..... Went with a variation on a theme with regards to using the belville washers. My washers were spec'ed such that at 60% deflection they were loaded at 243N. At 20% deflection, they were loaded at 117N The distance between the two 0.24mm. Thus a single part...

https://www.aliexpress.com/item/4000637879984.html?spm=a2g0s.9042311.0.0.32e94c4dC2suDn Thought it would be ok if treated 'gently'...lol. Only being used for the one off top balance, and i'm happy to keep the Amps low and take more time to get there.

@FilterGuy Yep....thinking outside the box....what issues do you forsee? The SCC sets the applied voltage, but BMS sets the termination voltage....back up protection on overall BMS 2(chargery unit), some some redundancy? I'm looking for a high input voltage but a much lower termination, as i...

@Justin Laureltec HELP... Having just purchased a 'new' Victron multiplus inverter, i immediately noticed on opening it up that there is a scorch(arc) mark on a positive battery terminal plus it appears to have already been mounted to a fixture, going by the screw mark on the casing. Is...

@Justin Laureltec Justin, when powering down an Easysolar 5kVA unit, must you disconnect the panels first, or can you simply throw the main power/breaker switch on the unit, without any damage? I'm thinking of situation in middle of full charging and if someone unfamiliar with the setup, threw...