Search found 6022 matches

by john61ct
Apr 09 2021 6:04pm
Forum: E-Vehicles General Discussion
Topic: Battery Three way switch - any issues with this design?
Replies: 5
Views: 154

Re: Battery Three way switch - any issues with this design?

yes all DC circuits should have a Common Reference, tied in with Negative Returns
by john61ct
Apr 09 2021 12:33pm
Forum: Battery Technology
Topic: Isolation between cells needed?
Replies: 4
Views: 140

Re: Isolation between cells needed?

Aha I thought you meant electrical isolation, like diodes or circuit protection between groups

rather than physical protection, insulation
by john61ct
Apr 09 2021 12:15pm
Forum: E-Vehicles General Discussion
Topic: High Power power supply for testing EVs motors controllers without battery pack
Replies: 1
Views: 128

Re: High Power power supply for testing EVs motors controllers without battery pack

But why?

How many watts for how long are needed?

Even a low Ah pack will deliver much more power than you could with a reasonable PSU

and if warm, then fully recharge in 10min or so, without losing too much lifespan.

So two more normal PSU/chargers, two packs, swapped out. . .
by john61ct
Apr 09 2021 9:27am
Forum: Battery Technology
Topic: Isolation between cells needed?
Replies: 4
Views: 140

Re: Isolation between cells needed?

If by group you mean (as is standard) cells in parallel only, at the "lowest" level in the layout at 1S voltage, then those (cell) groups connected together to create one series string then No there is no current flow possible between those groups, they do not affect each other even if at ...
by john61ct
Apr 09 2021 9:15am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 504
Views: 85651

Re: Spot Welding Copper Strips to 18650 Battery Cells

Think of each section (sub pack?) involving strips, whether soldered or welded as a rigid monolithic block, no flexing stresses allowed at all. Then the flexible wiring with zero solder involved, connecting between those blocks, their connection ends well supported so the crimped terminations are (o...
by john61ct
Apr 09 2021 9:07am
Forum: E-Vehicles General Discussion
Topic: Battery Three way switch - any issues with this design?
Replies: 5
Views: 154

Re: Battery Three way switch - any issues with this design?

You'll get longer range (higher actual Ah capacity) by paralleling for the whole ride.

Better current flow, less voltage sag and longer lifespan too.
by john61ct
Apr 08 2021 11:01pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 504
Views: 85651

Re: Spot Welding Copper Strips to 18650 Battery Cells

I am not talking about strip, at all. I am saying, where you are using the wire I spec'd to accommodate flexing, abstain from touching that wire with any solder. If you are connecting wire to strip, then do so via solid connectors with a wide contact surface area crimped to the wire, perhaps quality...
by john61ct
Apr 08 2021 7:33pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 504
Views: 85651

Re: Spot Welding Copper Strips to 18650 Battery Cells

No solder terminations, use crimp connections.

Again, no flexing until you get well into the insulated wire body.
by john61ct
Apr 07 2021 6:52pm
Forum: EScooters/EMotorcycles
Topic: Finding a battery - Alibaba?
Replies: 9
Views: 256

Re: Finding a battery - Alibaba?

LFP is only rarely used for EVs. Much longer lifespan, thus better value by far much safer, thermal runaway (boom, fire) less likely but also lower energy density, thus slower performance and/or lower range. Tesla using it in the China-produced models only. Otherwise the 3.6 - 3.7Vnominal chemistrie...
by john61ct
Apr 07 2021 6:44pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 504
Views: 85651

Re: Spot Welding Copper Strips to 18650 Battery Cells

Fine-stranded tinned wiring, ideally marine grade UL 1426 rated (BC-5W2 usually 105°C)

No movement at terminations obviously, just leave slack in the length portion.


by john61ct
Apr 07 2021 5:46pm
Forum: EBike Technical
Topic: Balance Discharger... or is there anything else?
Replies: 40
Views: 1057

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

There is a huge difference between "rough" discharging packs for storage and needing precise CC regulation for accurate capacity testing of individual cells. The purpose of using chargers like FMA PL and 4010 is to get the latter control functionality. Apparently at that 2-4V discharge ran...
by john61ct
Apr 07 2021 5:36pm
Forum: Alternative Energy
Topic: Inverter recommendations? 48V sine wave, no grid tie
Replies: 27
Views: 3656

Re: Inverter recommendations? 48V sine wave, no grid tie

spinningmagnets wrote: generic sine wave 500W for $80
Wow lots of flexibility there!

Apparently can order 72V input and output 240V 50hz

EV packs for multiple uses, off grid living, get away from inefficient USA appliances.

