Yeah mine erupted after using the cells. Definitely check under there the next time you have a chance.
Cinergi's 28 kWh / 4 kW Solar / 10 kW inverter RV build
- Thread starter cinergi
- Start date
Yeah mine erupted after using the cells. Definitely check under there the next time you have a chance.
It's been about a week since my last update. Video:
I also realized that the power draw of the relays (and technically the BMS) aren't being accounted for. I need to move the hall-effect sensor ... but it's too small to fit over the 3/0 lugs so moving it requires cutting cables and re-crimping lugs
so I'll do that fix when I create my final battery.
I'm still debating how I'll set up the final battery. I'm looking into Anderson for the battery-to-main-bus-bars connection as well as Anderson connectors to break up the pack into, say, 4 pieces (which will require me to break up the sensing leads with connectors). This would make moving them into the RV doable and I think provide for a better compression setup. I still need to play with the copper bars I got (I have a cutoff saw, drill press, and something to bend it with, in theory). I'm not entirely sure of the final physical layout inside the RV, so I'm not really sure what I want to do. With that design, there's also the issue of where to mount the equipment (like the BMS, breaker, and relays) that goes with the battery.
- Swapped in all my other unused cells to create a "new" battery and get all my cells tested at least once
- Swapped Class T fuse with Breaker
- Created small + and - bus bar inside for powering relays and BMS etc; BMS etc gets shut down with breaker
- Swapped 2 1 guage wires with 1 3/0 wire coming from cells
- "new" bank under load test
- Orion BMS back-n-forth, discussing a way to achieve something similar to 3-stage charging (2-stage only possible right now)
- Swapped out first-stage relay with a better one (less power and isolated/dry contacts)
I also realized that the power draw of the relays (and technically the BMS) aren't being accounted for. I need to move the hall-effect sensor ... but it's too small to fit over the 3/0 lugs so moving it requires cutting cables and re-crimping lugs
so I'll do that fix when I create my final battery.I'm still debating how I'll set up the final battery. I'm looking into Anderson for the battery-to-main-bus-bars connection as well as Anderson connectors to break up the pack into, say, 4 pieces (which will require me to break up the sensing leads with connectors). This would make moving them into the RV doable and I think provide for a better compression setup. I still need to play with the copper bars I got (I have a cutoff saw, drill press, and something to bend it with, in theory). I'm not entirely sure of the final physical layout inside the RV, so I'm not really sure what I want to do. With that design, there's also the issue of where to mount the equipment (like the BMS, breaker, and relays) that goes with the battery.
1 sec is enough for precharging the caps. Unless I missed something you can use that delay to precharge them
Choose one of the packs to mount all the accessories (probably the most negative one) or mount them all on a separate board/box/whatever. The best solution will obviously depend on the physical design in the RV, so you need to do that first.
1 sec is enough for precharging the caps. Unless I missed something you can use that delay to precharge them
Choose one of the packs to mount all the accessories (probably the most negative one) or mount them all on a separate board/box/whatever. The best solution will obviously depend on the physical design in the RV, so you need to do that first.
The caps on 2 5kva Quattros are impressively large. The 50 ohm resistor takes over 10 seconds to bring them up to about 50v (pack at 54). I'll get a new resistor like maybe 10 ohms (5 amps / 300 watts during precharge ... no problem for the contactors)
Yep, you'll need a low value resistor (I'd go as high current as what your relay can handle to shorten the time as most as you can). You also don't really need to bring them super close to the battery voltage so that will help
Forgot two things:
- I tested one of my highest cells using that tabletop tester: 278.5Ah. About time! And helps validate the tester being OK (versus just testing everything wrong at 270Ah; although that's already validated at the pack level)
- The Orion BMS beta firmware release notes says they're adding precharge relay control. Bam, problem solved.
Marinepower
Solar Enthusiast
- Joined
- Apr 24, 2020
- Messages
- 224
Cinergi,
this is a very interesting build you are undertaking and the use of the Orion BMS, the relay logic for LVC and the can bus communication is great to see evolve.
I have also been watching your thread as I have four of the EVE 280 en route to me via ship from China and am somewhat apprehensive about getting a reasonably balance pack. I see you are having some challenges in this regard.
I was recommend this Lifepo4 lecture in another forum. It's very long and oriented for EV, but really gets into some of the chemistry and manufacturing details of Lifepo4 and at the end of the video they give some recommendations as to how to sort batteries of different capacities. Thought you or others may find parts of it useful. I did.
this is a very interesting build you are undertaking and the use of the Orion BMS, the relay logic for LVC and the can bus communication is great to see evolve.
I have also been watching your thread as I have four of the EVE 280 en route to me via ship from China and am somewhat apprehensive about getting a reasonably balance pack. I see you are having some challenges in this regard.
I was recommend this Lifepo4 lecture in another forum. It's very long and oriented for EV, but really gets into some of the chemistry and manufacturing details of Lifepo4 and at the end of the video they give some recommendations as to how to sort batteries of different capacities. Thought you or others may find parts of it useful. I did.
