Search found 66 matches

by Mr. Mik
Mon, 23 Nov 2009, 15:47
Forum: Electric motors and controllers
Topic: big batteries and step up DC converters
Replies: 69
Views: 19545

big batteries and step up DC converters

How about going to the extreme and put all cells in parallel? A 3.5V to 600V DC/DC converter! Cells screwed directly to two thick bus plates that provide structural support as well as low loss conduction of say 10,000A? This would get rid of any cell imbalance, ever. No problem with cell reversals, ...
by Mr. Mik
Sun, 22 Nov 2009, 03:47
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 129533

Home grown BMS ideas !

From a few of the posts above I gather that replacement of the weakest cell (as a "sacrificial cell") during the life of the pack is not a commonly anticipated or planned practice. If this assumption is correct, then the used pack capacity should be limited to the percentage of capacity that the wea...
by Mr. Mik
Sat, 21 Nov 2009, 00:17
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 129533

Home grown BMS ideas !

My experience is with NiMH cells and might not fully transfer to Lithium chemistries. The point I'd like to add is that the weakest cell (speaking of total capacity) can also have other problems, is actually more likely to have other problems, like increased IR and increased self discharge rate. Thi...
by Mr. Mik
Thu, 17 Sep 2009, 12:36
Forum: Batteries, charging, management and monitoring
Topic: CAN BUS Monitor
Replies: 17
Views: 4161

CAN BUS Monitor

I would also like to build a Canbus display device, but for the Vectrix VX-1 scooter. I can interpret the canbus messages which can be accessed via the built-in connector. All I'd need would be a something that can be programmed with to display something more user-friendly when it sees certain CAN m...
by Mr. Mik
Sat, 12 Sep 2009, 00:19
Forum: Batteries, charging, management and monitoring
Topic: Battery Capacity Bench tester
Replies: 21
Views: 4313

Battery Capacity Bench tester

... I love the egg timer :) Sometimes that is all you need to test something! In saying that, I like the fact you want to use an inverter to actually "run" something useful whilst you are testing. It seems a waste of power otherwise just to heat up some ceramic. If we combine the two we can boil eg...
by Mr. Mik
Fri, 11 Sep 2009, 01:07
Forum: Batteries, charging, management and monitoring
Topic: Battery Capacity Bench tester
Replies: 21
Views: 4313

Battery Capacity Bench tester

How about two caps in parallel, but the second one with a small resistor in series? Or just the one cap with a small resistor? That should cause a time lag in the voltage, but a fairly smooth curve? I hope this is not totally nonsense... Ahem, ahem, cough, cough, .... that was nonsense! There is a ...
by Mr. Mik
Thu, 10 Sep 2009, 12:28
Forum: Batteries, charging, management and monitoring
Topic: Battery Capacity Bench tester
Replies: 21
Views: 4313

Battery Capacity Bench tester

i was thinking putting a cap in parrallel with the shunt, so the value measured in the 1ns sample will be more representative of the average value. Matt How about two caps in parallel, but the second one with a small resistor in series? Or just the one cap with a small resistor? That should cause a...
by Mr. Mik
Thu, 10 Sep 2009, 12:23
Forum: Batteries, charging, management and monitoring
Topic: Battery Capacity Bench tester
Replies: 21
Views: 4313

Battery Capacity Bench tester

Thank you, Matt and Squiggles! Great ideas. Finally an excuse to buy a scope! And putting globes in series will allow testing of practically any battery. My setup is of course too clumsy to change over all the time for testing vastly different battery types, but I have those 160 x 6s NiMH sticks out...
by Mr. Mik
Wed, 09 Sep 2009, 01:57
Forum: Batteries, charging, management and monitoring
Topic: Battery Capacity Bench tester
Replies: 21
Views: 4313

Battery Capacity Bench tester

Sorry, cannot help you with your questions, I can barely understand what your problem is! But I really hope you figure it out, because I would also like to have logging capability with my prototype bench tester setup. What I've built is a kind of "Ghetto" version of what you are trying to create, of...
by Mr. Mik
Tue, 04 Aug 2009, 12:42
Forum: General EV Discussion
Topic: Hybrids: heresy or handy?
Replies: 43
Views: 5077

Hybrids: heresy or handy?

I was contemplating buy a whole new lot of tagged D-cell NiMH batteries and spending a weekend with a soldering iron. Minimum purchase from China is 1000 units! But hey I haven't even got my hands on it yet so we'll see what the go is when I get it. That would make just 4.1 Prius Mk1 packs. But I d...
by Mr. Mik
Sun, 02 Aug 2009, 18:43
Forum: General EV Discussion
Topic: Hybrids: heresy or handy?
Replies: 43
Views: 5077

Hybrids: heresy or handy?

Hi Mik?, where did you get the batteries from and do you have a Gen 1 Prius yourself? Dave I bought them all from one person who imported seveal Prii from Japan, then replaced the batteries when error messages popped up. I do not have a Mk1 Prius, but if I am successful at restoring the batteries, ...
by Mr. Mik
Sat, 01 Aug 2009, 20:08
Forum: General EV Discussion
Topic: Hybrids: heresy or handy?
Replies: 43
Views: 5077

Hybrids: heresy or handy?

