Electric bicycle reliability. - Page 1
Forum section: electronics / general

author: schmitt trigger
author_rank: Super Contributor
timestamp: September 15, 2020, 05:16:22 pm
content: I have done a lot of biking my entire life, but with the older age I cannot bike as far or as challenging.Having said that, I borrowed an E-bicycle the other day and was beyond delighted! I plan to purchase one soon, perhaps this coming Christmas season.However, my concern here is reliability, and specifically, battery reliability.Those packs are expensive, and I don't want to be replacing packs every couple of years.Are there any bicycle enthusiasts out there which also can share experiences on E-bike ownership?

author: maginnovision
author_rank: Super Contributor
timestamp: September 16, 2020, 03:10:38 am
content: I had one about.... 15-20 years ago. Used SLA batteries but was still good for about 20mph uphill(with my 210lb body). I'd ride it to work fully powered. Ride during lunch unpowered, then ride back home powered... Battery was never an issue and in 4 years I don't think I ever replaced it and charged it every day. Motor never failed. I'm assuming you want lithium experience though?

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 16, 2020, 03:46:16 am
content: One girl's adventures in DIY bicycles:https://www.youtube.com/playlist?list=PLyjfBfFp2v2o_zug1bsCYm0C476x8Y58nKeep in mind that was back when lithium batteries were harder to come by so there was a lot of savings salvaging cells out of faulty packs. Nowadays, just buy a pack from places like Battery Hookup.I would suggest making it a hybrid designed to run on pedal and electric power at once, rather than electric with the pedals purely for backup. In other words, sense the chain tension to set the power.

author: schmitt trigger
author_rank: Super Contributor
timestamp: September 16, 2020, 02:10:25 pm
content: Nowadays, all I can find are units with lithium packs.Someone has advised me that I should plan replacing them every 5 years.Those packs are expensive, thus I wanted to know if anyone has had actual riding experience.And yes, I plan to actually exercise with my bike. The battery assist will be mostly used when biking up hills or against the wind, which as I age I am finding tougher to do.

author: maginnovision
author_rank: Super Contributor
timestamp: September 16, 2020, 04:38:44 pm
content: I will say that it depends on so many factors that 5 years is a guess no better than 1 year or 10. Perhaps you could find one with a smaller(capacity) battery pack since you mostly want it for assist, not primary propulsion like many people. That way it's not as much of an issue when it does require replacement.If you're doing it for your health I would recommend getting what you can afford and maybe set some aside every month for repairs etc... If you save more than you need it's a bonus. My SLA bicycle never had (brushed)motor issues or battery issues and was used 5 days a week. If you're not riding in extreme weather(hot/cold) and not doing full charge/discharge you likely will have years from the battery. Lifepo batteries have many charge/discharge cycles so that could even stretch to 10 years depending on primary factors. They typically are rated for 2000+ cycles.Other li-ion and lipo packs I think are typically rated for only 500 cycles.

author: peter-h
author_rank: Super Contributor
timestamp: September 17, 2020, 02:53:53 pm
content: Good Q.I bike daily for exercise and really enjoy it. Everybody is telling me to get an electric bike... looking around, the good ones seem to be about 5k!I am not going to get one because at 20kg+ they are all way too heavy to lift over stiles in the countryside. But the bigger long term worry would be parts going out of production. My current bike cost me 1.5k so it was a reasonably high-end mountain bike. It was bought about 10 years ago. Practically every part of it is no longer in production. The gas shock unit has just gone and even the seal kit for it is no longer made; a new unit is 0.3k+. Not a problem, due to bike parts being mostly standard sizes. But on an electric bike there are many special parts. And the industry is moving fast...

author: schmitt trigger
author_rank: Super Contributor
timestamp: September 17, 2020, 04:54:14 pm
content: “The industry is moving fast.....”Exactly!E-bike companies are sprouting like mushrooms after a rainy spring day.How many will be around in 2, 5 or 7 years?But eventually one has to take the plunge, and take the best care for the bike.

