Most reacted posts

Thanks jason, so at 2 in series, thats 2 x 40v = 80v open circuit. My battery bank would be at 48V. However, if i could get away with 3 in series, that would be approx 120v open circuit, but only 98v max operating voltage, which effectively takes me up closer to the 115v ideal. Its just trying...

My reading of xuba's supplied datasheet on the EVE 280 cells, suggests a difference in thickness of 0.5mm between 100% SOC and 30% SOC. The cells themselves can vary +/- 1mm also, irregardless of SOC. @cinergi @HaldorEE Can either of you folks give me your 'average' cell expansion(ie per cell)...

I believe that in the 280AH xuba cells, the effective thread hole depth is 6mm. The supplied busbars are a tad under 2mm thick. The threaded portion on the M6 screws is 10mm. Thus two busbars can be utilised perfectly with the existing screws. If attaching a balance lead, this can be done by...

Filterguy, in your drawing, i note that your two bms small discharge relay outputs are connected in parallel to the one coil. Excuse my ignorance, but how exactly does that impact the spec of the relay needed?

Hi folks, i'm looking specifically to UK van/motorhome dwellers to provide a schematic or rough diagram of their layout, with specific reference to meeting UK code on grounding/earthing, chassis ground etc. Some appear to have no 'units' bonded to chassis, only the negative busbar. It all seems...

If all mosfets are closed, how can any power get to the cells...there is no path. On each 1/10 of a second, 16 mosfets are open allowing current to pass, ie 1 opens on each rail.

Joe, i'm not using an ac adapter to power it, i want to power it from the 24v280Ah battery pack. So instead of having it powered through the chargery sensing wires, i would like to run extra cabling from the main unit dc input to the battery pack. If this is ok to just wire direct from the 24v...

Anyone that has these, able to tell me the diameter of the contact area of the terminal posts? Thanks.

I'm not explaining myself very good... Another example... Cell 1 is lowest, mosfet 1 on the top rail opens and supplies current to the line one busbar. This is the only current going to cell1 Cell 4 is the next lowest, mosfet 4 on the 32A rail opens. This is the only current being supplied to...

Anyone know where i could get charging profile curves for the EVE xuba 280AH cells? Discharge profiles are readily available, but little on charging. Thanks

@Justin Laureltec / anyone If a Victron 5kVA Easysolar system is connected to a 48v300Ah lifepo4 battery bank, but is powered down for the winter, is there likely to be any inrush current damage when powering it back up? Is this handled internally as it is an all in one unit or else, are other...

cinergi, going off topic briefly, when you were configuring your victron quattro's, and input the low voltage discharge cut off, did your system give a default minimum 2v as the DC input reset value? I only ask, as i was doing a multiplus and it is a bit of a pain. If you run the discharge down...

My 2 cents worth.... As a beginner, you start to appraise your cells/battery pack using very low C rates, eg Bench power supply to charge up, 150w capacity tester to discharge down. This provides basic info about your pack. As a 'first time' beginner, much of the theory seems confusing, but only...

@Steve_S In relation to this 'Chargery' unit...(48v 16S) I'm not electrical, so steep learning curve for me...please bear with me... So, if my understanding is correct, the delay board has three relay outputs, which in total cant exceed 2.5A output. In relation to using an 'All in one'...

I thought Permatex red threadlocker was just the same as red loctite? I thought the idea was to get a permanent bond between the terminal threads and the lower stud threads only? Everything else can be removed, but the stud stays put permanently? I assumed the minimalist smidgen of noalox...

I know i rubbished passive balancers previously(@1.2A etc) as they appeared to do little in the time they have to operate between say 3.4v and 3.6v, however on second thoughts, every time you reach the top of a cycle, the high ones are always getting held back a little and the lower ones come...

Fantastic video Will P. I also noted that if buying larger numbers of cells the price increases considerably for matched cells. ie 4 orders of 8cells = £3740.64 where as 1 order of 32cells =£4138.99 (same supplier - CATL but not BLS) I couldn't understand why the 32cell single order was working...

I felt it was more important to monitor every single cell. I was also looking to add in an active balancer on every cell, thus maintaining balance on both the way up and down. Moving 6A about between cells actively is going to be far better than 1.2A passively, when it comes to a large bank...or...

In a scenario, where a SCC is set to charge at say 3.6v/cell and an inverter/charger set to charge at 3.5v/cell, would there be any issues with the different voltage settings when both charging at the same time? I'm assuming not, but always better to get confirmation. :)

I think even the 5A ones don't actually apply that level of amperage, until the cell difference is pretty large, rendering it fairly useless in the very short time it takes for the 'runner' to hit the ceiling.....imo.

