Search found 688 matches

by kdog
Dec 09 2020 7:54am
Forum: Battery Technology
Topic: Is a little rust normal for nickel strip in salt water
Replies: 12
Views: 732

Re: Is a little rust normal for nickel strip in salt water

I've often had a little rust colour (exactly like in your pic) with pure nickel. I think if you have old gal pipes some dissolved iron precipitates out causing the colour, usually rubs off showing bright nickel inderneatg. The rust you get with nickel plated steel is very obviously part of the metal...
by kdog
Nov 26 2020 5:23am
Forum: Motor Technology
Topic: 3000 watf controller
Replies: 1
Views: 181

Re: 3000 watf controller

Yep you can also use a 10kw controller. The question really is 'how long will my 1500w motor last being driven by a 3kw controller? ' Can't tell you haha! Depends on waay to many factors, but if you install a temp sensor in your motor then you can push it hard and back off if it gets too hot. It's t...
by kdog
Nov 24 2020 8:27am
Forum: Motor Technology
Topic: Again...3T, 4T, 5T, 6T difference
Replies: 57
Views: 1850

Re: Again...3T, 4T, 5T, 6T difference

Whoa chalos back! Had to re read to check the date.
by kdog
Nov 05 2020 6:27am
Forum: EBike Technical
Topic: A2B Metro BMS Replacement options
Replies: 1
Views: 104

Re: A2B Metro BMS Replacement options

Not sure if a2b parts are available in other parts of the world but here (aus) they are long gone. Full functionality requires the proprietary bms. I think the system still works with a simple bms with a 2 wire output (pos + neg only) but you loose battery charge level indicator on the display. I co...
by kdog
Nov 02 2020 4:53am
Forum: Battery Technology
Topic: Cell fuse with battery pack fuse
Replies: 5
Views: 282

Re: Cell fuse with battery pack fuse

Usually not. Fuses take a definite period of time to blow and that is usually a lot longer than the time it takes the bms to die. Just get a bigger bms. Don't know why you have a 100amp CB on a 45a bms, that won't protect bms. If you have a CB rated at the peak load of the bms then maybe it would bu...
by kdog
Oct 30 2020 8:08pm
Forum: Battery Technology
Topic: Battery Design advice sought
Replies: 22
Views: 1198

Re: Battery Design advice sought

Between those stacks I'd be looking at a minimum of 4mm insulation thickness better 5-6mm. Must be fail safe. Must be resistant to pounding and vibration. 3mm plastic board, with softer lining each side like silicon sheet would be good. Fish paper alone is not adequate. Avoid at all cost any sensing...
by kdog
Oct 27 2020 3:45pm
Forum: E-Vehicles General Discussion
Topic: Downsize from 60v to 48 v
Replies: 9
Views: 678

Re: Downsize from 60v to 48 v

The motor doesn't give a rats what voltage of battery is so you're fine there. As mentioned you will need a new controller and any associated equipment that goes with that such as display (unless you can change the LVC of the one you have) I don't know how sophisticted this controller is, some are s...
by kdog
Oct 27 2020 6:04am
Forum: E-Vehicles General Discussion
Topic: Downsize from 60v to 48 v
Replies: 9
Views: 678

Re: Downsize from 60v to 48 v

Why do you want to lower the battery voltage? If it's to get a smaller battery, buy a lower AH version. If it's to lower the top speed, don't drive as fast. I can't think of many good reasons to change the system is such a way, but here are a few draw backs. It will be slower, and sluggish through t...
by kdog
Oct 16 2020 5:41pm
Forum: Battery Technology
Topic: Bad weld from spotwelder
Replies: 6
Views: 271

Re: Bad weld from spotwelder

Have you tried actually spotwelding some nickel?looks like you're just hitting the can there.
by kdog
Oct 16 2020 5:38pm
Forum: Battery Technology
Topic: Bad weld from spotwelder
Replies: 6
Views: 271

Re: Bad weld from spotwelder

Minor variation in electrode pressure or electrode tip shape would be my main guess in that order. My spotwelder is AC so I'm not sure about DC, but welders pay attention to polarity of their workpiece, try swapping tip polarity and see if it reverses. Can't think of anything else ottomh.
by kdog
Oct 16 2020 12:33am
Forum: Large EV General Discussion
Topic: 3.8Mw Electric hypercar
Replies: 18
Views: 1323

Re: 3.8Mw Electric hypercar

Quite the gamble if you drop the $$ on the pre-order. But unless you're into EVs how would you know?
by kdog
Oct 16 2020 12:16am
Forum: Large EV General Discussion
Topic: 3.8Mw Electric hypercar
Replies: 18
Views: 1323

3.8Mw Electric hypercar

What do you think of this? Is this hyperBS or actually possible in a car.....3840kw?
Seems like fantasy but what can $2.4mill get you?
Even at 1000v that's 3840 amps, or 7.7kA at 500v :shock:
https://www.caradvice.com.au/892354/ali ... -hypercar/
by kdog
Oct 08 2020 3:38am
Forum: Motor Technology
Topic: Weird controller behaviour
Replies: 3
Views: 493

