Search found 604 matches

by 4Springs
Sat, 04 Apr 2020, 17:37
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

So what happened? Why have these cells gone bad? With this fastening system the top and bottom cells in each pile of 10 have quite an angle on the tabs. The first failure I saw was one of these. But since then I've found others that were not the furthest ones, but ones in the middle where the tabs a...
by 4Springs
Sat, 04 Apr 2020, 14:30
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

What a week! On Monday I didn't drive the Brumby to work because I had a failed BMS celltop board. Today I'm wondering whether I even have a battery at all... I opened up the rear battery box today. Both to look at some of those warm cells identified by the graphs above, but also to look for more el...
by 4Springs
Thu, 02 Apr 2020, 18:12
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

jonescg wrote:
Thu, 02 Apr 2020, 18:04
Yeah, aluminium and anything other than aluminium will set up a galvanic reaction, and iron is a good candidate as it's further down the reactivity table.
Doesn't a galvanic reaction require a liquid? Electrolyte leaks aside, these connections should always be warm and dry.
by 4Springs
Thu, 02 Apr 2020, 18:06
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

I did some banana cleaning today. The aluminium tabs are somewhat corroded - they will need to be polished up. The copper tabs have lost some of their (nickel?) coating as well. I found another cell that suffered some damage. This is the one underneath the leaky one. Several spots around the anode. ...
by 4Springs
Thu, 02 Apr 2020, 18:01
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

I had no idea this clamping system used steel - at the very least use nickel plated steel, or just plain old aluminium if you have enough Alminox to throw around. Hmm... Would you like to elaborate? I've looked up Alminox, and it appears to be a compound to help aluminium surfaces make good electri...
by 4Springs
Wed, 01 Apr 2020, 17:19
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

I discharged the battery down to a minimum cell voltage of 3.1 V the other day. Took me 160 km to do it. Then I charged up to a maximum cell voltage of 4.1 V. The next day I found the BMS reporting "Fault 1". This means that it wasn't hearing anything from the celltop boards. The first cell up the l...
by 4Springs
Fri, 27 Mar 2020, 18:31
Forum: Renewable Energy and Storage (Non-EV)
Topic: AVASS cells 2nd lot
Replies: 50
Views: 3837

Re: AVASS cells 2nd lot

For those that have manufactured custom links from rigid conductors, what materials and cross section dimensions do you recommend? Here are mine. You've reminded me that I haven't updated the thread describing my build for a while. IMG_20191004_172325964.jpg I used flattened copper pipe. I got it a...
by 4Springs
Fri, 27 Mar 2020, 16:00
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

This is what i did on my board but i found that when the bypass is running it warms up the board and that causes the sensor to detect a higher temperature. I placed the sensor very close to the contact and far away from. The hot parts of the bypass circuitry but it still detects a few degrees highe...
by 4Springs
Thu, 26 Mar 2020, 17:19
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

How did you attached the temperature sensors? When I did some testing for the first time I found that if the contact overheats the tab conducts the heat to the cell quite efficiently. The temperature sensors are on the celltop circuit boards - surface mount component very close to the negative term...
by 4Springs
Wed, 25 Mar 2020, 18:54
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 441
Views: 60654

Re: Low cost BMS

Do the nodes turn off or go into some low power mode to avoid discharging the battery when not being used? At 40% that means you generally bypass at about 0.24A? After doing the balancing yesterday I am starting to think that maybe 5A is an overkill. I have also dropped the max current to about 3A....
by 4Springs
Wed, 25 Mar 2020, 18:35
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

I'm not completely convinced that the Brumby has the full power that it used to. Neither is my wife, Zara, who took it into Launceston the other day. Mind you, we haven't driven it for a couple of months, and we've been driving our new Kona in the meantime. So perhaps we are just spoiled! One potent...
by 4Springs
Wed, 25 Mar 2020, 17:41
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

are you trying to drive on the pre-charge resistor only? Ah, I know what it is like to drive on the pre-charge resistor. This happens every time I forget to click around to 'Start' on the key. It goes 'eh', and just moves enough to tell me that it tried. This was giving me more than that, but not n...
by 4Springs
Wed, 25 Mar 2020, 16:12
Forum: Members Machines
Topic: Francisco's Electric Pajero
Replies: 133
Views: 15325

