After 6 moths going from conception to 3 months waiting for delivery to finaly seeing implementation last week, I finally got everything set up and have been using the system for a couple of weeks now. (Hell-of-a project and note for the impatient - just take out a loan and order the battleborne and be done with it). I bought two 4S 3.2 280A systems and two JBD 200 BMS units, plus an A & B battery switch that works either/or/and to control the two banks to off, separate or in parallel (redundancy setup).
Here are some questions that people posted here that I didn't see answered:
- "yes" to my own question if 2 bluetooths can be used in the same small space (show up in the android list with the names of the BMS that you name them).
- "maybe a good idea" to the poster who wants the USB computer interface as a backup; redundancy is excellent idea but I've been switching between these two devices during testing maybe 50-100 times a day using an android and it's solid as a rock, even through the transmitters are both in an all metal battery case (granted I'm only 12' away)
- "yes" to my own question regarding selecting between multiple bluetooth signals in one location; positives are that the BMS can be named but negative is that xiaoxiang insists on their name as the marque rather than using the name you named your BMS (have to click on settings and "app setting" if you forget which BMS you are attached to)
The poster who wanted to know what that small 2 wire (red/black) lead is for, if you enable the disconnect feature in the BMS settings, then you have to place a switch to short the leads to turn on the discharge capability. (If they only offered a "charge" instead and I could flip on one bank at a time to charge from my alternator - true you can control this with the phone but just another thing to cause a wreck when a couple of switches would serve a driver better).
While I love the concept of this BMS, I'm a little confused on some of it's antics. For example in a run-down test with both banks switch on (in parallel) with about a 20A load, with the two setups with everything exactly the same, including wire size, cell size, type, and shape, with both BMS exactly the same from the same mfg lot, after 12 hours one BMS showed capacity of 78% while the other showed 34% (they were in parallel). The voltage of both BMS units was showing all cells on both banks around 3.21V at this point. Charging is a different story. From 450W solar, both BMS show 15A in (30A split) and the SOC is the same now on both BMS, showing 62% SOC and all cell voltages in the 3.35V range.
The past week of freezing weather allowed me to test my heating setup. I had elected not to use the BMS for heat sensing even though I had ordered the feature. I decided to remote my BMS about 6" away from cells which are in an insulated container. This worked well as I set the ad-on thermostat at 3C cut in and 6C cut out and my cells averaged 4-6C during the entire night of sub freezing temps. The probes for these thermostats were siliconed on the top of each group of 4 and heated the separate aluminum plates with heaters also under each group of 4). The BMS was down into the negative during this time but still was performing of course. Another reason not to rely on BMS controlling heat is the BMS of course is running warmer than ambient temp during a notable load. (Noting here that research needs to be done and if the BMS uses the probe to the cell itself, then the heating feature should be just fine to use.)
Anecdote and not technically related:
I was using lead/acid before and while with a good education in electronics, I first anticipated this would be a breeze to set up and get a handle on, but instead it's quite the learning curve and actually goes in my bucket of life's experiences titled "things I thought I wanted to know but really didn't". With all the cell balancing and intricate piece work, wiring requirements, adjustments, gotchata's and watch-for's and whatchamacall-its, at least at this stage I wish I had the room for lead/acid and thus it would have made my life a lot less complicated LOL (Hoping I change my mind later.) The skill itself is only beneficial if you work in the trade or spend a lot of time helping others or anticipate trouble, and it's a bit frustrating adding this as another maintenance task especially if you exist with a "massive life full of THINGS". I have to laugh because I relate this to my recent experience waiting in a long line for a new cell chip at the phone store. There was an old country couple who was being served by the tech in the back and while waiting they were strolling around the store reading all the glossy ads on the wall. They both are talking loud and the guy turns to his wife and says "hey hon did yew see this here interneta-thangs - do yew thank we need tha-ut". She replied in her slow country voice "I don't thank so and I don't even know what uh interneta-thangs is". So right about now I'm thinking I ordered the interneta-thangs and don't really need it LOL.