I'm spending a LOT of time with Andrew Ewert (Orion BMS) figuring out how to get effectively the same thing as a 3-stage charge so that the cells spend SOME time above a float voltage so that balancing and SOC drift correction work properly. It takes a lot of time to iterate through the changes and testing if they're effective. I'm not holding my breath, but this "float" feature does at least give me the ability to charge at a higher voltage until the pack is nearly full. Trying to charge at a float voltage of 54.4 is quite slow above ~30% SoC. Meanwhile, I'm topping off a couple of cells to swap in with the 2 low cells so I can do another capacity test on the pack, and I'll capacity test those two cells. I've upgraded the wiring on the cell tester so I'll lose less to wire resistance and run at 15-20 amps so I get faster results. This wire is incredibly flexible. I bought multiple gauges. Happy so far.
Thanks. that was really useful LiFePO4 context. I watched the whole video but for those who just want the cell matching part, start at 1:04:40.
I just watched the video. I'm so glad I did. I don't know that it will change what I'm doing for this build but that was cool stuff!
Marinepower
Solar Enthusiast
- Joined
- Apr 24, 2020
- Messages
- 224
Well, I'm glad that you still found the video worth the time invested. I did warn all it is very long.
I found the information on topics such as why different manufacturing process yield high vs. low C rates; what chemically happens to a cell during overcharging, over heating, over discharging, etc. to really up my LiFePo4 understanding and to a certain degree inform the design of my build.
MP
OK, swapped out two cells and I got my best results so far. 268Ah according to Victron. I'm starting to think the Victron is off by maybe 8-10Ah ... the Orion counted 278. My tabletop tester is testing the strong cells around 278 as well... and the times when the pack tested to 260, the tabletop tester got 270. So now I'll begin getting capacity numbers for all my cells so I can try to match on capacity. I don't have a great way to match on IR but hopefully that won't matter with the C rates these cells will typically see.
Andrew at Orion doesn't think he can get me the charge curve I want ... I'm going to try 1-2 more things ... if that doesn't work, I'll still use the float feature so I can charge at a higher voltage until the pack is nearly full. I'll then use something to externally influence a higher-voltage balance cycle ... I guess I'll see how often I need to end up doing that based on those results (which won't be for many months).
Andrew at Orion doesn't think he can get me the charge curve I want ... I'm going to try 1-2 more things ... if that doesn't work, I'll still use the float feature so I can charge at a higher voltage until the pack is nearly full. I'll then use something to externally influence a higher-voltage balance cycle ... I guess I'll see how often I need to end up doing that based on those results (which won't be for many months).
I've been playing with the Grafana/Victron integration and also using it to help me tune the Orion to do what I want ...
In the second graph (Battery Voltage) the Red line represents an arbitrary line at 58v and the blue another arbitrary line at 54.4. The dotted yellow is the max voltage the BMS is telling the system to use and the green is the actual voltage. You can see the SoC graph above and the DC Power below to see that I started charging at 15:13, SoC hit 100% at 16:00, and how the voltage temporarily ramped up towards 56.5v and then down to around 54.4 where it will stay. I have some more tuning to do (I want the voltage to stay higher longer so balancing can be effective, and I want to visit the SoC drift correction voltage setpoints), but the "algorithm" is working out it seems! Finally!
In the second graph (Battery Voltage) the Red line represents an arbitrary line at 58v and the blue another arbitrary line at 54.4. The dotted yellow is the max voltage the BMS is telling the system to use and the green is the actual voltage. You can see the SoC graph above and the DC Power below to see that I started charging at 15:13, SoC hit 100% at 16:00, and how the voltage temporarily ramped up towards 56.5v and then down to around 54.4 where it will stay. I have some more tuning to do (I want the voltage to stay higher longer so balancing can be effective, and I want to visit the SoC drift correction voltage setpoints), but the "algorithm" is working out it seems! Finally!
This is a little random but in reviewing my thread I saw this and I've since learned that I can connect to single or split phase without reprogramming or power loss or anything special (e.g. works with standard RV dog bone adapters). I'm not sure if I mentioned that elsewhere in my thread. I can leave the Victron's set to NOT switch as group, and it works no matter what I connect it to. I've yet to find a downside of having "switch as group" turned off.
Yeah, I think the main issue comes when using a 120V generator. You can't feed a single phase from one of those generators into both inverters if they are in split phase, so people in that scenario only end up able to use "half" of the generating capacity.
I went up thread to look at this conversation, and I'm not sure how I got off on that tangent, since you didn't even specify whether you will have a generator in the first place.
(There is a secondary issue with "switch as group" disabled when loading a 240V generator: the decision-making is not guaranteed to be simultaneous, and timing variation could result in overloading the generator if one switches first and delivers a large, asymmetric load. I'm not sure in real life how often that occurs, but I've heard of people having trouble with it.)
Late in reacting...
I'll be jelly if you get your 2X 5kW Quattros in split phase before me... I've had one running for a year with the other sitting NIB. The single providing off-grid "shore power" to the single 5th wheel (L1 and L2 jumpered at the 50A shore connection) is almost always adequate - always able to run at least 2X high power items simultaneously (elec W/H, microwave, Rooftop A/C, coffee maker, induction cooktop) with enough reserve surge to handle a 3rd item long enough for me to identify and shut it down before the inverter objects.