Re: Francisco's Electric Pajero

What voltage is considered 100% capacity? In other words, at what voltage does the cell voltage rise rapidly yet only a small current going into the cell. LFP and LYP cells will voltage balance quickly below fully charged but that has nothing to do with the state of charge being balanced. The only ...
by 4Springs
Tue, 24 Mar 2020, 18:23
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

So - how'd it go? As far as I know, nobody has tested these cells yet in a full-blown vehicle. And certainly nobody has tested my method for connecting them together into modules. My biggest fear is that the clamping arrangement that I developed won't take the current. IMG_0342.JPG The top and botto...
by 4Springs
Tue, 24 Mar 2020, 17:58
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

IMG_20200321_155657414.jpg Photo of the new-look underbonnet. The battery boxes are longer, thinner and shorter than before. The controller has been moved from the end to the top of the right battery box (left in the photo). The grey box with the red isolation switch has also been moved from the en...
by 4Springs
Tue, 24 Mar 2020, 17:45
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

IMG_20200301_093516174.jpg This photo shows the six rear battery modules in place. The blue string is to carry them with, and then tuck away once in place. All of the connections are at the tops of the modules. I've left the threaded rods on the shorter modules quite long still, with the idea that ...
by 4Springs
Tue, 24 Mar 2020, 17:32
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 441
Views: 60654

Re: Low cost BMS

I do a two point calibration and the master is the one that does all the calculations. In my BMS the nodes have very simple logic. To avoid any chance of the bypass flattening the cells the bypass only runs for a short time (which is settable by software) so if you stop sending the bypass command i...
by 4Springs
Mon, 23 Mar 2020, 18:32
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 441
Views: 60654

Re: Low cost BMS

New version of the Low Cost BMS - this one for the LG E63 NMC cells that Francisco has been importing https://forums.aeva.asn.au/viewtopic.php?f=17&t=5909 Since these cells have the terminals at each end, the old celltop board needed a bit of modification. This version bolts on to the negative termi...
by 4Springs
Mon, 23 Mar 2020, 17:33
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

IMG_0400.JPG Here are some battery modules, sitting in the tray since that is a handy place to put them. At the front are four of the large ones (30 cells), and towards the rear are two of the small ones (20 cells). One of the small modules has a yellow fuse holder on it. The holder takes a 30 A fu...
by 4Springs
Mon, 23 Mar 2020, 17:00
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

It has been a while since I've posted, but I have been very busy! I'll go back through my photos and make some posts in order of date.... IMG_0378.JPG I found four cells out of my 200 that had discolouration. The worst one is in the photo. It looks like something has leaked at some stage, but it is ...
by 4Springs
Mon, 23 Mar 2020, 16:53
Forum: Technical and conversion discussion
Topic: Prelude conversion project - some questions
Replies: 556
Views: 47318

Re: Prelude conversion project - some questions

jonescg wrote:
Mon, 23 Mar 2020, 14:33
So I'm thinking that the reservoir probably needs to be bigger, or a harder vacuum needs to be pulled.
What is the volume of your reservoir out of interest?
by 4Springs
Sat, 08 Feb 2020, 17:28
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

I'd go with the PET sheet because it gives you electrical isolation as well. The aim is the keep the cells above 0*C when charging and I believe the PET sheet will not conduct the cold from outside the way the aluminium would and therefore provide a more even heat. I've gone with the PET - mainly b...
by 4Springs
Sat, 01 Feb 2020, 13:58
Forum: Hyundai
Topic: Hyundai Kona road Noise
Replies: 13
Views: 773

Re: Hyundai Kona road Noise

Hi All, Within a week I sourced 2 rolls of Jaycar AX-3687 sound deadening and put it all around on the metal in the boot area and over the metal area just behind the back seat. I was careful to leave the plastic shield over the sticky mastic near any wiring, so the sound deadening did not stick to ...
by 4Springs
Fri, 31 Jan 2020, 18:35
Forum: Hyundai
Topic: KONA EV tailgate story
Replies: 12
Views: 671

Re: KONA EV tailgate story

Interesting. We don't have to slam ours. Might be able to be adjusted?
by 4Springs
Thu, 30 Jan 2020, 15:11
Forum: Members Machines
Topic: 4Springs' Brumby
Replies: 273
Views: 45367

Re: 4Springs' Brumby

Ok, so I've done an experiment. It looks like I should put something between my Nichrome and my cells. The two options are plastic or aluminium sheet. Plastic is thinner, cheaper, an electrical insulator, easier to cut and less likely to damage the cells. But it is a relatively poor conductor of hea...