13 kWh Lishen van build

[TexasFan]

Thanks. Good choice going with Michael, it made the waiting a little less stressful for me.

So are you a fan of TX the state or the Longhorns? I bleed orange and have 2 aggie kids, so we're one of those divided families.

I am a fan of the state of TX my adapted home state. After all my travels in the military ended up in Fort Hood and been our home state since 2009.

 

[blutow]

I am a fan of the state of TX my adapted home state. After all my travels in the military ended up in Fort Hood and been our home state since 2009.

Yeah, there is a lot to like in TX. No place is perfect, but it checks a lot of boxes for us. You are right up the road, I'm in the Austin area. I've done a few bike races at fort hood, they host the TX state championship road race every year. Thank you for your service.

 

[Kodack]

The threads are definitely my biggest concern since they are going in a high vibration environment. They seem solid with the loctite, but it’s just not a lot of threads. Wish I could have gotten more loctite to go into the threads, but it was basically pumping out the top with the hydraulic effect. Even with just a little applied to the threads. If someone made a stud that was hollow down the center, it would be much better to allow the loctite to flow freely.

With loctite, you may get better results applying it to the threads of the bolt, and letting it cure in the open air for a few days until it dries. It does not need to be liquid in order to work. Once it dries onto the bolt like a thin crust, you shouldn't have any problems with fluid pressure, and once torqued down in an oxygen free environment, the loctite will bond to full strength.

 

[blutow]

With loctite, you may get better results applying it to the threads of the bolt, and letting it cure in the open air for a few days until it dries. It does not need to be liquid in order to work. Once it dries onto the bolt like a thin crust, you shouldn't have any problems with fluid pressure, and once torqued down in an oxygen free environment, the loctite will bond to full strength.

I know the low strength blue loctite can be used that way, but I don’t think that works for red (permanent) loctite. I could be wrong, I’ve never tried using red that way.

 

[JRG]

My biggest concern with the stock bus bars at this point is that they are all a little cupped. If you run them on a flat file, you get marks along the edges on one side and marks down the middle on the other. I'm not just talking about the stamping rough edges, but the entire bus bar is just slightly cupped. I debated filing them totally flat, but you'd be removing most of the plating, so I just corrected them a little bit. I decided to do "middle bulge down" and they seem to be working well in my testing.

Good to know. I'll need to check mine!

 

[JRG]

deleted

 

[blutow]

Battery box #1 is pretty much complete and functional. I'm not going to drill cable holes until it's time to mount the batteries in the van and I know the ideal exit points. I'm also planning to weld some mounting tabs on.

I plan to cycle the battery several times in the next few days and see if there is anything noteworthy on the expansion/contraction of the cells. The cells are about 50% charged, so I applied light pressure with the end fixture and I'll adjust by feel based on how compressed they seem full and empty. It's not a very scientific approach, but I'll drive myself crazy on this compression stuff if I try to outthink it.

I am still going to work on cable strain-relief and better protection. I want to do everything possible to reduce the chance of something working it's way loose or a wire rubbing through the insulation due to vibration.

The battery is a bit of a pig at 60.5lbs. If I could weld aluminum, I would have gone that route to save weight. Total cost for all 4 boxes is going to be about $210. The HDPE sheet was almost $100 of that. Another ~$70 for steel and the balance in hardware and paint. I've probably got at least 3 full days work (and rework) into this first box. I think I can knock the next 3 boxes out in a couple weekend days. Mass production.

 

[JRG]

You got really close to that Victron blue.

 

[HoboDownByTheRiver]

Is the point of your battery box to keep the batteries under compression? Or are you trying to keep them solidly mounted while you're driving around?

If you're trying to keep them under compression, HDPE is susceptible to heat induced creep, so you may run into issues with your tensioners "loosening" over time

 

[blutow]

Is the point of your battery box to keep the batteries under compression? Or are you trying to keep them solidly mounted while you're driving around?

