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Lithium cell multi pack replacement

dr pepper

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First off I'm an industrial electrician and a fairly well experienced electronics enthusiast, so I'm well aware of the risks.

I had a bump on my wifes Ebicycle, the battery ended up skidding down the road, popped one of the cells (tore open rather than shorted & exploded), all others seem ok mechanically.
I can get a similar battery as a replacement, I was wondering how to balance the charge, as the cells in the pack (50 x 18650) will be a different level of charge.
I was thinking maybe something like a 1 ohm power resistor in series for the initial charge.
Is there a 'safe' way to do this.
 

gophert

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Carve them all to the same voltage, not through the same resistance. E.g. charge everything to 4.15v
 

Pommie

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How are the batteries arranged (serial parallel etc). You'll need to get the new cell to the same voltage of the other parallel cells. Check the voltages and use a suitable resistor to balance the parallel bank then the scooter charger should take care of everything else.

Mike.
 

rjenkinsgb

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Agreed, it's matching the new cell voltage (and capacity) to the existing pack & it's parallel cells that are critical.

Once it's in, the normal balance charge system should take care of any final equalisation.
Any lithium pack/charger setup with series cells must have a balance system included somewhere, otherwise things either stop working or go bang.
 

Nigel Goodwin

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I can get a similar battery as a replacement, I was wondering how to balance the charge, as the cells in the pack (50 x 18650) will be a different level of charge.
Get everywhere these 18650's :D

I presume my car uses them? - it's a 'mild hybrid', which uses a motor generator to charge a small Li-Ion pack under the passenger seat during deceleration and braking, and uses the energy as an added 'burst' of power when setting off. It also uses the Li-Ion and motor/generator to work the auto stop/start for the engine which restarts seamlessly without using the normal starter motor.

No idea if it's a worthwhile addition or not (but it's standard on the 4x4 version so I had no option), I suspect it's there mostly in order to reduce the emissions and slightly improve the fuel economy - basically it pretty well balances out the addition of the 4 wheel drive, and keeps the emission class below where it wants to be for many countries.

It's not too bad in the UK now, there was a bewildering array of many different car tax classes, now this one now fits in the lowest class based on it's emmisions, which is £140 a year - bit unfortunate, as under the previous scheme it would have been lower. Full electric cars are still zero tax, but any new hybrids start at £140 like mine.

As my daughter lives in the Netherlands, you don't want to know what car tax is there - it's based on the weight of the vehicle - starts off expensive, and gets much more so. It's not a good sign when the price is quoted per month :eek:
 

dr pepper

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Its a 10s 5p setup, so the cell has 4 others in parallel with it.
There is a balance charge system, but it only operates on 10 banks of 5, ie 5 cells are hard wired parallel.
So I'll measure the 4 parallel cells, charge the new one to a little higher, then flatten it a bit with a 12v 21w lamp till its as near as.
good idea.

I'm not an expert but I'm sure there are 20 quid a year tax bracket vehicles that are petrol only powered, theres a 1.0L toyota aygo in that class, I spose it depends on the amount of clag they spew out into the atmosphere, my 13 year old rolling coal heap of junk probably doesnt do so well, but it keeps passing the inspection.
 

Pommie

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I'd go with your original idea, get it as close as, insert via a 1 ohm resistor, wait till no voltage across resistor then let the scooter charger sort it out.

Mike.
 

Nigel Goodwin

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I'm not an expert but I'm sure there are 20 quid a year tax bracket vehicles that are petrol only powered, theres a 1.0L toyota aygo in that class, I spose it depends on the amount of clag they spew out into the atmosphere, my 13 year old rolling coal heap of junk probably doesnt do so well, but it keeps passing the inspection.
There were - until the car tax system changed - and if you've still got one of those, as far as I know, you still pay the old tax rate. But for any bought after the changes, the new minimum rate of £140 applies - I must admit I wasn't aware of any of this, until I bought a new car :D I'm quite happy, as my previous car (a Suzuki Jimny), while good on emissions fell foul of the previous four wheel drive rules, which penalised people with 4x4 (introduced because of all the idiots taking their kids to school in 5 litre Range Rovers), it cost £220 a year car tax.

New car is fairly economical, as it shown by it only having a 30L tank - according to it's on-board computer, it's averaging 55.1mpg - and according to the fuel I've put in it, isn't far short of that. The Jimny averaged about 37mpg.

Your 13 old car has to pass it's MOT, one part of which is checking it's emmisions, so presumably it must be 'doing OK' :D
 

audioguru

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I think an all electric or a hybrid petrol and electric car costs more so it makes more profit for the car manufacturer.
What is the cost of a replacement battery when it wears out in a few years?
Isn't the cost of petrol mostly taxes?
 

Nigel Goodwin

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I think an all electric or a hybrid petrol and electric car costs more so it makes more profit for the car manufacturer.
I think you're missing the point?, I'm pretty sure that in not so many years internal combustion engines will be banned, and electric vehicles will be the norm. The only thing stopping it so far, is the relatively limited range and slow 'refueling' time.