Re: Weird controller behaviour

Well done. AFAIK the way the self learning works is the controller puts an ordered firing sequence through the phases then checks the hall response. If it isn't suitable it tries a different phase combo then checks again. Then it runs through the sequence through the halls and sorts the best combo a...
by kdog
Oct 08 2020 12:01am
Forum: Battery Technology
Topic: Thread for new battery breakthrough PR releases
Replies: 1670
Views: 268575

Re: Thread for new battery breakthrough PR releases

NAWA are make headlines again... Not sure what happened to the ultracap breakthrough a few years back but this time they state they are ready to commercialise the tech with scalable process. https://newatlas.com/energy/nawa-vertically-aligned-carbon-nanotube-electrode/ Not holding my breath but one ...
by kdog
Oct 06 2020 7:33am
Forum: Motor Technology
Topic: Weird controller behaviour
Replies: 3
Views: 493

Re: Weird controller behaviour

It sounds lime the self learning procedure that the controller is running through. The throttle during this time may be an instruction to reverse the rotation. You need to find out what the condition of the procedure is... Some controllers you just leave for a minute or two but others require a spec...
by kdog
Oct 02 2020 7:54am
Forum: Battery Technology
Topic: Dropped battery, one cell dented. Trying to understand failure mode.
Replies: 3
Views: 227

Re: Dropped battery, one cell dented. Trying to understand failure mode.

The cell group in question acts, electrically speaking, like a single cell. The dented cell is as you state, likely internally shorted and has drained both cells in this group to zero. Both cells in this group are now dead on account of being pulled to 0v. :flame: Do not charge it....this is when th...
by kdog
Sep 30 2020 6:24am
Forum: EScooters/EMotorcycles
Topic: Need help understanding / picking fuse for 24v 250w motor batteries
Replies: 4
Views: 281

Re: Need help understanding / picking fuse for 24v 250w motor batteries

Ill second aussieriders views. Fuses that are only marginally above the controllers rated output get hot, melt stuff and often don't die. They just make trouble. You want it to waltz in a long hill, or sustained high speed. So think double your Max controller output (15a?) as a starting point. Most ...
by kdog
Sep 30 2020 5:49am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 504
Views: 85661

Re: Spot Welding Copper Strips to 18650 Battery Cells

Hole punch is by far the quickest and cleanest way for thin sheet/foil. Only problem is locating it exactly where you need it. A highly ordered layout would lend itself to an automated process, or a jig, or some other way of punching it all out in a very short time.
by kdog
Sep 25 2020 6:09am
Forum: Battery Technology
Topic: Electrolyte leak?
Replies: 3
Views: 346

Re: Electrolyte leak?

Most likely stable if flat, but obviously don't charge or try to use them. Chuck them in a battery recycle facility near you. If they have charge then they could be an issue if severely rusted (like though the case) and then subject to an impact, or if they are charged. Then you have a fire risk. Di...
by kdog
Sep 25 2020 5:55am
Forum: Items for Sale - Used
Topic: Unitek welders for sale
Replies: 5
Views: 604

Re: Spot Welding Copper Strips to 18650 Battery Cells

Agreed, why the hell would you post that...share/contribute or leave ES for good please.
by kdog
Sep 17 2020 7:37am
Forum: Large EV General Discussion
Topic: Building a pack for Engine Starting
Replies: 6
Views: 907

Re: Building a pack for Engine Starting

4s lifepo4 is good replacement for the LA battery. Has many benefits, but your issue is more the bms side of the project. A quality 500amp+ bms is going to be pricey or difficult to find, you might even need more amps. First thing I'd do is measure your cranking amps with a clamp metre so you know w...
by kdog
Sep 14 2020 10:10am
Forum: Battery Technology
Topic: Stress Testing 3.2V 100AH prismatic cells
Replies: 25
Views: 1787

Re: Stress Testing 3.2V 100AH prismatic cells

Nah re read. 3.2v (not exactly high), and dumped in a bucket of water would keep it cool enough to use a lump of wood as a substrate. I'm sure the OP can figure out how to be safe. My ebike battery discharge station is an air cooled coil... hence 'makes a nice bench top heater'. Who said anything ab...
by kdog
Sep 13 2020 11:17pm
Forum: Battery Technology
Topic: Difference in range
Replies: 14
Views: 459

Re: Difference in range

Very true! but all things equal is my presumption, otherwise it's hard to compare anything.
by kdog
Sep 13 2020 10:11pm
Forum: Battery Technology
Topic: Difference in range
Replies: 14
Views: 459

Re: Difference in range

More voltage= more Whrs not more Ah. Probly just a typo... Also, the motor won't 'draw more' just because the battery V is higher. The motor draws the power it needs based on torque and rpm required by you at any particular point. The controller sends the required voltage (always </= to battery V to...
by kdog
Sep 13 2020 9:43pm
Forum: Battery Technology
Topic: Stress Testing 3.2V 100AH prismatic cells
Replies: 25
Views: 1787

Re: Stress Testing 3.2V 100AH prismatic cells

If you're just testing one cell at a time, at. 5c that's up to 50amps @3.2v. Most dischargers won't go to 50 amps even if they are 150w I would go and buy a roll of nichrome wire and make your own wire wound resistor. You'll only need a few meters. Wrap it around something heat proof and/or non cond...