Search found 40 matches

by Dak77
Sep 18 2019 11:23pm
Forum: Battery Technology
Topic: Cell balancing
Replies: 4
Views: 54

Re: Cell balancing

Awesome. Thanks. I just don't trust having a cheap bms permanently wired in and I can't fork out what a good one costs right now.
by Dak77
Sep 18 2019 10:30pm
Forum: Battery Technology
Topic: Cell balancing
Replies: 4
Views: 54

Cell balancing

I was wondering; since a bms can put a load on one cell group to bring it in line with the others, can you also charge one cell group independently of the others? For instance , if you have all groups at 4.1v , with one group at 4.0v , can you just attach a 4.1v supply to that low group and " catch ...
by Dak77
Sep 10 2019 12:19am
Forum: Battery Technology
Topic: In over my head with an unbalanced 14S5P battery
Replies: 8
Views: 383

Re: In over my head with an unbalanced 14S5P battery

"A BMS" is a collection of functionality. As long as you are **sure** you stop discharging before the **lowest** cell/group hits your bottom cutoff voltage, and **sure** that you terminate charging when the **highest** cell/grouo hits your top voltage stop setpoint then you are fine. As they get mo...
by Dak77
Sep 09 2019 1:48am
Forum: Battery Technology
Topic: In over my head with an unbalanced 14S5P battery
Replies: 8
Views: 383

Re: In over my head with an unbalanced 14S5P battery

i think there is a bad cell in 7, it would be the logical explanation. do you have a "mate" with a spot welder that can weld cells? you might ask em3 for a handful replacement cells so you can replace the whole group if you have warranty. you can also use a smart bms that you can program to balance...
by Dak77
Sep 02 2019 6:28pm
Forum: Battery Technology
Topic: Charging procedure
Replies: 3
Views: 248

Re: Charging procedure

Thank you both. Exactly the answers I needed.
by Dak77
Sep 02 2019 5:06pm
Forum: Battery Technology
Topic: Charging procedure
Replies: 3
Views: 248

Charging procedure

When bulk charging to 4.1v per cell (or less) using an LED supply , is it recommended to hold at terminating voltage level until the amps drop to 100mA like you would charging to 4.2v ( or does that even happen at lower voltage? ) , or should it be shut off as soon as the voltage hits the set termin...
by Dak77
Aug 28 2019 7:16pm
Forum: Battery Technology
Topic: Build your own charger
Replies: 153
Views: 9876

Re: Build your own charger

if you set the voltage to 58.8 and whatever current , 6 amps , and you didn't turn it off , would it continue to push 6 amps until it went up in flames? A power source only makes X amps available. It is the load / battery that demand / pulls the current level it wants. Overload protection, or even ...
by Dak77
Aug 28 2019 7:11pm
Forum: Battery Technology
Topic: Boston-Power Swing 5300 Li-ion cell test
Replies: 117
Views: 12313

Re: Boston-Power Swing 5300 Li-ion cell test

These cells have a slightly diameter than an 18650. I have a variety of battery holders for 18650's that I have made into tools for mass charging of cells or for cell capacity testing or for some pack needed and used old 18650's. What I've discovered is 2 of the BP cells side by side in an 18650 ba...
by Dak77
Aug 28 2019 4:24pm
Forum: Battery Technology
Topic: Build your own charger
Replies: 153
Views: 9876

Re: Build your own charger

Ohhh ok. So no grounding the input to the same case that the output is grounded to . Thanks for clearing that up for me. So if I had 2 meanwell led supplies to connect in series, does that mean I would have to find outlets that aren't on the same breaker? By definition, ground literally means the d...
by Dak77
Aug 27 2019 7:24pm
Forum: Battery Technology
Topic: Build your own charger
Replies: 153
Views: 9876

Re: Build your own charger

if you set the voltage to 58.8 and whatever current , 6 amps , and you didn't turn it off , would it continue to push 6 amps until it went up in flames? A power source only makes X amps available. It is the load / battery that demand / pulls the current level it wants. Overload protection, or even ...
by Dak77
Aug 26 2019 9:58pm
Forum: Battery Technology
Topic: Build your own charger
Replies: 153
Views: 9876

Re: Build your own charger

"4 big things you are looking for: 1. The outputs are 100% isolated from the AC input. Without this, STOP NOW! 2. 170 watts is 8.5 amps at 20v. Expect to get more like 9-9.5 amps. 3. These specific PSU's are over load and over temperature protected. They won't die easily. 4. Buy legit Lenovo PSU's,...
by Dak77
Aug 26 2019 5:58pm
Forum: Battery Technology
Topic: clamp meters
Replies: 17
Views: 414

Re: clamp meters

Ahhh ok that makes sense. I've never used one of the included shunts, I get them from a local industrial electronics place and he calibrates them by hand. I never considered using the included ones because they're physically huge. yup, that's the ticket. i got some pretty expensive shunts in my "go...
by Dak77
Aug 23 2019 6:16pm
Forum: Battery Technology
Topic: clamp meters
Replies: 17
Views: 414

