Search found 17 matches

by mk77
Sep 17 2018 1:00pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 460
Views: 54523

Re: kWeld - "Next level" DIY battery spot welder

2. What do you mean with "resistance issue"? I've read/re-read the posts which prompted this question. Some users were reporting lower (~900A) than desired target current levels (~1400A) and now seems more of a battery capacity issue than anything else. As you say the observed results dictate the p...
by mk77
Sep 16 2018 11:13am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 460
Views: 54523

Re: kWeld - "Next level" DIY battery spot welder

NIce work! a definite improvement - I like the automated feature - wish I could get it implemented in my dual pulse unit.... anyway.... Couple quick questions: 1. Which PIC/MCU is used? ((not that it matters - just curious)) 2. Will cleaning the electrode tips help with the "resistance issue"? I use...
by mk77
Sep 20 2013 7:55pm
Forum: Battery Technology
Topic: NCM vs lifepo4?
Replies: 128
Views: 13630

Re: NCM vs lifepo4?

One of my packs that I built is 128v nominal with 40 cells(142v hot off the charger), but soon as I put it under load, and in my application, it operates at 132v and down as low as 128v for the remainder of the capacity until it falls off the cliff at 100% depth of discharge. I am looking to build ...
by mk77
Sep 25 2011 8:49am
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

...and then for those of you whom wish to shave every last milligram off the weight of your ride ... here is a hybrid surface mount version :D but be advised, I have not built nor have I tested this board layout... so the usual disclaimers apply. The attached collage is the led board, the top view o...
by mk77
Sep 24 2011 10:54pm
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

Here is the artwork for the two boards that make up the original Battery Monitor circuit. I have many blank boards all ready for components. No need to have more built up. So if you would like some please pm me and I'll set up an ebay auction again. Main board is double sided and can be mod'ed for a...
by mk77
Jun 25 2011 10:40am
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

...and here is the 36 volt (or 12S) version. Basically the same setup but with seven of the 7.2 volt 6.5 ahr Prius Battery Modules for input volts. I know there was interest for this version so please PM me if you would like some of these... or if you have a particular voltage range/window (within r...
by mk77
Jun 24 2011 3:11am
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

Finished the 48v version of the battery monitor/gauge. Two videos: the first shows the overall voltage range limits and the second shows the resolution between led's. Test pack is 9 modules of a Prius NiMhd pack. The adjustment is a 25k pot connected across the test pack with the wiper going to the ...
by mk77
Jun 22 2011 8:12am
Forum: Battery Technology
Topic: Must-see lecture on lithium-ion construction and behaviour
Replies: 19
Views: 2897

Re: Must-see lecture on lithium-ion construction and behavio

I don't know about anybody else but to me this is the kind of presentation that should be added to the "stickified" thread.

eh?
by mk77
Jun 20 2011 12:12pm
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

that's ok... no problem. I might build one up as knoxie mentioned with the series 30v zener, but I hesitate with this as it has been my experience that diodes usually fail shorted; which, could possibly make for some interesting fireworks on an otherwise peaceful ride....but then again that could be...
by mk77
Jun 20 2011 7:20am
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

... but at 48V your dropping 30V across the Zener and it runs a little warm... I'll say!! :lol: especially since this circuit is designed on the premise of only being used for 12v or less batteries. Heck the chip is only supposed to run at a max of 15v (absolute max is 25v) The idea behind this met...
by mk77
Jun 19 2011 8:20am
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

sorry about that... think I may have gotten the cart before the horse... :oops: here is the schematic for the board set shown previously. I have used it in a couple of other projects and it does have a near real time response.... better than the sample rate of a vom. The range or window is easily ad...
by mk77
Jun 19 2011 5:36am
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

Way too professional-looking for me. ;) I'd've had to leave the bare PCB hanging out or something. :P awww gee, I'm flattered :wink: ...I have some available. if there is any interest I will set up an ebay site. I have some already assembled and also have some blank boards. maybe $5 for a set of th...
by mk77
Jun 18 2011 11:54am
Forum: Battery Technology
Topic: Super Simple Cheap Battery Gauge
Replies: 44
Views: 8311

Re: Super Simple Cheap Battery Gauge

here is a version I made... :)
by mk77
Jun 18 2011 11:32am
Forum: Battery Technology
Topic: lcd battery monitor
Replies: 22
Views: 1885

Re: lcd battery monitor

this is probably a step backwards.... but
the lm3914 is a dot/bar driver chip....

pic is a finished near real time voltmeter/battery monitor
which I built.... also have a bank of 12 of them. I have
to admit that it is kinda heavy (brickish) but it does do
well.
by mk77
Jun 05 2011 10:57pm
Forum: Battery Technology
Topic: lcd battery monitor
Replies: 22
Views: 1885

Re: lcd battery monitor

...i made a 7 led system to check for bad cells many years back using just red leds, it worked perfecto, i had quite a few old packs to check if any bad cells present it was a nifty quick checker, just plugged it into each pack ( each pack had an 8 pin plug they were old cyclone cobalts) This syste...
by mk77
May 20 2011 6:00am
Forum: Battery Technology
Topic: Lithium Battery Reports & Tests' 9/08
Replies: 288
Views: 48151

Re: Lithium Battery Reports & Tests' 9/08

LOWRACER wrote: .... Also I charge it with my pedal alternator.
If I am not lazy I've got an unlimited range...
Wow! You da man! :shock:

...uh, sorry... didn't mean to interrupt the thread.
couldn't help myself.. anyone who makes a comment
like that on an eBike forum....nevermind.... Carry on.
:oops:
by mk77
Mar 27 2010 10:09am
Forum: Battery Technology
Topic: Prius Batteries - How to make them work
Replies: 149
Views: 43042

Re: Prius Batteries - How to make them work

jmygann wrote:
How many cells in a standard prius pack ?

28 - by way of introduction, name is Matt and
been lurking for awhile. Really enjoy reading about
all the activity and saw this post - thought I would put in
my 2 cents - hope it helps...
Cheers.