Yes, Prius NHW10 sticks, 4 whole batteries of them.
by Mr. Mik
Sat, 01 Aug 2009, 17:04
Forum: General EV Discussion
Topic: Hybrids: heresy or handy?
Replies: 43
Views: 5077

Hybrids: heresy or handy?

I'm hip deep into learning how to test and recondition these cells at the moment. Need to build a discharger that allows testing at 100A or thereabouts, interesting project... So far all sticks have tested at about 6.2Ah capacity at 6.5A (=1C) to 0.9V per cell cutoff level. The BMS is very interesti...
by Mr. Mik
Tue, 28 Jul 2009, 12:52
Forum: General EV Discussion
Topic: Cheezy EV number plates
Replies: 51
Views: 7374

Cheezy EV number plates

NO ICE was for sale in QLD including the Yamaha Virago which it was attached to about a year ago. I did not have the money to buy it, buh-huh...
by Mr. Mik
Tue, 28 Jul 2009, 04:21
Forum: General EV Discussion
Topic: Cheezy EV number plates
Replies: 51
Views: 7374

Cheezy EV number plates

OOC02
by Mr. Mik
Tue, 21 Jul 2009, 13:18
Forum: General EV Discussion
Topic: Hybrids: heresy or handy?
Replies: 43
Views: 5077

Hybrids: heresy or handy?

....... ....... I'm thinking of course of the only truly mass produced hybrid car to date, the Toyota Prius. They've been manufactured for 10 years now, and the third generation is on sale now in Japan. The 2010 Prius will probably be available in Australia in August. It's probably going to be too ...
by Mr. Mik
Fri, 17 Jul 2009, 01:25
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 129533

Home grown BMS ideas !

The manual BMS (M-BMS) which I built for my Vectux uses a similar, but more sophisticated approach to the "half-pack monitoring": On the right I can select the entire string voltage (102s), or first 27s, or last 27s, or any of the 12 modules of 9 or 8 cells, or groups of 5s cells, 3s cells and indiv...
by Mr. Mik
Wed, 15 Jul 2009, 12:01
Forum: Batteries, charging, management and monitoring
Topic: Prius Batteries in Australia
Replies: 26
Views: 5784

Prius Batteries in Australia

I managed to get a hold of 4 complete Prius batteries, older model, one with 12V powered charger.

Time to play!
by Mr. Mik
Wed, 01 Jul 2009, 03:36
Forum: The Lounge
Topic: Electricity Meter
Replies: 20
Views: 9606

Electricity Meter

I just copy and paste the symbols.

Whenever I spot a symbol that is missing in my collection, I add it to a text document which I keep for this purpose.

Lines of cryptic code to help post links, pictures, video etc also go into the document for ready re-use when needed.
by Mr. Mik
Thu, 11 Jun 2009, 12:28
Forum: Batteries, charging, management and monitoring
Topic: Prius Batteries in Australia
Replies: 26
Views: 5784

Prius Batteries in Australia

Thanks, antiscab and coulomb!

Re: use in the Vectrix: Yes, that is a distinct possibility!

But if I can get enough of them, then they can be used for all sorts of interesting projects!

by Mr. Mik
Thu, 11 Jun 2009, 03:00
Forum: Batteries, charging, management and monitoring
Topic: Prius Batteries in Australia
Replies: 26
Views: 5784

Prius Batteries in Australia

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by Mr. Mik
Thu, 11 Jun 2009, 02:58
Forum: Batteries, charging, management and monitoring
Topic: Prius Batteries in Australia
Replies: 26
Views: 5784

Prius Batteries in Australia

Sorry, double post. When I posted the first one I got an error message.

After the second post I got the same error message, and then i saw that both posts were actually on the forum despite the apparent error.
by Mr. Mik
Thu, 11 Jun 2009, 02:55
Forum: Batteries, charging, management and monitoring
Topic: Prius Batteries in Australia
Replies: 26
Views: 5784

Prius Batteries in Australia

How can you get your hands on used Prius batteries in Australia?

All the wreckers I phoned so far could not help me...
by Mr. Mik
Fri, 29 May 2009, 20:41
Forum: Technical and conversion discussion
Topic: Soapbox on regenerative braking
Replies: 278
Views: 37370

Soapbox on regenerative braking

As a corollary to my earlier post, I also believe we are hugely under -playing the importance of vehicle efficiency, which can have a far greater impact on your range than regenerative braking. Factors in particular are aerodynamic drag, rolling resistance, vehicle mass, and frontal area. Your aver...
by Mr. Mik
Fri, 29 May 2009, 01:28
Forum: Batteries, charging, management and monitoring
Topic: Air-fueled battery
Replies: 1
Views: 786

Air-fueled battery

Interesting!

That battery must be getting heavier as it discharges and absorbs oxygen.

They probably calculated the energy density per gram using the lower charged weight.

Cycle life might of course be disappointing.