Search found 7433 matches

by john61ct
Sep 25 2022 6:39pm
Forum: EBike Technical
Topic: If I give a BMS slightly lower volts, will it still balance?
Replies: 7
Views: 220

Re: If I give a BMS slightly lower volts, will it still balance?

If you want good longevity and proper balancing

buy an active balancer that will do the job in a short time (at a decent current rate) and at any SoC/voltage point you desire.
by john61ct
Sep 25 2022 6:29pm
Forum: Battery Technology
Topic: lifepo4 chemistry(s)
Replies: 2
Views: 87

Re: lifepo4 chemistry(s)

Marketing BS. The internal voltage often is irrelevant, power conversions going on input and output. YT is not a good primary source to educate yourself. LFP is one chemistry. There are HUGE variations in the build quality of different cell manufacturers, purity of their slurry, QA processes in bin...
by john61ct
Sep 18 2022 2:59pm
Forum: EBike Technical
Topic: New motor, USA made: Optibike Powerstorm MBB
Replies: 2
Views: 219

New motor, USA made: Optibike Powerstorm MBB

Hype, but interesting
https://electrek.co/2022/09/12/optibike ... ycle-motor

Wonder if adaptable for a multi-drive cargo bike?

Or maybe use the whole OTS bike and adapt?

Or with a trailer?
by john61ct
Sep 15 2022 11:56am
Forum: EBike General Discussion
Topic: My custom frame full suspension long tail dual hub cargo bike
Replies: 29
Views: 697

Re: My custom frame full suspension long tail dual hub cargo bike

Once you get past testing prototypes, China will be the way to go
by john61ct
Sep 13 2022 8:27pm
Forum: EBike Troubleshooting
Topic: Battery early discharge cuttoff.
Replies: 23
Views: 739

Re: Battery early discharge cuttoff.

OK a is fine too

None of the above is the real answer, do not use voltage to guesstimate SoC / Ah

unless you have thoroughly calibrated for your cells and use case
by john61ct
Sep 13 2022 11:41am
Forum: EBike General Discussion
Topic: Putting batteries in series
Replies: 10
Views: 644

Re: Putting batteries in series

Yes, makes you wonder how people accumulate the knowledge to "get fancy" in their dangerous experimentation without ever absorbing the most basic 101-level "guidelines" to ensure they don't kill themselves and those around them. As more people take on our hobbies I fear such avoi...
by john61ct
Sep 13 2022 11:36am
Forum: EBike Technical
Topic: Mystery charge port/charger
Replies: 1
Views: 116

Re: Mystery charge port/charger

The physical plug/port can always be adapted with pigtails

so do not let that limit your choices of charger.

Best FFR to avoid such proprietary stuff
by john61ct
Sep 13 2022 11:33am
Forum: E-Vehicles General Discussion
Topic: Battery capacity display that actually is accurate
Replies: 8
Views: 413

Re: Battery capacity display that actually is accurate

Battery SoC% calculation is rarely accurate Even with dedicated shunt based monitors costing hundreds of dollars, a 6-8% accuracy (well away from HVC 100% and 0% LVC) is considered state of the art. Better to rely on the experimental method with YOUR unique rig and use case, and develop your intuiti...
by john61ct
Sep 13 2022 11:19am
Forum: Battery Technology
Topic: Thread for new battery breakthrough PR releases
Replies: 1860
Views: 299009

Re: Thread for new battery breakthrough PR releases

And if you treat the content posted by all members equally you are in for a world of hurt. The key to learning from online discussion forums is developing your discernment, as to who to pay attention to, and most importantly, who to ignore. Otherwise you may as well just try to learn from random SM ...
by john61ct
Sep 13 2022 11:09am
Forum: EBike General Discussion
Topic: Putting batteries in series
Replies: 10
Views: 644

Re: Putting batteries in series

Too bad OP did not engage with the knowledgeable members here more

educate themselves further

before pulling the trigger on dangerous ideas.
by john61ct
Sep 13 2022 10:33am
Forum: EBike Troubleshooting
Topic: Battery early discharge cuttoff.
Replies: 23
Views: 739

Re: Battery early discharge cuttoff.

Should a battery be used around it's nominal voltage? 100% yes > Say it's 3.6V nominal, and the rider uses 0.8v per cell. Note the proper unit is SoC, % of capacity or in Ah. So if you are using 90% of capacity each cycle, your cell lifecycles may be 5x compared to 100% 80% much longer, maybe tripl...
by john61ct
Sep 11 2022 4:34pm
Forum: Battery Technology
Topic: 'Li-ion' battery nomenclature
Replies: 5
Views: 240

Re: 'Li-ion' battery nomenclature

[Do you happen to know what chemistries these places are using? Amberwolf made it clear in the first answer, NO, they likely don't know themselves. > No one would use Li-Po now-a-days would they? LiPo is just lightweight packaging tech, can have just as much chemistry variation as other types. And ...
by john61ct
Sep 04 2022 8:23pm
Forum: EBike Troubleshooting
Topic: Battery early discharge cuttoff.
Replies: 23
Views: 739

Re: Battery early discharge cuttoff.

