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Dave's Build Thread
#31
Batrium Arrived!! Hurrah!

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#32
It looks like you’ve gone for the bare minimum with no shunt?
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#33
(07-31-2018, 12:54 PM)brwainer Wrote: It looks like you’ve gone for the bare minimum with no shunt?

Hahahahahahaha! With import duty and shipping I ended up paying £520 for this. Damn right I'm not having the shunt or the expansion board!
I did buy a spare longmon just in case I broke one...so it's not quite the bare minimum!
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#34
Small update. I went away on vacation for a week, and I thought it was a great opportunity to test the system out, unmanaged for a week. In preparation, I wired up the next row of cells. So i'm now at 14S40P. I installed the Batrium and got that working. Then Sonic walked me through setting up RDP on my android phone, so I could see Watchpower and Watchmon on my phone. It all worked flawlessly for 5 days. On the 6th day I lost communications with my garage pc. When I returned home, all that had happened is the laptop i'm using had just locked up and near non responsive. Powerwall, inverter, solar and batrium were all still functioning perfectly. I had no power interruptions at all and thats even with 2 days of heavy rain and thunderstorms.
I couldn't be happier with it!
Now I need to crack on with wiring up the rest of the packs and getting this connected to my house.
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#35
A few days ago my Sunkko 709A Spot welder packed up. I had no response from the seller on Ebay, So I thought i'd might as well take it apart to see if there were any obvious blown components. unfortunately, there is nothing visibly wrong with it. I'm not skilled enough to be able to test the pcb, plus that fact I can't power it up. It just trips the 16A breaker in m garage. I also tried it on my cooker power supply in the house, which is 50A it turns out. but this just blew the Sunkko fuse in the back.
So all work on the powerwall has stopped for now as I don't have the money to just go buy another welder.
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#36
(09-01-2018, 07:01 AM)Daveyboy Wrote: A few days ago my Sunkko 709A Spot welder packed up. .... I also tried it on my cooker power supply in the house, which is 50A it turns out. but this just blew the Sunkko fuse in the back.
Sounds like there's a serious short in there, maybe the transformer?

Re the Batrium shunt, the point of having the shunt is to know the battery SoC by tracking current in & out.
Running off solar, DIY & electronics fan :-)
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#37
(05-05-2018, 10:32 PM)Daveyboy Wrote: Go for it! 
I paid a local print shop to do mine. I've got too much on right now to spare time setting up a 3d printer.  Rolleyes
The only thing i'd say is make sure you print them on their side such that the grain is from top to bottom when they are on the wall and not grain left to right. I learned this the hard way as it isn't strong and WILL break along the grain of the print if sufficient force is applied. Mine snapped when taking a pack out, as the holder needs to flex a little.
I had mine printed in PLA at 25% infill. Plenty strong now. Would def hold your 40p packs.
And if I was to print them again, I would recess the screw holes a little deeper to allow screws with a thicker head to sit further into the holder.

I was debating starting with 20P pack and then adding more as needed. I only have about 125 cells so far and only started capacity testing last night. With only one Opus at hand you can imagine its a slow process. Prior to this phase was mostly charge and leave it to settle. Prior to capacity test I checked voltage of each cell. Got rid of few that were below 4.1V. Some are on the border and will need to be monitored.

The thing I like about 20P pack is that its small enough to be isolated and unplugged. Thinking of crimp or XT60 connector to simplify this process. A circuit breaker per pack or a removeable fuse should simplify TLC work.

Not adding any fuse to the packs ?
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#38
(09-01-2018, 11:08 AM)Redpacket Wrote:
(09-01-2018, 07:01 AM)Daveyboy Wrote: A few days ago my Sunkko 709A Spot welder packed up. ....  I also tried it on my cooker power supply in the house, which is 50A it turns out. but this just blew the Sunkko fuse in the back.
Sounds like there's a serious short in there, maybe the transformer?

Re the Batrium shunt, the point of having the shunt is to know the battery SoC by tracking current in & out.
 I've tested the transformer for short. No short. Definitely something up with the PCB. I've seen some continuity between live in and live out when the power switch is on, but foot pedal not engaged and that's not right at all. I don't know whats causing that though. 

Yeah, the Shunt will give me SoC. I get that. I just don't need it. I know when the battery is going flat based on voltage under load and current draw. My aim is to oversize the battery by quite a large margin, so as to only use half the capacity anyway.

Hi Hermit, yes, the 20P design allows the powerwall to go into service sooner than waiting until you have enough cells for 80P for example. It will also be easier to fix problems. I intend to leave the battery online when removing a 20 cell pack for replacement / repair. It would be great to not have to shut it all down for maintenance.

I wouldn't be discarding cells that are <4.1V. My cutoff was 0.5V, which worked well as Opus tends not to register them below 0.5V anyway. Some of my best cells were as low as 2V, but recovered well. I stick them all in the charger and those that don't take a charge well, will top out at about 2V then say they are fully charged. I also remove any heaters. Then let the cells sit for a good month and remove any that are below 4.05V after resting. I don't want that level of self discharge in my wall.
I considered using XT60 or XT90 connectors, but finally settled on ring terminals. Easier to install with just a crimper, plus you don't put much strain on the cables when trying to disconnect the pack.

I haven't fused the packs, no. I'm thinking about it. I have cell level fuses, but yes, additional fuses are a good idea as Fullycharged pointed out to me recently.

My offer to lend you spot welder is subject to me fixing the thing first too. I need to finish my packs, and I can't get the welder working. Its going to be either a new (same) PCB, or for around the same money, go with an arduino controller. Offer still stands to borrow my 5x Opus chargers though if you want to speed up testing. I'm not processing any more laptop packs for a few months now.
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#39
(09-01-2018, 03:29 PM)Daveyboy Wrote: Hi Hermit, yes, the 20P design allows the powerwall to go into service sooner than waiting until you have enough cells for 80P for example. It will also be easier to fix problems. I intend to leave the battery online when removing a 20 cell pack for replacement / repair. It would be great to not have to shut it all down for maintenance.

I wouldn't be discarding cells that are <4.1V. My cutoff was 0.5V, which worked well as Opus tends not to register them below 0.5V anyway. Some of my best cells were as low as 2V, but recovered well. I stick them all in the charger and those that don't take a charge well, will top out at about 2V then say they are fully charged. I also remove any heaters. Then let the cells sit for a good month and remove any that are below 4.05V after resting. I don't want that level of self discharge in my wall.
I considered using  XT60 or XT90 connectors, but finally settled on ring terminals. Easier to install with just a crimper, plus you don't put much strain on the cables when trying to disconnect the pack.

I haven't fused the packs, no. I'm thinking about it. I have cell level fuses, but yes, additional fuses are a good idea as Fullycharged pointed out to me recently.

My offer to lend you spot welder is subject to me fixing the thing first too. I need to finish my packs, and I can't get the welder working. Its going to be either a new (same) PCB, or for around the same money, go with an arduino controller.  Offer still stands to borrow my 5x Opus chargers though if you want to speed up testing. I'm not processing any more laptop packs for a few months now.

I meant that those that were charged and then discharged... discarded a few below 4.1V.. will retest them.
I will ping you w.r.t Opus.. Might pop around in a week or two. I might make myself a MOT spot welder now that my soldering effort (dyson 30A 6P) failed last night.

Looking to recycle a microwave Smile
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#40
Oh, I see Big Grin Yeah, I'd still call 4.1V good, but I leave them for a month.
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