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by john61ct
Feb 27 2021 9:31am
Forum: Battery Technology
Topic: 'on board' 1.5kW charger. Which alibaba supplier?
Replies: 99
Views: 1872

Re: 'on board' 1.5kW charger. Which alibaba supplier?


serious_sam wrote:Whatever that means
It means go take a hike,

post as I like, I will!



Sent from my Nexus 6 using Tapatalk

by john61ct
Feb 27 2021 5:02am
Forum: Battery Technology
Topic: 'on board' 1.5kW charger. Which alibaba supplier?
Replies: 99
Views: 1872

Re: 'on board' 1.5kW charger. Which alibaba supplier?

The modern world now tolerates

if not celebrates

neuro-diversity
by john61ct
Feb 27 2021 4:58am
Forum: Battery Technology
Topic: Safe RC-LiPo undercharge when bulk charging without BMS?
Replies: 17
Views: 308

Re: Safe RC-LiPo undercharge when bulk charging without BMS?

Packs in parallel can connect the balance leads "across" so one balancer handles them all at once. If the only connection is at the pack-level voltage main power leads then you get unbalanced current flows causing uneven wear shorter lifespan. But **cells** paralleled at the 1S level, then...
by john61ct
Feb 27 2021 4:25am
Forum: General Discussion
Topic: Daly BMS question
Replies: 6
Views: 142

Re: Daly BMS question

Building up your DIY wiring and connector skillz is a 101-level requirement of the hobby, better to start sooner than later.
by john61ct
Feb 27 2021 4:09am
Forum: Battery Technology
Topic: 'on board' 1.5kW charger. Which alibaba supplier?
Replies: 99
Views: 1872

Re: 'on board' 1.5kW charger. Which alibaba supplier?

I have never claimed that isolating the cells from a floating charge source is required for any reason to do with safety nor "damage" in the usual sense. My point is simply that LI charge cycles should be terminated at or before the specified endAmps / desired trailing current is reached w...
by john61ct
Feb 27 2021 3:56am
Forum: Battery Technology
Topic: Panasonic NCR21700T
Replies: 11
Views: 784

Re: Panasonic NCR21700T

Pajda,

could you please link to the test threads that give specific comparison data between these two reco cells?

And how do those compare to Samsung 29E7?

Longevity is my top concern

aside from availability in the USA and cost per kWh of course.

Low C-rates, usually.
by john61ct
Feb 27 2021 3:45am
Forum: EBike Technical
Topic: Balance Discharger... or is there anything else?
Replies: 11
Views: 208

Re: Balance Discharger... or is there anything else?

Battery Medics… ALL the passive dischargers/balancers listed above ARE rebadged BM's. That's very interesting and valuable insight if true. But I posted lots of powered units, and came across hundreds of others googling just in case some readers do not realise the distinction. So long as the "...
by john61ct
Feb 27 2021 3:29am
Forum: Battery Technology
Topic: Chargery C10325 not doing CV phase?
Replies: 45
Views: 716

Re: Chargery C10325 not doing CV phase?

this PSU=charger nonsense should be condemned everywhere it's reposted I agree > A PSU does not have the safeties a charger has I agree. > using one to directly charge a pack is inherently unsafe I disagree, **if** the charging is always attended by a knowledgeable and attentive "compos mentis...
by john61ct
Feb 27 2021 3:22am
Forum: Battery Technology
Topic: Chargery C10325 not doing CV phase?
Replies: 45
Views: 716

Re: Chargery C10325 not doing CV phase?

My statements here apply to the general principles, not a specific type of gear or any particular usage. The vendor data sheets for batteries create "cultural norms" for specific industries, that then get slavishly followed by the designers of charge source regulation circuits. That does n...
by john61ct
Feb 27 2021 2:10am
Forum: Battery Technology
Topic: how to choose BMS in a battery pack?
Replies: 14
Views: 377

Re: how to choose BMS in a battery pack?

The most straightforward cheapest backbone for short distances of DC transmission is 12V that should always be your default starting point. Are your DC loads spread out over a large area? If you were buying a small inverter, cheap as you can get away with for each AC device, all spread around a big ...
by john61ct
Feb 27 2021 1:57am
Forum: Battery Technology
Topic: Safe RC-LiPo undercharge when bulk charging without BMS?
Replies: 17
Views: 308

Re: Safe RC-LiPo undercharge when bulk charging without BMS?

Note that 4.15V or even 4.05V can still get to the same definition of 100% Full as using a 4.2V or even 4.35V charge setpoint. Not of course if you are using a Bulk / CC-only "charge to X and stop" profile, which works just fine and in fact is what I recommend for normal daily-usage cyclin...
by john61ct
Feb 27 2021 1:38am
Forum: Battery Technology
Topic: 4 20amp 12v batteries to lithium advice plz
Replies: 5
Views: 122

Re: 4 20amp 12v batteries to lithium advice plz

So if your system is 24V, and the batteries are currently 20Ah each at 12V which are tiny capacity take the above as questions, the most basic information you should know before thinking about making changes! Then you will be putting eight LFP chemistry cells in to get to 24V, best to get the larges...
by john61ct
Feb 26 2021 8:27am
Forum: Battery Technology
Topic: BMSs
Replies: 11
Views: 240

Re: BMSs

BMSs are usually designed to maintain balance, but you need to be able monitor their work, cell/group level voltages keep the delta from getting so great that it takes days of float charging to give them time to finish. A full volt shows extreme neglect, usually 30-60mV requires a rebalance session....
by john61ct
Feb 26 2021 8:15am
Forum: EBike Technical
Topic: Balance Discharger... or is there anything else?
Replies: 11
Views: 208

Re: Balance Discharger... or is there anything else?

