Search found 143 matches

by andrew.box
Aug 13 2018 10:30am
Forum: Battery Technology
Topic: Diy ltc 6802-2 BMS?
Replies: 10
Views: 1065

Re: Diy ltc 6802-2 BMS?

FYI - I'm nearly finished building a BMS based on four-forty's 12 cell BMS board that uses the 6802 chip. I'll post a build thread soon, but overall I'm happy with how it turned out. (except that my cheap ebay 48v 1500W inverter failed short this weekend, but that's not the BMS's fault). Here's the ...
by andrew.box
Feb 05 2018 11:04am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 615
Views: 74566

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

Cool, thanks! I'm currently wasting all my money on a Volt module based battery backup portable inverter project, but I may want to pick one of these up eventually. They look like great quality little spot welders and price is reasonable.
by andrew.box
Feb 03 2018 12:10pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 615
Views: 74566

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

Wow, nice project. If you end up selling boards or kits please say so here. I bet we could get a number of people who'd reserve a board and parts. Also try the DIY power wall forums, those folks love spot welders.
by andrew.box
Feb 02 2018 11:04pm
Forum: Battery Technology
Topic: bluetooth BMS?
Replies: 978
Views: 66291

Re: bluetooth BMS?

Interesting thread, but a bit hard to follow. There appear to be at least 3 different bluetooth capable BMS products being discussed here, and not always a clear reference to which one is being discussed in a given post. Like, which software screenshots go with which BMS? Could it be valuable to th...
by andrew.box
Jan 31 2018 2:28pm
Forum: Battery Technology
Topic: bluetooth BMS?
Replies: 978
Views: 66291

Re: bluetooth BMS?

Interesting thread, but a bit hard to follow. There appear to be at least 3 different bluetooth capable BMS products being discussed here, and not always a clear reference to which one is being discussed in a given post. Like, which software screenshots go with which BMS? Could it be valuable to the...
by andrew.box
Jan 30 2018 7:41pm
Forum: Battery Technology
Topic: Diy ltc 6802-2 BMS?
Replies: 10
Views: 1065

Re: Diy ltc 6802-2 BMS?

I'm not 100% sure on interfacing with the Bestech units, the last ones I got from them weren't 'smart', but the units I linked appear to support a few things including I2C and serial UART. I think the idea is they have software that will program it through a USB to Serial adapter setup into the UART...
by andrew.box
Jan 29 2018 10:44pm
Forum: Battery Technology
Topic: Diy ltc 6802-2 BMS?
Replies: 10
Views: 1065

Re: Diy ltc 6802-2 BMS?

Awesome. Yeah I know of Peter from the Insight forums. He had a lithium insight back before it was even a commercial option for most cars. That guy knows his stuff. Would be great to see a community driven "open" BMS project become active. There are few things like this around, somewhat surprisingly...
by andrew.box
Jan 29 2018 3:27pm
Forum: E-Vehicles General Discussion
Topic: Looks like Sondors is at it again...(E-car)
Replies: 46
Views: 5562

Re: Looks like Sondors is at it again...(E-car)

This looks cool, do they have a chance at success? I was hoping Elio was more than vaporware, but they disappeared a while ago. Either Elio is a moron/dreamer, or he's a crook, not sure which and maybe a little of both. I gave them $100 for a pre-order fully expecting I might never see it again. I h...
by andrew.box
Jan 29 2018 11:15am
Forum: Battery Technology
Topic: Diy ltc 6802-2 BMS?
Replies: 10
Views: 1065

Re: Diy ltc 6802-2 BMS?

Oh, nice. That does seem to do most or all of what I want. Do you plan to have any boards made up? If so I might be willing to pick up a couple. Or if you have the board design files, I guess could order one or two from a PCB manufacturer. Is it at all cost effective to order low numbers of boards, ...
by andrew.box
Jan 27 2018 11:53am
Forum: Battery Technology
Topic: Diy ltc 6802-2 BMS?
Replies: 10
Views: 1065

Diy ltc 6802-2 BMS?

Hey folks, does anyone here have experience putting together something like this and setting custom voltages for cell cutoffs and balancing initiation and using higher current off chip balancing? https://sourcelion.wordpress.com/2014/07/20/battery-management-system-ltc6802-arduino/ Eg any pcbs built...
by andrew.box
Oct 29 2014 7:33pm
Forum: General Discussion
Topic: Elio..... The new Aptera???
Replies: 24
Views: 3765

Re: Elio..... The new Aptera???

Ya, sort of sounds promising and the vehicle looks really good in terms of specs and in my opinion aethetics too. I'd consider getting a reservation, but have mixed feelings about having to pay to reserve something that may very well never exist. But I guess it's really just the crowd funding model ...
by andrew.box
Oct 27 2014 3:03pm
Forum: General Discussion
Topic: Elio..... The new Aptera???
Replies: 24
Views: 3765

Re: Elio..... The new Aptera???