If you're trying to keep them under compression, HDPE is susceptible to heat induced creep, so you may run into issues with your tensioners "loosening" over time

Trying to achieve both. Thanks for pointing out the potential issue. I realized HDPE isn't really suitable for structural support, but I didn't realize it could be compressed over time. I will keep an eye on it for sure.

I considered using 1/4" steel or aluminium plate on the ends, but steel was adding even more weight and aluminum was expensive and I figure it's an easy swap if I want to switch later. It's also really easy to periodically add some compression with a 1/2" wrench and an allen key if things get loose over time.

 

[blutow]

Digging into the HDPE creep issue a bit - I found a study here:

file:///C:/Users/grwoolf/Downloads/polymers-10-00156.pdf

Based on initial review, I'm not too concerned. Even the low end of the the forces they are talking about (7 MPa) are pretty extreme compared to how I'm using it. It will be something to watch though.

 

[blutow]

I've continued to cycle the batteries pretty much every day, running 2 at a time in parallel. I've been charging to 14.1v and then recharge once they consume 544Ah (272Ah x2). They are typically getting close to 12v at that point, so they seem like they have full capacity without hitting the steep drop under 12v.

I started working on my other 3 battery boxes today. The main cages are all welded up, I just need to do the compression bars and the panels. Next weekend probably. I'm not in a rush, my van delivery is delayed.

I decided to go ahead and capacity test all my individual cells. I have a tester, but it won't operate any higher than about 6.5a. That will take ~2 days per cell, so it will take at least a month for all 16 if I can keep them running continuously. Maybe my van will be built by the time my cells are fully tested.


My old harbor freight abrasive chop saw is dying, so I used it as an excuse to buy one of these evolution saws that cuts steel with a carbide blade. I have never used one and it takes a leap of faith to bring the blade down on the steel material for the first time. It cuts steel almost like it is a piece of wood. I tried it with some thick walled tubing and it cuts through in a few seconds. You get little chips instead of the metal dust you get from an abrasive blade, so it's still messy, but the cuts are super clean and precise and the part isn't hot after cutting. It made cutting all the angle for the battery boxes go really fast with much more accurate cuts.

 

[blutow]

I just finished doing individual cell capacity testing on my first 4 cells.

Here's the process I've been using:

• Configured a group of 4 cells in series and charge up to 14.1v
• Remove bus bars, but keep compression in place
• Charge the cell to be tested up to 3.62v (goes really quick since the cell is mostly full)
• Capture IR and voltage at beginning of test
• Connect to cheap fan-based capacity tester. Low voltage disconnect is set to 2.5v. Discharge rate is set to ~6.5a. My tester won't go much higher than that and it's a pretty good rate to comfortably test a cell every 2 days. I made sure to throttle the amps back as needed to make sure the test didn't complete while I was away or sleeping.
• Connect the test cell to my victron smart shunt and set an alert for low voltage at 2.7v. I'm just using the "starter voltage" connection on the shunt to get the alert, not actually using the shunt for the capacity test.
• When I get the alert for low voltage (2.7v), I stay close by for the remainder of the test because I'm not totally trusting the cheap capacity tester to shut off properly. I'm starting to trust it more since it's worked on my first 4 tests, but I feel better if I can watch it at the end.
• The battery tester shuts down when it hits 2.5v. This is actually ~2.61v at the cell, but there is some voltage drop. I've seen people set these capacity testers to 2.3v to get a cutoff at 2.5v cell voltage, but there is so little capacity in this part of the curve that I just kept it at 2.5v. I just wanted all cells tested consistently, not trying to maximize the number.
• Measure ending capacity, voltage, and IR.

All 4 cells were very consistent, within about 1Ah spread. See spreadsheet shot below. They were all over 285Ah, so that's pretty close to what I saw w/ pack testing at much higher discharge rates.

I expect the results would be much closer to the rated 272Ah capacity if I could do a discharge test at 1C, but I have no way to test them that way. 12 more cells to go, so ~24 more days of testing. Still working on battery boxes also. Not in a hurry, van delivery is still delayed. Supposed to be built in early April, we'll see.