Fancy version with bulb protection https://www.rcgroups.com/forums/showthread.php?1901849-Best-yet-Auto-Disconnector-for-LiPo-Storage-Discharge/page20#post29745666 This will be more accurate, general coulometer and voltage monitor http://www.isdt.co/bg-8s.html _______ Fancier tester, charger + dummy...
by john61ct
Feb 26 2021 8:01am
Forum: EBike Technical
Topic: Balance Discharger... or is there anything else?
Replies: 11
Views: 208

Re: Balance Discharger... or is there anything else?

Light bulb, resistor, just wire, regular silicone insulated or bare nichrome, hairdryers toasters water heating elements

Basically a DIY version of this
http://store.evtv.me/proddetail.php?prod=250wresistor
by john61ct
Feb 26 2021 7:10am
Forum: Battery Technology
Topic: Safe RC-LiPo undercharge when bulk charging without BMS?
Replies: 17
Views: 308

Re: Safe RC-LiPo undercharge when bulk charging without BMS?

Yes many think that once a pack is "balanced" that means the differences in voltage go away at all SoC% points Or even worse that it is possible to balance at more than one SoC% point. I mean it "is possible", but counterproductive; balancing say at 3.65V "undoes" your ...
by john61ct
Feb 25 2021 11:14pm
Forum: General Discussion
Topic: Daly BMS question
Replies: 6
Views: 142

Re: Daly BMS question

Your controller/ESC will ask the battery for whatever the controller is rated for. If your controller/ESC is 48V 20A the controller will try to pull 20A no matter what your battery is, depending on your throttle position No, it is the throttle + **motor** that pulls current. The function of the con...
by john61ct
Feb 25 2021 11:04pm
Forum: Battery Technology
Topic: Safe RC-LiPo undercharge when bulk charging without BMS?
Replies: 17
Views: 308

Re: Safe RC-LiPo undercharge when bulk charging without BMS?

Proper balancing only pertains to the chosen balancing point. That's why I used "unevenness" for away from the chosen balancing point. Imbalance at any other point is not actionable or even meaningful data, the cells are **supposed** to be uneven there. Only midpoint balancing minimises th...
by john61ct
Feb 25 2021 10:59pm
Forum: Battery Technology
Topic: 'on board' 1.5kW charger. Which alibaba supplier?
Replies: 99
Views: 1872

Re: 'on board' 1.5kW charger. Which alibaba supplier?

It is normal practice to just ignore those you have determined are a waste of energy.

No forum function is required, just stop reading their posts, or at least don't take the bait and respond.
by john61ct
Feb 25 2021 10:07pm
Forum: Battery Technology
Topic: 'on board' 1.5kW charger. Which alibaba supplier?
Replies: 99
Views: 1872

Re: 'on board' 1.5kW charger. Which alibaba supplier?

If you connect a cell @ 4.2V to a charger (voltage source) @ 4.2V, no current flows. It's exactly like connecting a cell @ 4.2V to another cell (voltage source) @ 4.2V, no current flows. By definition, when no current flows, NOTHING IS HAPPENING. This is sort of pedantic. Two equal cells in paralle...
by john61ct
Feb 25 2021 9:53pm
Forum: Battery Technology
Topic: BMSs
Replies: 11
Views: 240

Re: BMSs

What we call "a BMS" is really just a collection of functionalities certainly just a subset of what would be needed for fully automated protection usually several key factors are just ignored. Especially true for a BMS costing under $100, compared to one costing $5000, the latter will offe...
by john61ct
Feb 25 2021 9:38pm
Forum: Battery Technology
Topic: Safe RC-LiPo undercharge when bulk charging without BMS?
Replies: 17
Views: 308

Re: Safe RC-LiPo undercharge when bulk charging without BMS?

The spot in the SoC% curve where you choose to balance the cells, is the only spot where they will match precisely. The manufacturer usually IME delivers them balanced at the midpoint, close to the (rounded) nameplate nominal voltage. In that case (IMO ideally left that way) there will be imbalances...
by john61ct
Feb 25 2021 9:07pm
Forum: General Discussion
Topic: Daly BMS question
Replies: 6
Views: 142

Re: Daly BMS question

Someone with experience with these specific models may (hopefully) come along and contradict me. You are supposed to buy a big enough ampacity so that in normal operation including unreasonably continuous WOT going up a hill with a heavy load and a headwind your controller will not ask for more than...