Re: clamp meters

Clamp ammeters are the wrong tool for your job. If you want to know current put in a shunt and log! Aka, get a watt meter. Are those cheap watt meters reasonably accurate? Like the $12 -$30 ones everyone seems to put their nameplate on , but they look exactly the same . https://www.ebay.com/itm/Pre...
by Dak77
Aug 23 2019 6:10pm
Forum: Battery Technology
Topic: clamp meters
Replies: 17
Views: 414

Re: clamp meters

please separate your current needs. try to use 2, one for low ranges up to 60ish amps and one for the big ranges beyond 100amps. that way you get a smaller meter that is WAY more practical for measureing in tight spaces or one devices as the uni-t i mentioned is quite small and light. big 100+ amp ...
by Dak77
Aug 23 2019 3:56pm
Forum: Battery Technology
Topic: clamp meters
Replies: 17
Views: 414

Re: clamp meters

Thank you both . I definitely will never need a 600 amp or even 400amp range. I was having problems finding a meter that will do DC amps with an inductive pickup in my usage range . I just need an accurate volt meter ac and dc up to about 300v , inductive dc amp "clamp" that is accurate from 0- 200i...
by Dak77
Aug 23 2019 3:12pm
Forum: Battery Technology
Topic: clamp meters
Replies: 17
Views: 414

clamp meters

I am an electronics noob , and I am looking for a clamp meter to read dc amps from battery leads and motors . Two that I've been looking at are the Fluke 324 plus and the Klein cl 800 . When looking at the specs, the Fluke's dc current range shows 40A/400A and Klein's shows 60A/600A . Does that mean...
by Dak77
Aug 22 2019 1:58am
Forum: Battery Technology
Topic: Testing a 10S 36 Volt BMS
Replies: 64
Views: 1405

Re: Testing a 10S 36 Volt BMS

What is an acceptable voltage variance between cells , at which point you can string them in parallel to allow them to balance themselves naturally before assembling the pack ?
by Dak77
Aug 21 2019 9:17pm
Forum: Battery Technology
Topic: Testing a 10S 36 Volt BMS
Replies: 64
Views: 1405

Re: Testing a 10S 36 Volt BMS

I know I'm gonna get slapped for asking this , but is a cheap bms more liability than benefit? If so , what are some suggestions for "some of the least expensive , yet reliable bms modules ?
by Dak77
Aug 12 2019 9:11pm
Forum: Battery Technology
Topic: Nishi 18650 pack building kit
Replies: 35
Views: 1711

Re: Nishi 18650 pack building kit

I wonder about adding into the design , a small clamp similar to the seatpost clamp on a bike with a torx screw at the opening of those types of caps, wouldn't take much compression on them to hold them securely. Maybe add $ .25 to the cost of each pair ,but to me it would seem worth it.
by Dak77
Jun 14 2019 1:35am
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1395

Re: Which cell for long lasting battery

docware wrote:
Jun 14 2019 1:28am
Dak77 wrote:
Jun 14 2019 12:57am


What kind of amp loads are you hitting that GA pack with? Ball park figure
Amp load peaks are usually about 2,2 A, very seldom 3 A.
Charging amps 0,8 A for the first year, now cca 0,5 A.
:thumb: Gracias
by Dak77
Jun 14 2019 12:57am
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1395

Re: Which cell for long lasting battery

I give you an example a hard data from my measurement. Tesla Model S 85 cell is after 500 cycles (the same settings: 0.5C-1C 100% DoD) at 81% of its nominal capacity and after 1000 cycles at 71%. This is much worse result than almost all above mentioned cells. Do we heard about any significant Tesl...
by Dak77
Jun 13 2019 4:25pm
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1395

Re: Which cell for long lasting battery

Is HG2 in that 1000cycle club? Sure it is. But HG2 also has its own issues. The problem with HG2 is that it loses capacity very quickly during the first 50 cycles (ca 8-10% of nominal capacity). Between 50-100 cycles the capacity drop start with stabilization and after ca 150 cycle there is only mi...
by Dak77
Jun 12 2019 9:54pm
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 1395

Re: Which cell for long lasting battery

Hey guys, at the moment i have a 7P13S battery consisting of 91 LG MG1 and after only about 170 cycles it lost already about 40%. I tested it multiple times and its quite disappointing. My setup looks like following: Charge overnight with about 3A or 0,3C. Commuting to work and back, each way is ab...
by Dak77
May 30 2019 12:20am
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1528

Re: Panny or Sanyo?

Yeh I see your points . Having an opening of any kind is a bad idea , I admit.
by Dak77
May 29 2019 7:42pm
Forum: Battery Technology
Topic: Panny or Sanyo?
Replies: 44
Views: 1528

Re: Panny or Sanyo?

It was either Thunderheart or Mooch from the flashlight forum saying it's a PF rewrap.

Edit: This is where I read that. https://lygte-info.dk/review/batteries2012/Orbtronic 18650PD 2900mAh (Black) UK.html