Search found 193 matches

by hemo
May 19 2020 4:51am
Forum: Battery Technology
Topic: 72v Battery showing 80v on multimeter
Replies: 6
Views: 158

Re: 72v Battery showing 80v on multimeter

Matt in plain English your battery if 20s/72v nominal will have a min voltage and a max voltage. A safe use min voltage will be approx. 64/66v and a max charge voltage will be 84v, the 72v is a nominal voltage which is approx. 50%. For better cell life/longevity charging only to about the 90% mark o...
by hemo
May 11 2020 5:54pm
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 318
Views: 54568

Re: Common pack design mistakes, how to avoid?

10s 60p we are talking 600 cells here yes or is this a typo ?
A theoretical 600a current draw.
by hemo
May 11 2020 2:40am
Forum: Battery Technology
Topic: Parallel yes or no
Replies: 5
Views: 194

Re: Parallel yes or no

I also parallel batteries and do so using different celled packs and capacity with no issue, just make sure SOC is as close as possible before connecting I aim for less then 0.2v. A simple led £2 volt metre wired to each pack allows me to keep an eye on the voltage every now and then.
by hemo
May 11 2020 2:32am
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 318
Views: 54568

Re: Common pack design mistakes, how to avoid?

I only see a 2s wired battery pack, but guess this is just a trial design for the bigger one to come ?

10S60P is going to be mahoosive.
by hemo
Apr 30 2020 5:36pm
Forum: Battery Technology
Topic: 18S LiPo Wiring diagram
Replies: 24
Views: 520

Re: 18S LiPo Wiring diagram

mcclead2 wrote:
Apr 30 2020 5:31pm
Thank you dogman dan for you guidance

So my balance wire harness should look like this?
18S Lipo Wiring - 1 (1).jpg

Just waiting for some female JST-XH 6S connectors coming and I'll get it soldered up ready to test
Lovely much better.
by hemo
Apr 07 2020 3:57am
Forum: Battery Technology
Topic: bosch batteries
Replies: 14
Views: 307

Re: bosch batteries

In the UK many ride speed bikes/self builds illegally, enforcement is very low and most just rely on getting away with it or a ticking off if caught and possible bike confiscation. There is a process to get a self build faster bike legalised but the hoops to jump through are many and then the bike i...
by hemo
Apr 06 2020 5:19pm
Forum: Battery Technology
Topic: bosch batteries
Replies: 14
Views: 307

Re: bosch batteries

Simply don't buy Bosch as they are anti competition based and only they can repair the motors, in fact they don't even repair your motor they swap it for supposedly another new one. Bosch are simply anti competitive if you keep the bike for two years then develop a fault after warranty ceases you ar...
by hemo
Apr 04 2020 5:54pm
Forum: E-Bike Non-hub Motor Drives
Topic: 7 mile range on new fat-tire bike with Ultra. Am I doing something wrong?
Replies: 10
Views: 526

Re: Beginner needs help balancing new batteries

What final voltage or cell group voltage are charging to/trying to achieve ?
by hemo
Apr 04 2020 5:51pm
Forum: Battery Technology
Topic: Watt hour for lippo and lithium-ion
Replies: 6
Views: 184

Re: Watt hour for lippo and lithium-ion

In real world use the lion should edge it due to it's safer lower discharge, lipo will hit the cliff at a bit below 3.6v for ebike use where as lion will be ok down to 3.2 - 3.3v. No one takes lion to 2.5v and again not many would take lipo to 3v let alone much below 3.6v.
by hemo
Mar 28 2020 4:39am
Forum: Battery Technology
Topic: 48v 13s4p 18650 showing 0v for 12th cell group
Replies: 5
Views: 455

Re: 48v 13s4p 18650 showing 0v for 12th cell group

Looks like they might be Samsung 26F/J series clone. You can try the manual charge route but group 12 are not trustworthy and a liability, so be warned. Any attempt should be done using low ma say no more then 400- 500ma charger out side and keep a very careful eye on the process. If they were aroun...
by hemo
Mar 27 2020 7:27pm
Forum: Battery Technology
Topic: 48v 13s4p 18650 showing 0v for 12th cell group
Replies: 5
Views: 455

Re: 48v 13s4p 18650 showing 0v for 12th cell group

Group 12 is toast, cause could be bad cells, Bms faulty or sense wire connection failed.
Some pics of the battery cells, maybe someone can help out if your location is known.
by hemo
Mar 23 2020 3:34am
Forum: Battery Technology
Topic: Capacity difference
Replies: 9
Views: 421

Re: Capacity difference

Any battery will be dominated by the capacity of the lowest cells, more importantly is battery sag. The IR's need to be very close as does the voltage, test cells and weed out the poor ones. Charge cells first and then weed out any that self discharge. A mix of 2950 & 3000mah cells, the pack will al...
by hemo
Mar 19 2020 6:49pm
Forum: Battery Technology
Topic: Help me troubleshoot this pack please. How are these voltages?
Replies: 59
Views: 1719

Re: Help me troubleshoot this pack please. How are these voltages?