A more stable imports source would be ideal, not sure if SPIPOWER is the canonical branding
by john61ct
Apr 06 2021 9:42am
Forum: Alternative Energy
Topic: Running a house on an e-motorcycle battery?
Replies: 63
Views: 1162

Re: Running a house on an e-motorcycle battery?

Yes as stated, the only grid connection being your bank charger, makes for a very simple, inexpensive and safe design. No aircon obviously. There is no need for any 3-way switch, just power off your mains charger and there is no input from the grid. The SC will always be active. ______ I also read t...
by john61ct
Apr 05 2021 7:35pm
Forum: Battery Technology
Topic: Where dispose of potted lifepo4 battery
Replies: 3
Views: 147

Re: Where dispose of potted lifepo4 battery

Some towns/counties have a few Hazmat disposal days per year where they accept most anything
by john61ct
Apr 05 2021 11:46am
Forum: EBike Technical
Topic: BMS destroyed my battery?!
Replies: 51
Views: 938

Re: BMS destroyed my battery?!

This looks like a good seller?
https://www.ebay.com/itm/313014455885
by john61ct
Apr 05 2021 11:42am
Forum: Alternative Energy
Topic: Running a house on an e-motorcycle battery?
Replies: 63
Views: 1162

Re: Running a house on an e-motorcycle battery?

That's a bit too strong, overstated IMO but yes, this use case is not motivated by too many practical benefits. But getting off the grid completely is IMO a fine goal if you can afford it. I lived that way for decades, but in a place where just connecting to utilities would have cost more than the l...
by john61ct
Apr 05 2021 9:04am
Forum: EScooters/EMotorcycles
Topic: how to program a sevcon gen4
Replies: 311
Views: 92627

Re: how to program a sevcon gen4

In my experience asking dealers, they only supply the software and license to paying customers, either buying the hardware or retaining them on an annual service contract. My impression was the goal is to reduce the value of secondhand units in circulation. I don't understand why there aren't freela...
by john61ct
Apr 05 2021 2:11am
Forum: EBike Technical
Topic: BMS destroyed my battery?!
Replies: 51
Views: 938

Re: BMS destroyed my battery?!

if they had a bluetooth bms like the Ant bms you could set the lvc at 2.5v program balancing to start at 2.8v I've never heard of a protective BMS that bottom balances. Only dedicated balancers ( marketed as "non-protective BMS") or node charging can middle or bottom balance afaik > i thi...
by john61ct
Apr 05 2021 2:01am
Forum: EBike Technical
Topic: BMS destroyed my battery?!
Replies: 51
Views: 938

Re: BMS destroyed my battery?!

if you top-balance at 4.2V and discharge to 4.1V, the cells will necessarily be closer than if you top-balance at 4.1V and discharge to 4.0V. Not practically relevant, just refuting the claim that top-balancing at 4.2V would "throw the pack out of balance" But it does do that! In my case ...
by john61ct
Apr 05 2021 1:18am
Forum: EBike Technical
Topic: Balance Discharger... or is there anything else?
Replies: 40
Views: 1057

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

Node chargers are a different category, maybe you don't think they are useful in general but if you want to say it is a bad node charger, then specify those that are better please. It puts out a pulsed current in order to measure the "reverse bounceback" delta, kind og like getting a bead ...
by john61ct
Apr 04 2021 2:08pm
Forum: Alternative Energy
Topic: Running a house on an e-motorcycle battery?
Replies: 63
Views: 1162

Re: Running a house on an e-motorcycle battery?

A smart charger seems to be a possible answer, as that will be the way to keep the solar power and the grid power seperate with energy only flowing in one direction. I wonder how much a charger would cost that can provide a 48v 40amp charge and be able to turn on and off automatically at predefined...
by john61ct
Apr 04 2021 1:58pm
Forum: Alternative Energy
Topic: Running a house on an e-motorcycle battery?
Replies: 63
Views: 1162

Re: Running a house on an e-motorcycle battery?

Yes of course if you have grid power available anytime on demand

and doing so does not violate your goals

then just a couple of dirt cheap FLA GCs will do, and keep the moto side simple and separate at 96V


by john61ct
Apr 03 2021 11:12pm
Forum: EBike Technical
Topic: BMS destroyed my battery?!
Replies: 51
Views: 938

Re: BMS destroyed my battery?!


goatman wrote:still waiting for someone to tell me the right term :D
It's your baby, you name it.
by john61ct
Apr 03 2021 11:11pm
Forum: EBike Technical
Topic: BMS destroyed my battery?!
Replies: 51
Views: 938

Re: BMS destroyed my battery?!

Balancing with unmatched cells is inherently temporary. It doesn't matter if you top balance at 4.1 or 4.2V, or bottom balance at 3.0V -- the pack will only be balanced at the voltage you balanced it at, and necessarily must be unbalanced everywhere else. Truth, and another one many do not grok > I...