Also, if you are drawing down anywhere near 3Vpc isolated at rest you will not get good lifespan even out of the best li-ion cells.

Shorten your trips or expand your Ah capacity, or you will need to replace your packs in a third the time, maybe even every few months.
by john61ct
Aug 31 2022 4:22am
Forum: Battery Technology
Topic: High Amperage 72v BMS suggestions?
Replies: 3
Views: 195

Re: High Amperage 72v BMS suggestions?

Terminology / units nitpick. Energy capacity is Ah. Power output guesstimates then use C-rate rather than amps directly makes it easier for members to give reality checks. Next Handling 800-900A requires dedicated, very well engineered mechanical contactors, big and heavy, otherwise you need to deal...
by john61ct
Aug 31 2022 4:10am
Forum: Battery Technology
Topic: Real Usable KWh standard?
Replies: 6
Views: 245

Re: Real Usable KWh standard?

Use Ah as your primary unit for energy capacity when talking about a given chemistry, voltage is a given

Wh and Kwh are derived from that, and only useful if comparing packs at different S-counts.
by john61ct
Aug 31 2022 4:06am
Forum: Battery Technology
Topic: Modular Battery suitcase
Replies: 34
Views: 1135

Re: Modular Battery suitcase

If you can get groups to within 0.1V before joining then no worries with fat connections. Limiting flow by using high resistance thin wire can be dangerous. Consider getting everything above a certain voltage, then using a cheap resistance based device designed for the purpose to discharge to a comm...
by john61ct
Aug 31 2022 3:50am
Forum: Battery Technology
Topic: charger keeps cycling
Replies: 6
Views: 220

Re: charger keeps cycling

An accurate DMM at the battery posts while charging should be the reference, assume your charge termination is just based on voltage (CC only)

An ammeter is required if holding Absorption / CV stage down to a certain trailing amps.

Adjust the charger until you get your desired result profile.
by john61ct
Aug 29 2022 7:16pm
Forum: E-Vehicles General Discussion
Topic: Votol EM-100 & EM-150 controllers
Replies: 2252
Views: 273799

Re: Votol EM-100 & EM-150 controllers

Ah yes, good ol' "turn it off and on again" carried to its logical conclusion
by john61ct
Aug 27 2022 1:45am
Forum: EBike Troubleshooting
Topic: Battery early discharge cuttoff.
Replies: 23
Views: 739

Re: Battery early discharge cuttoff.

Note that voltage sags very quickly as peak current is demanded especially with worn cells or poor quality in the first place.. BMS LVC may be opening at its measurement of 31V, while bounceback recovery and/or other slower-adjusting voltmeters are still showing 34V Going to better power-draw perfor...
by john61ct
Aug 27 2022 1:32am
Forum: EBike Technical
Topic: Battery amps and ah. Difference and testing
Replies: 10
Views: 313

Re: Battery amps and ah. Difference and testing

There is no reliable way to know the actual C-rate performance of a given model cell when new without testing to destruction. And your definition of timing for peak vs continuous and resisting V sage, and the thermal limits will all be arbitrary choices based on your use case. So, unless you are a k...
by john61ct
Aug 27 2022 1:19am
Forum: Battery Technology
Topic: Picked up some Lifepo.. Ratings?
Replies: 9
Views: 296

Re: Picked up some Lifepo.. Ratings?

If you want to go higher voltage break them down to bare cells, CC cap test for go/no-go, match into groups and use a single BMS for the pack-level voltage, designed to tolerate 120% of the amps you want to pull.
by john61ct
Aug 27 2022 1:14am
Forum: Battery Technology
Topic: charger keeps cycling
Replies: 6
Views: 220

Re: charger keeps cycling

54V is actually perfect as FULL for 13S

Nothing to be gained going higher just lifetime cycles reducing stress
by john61ct
Aug 27 2022 1:04am
Forum: Battery Technology
Topic: Modular Battery suitcase
Replies: 34
Views: 1135

Re: Modular Battery suitcase

It is fine to ask questions but your hunger for more and more information is expressed as entitlement, comes off as belittling and aggressively confrontational. Be grateful they are going to so much trouble already to share their obviously superior level of skills and knowledge, and just back off w...