2600mah cells of which make, for instance if they are say Sam's they will be a crappy variant of the 26F. A very low current rated cell.
by hemo
Mar 19 2020 4:57am
Forum: Battery Technology
Topic: Help me troubleshoot this pack please. How are these voltages?
Replies: 59
Views: 1719

Re: Help me troubleshoot this pack please. How are these voltages?

What cells are being using and the current draw ?
by hemo
Mar 19 2020 4:52am
Forum: Battery Technology
Topic: controller for torque sensing BB
Replies: 19
Views: 745

Re: controller for torque sensing BB

KT make a TS controller but I have only seen it for sale as part of a kit.

This Bafang TS controller is available.
https://www.aliexpress.com/item/3278706 ... 2e0eisHcK6

The issues might be compatibility as they are thin on the ground.
by hemo
Mar 08 2020 6:27pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 441
Views: 46655

Re: Li-ion cells cycle ageing

As John & Honk have said this really is fantastic testing by Docware, so kudos for the time consuming work being put in and aired here for all to view the results :bigthumb:.
by hemo
Mar 04 2020 5:56pm
Forum: E-Bike General Discussion
Topic: eBike related abuse
Replies: 22
Views: 1922

Re: eBike related abuse

I once passed a peleton of MAMIL's one Sunday morning and must have pissed off the Alpha male big time as he came riding after me throwing a few insults and then finally asking how I liked my girlie ebike, I replied it was very nice and popped the assist to PAS 5 and sped off leaving him behind prob...
by hemo
Mar 02 2020 5:50pm
Forum: Battery Technology
Topic: How do I choose which battery is the best for my application
Replies: 6
Views: 548

Re: How do I choose which battery is the best for my application

I think the Op has done so by the choice of the two cells he is thinking of .
by hemo
Feb 29 2020 7:00am
Forum: Motor Technology
Topic: KT36SVPR-LCD Controller
Replies: 3
Views: 971

Re: KT36SVPR-LCD Controller

The 6 fet KT's suffer from thermal cut outs, warm weather riding especially when cooling is limited. Slow riding up inclines in high power mode is one cause asking for to much current. One needs to find ways of adding cooling for the mosfets extra heat sink or better still the addition of mini compu...
by hemo
Feb 24 2020 5:40am
Forum: Battery Technology
Topic: What is wrong with this product?
Replies: 15
Views: 1177

Re: What is wrong with this product?

The labelling is woefully wrong, 28ah ? Claims of over 9000mah per cell and only 3p for 18650, devil is in the detail or not in this case. Pack size is about right for 13s 3p config but certainly not top cells used and likely really crappy " fire brand cells" used, give it a wide berth and don't b s...
by hemo
Feb 17 2020 10:34am
Forum: Battery Technology
Topic: Bosch powertube repair
Replies: 6
Views: 598

Re: Bosch powertube repair

Jimmy in London at ebikebatteries.co.uk I believe parallels the BMS to another source (likey the new cell pack) once this is done the old cells can be disconnected. Though if a cell group is toast the BMS may well be bricked.
He recelled my brothers Bosch pack but that was a Gen 1 or 2 pack.
by hemo
Feb 13 2020 7:54am
Forum: E-Bike General Discussion
Topic: Small hub motor
Replies: 22
Views: 3306

Re: Small hub motor

I have been interested in building a small hub motor ebike as a road bike conversion. I have been an off and on bike rider, so have a road bike that I am looking to augment with a small motor to give it an occasional boost (throttle only), but intend to ride it 99% of the time on pedal only. As suc...
by hemo
Feb 11 2020 12:35pm
Forum: Battery Technology
Topic: BMS not charging or discharging
Replies: 40
Views: 2062

Re: BMS not charging or discharging

Tbh that BG BMS isn't conducive for great cell cycle life, lvc detection/release is to deep.
by hemo
Feb 08 2020 7:05pm
Forum: Battery Technology
Topic: Would anyone have specs on this cell?
Replies: 42
Views: 1383

Re: Would anyone have specs on this cell?

Yes it was a typo on my part, I have modified the post to reflect the error.
by hemo
Feb 08 2020 8:32am
Forum: Battery Technology
Topic: Would anyone have specs on this cell?
Replies: 42
Views: 1383

Re: Would anyone have specs on this cell?

From my experience the top 0.1v carries little capacity ( In a typical 10s5p or 13s 5p pack) and certainly no where near 10% of cell capacity or range. I find within 1 -1.5 miles that any voltage if charged to 4.2v is used up very quickly and cells are down to 4.1v or there abouts. For the sake of s...