Anyone know if this Elio outfit is going anywhere or actually any closer to building a production vehicle? It seems like this thing hits the sweet spot in terms of price/performance/fuel economy but perhaps too good to be true.
by andrew.box
Jul 21 2014 3:07pm
Forum: E-Bike General Discussion
Topic: shipping tadpole trike
Replies: 2
Views: 318

Re: shipping tadpole trike

Update - just discovered you can ship stuff through Greyhound, the buyer of the bike got a quote from them for $115.00 to ship a box of that size and weight. May be a good option for anyone needing to ship a trike or other bulky things. I think that's what we're going to do, I just need to see if th...
by andrew.box
Jul 21 2014 2:05pm
Forum: E-Bike General Discussion
Topic: shipping tadpole trike
Replies: 2
Views: 318

shipping tadpole trike

Had an offer on my KMX on ebay that's in a range I"ll accept but the potential buyer is in Portland. With wheels and the front boom detached, the bike would go in a box 58 x 32 x 18 and weights 73 lbs. UPS wants $450 + $160 to make a custom box to ship it to Porland zip code. That's std ground. That...
by andrew.box
May 11 2014 9:14am
Forum: E-Bike Build Threads / Photos & Video
Topic: KMX X-class commuter build
Replies: 7
Views: 1152

Re: KMX X-class commuter build

That's first class, nice work!
by andrew.box
Oct 08 2013 8:10am
Forum: Battery Technology
Topic: eBike Master Switch Design
Replies: 331
Views: 30800

Re: eBike Master Switch Design

This is a great idea, I just cooked my master power switch this weekend. Forgot to pre-charge one too many times and it welded itself closed. It was a 30A rated heavy duty toggle switch and I'm running a 25A controller, but inrush current vastly exceeds 30A, obviously, and it just couldn't take it. ...
by andrew.box
Oct 02 2013 8:27pm
Forum: Battery Technology
Topic: slow balancing with Bestech BMS
Replies: 21
Views: 2144

Re: slow balancing with Bestech BMS

That's certainly simpler. I'll try it, thanks!
by andrew.box
Oct 02 2013 7:41pm
Forum: Battery Technology
Topic: slow balancing with Bestech BMS
Replies: 21
Views: 2144

Re: slow balancing with Bestech BMS

I guess I sort of mis-understood how the thing worked, but if I understand correctly what it does is activate the shunts to bleed off current from the high cells that are high enough to activate the shunt circuit but not yet at the HVC voltage, this allows low cells to catch up, but if this doesn't ...
by andrew.box
Oct 02 2013 7:09pm
Forum: Battery Technology
Topic: slow balancing with Bestech BMS
Replies: 21
Views: 2144

Re: slow balancing with Bestech BMS

but you need to measure the gate voltage and charging currents. There's no measurable current going in from the charger and none of the 100 ohm resistors are warm. I checked for voltage across a couple of them and there wasn't anything on the ones I checked, but many of them aren't easily probed un...
by andrew.box
Oct 02 2013 12:19pm
Forum: Battery Technology
Topic: slow balancing with Bestech BMS
Replies: 21
Views: 2144

Re: slow balancing with Bestech BMS

I can check gate voltages and shunt currents tonight. I think the resistors are 100 ohm. I do have hobby balance chargers but just wanted to try and evaluate how the BMS does with balancing. The pack wasn't terribly out of balance so I thought it should be within the range of what the BMS can do in ...
by andrew.box
Oct 02 2013 8:24am
Forum: Battery Technology
Topic: slow balancing with Bestech BMS
Replies: 21
Views: 2144

slow balancing with Bestech BMS

I just installed a Bestech D166-18S on a brand new 18S hobby king lipo pack and have been trying to let it balance. The pack is made of 6S, 5,000 mAh sub-packs. It's been charging for 4 days with the charger set to 4.25 volts per cell and while may cells have now come up to the HVC and are between 4...
by andrew.box
Sep 23 2013 8:50am
Forum: E-Bike General Discussion
Topic: Let's talk about brakes
Replies: 283
Views: 9866

Re: Should you use extra powerful brakes on an ebike?

My last ebike was a 3 speed Raleigh with rim brakes, I once hit the side of a truck that ran a red light at an intersection that I certainly could have avoided with better brakes. I was doing 20 mph and it really caught me off guard how poor the rim brakes were on that bike. That said, any decent di...
by andrew.box
Jun 29 2013 2:24pm
Forum: General Discussion
Topic: Reading 7 mV voltage span
Replies: 1
Views: 405

Re: Reading 7 mV voltage span

Did some thinking and I think I need an op-amp based transconductance amplifier to convert the small mV changes to a current output which can then be read as a higher voltage across a resistor, I think.
by andrew.box
Jun 29 2013 8:32am
Forum: General Discussion
Topic: Reading 7 mV voltage span
Replies: 1
Views: 405

Reading 7 mV voltage span

I'm thinking it would be fun to have a differential pressure sensor in my home HVAC system so I can actually see how clogged up my expensive 3m filters are before replacing them. I'm looking at the All Sensor 1 inch G basic sensor which measures in the 0-1" H20 range. The output voltage span is 7 mV...
by andrew.box
May 23 2013 8:09am
Forum: Battery Technology
Topic: 24s BestechPower BMS Thread
Replies: 343
Views: 30204

Re: 24s BestechPower BMS Thread

I'm buying all new cells, the ones that went to 0V are no good and won't take a charge.