 

[jpcjtrtj]

Impressive build and good news on the assembly/testing. I very much appreciated the step by step description of the assembly and testing; and the safety reminder. Those battery boxes are unreal. How many days do you think you can go without anything but solar?

My 4 cells are allegedly on their way ordered two weeks ago ....and my Overkill BMS is on back order from Florida. I’m hoping the set fits into a plastic ammo box with terminal on top.

Can I ask how you picked the size of the internal leads and main positive and negative cables? I keep seeing 4/0 used on these batteries and in professional installations, but the small 120 Amp DC load of my trailer (6 20 amp circuits/no inverter) doesn’t seem to justify cables of that size. My battery will be a single 280 AH 4s setup (replacing two 92 ah AGMs). Solar will be limited to 200-400 watts so most charging will be through the 55 amp converter from shore power or through a renolog 40 amp dc-dc charger when driving. So, I’m looking at bus bars inside ans 2 OR 4 AWG for main leads. Airstream used 6 AWG for the existing dual battery set up. So this is better than what I started with, but I worry I ahouls

 

[blutow]

How many days do you think you can go without anything but solar?

It depends on how wasteful we are and how much the sun is shining. If we are taking hot showers and cooking a bit, we could probably get low in under a week, but I really don't anticipate any issues except situations where we run the AC. I don't have plans to run AC on batteries on a regular basis, but there could be times we're travelling in the summer and need to run it overnight to sleep. That could drain the entire bank very quickly and would require a long drive or shore power to get caught back up.

 

[blutow]

Can I ask how you picked the size of the internal leads and main positive and negative cables?

I used ampacity charts that are available online and I went pretty conservative on mine. I'm using 4/0 between my bus bars and inverter, but not anywhere else. I'm running 2 AWG from each battery to posts where sets of 2 batteries will combine. From those 2 posts, I'll be running 2/0 (a run from each pair) to my "combiner" battery switch. The switch is able to select all 4 batteries or can individually run either set of 2. So, there are 4 2AWG cables come from individual batteries into 2 2/0 cables going to the switch, and then 4/0 going from switch/bus bar into inverter. At the individual battery level, I don't anticipate ever running more than around 60a- 70a continuous, so 240a - 280a for all batteries combined.

 

[blutow]

No progress on battery boxes this weekend. Out of the blue, my van got built and delivered and I picked it up this weekend. I wish I had not been taking my time, now I feel like I'm behind. Oh well, it's all good. I installed a bed in the van today and I'm still running capacity tests on all my cells. Electrical install won't happen until some other stuff is done like floors. It is good to have the van so I can figure out location for mounting tabs on the battery boxes. I was going to try to guess and figured I might end up cutting them off and adjusting placement.

She's a big empty shell of nothing (except the bed now). I'll probably try to get the windows in this week, I just need to get the nerve to start cutting big holes.

 

[jpcjtrtj]

That’s really exciting!!! Enjoy the ride...

 

[pau1phi11ips]

Great work on this thread!

I've just started my van conversion. The batteries were ordered a month ago. Can't wait to start building.

I'm going for a single 8S string with the 280Ah cells

• Victron Multiplus II 24/3000.
• Victron Cerbo GX + Screen
• Victron Orion-Tr Smart 12/24-15A (360W)
• Victron 100A Battery Protect
• Victron BMV-712 Smart
• Daly 120A Smart BMS

I think I'm just going to use the BMS to turn the Victron Battery Protect on/off instead of actually running current through it tbh.

The lights, fridge, heater and USB adapters are all 24V so shouldn't be that much hassle with the wiring.

 

[pau1phi11ips]

PS. Are you aware you can hook-up the BMSs you've used to the Cerbo to get the data in the Victron VRM?

GitHub - Louisvdw/dbus-serialbattery: dbus driver for serial battery in VenusOS

dbus driver for serial battery in VenusOS . Contribute to Louisvdw/dbus-serialbattery development by creating an account on GitHub.

github.com