Met a bloke earlier this year at Port Campbell that used a couple of the first one on his 400amp lifepo4 (4x100amp), he used them with a standard lead acid controllers for when the voltage of a cell went over or under his limits and the alarm triggered a relay which shut off charge. Only spent a few minutes with him so have no idea how it works or what capacity they can handle, whenever I come across someone who shows me something different, always check it out. Like a few others we've run across using lifepo4, he had lots of bits and pieces for his system and was impressed enough with our simple charging and control system to want to see it in an off grid situation when they come to Tas either this year or early next. They want to go off grid with their home, so invited them to drop in on us if we are around, or will put him in touch with one of our buying group, to see one of their off grid setups.T1 Terry wrote:Not quite Native Pepper, the first one is extremely unreliable and has very few of the functions required, the second one I have to admit I've never tested but I have my doubts it would be capable of testing the capacity of a 400Ah 24v battery pack for instance, more rated for a few Ah model batteries I would guess. The other issue is no driver alarm port that I can make out and no idea if it is configurable between N/O and N/C and the various alarm points adjustable and the ability to switch off the alarm port facility but leave the audio, change various audio alarms so a particular alarm gives a particular sound.... lots of stuff the Junsi does that the others do not, being able to store and download a data log yet the unit remains the same case size puts them well ahead of anything in its class. It's not that they don't have their faults mind you, but at the price they are miles in front of the next level up and way in front on size.
Then there is the bonus of the donationware support for the downloaded files, what can be extracted from this information is quite extraordinary and I don't know why the techno-tinkers haven't dabbled in these little beasties capabilities, it really does make all the data collection by a certain person rather lacking and adds a whole world of learning into the cell level behaviour of LYP and LFP cells under each different yet every day load/charge condition. A whole world of learning the differences between information gathered from electric vehicle use and the information gathered from house battery use, the two are really nothing alike even though the same cells are used for both tasks.
T1 Terry
With e the set up we fit the automated system takes care of it long before the monitoring Junsi records an out of range voltage and sets off the alarm. The alarm is only there to tell you the system didn't do what it should have and to give a visual of how the cell balance is going and if it will need attention at sometime when it suits you. The system should really be a fit and forget type that only gives information if you are interested, or to tell you something has gone wrong, but there is a final level that isolates the battery if there wasn't a response to the warning alarms, then the fridge and all looses power so it is the very last line of defence/protection.Jon and Kay wrote:Ah....thought you had to cut the Yellow wire....I can see Martin staring at the alarm ..... looking for the yellow wire.
I saw the Volt meter climb rapidly from 14.2 volt to 16 volt the other day, in about 5 seconds. Don't know what I would have done of I had heard an alarm. within 3 seconds....couldn't have done much to fix it in the following 2 seconds before the BMS cut all supply to the batteries.
Lesson....if the batteries are already full...don't use the alternator to further charge them
Used computer battery packs, voltage test the cells, separate the very low voltage cells into one pile and the others into marked advertised capacity piles. The 4 cell in parallel holders are an evil bay made in China thing so easy enough to get. Charge the cells to 4v and let them rest for 1 hrs, then load test with a known value resistance load or watch the video where he determines the cell capacity and labels each cell, have watched that one yet.native pepper wrote:This Aus bloke sure has lithium, check his pack on youtube out, no BMS, no fuses, no balancing and no soldering. Expect you could do the same thing with lifepo4 instead of li-ion, doubt the economics would add up though. But extremely interesting and its seems a few are going down this path, the amateur approach to the Tesla power wall. If you could get a stack of these small cells really cheap, it may be worth the effort, if you have the time an patience. Don't know where you'd source the cell cradles though.
https://www.youtube.com/watch?v=eCK0wjYe7sg
