So aside from one guy on youtube that made a rotary real time lithium battery management system where he can check individual cell voltages and adjust as necessary there haven't been many choices. Granted individual balance boards try to do the same but as posted are not sufficient for many reasons.
Retrieving individual cell voltages in real time is important and if you see one going south. So therein lies the dilemma. How now will the liveabord cruiser balance his pack?
After having played around with my trial pack of 72ah calb cells I concurr with many of the stated quality control aspects. I had to replace two of the cells in a relatively new 48v pack for reasons I'm unsure of.
Splicing two new cells into that pack and top balancing again was no picnic. To say that top balancing cells according to MaineSail and Pbase is time intensive.
I used a 4 port RC charger
as many have I"m sure to accomplish this. Tops them up to 3.6v and shuts them off without fail. I set the charger
on 4 cells and went to work for the day. Took four days to top them up. Then whatever else I did - wired in parallel let sit for a few days then charge all in parallel. From recollection.
What I had wished for in this case was three more of the HiTec chargers. I ran this off a MaxBurton 120vac to 12v 15amp converter. You can get the ac/dc HiTec chargers.
I'm making a jump here and I've connected mine to a 48v bank on one cell when all wired up and it started and read the correct cell voltages on my trial bank. So...
Would having 4 X4 AC Plus 4 Port AC/DC Multi-Charger | HITEC RCD USA
hooked up to 16 batteries work.
It provides real time monitoring of cell voltages via USB. They don't have to be on all the time and I or another as the operator can make decisions to add or reduce current to individual cells as needed.
would certainly be less when compared to having 16 balance boards waiting to corrode and trigger the unforeseen HVC/LVC that spikes your charge controller under load.
So what I have to find out and work on more is how to wire the contactor to disconnect all the eventually out of balance boards. It is just not a factor I would like to be pursuing maintaining these little boards when 32 leads from the battery posts will be more than reliable enough and not prone to failure.
I don't have the luxury of going Dual Bus with my system. From my experience with my trial bank once done right the cells do not drift. I have read all of this thread and lean heavily towards the third day deckofficer and t1terry aspect of lithium battery management.
I'm not entirely impressed with the Junsi products as they have no option to take immediate corrective action while underway to avert cell imbalance. This way I could top balance the pack but am unsure if this can be done with the batteries still hooked up as 48v or would I have to wire them all in parallel? In essence I'm looking at it like larger cell monitoring boards but these ones actually pack a punch.
For all intensive purposes I have a 48v 400ah balqon pack. When the first cell monitoring board goes I will pursue this method. I need to be clear on how to simply wire the contactor to a simple on off switch that I manually operate.
During normal operation Low Voltage alarms are two 3000w dc smart generators. Tested these generators and they auto stop auto start at 45v and 56.5 volts. They are variable load generators and quite powerful in DC charging amps.
and you can find them on ebay for one boat
dollar each. I've tested two so far and although the quality upon delivery
is not great they do produce 40amps or more at peak output. They can be ran in parallel and I have done so during my testing. Here is one in operation:
We tested both the Ray Electric
Outboards during this past spring and both of the smart generators. The first time out we ran with for the most part 52.5 with one bad cell in the pack and the Ray Happily accepted that voltage. The videos reflect a proper functioning 48v bank with 16 good cells. There was a marked increase in power with all 16cells.
I output the generator
current to my 440HVA Coleman Air charge controller. It took me awhile to get the exact setting 57 volts for the dump load on the controller but it comes on before the warning light on my HiQap balqon bms starts to flash.
So low voltage is covered by the generators starting or trying to start as the case may be. Choke helps but I'm sure they would start after a couple of attempts. By this I mean they try to start 3 times in each starting cycle. So far as I now this continues until they start so eventually they would warm up enough to start.
I'm coupling this with a large array of solar panels
2160w of 180amp 24v panels
doing 80volts more or less at 35amps possible. So mostly I'm probably going to reduce the 57v dump load when away from the boat for long periods of time. The solar
is simply disconnected from the battery when dump load occurs. I wanted to get away from having to have a dump load resistor wired in and that is possible because I'm using these two small generators instead of a wind generator
I have not tested what would happen if I removed the battery from the generators during running to simulate a LVC/HVC cutoff from the BMS. All the more reason for me to remove the infringing LVC/HVC mechanism from the BMS. I don't think allowing some failure prone balance boards to manage my system to be a good thing.
On that note on a single bus sytem if I ever suffered a HVC/LVC event and it triggered a disconnect for whatever reason and my solar
was charging would it damage more than my charge controller (sensitive electronics
etc)? 440HVA has a fuse that may or may not prevent damage if battery is disconnect. Thus I will carry a spare board for the 440HVA and also a fuse. Just wondering about all the other circuit protected runs and if they would be affected.
I'm going to include some pictures and I'm bracing for the worst. I've spent the better part of three years building towards a very simple system for my 8m Catamaran and I'm about to start the installation
Nobody said Marine electrical
was easy or cheap
but I did eventually get the pack wired up and tested various functions only to realize a little later I used the wrong color of wire for my positive leads. ChaChing and now will redo all those connections on install.
Here is a great video of my Ray Electric Outboard
on my CraigCat running from my 72ah calb 48v bank. https://www.youtube.com/channel/UC6B...1XlLYww/videos
and a good video of the Ray running full out
I must admit I'm a little perplexed on how to wire the shunts to look neater but thinking they will all get placed in an enclosure. I will have five shunts. EV Display shunt, 2 for the Ray Electric Outboards, one for the generators/Lestronic II input will be on the 440HVA and the one shown for the solar input - it still needs a blocking diode installed.
I did easily manage to run my incinolet from the 3000w cotek 48v inverter
at 38amps off and on for a couple of hours as that is how it cycles. I did manage to charge at around 24amps from my makeshift solar mounting options. I was able to charge at idle in parallel with two of the smart generators at around 24amps no load. I was able to charge on the solar input and generator
input to around 22amps with both the Lestronic II battery chargers (I'm unsure if these can be ran in parallel.).
I intend to attempt some form of capacity testing on the bank once it is onboard and hooked up to my systems as otherwise there was no way I was dropping 400ah to 20%SOC during testing.