newer
lead acid
Uh, wtf?
The headline means newly manufactured e-bikes with lead acid batteries.
However, safety concerns regarding rare yet dangerous lithium-ion battery fires have put a pause on that proliferation.
Urging citizens to buy new and inferior instead of increasing safety standards?
I’m Swiss and it’s common knowledge here that chinese imported transportation devices can be russian roulette to use.
Are AGM batteries really inferior? Sure, they’re heavier, but they aren’t vulnerable to autoignition and thermal runaway. They also contain less conflict minerals than other types of batteries.
AGM are absolutely awful compared to even the absolute worst lithium batteries, and won’t last long at all if regularly cycled below even 50% SoC. LFP chemistries are a bit worse for energy density compared to NCA/NCM chemistries, but they don’t contain any nickel or cobalt, and won’t autoignite in the same way other chemistries will. Absolutely ridiculous they’re suggesting lead batteries over better lithium options.
I thought AGM were considered “deep cycle”, as in designed for their full capacity to be used between charges.
AGM just means the acid is held inside a glass mat, like fibreglass structure so instead of liquid it’s like a sponge. This gives it less maintenance and more shock absorption, can also be turned or tipped over without issue. It’s still lead acid just not held in liquid form.
A lead acid based battery can be deep cycle or starter or both. Being deep cycle basically means the plates inside the are battery thicker, which allows it more tolerance for being depleted as well as generally more reserve.
A real easy way to understand it that I found (when explaining it to customers without a technical background.)
Imagine instead of electricity it’s water. A deep cycle battery is simply a larger tank of water with a regular size pipe to get the water out. A starter battery is a regular size tank with a large pipe to get the water out.
So if you need to start a engine that needs a chunk of water(electricity) all at once to start it , a starter battery can provide it but doesn’t have alot of reserve behind it so the pipe cant stay open very long.
The deep cycle can’t provide the large rush of water at once(cca) but does have lots of reserve so the pipe runs longer.
Both suffer from reduced flow(voltage drop) as the tank empties. Imagine the pipe not able to be completely filled as the tank drained, you still get water but the rate is reduced as the pressure behind drops. Both suffer damage if left too empty or are drawn too low, a deep cycles design just gives it far more tolerance to that depleted state, allow it to be cycled more( charged from empty) more times before the battery fails.
Dual purpose batteries are basically large tank, large pipe.
It’s worth noting that DC voltage only draws what it needs, you can hook up the largest battery bank to the smallest load with no issue as far as the size of the bank etc if everything is setup and function correctly.
Lithium suffers from none of these drawbacks. (As well as many more advantages) Gotta use the newer tech that is far safer though. Early Lithium and most cheap none reputable stuff is using the riskier tech with substandard QC.
And even if you only cycle lead batteries above 50% SOC, they will still last a significantly shorter amount of time, especially compared to LiFePo4 batteries.
Ehh they need to do sodium batteries
I thought they would have been pushing for sodium ion batteries instead. Lead acid batteries are a bad choice for anything that needs to be cycled frequently.
They’re a also bad choice for e-bikes because they’re heavy as hell. I had an e-bike a while back that had two lead acid batteries, and they were about 15 lbs each. The added weight made it almost impossible to go uphill with the motor, so you’d have to pedal a much heavier bike up hills. Not a good experience at all.
Last part of the article basically says sodium ion batteries are where they’re going next.
Damn I’d have atleast waited until sodium ion was built out
I mean there are quite many fires in China started by those e-bikes but I thought it was because of bad quality.
There are chemistries that are less volatile But they’re less energy dense as well.
The biggest problem I see on most of the Chinese stuff is a lack of safety in the battery packs. They’re just mass-producing cells and shoving them together, It wouldn’t be very expensive to put a small battery management system on every cell. Watch each cell for voltage and temperature. Have them shut down when they’re out of safety margins
LiFePO4 is still superior to traction lead-acid in pretty much every way: energy density, safety, time and cycle life, internal resistance… Yes, they need a BMS but those are very cheap and lots of batteries have them built-in. In fact, I was unable to find 4-cell packs without a BMS inside so I could put two of them in series and balance the 8S cells with each other using an active BMS of my choice, and ended up ordering individual cells and screwing them together.
Also worth mentioning LiFePO4 is like half the weight of lead acid and it’s far less susceptible to voltage sag under load. The only area I think LiFePO4 runs into challenges is the inability to charge below freezing. Lead acid is a real workhorse when it comes to the extremes.
Less than half in my experience. I bought two 100ah 12v lifepos and they are under 30 lbs. 23lbs I believe. I have a lead acid deep cycle of the same power and it’s like 80-90.
The article also mentions sodium ion batteries as an alternative. Can’t wait to see how they perform in real life.
IIRC there is already an e-scooter you can buy that has a sodium ion battery. From a chinese company (ofc) that I forget the name of. It touts fast charging and basically performs just fin down to -20C.
48 V and a capacity of 24 Ah
400 W power and a 25 km/h top speed.
They’re from $450 to $590, so amazingly priced.
Fun fact: it would not be classified as a e-bike nor a moped in Estonia because it’s less than 1000w and max speed is no more than 25 km/h, but an mini-moped, which doesn’t need a license to drive, but you have to be older than 16 and need to wear at least a bicycle helmet.
Estonia
Bestonia
This is big news. Why isn’t everyone already talking about SIBs? Also, the 145 Wh/kg sits neatly between LFP and NMC. As long as the other properties are reasonable, it should stand a chance against NMC.
If you need to charge LiFePO4 batteries below freezing, you can add a heater to the pack. There are even some batteries available now with built in heaters that come on automatically below freezing.
From what i know the issue seems to be too lax safety margins in packaging, to increase density.