Sounds like an awesome project. Good luck with the continued cell testing! There's less than a 5% difference between your 268-281Ah cells thus far. While the deviation from rated/expected is a little disappointing, that's a small variation, and should pose no issues.
Maybe I'm misunderstanding you -- but yes, you can charge from 120v generator with both hots going to both inverters -- that's what I mean to say. I'm able to charge from either 120 single phase or 240 split phase without reconfiguring. I use a dog bone adapter on my 20amp 120v plug which provides both hots of 120 to both inverters. The master unit will take the hot 120 and the other will ignore it and remain inverting.
Ah, I understand the switch as group downside. For what it's worth mine have always simultaneously switched anyway *and* it slowly ramps up power (since I have that feature turned on as well), so it would have to switch many many seconds out of sync and mine are nearly simultaneous.
Late in reacting...
I'll be jelly if you get your 2X 5kW Quattros in split phase before me... I've had one running for a year with the other sitting NIB. The single providing off-grid "shore power" to the single 5th wheel (L1 and L2 jumpered at the 50A shore connection) is almost always adequate - always able to run at least 2X high power items simultaneously (elec W/H, microwave, Rooftop A/C, coffee maker, induction cooktop) with enough reserve surge to handle a 3rd item long enough for me to identify and shut it down before the inverter objects.
Sounds like an awesome project. Good luck with the continued cell testing! There's less than a 5% difference between your 268-281Ah cells thus far. While the deviation from rated/expected is a little disappointing, that's a small variation, and should pose no issues.
I've been running them in split phase for at least a month now. It's been awesome. I've charged my Tesla with it (LOL) and I've plugged my existing RV into the Victrons (as if they're shore power) and turned on 12kW worth of stuff in my current RV and they handled it fine. Crazy awesome.
I've also run 8kW through the Quattro's with 1.5kW coming from shore and the other 6.5 coming from batteries (power assist). I would disconnect and reconnect that 1.5kW shore link while charging the Tesla and the Tesla was none the wiser. It's complete magic.
You can charge, but only at half of the capacity. Some people need that other leg to contribute as well.
I imagine they are pretty deterministic, yeah. I know of one rig where it was a big issue, but they had a device introducing a delay on one leg.
Gotcha, yes - of course true. I haven't determined my generator config yet. One option is a 3.5kva model capable of 2800w sustained so I can plug in a 30amp to 50 amp adapter and set the max AC power to about 20 amps so I'd get like 2.4kW going into my system. That would be plenty and only necessary if I've had really bad solar and I'm off-grid. On the other hand, I could just go with a built-in 6.5kW propane 240v split-phase ($$$$) and just set auto-start and never think about it again. Decisions decisions lol
JELLY!
I'm grinding through individual cell testing ... about the only other item of note is that I swapped out the GFCI breaker at the house because it's overly sensitive (I hate those damn things) so now I'm powering the Quattro's from a 50 amp plug and my existing RV from the Quattro's. I have the Quatto's set to limit "shore" power to 22 amps which means sometimes I'm charging the battery and sometimes I'm discharging the battery (power assist), as this RV does occasionally use 6.5kW of power in my current Winter setup.
I have a 120vdc variable power supply in hand now which I'll use to simulate solar panels because I really need to add solar into this mix and make sure it works properly. I'm going to pull the trigger on some Victron SCC's. It's looking like I can get 12 of these on the roof but I'm awaiting confirmation. I like these because their temperature coefficient is crazy low and they have excellent low-light performance. Would be 2 3s2p configurations (their Voc is over 70v so I'll need the MPPT 250/60's).
I'm still ruminating over the physical configuration of the battery (e.g. splitting the pack into pieces, connected with Anderson connectors) and bus bar design and compression design. I am amazed at how loose the cells are at ~0% SoC given how "tight" I tightened the wing nuts at ~50% SoC. Makes me worry about jostling at low SoC's as well as too much pressure at high SoC's. Good thing I have all this time to figure it out! I'm assuming RV delivery will be ~March, so ...
I have a 120vdc variable power supply in hand now which I'll use to simulate solar panels because I really need to add solar into this mix and make sure it works properly. I'm going to pull the trigger on some Victron SCC's. It's looking like I can get 12 of these on the roof but I'm awaiting confirmation. I like these because their temperature coefficient is crazy low and they have excellent low-light performance. Would be 2 3s2p configurations (their Voc is over 70v so I'll need the MPPT 250/60's).
I'm still ruminating over the physical configuration of the battery (e.g. splitting the pack into pieces, connected with Anderson connectors) and bus bar design and compression design. I am amazed at how loose the cells are at ~0% SoC given how "tight" I tightened the wing nuts at ~50% SoC. Makes me worry about jostling at low SoC's as well as too much pressure at high SoC's. Good thing I have all this time to figure it out! I'm assuming RV delivery will be ~March, so ...
Similar threads