So, instead of drawing off 0.8A from one relay output, it would only draw 0.4A from each, thus reducing the overall wattage 'wastage'???

Thanks ella. What exactly do you make of this below, from an inverter manual? "This product is a safety class I device (supplied with a ground terminal for safety purposes). Its AC input and/or output terminals must be provided with uninterruptible grounding for safety purposes. An additional...

Mine says im on the newest firmware, with no updates available....it is a right bugger not being able to decrease this value down to 1V, which might prove reasonable for the flat curve of lifepo4 When you said yours got fixed, i take it you can lower that value now....what options do you get?

Cheers mate (y)

Just goes to show how many people are stripping these threads no matter how careful they try to be !

Thanks. i just needed to confirm that the 45A is the output limit, but there is minimal loss of efficiency only supplying say 11A from the panels max(in series).

I have already thought about simplifying everything...if i go down that route, then i will simply go for 16S 400ah cells....job done, one bms, less relays, balancers etc etc(still pondering such)...no redundancy or emergency power in that scenario though. If you lose your power on route 500...

Thanks martan, thats perfect. (y)

I wasnt looking to reduce the number of BMS's, i was looking to boost the amperage of the active cell balancing....but my idea was shot down ...lol.

I'm kinda thinking, the unit can handle 145v OCV, but the MPPT is calculated on the max operating voltage, which is always much less. Hence, you could use 2 panels in series up to 57.5v max operating voltage each, or 3 panels in series up to 38.33 max op voltage each or, 4 panels in series up to...

We need to find out if 4nm or 5nm or 6nm is enough torque to suffice. It needs someone with an already destroyed cell to find the genuine 'stripping' point.

The is great practical info cinergi. I'm only now starting to get to grips with the balancing thing. (y)

Sorry, where was the 55V mentioned? I was looking to power from a 24v nominal battery pack(max voltage 29.2v at full charge) which was well within even the 30v spec, so why was a buck converter recommended, when the simple answer would be to connect direct to the pack. This is where my lack of...

Yeah, but the compression came later with the metal plates(at 2.05) on the outside to stop " irreversible swelling".

I think for a lot of folks new to this DIY battery pack caper, (myself primarily) we are purchasing tools and equipment that we have never used before. For top balancing for example, many have purchased a 0-30v 10A BTPSupply. Now ideally on a 280AH cell your looking for 140CA with a clean 14A...

Filterguy... Could one of these be modified to work??/...

@Craig Craig...just realised you are talking about a four cell battery pack. My testing was only on a single cell. I have now changed the type colour in the original post to ensure that idea's are based on single cell. Thanks

Parallel circuits. 128A input splits into 2x 64A. one leg of the 64A splits into 2 x 32A, one leg of the 32A splits into 2 x 16A Effectively, you have this....

@Steve_S Great post...very informational in building up some insight into these cells behaviours. AS regards "was thinking of running leads off the battery terminal posts to the BMS so that it is not powering itself through the harness. Will that make any difference anywhere ? I dunno. Can't...

Ran my first ever capacity test on my xuba 8S 280Ah pack at 0.02C discharge rate and after over 46 hours i achieved 275.4Ah (98.4%) I had a stubborn high cell and a run away low cell within the 8 cells. All cells were very well behaved up to approx 93% discharged capacity with the maximum cell...

I'm going to use a flanged grub screw. Any idea how much torque can be achieve with a hand tighten alone? I'm thinking if i hand tighten the screw with permatex red on bottom, once that cures, i should be able to torque to 5nm on the subsequent connections above the flange. The only part i'm...

Anyone care to comment on my proposed set up. Unsure about fuse sizing. Over sizing my SCC deliberately, but assume that has not significant detrimental effect on energy harvested? Would 600A 'welding cable be ok to use between the battery and inverter if kept less than 1 metre length? Thanks.

@Justin Laureltec .. post removed due to realising errors in diagram

:-( not another issue to deal with. Just when i thought i had resolved most....now we have to adjust set ups to compensate for inaccuracies. So now i need a 24v3A power adapter....schucks. I didnt mind so much SOC calculations being astray, but the voltages were paramount. Will be following...

Gazoo, from your results so far, what would you reckon the capacity is, simply running between 3.2v/cell to 3.4v/cell?

@Justin Laureltec Brilliant Justin...many thanks for your input. I'm assuming, you might still get a spark at the battery terminal or disconnection switch(if using physical disconnection)

Just to explain Steve, RV setting. Wishing to run the SCC at a much higher voltage(much faster moving electrons) but terminating via a dedicated BMS on hitting a lower voltage threshold. This would get the solar wattage into the batteries the quickest, but terminate before doing damage...

wow...eye opener