author: maginnovision
author_rank: Super Contributor
timestamp: September 17, 2020, 05:25:39 pm
content: I myself am somewhat partial to the bmw active e bike. 600wh battery and 90nm torque motor with decent ergonomics and 3 sizes. If I got one today that's what I'd get.https://www.shopbmwusa.com/product/8414/BMW-ACTIVE-HYBRID-E-BIKE

author: Unknown
author_rank: Unknown
timestamp: September 17, 2020, 06:35:25 pm
content: Check out Louis Rossmann which I'm assuming many of you know. He's been riding round in New York on his e-bike for a while. Not sure which one he's got though.

author: Prophet2020
author_rank: Newbie
timestamp: September 18, 2020, 03:38:32 pm
content: Don't know if you saw what happened, but his good one had a bad incident. That poor guy has the worst luck, but I'm glad he has some humour about it all.

author: e100
author_rank: Frequent Contributor
timestamp: September 18, 2020, 04:44:26 pm
content: If you plan to keep the bike in your house then LiFePo4 batteries are the least likely to catch fire.However most e-bikes today ship with batteries that use a different lithium chemistry because of the higher energy density and lower weight. Unfortunately these tend to go into inferno mode when a fault develops.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 18, 2020, 06:00:04 pm
content: Quote from: e100 on September 18, 2020, 04:44:26 pmNot true. Proper high-quality NCA cells are safer than sub-standard LFP cells, and the problem with LFP is, you practically only get substandard cells.

author: e100
author_rank: Frequent Contributor
timestamp: September 19, 2020, 02:14:56 am
content: Quote from: Siwastaja on September 18, 2020, 06:00:04 pmfromhttps://batteryuniversity.com/learn/article/types_of_lithium_ion"High energy and power densities, as well as good life span, make NCA a candidate for EV powertrains. High cost and marginal safety are negatives."

author: james_s
author_rank: Super Contributor
timestamp: September 19, 2020, 06:37:24 am
content: My friend's family has several e-bikes, they've had them for about 3 years now I think and so far they're all going strong. Battery life will depend heavily on how you much you ride and how you treat it. If you keep the battery away from high temperatures and don't store it fully charged (unless it's LiFePO4) it should last well. 5 years is probably a reasonable minimum if not abused.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 19, 2020, 07:07:22 am
content: Quote from: e100 on September 19, 2020, 02:14:56 amCathode material theory is different from actual products on the actual market. Actual cells have much more than just the cathode material, including flammable electrolyte, for example.Claim about cost is similarly wrong, At about $300/kWh, LFP is almost twice as expensive as NCA as it stands; again, looking at actual production cells, not some theoretical raw material cost. This is due to price fixing in Chinese LFP market, the small size of said market, and the economies of scale of modern high-energy density cell types such as NCA.LFP cathode also has potential thermal runaway, just the onset temperature is higher and released energy is smaller. Energy and power density of LFP cells is more than enough to bring the cells to runaway (somewhere around 300 degC IIRC) whenever the cells fail internally or are abused externally. The result is slighly less dramatic than with NCA but can nevertheless easily lead in total loss of property. A few youtube videos showing a single LFP cell shorted in open air and "only" releasing smoke and not fire does not mean they don't cause fire when packaged as larger packs in real-world installations. A modern NCA cell in similar abuse conditions typically does not releaseeventhe smoke, because it has several layers of protection (missing from the typical LFP cell).LFP was dead-end; NCA has seen all the development by the big players, including safety.Numerous fires have occured in DIY LFP conversions.Really, the key is to only use good brand cells. If you have/want to buy crap (which I don't have objection against), I wouldn't lull into the false sense of security of LFP, just accept crap is crap and may catch fire regardless of the claimed cathode chemistry. I will correct each time someone posts this "LFP is safer" crap on forums. I have seen enough evidence of the exact opposite.The root problem is mixing battery science with consumer product selection. There is a long way from not understanding theory, to understanding it, andthenunderstanding the market. If you try to make engineering / buying choices based on science popularization sites like Battery University, you are guaranteed to go wrong.