It might only move the pollution from one place to another, but it will (and is now!) be needed in the large cities, and the pollution is considerably lower than burning oil, and of course much now comes from renewable sources.

What is the cost of a replacement battery when it wears out in a few years?
Pretty expensive, but they have proven extremely long lasting.

Isn't the cost of petrol mostly taxes?
Yes it is, but I don't quite see the relevance?.
 

picbits

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My non-hybrid Skoda Octavia 1.5 turbo petrol will do 0-60 in a shade under 8 seconds but return 65mpg if driven in a more saintly fashion.

In the two months I've owned it, I've done around 1500 miles averaging 55mpg overall with a mix of town / stuck in traffic and dual carriageway driving. Best I've seen on a nice flat stretch at 55mph is 72mpg.
 

audioguru

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All over the world Ford, General Motors and Chrysler are closing car factories and laying off workers so they can make monster SUV trucks (lorries?) that people are buying.
The poorest selling car in North America is the little Fiat from Italy. Most other tiny cars also sell poorly. Fiat also owns Chrysler, Dodge and Jeep. The new Jeep is a little Fiat car that looks like a Jeep. Fiat Chrysler will soon merge with Renault. A neighbour has a monster Volkswagen SUV truck. Hyundai and Kia are also selling expensive petrol-guzzling monster SUV trucks.
Oil still comes from the ground and sea in many countries. The taxes on petrol in Canada pay for many benefits for citizens.
 

gophert

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Oil still comes from the ground and sea in many countries. The taxes on petrol in Canada pay for many benefits for citizens.
Don't worry, when people stop buying petrol for their cars, benefits for citizens won't go away. The government will just start taxing solar and wind power production.
 

dr pepper

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I found some cells on ebay with the same part No. and rating so I ordered just one, and will see if I can balance it & fit it.
Might have to do something to spot weld it on.
Also got another panier so the pack wont get jammed in the spokes again.

Another present issue with electric cars is that the grid is already loaded to the max, 32 amps per house all night is probably going to be an issue.
And what do you do when you run out of juice, you cant just go to the garage with a jerry can.
One way is to have garages with a machine that changes the battery for you.
Agreed gophert, taxation will soon catch up.

My 13 year old shed does pass its test, however its classification is not as strict as newer cars, so a certain amount of clag is 'OK', the government wants to ban rolling coal, thing is I've never seen an electric HGV, ship or battery big enough to replace a gen set.
 
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Nigel Goodwin

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Most Helpful Member
All over the world Ford, General Motors and Chrysler are closing car factories and laying off workers so they can make monster SUV trucks (lorries?) that people are buying.
The poorest selling car in North America is the little Fiat from Italy. Most other tiny cars also sell poorly. Fiat also owns Chrysler, Dodge and Jeep. The new Jeep is a little Fiat car that looks like a Jeep. Fiat Chrysler will soon merge with Renault. A neighbour has a monster Volkswagen SUV truck. Hyundai and Kia are also selling expensive petrol-guzzling monster SUV trucks.
Oil still comes from the ground and sea in many countries. The taxes on petrol in Canada pay for many benefits for citizens.
Which is why North America is one of the biggest sources of pollution in the world, and don't seem to give a damn they are destroying the planet.
 

gophert

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Which is why North America is one of the biggest sources of pollution in the world, and don't seem to give a damn they are destroying the planet.
Yes, that is what AG was pointing out by calling SUVs, "Lorries" and "petrol-guzzling monster SUV trucks". But, if you understood his sarcasm and discuss, thanks for repeating him.
 

audioguru

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North America is cleaning up their air pollution. Car exhaust used to stink and burn your eyes. Many cars smoked. Now they don't.
Trucks, buses and a few diesel cars produced black smoke every time they accelerated. Now many of them don't.
The old coal burning electricity stations are gone.
 

Nigel Goodwin

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North America is cleaning up their air pollution. Car exhaust used to stink and burn your eyes. Many cars smoked. Now they don't.
Trucks, buses and a few diesel cars produced black smoke every time they accelerated. Now many of them don't.
The old coal burning electricity stations are gone.
I thought Trump had stopped all that?, and the coal companies lot's more freedom?.
 

gophert

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I thought Trump had stopped all that?, and the coal companies lot's more freedom?.
Just because a coal company is given more freedom, doesn't mean they are going to rip out all the scrubbers and particulate filters they've spent millions of dollars installing. What happens when the next administration changes the rule the other way? These are business people trying to manage their own reputations and execute long-term business plans.
 

audioguru

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I did not know that United States still uses polluting coal fired generating stations. As far as I know Canada does not, instead we use Niagara Falls (for 127 years) and nuclear stations. Here I see more and more huge windmills producing electricity and some huge solar panel farms. The electrical utility company gave away compact fluorescent light bulbs and LED Christmas tree lights to reduce electricity consumption.
 

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