48v GM Battery in Bike Frame

[Bedmountain]

Hi Everyone

I would really love to source a bike frame that's big enough to fit a standard GM 48v battery inside the frame (below the top tube).
The problem is trying to source this online - some sellers will agree to send inside measurements of the frame but then it is difficult to work out if the battery will fit without knowing the exact angles of the frame...
I've asked this question before and the responses have been around trying to measure the frame from images using the wheel as a guide etc... but this just isn't very practical and I can't afford to order something that isn't big enough.
I have seen one image on this forum of a battery fitting into a Rockhopper M4 but without knowing the size of the frame and the year of the frame I can't track one down.

Has anybody here had any experience of fitting a battery into a frame? If so please could you let me know make/model/year?

p.s I'm ideally looking fro something with disc brake mounts - there are lots of 'vintage' frames out there that would fit the battery but I'm keen on having disc mounts.

Many thanks in advance...

[OCD]

Why not buy a battery that's shaped to fit in the triangle, that way you could forget about the old LiFePo4 chemistry and pack a lot more amp/hr in the same space. This one is made from Samsung 18650 cells http://www.aliexpress.com/store/product/Traingle-shape-1000W-Electric-Bike-Battery-48V-30Ah-with-battery-bag-built-in-Samsung-cell-30A/1761558_32530375988.html 

[Bedmountain]

Thanks for the reply OCD. I like the look of that...
I didn't realise LiFePo4 was considered 'old' tech. How does the battery you've linked to differ in its chemistry and what advantages does it have?

[OCD]

The battery packs currently sold by GM and others have LiFePo4 chemistry cells, the current technology is based on Lithium manganese (I believe) with cells in the 18650 size (similar to what Tesla cars use) they pack 2x the energy density. The newer chemistry puts 20amp/hr in the same space/weight as the 10amp/hr GM battery http://www.aliexpress.com/store/product/Top-Classic-Big-Capacity-150W-1400W-48V-Ebike-Battery-48V-20Ah-Lithium-ion-Battery-built-in/1761558_32354857667.html. However, the cycle life is lower unless you buy an adjustable charger which can bring the battery up to 80% charge state (for shorter trips). Not fully charging the battery after shorter trips is said to at least double the life of the battery. https://www.youtube.com/watch?v=2uGD2y3Km1M Hope that helps. 

[Ecobully]

It's good to get a quality charger that can adjust its charge voltage as well as its amperage.

50% low amps ~ 2A is good for storage (more than 2 weeks without usage)
80% low amps ~ 2A is good for short(er) trips where you will not use the entire battery capacity
90% low amps ~ 2A is good for daily usage that requires longer distances
100% high amps ~ 5A+ is good when you need longest range and don't have time to wait for a slow charge

These are some actions one can take to prolong their batteries. This really applies to all types of lithium chemistry cells. The chemistry is improving lately with more hybrid materials ICR/INR/IMR and including changes in oxides to increase amp in/out and capacity.

LiFePO4 is heavier, but the more inert nature and its durability has it replacing SLA cells, when applicable.

** With a bit of research anyone can build their own packs without even soldering these days -- just look up Hailong "Dolphin" battery cases. Just buy 18650 cells, and toss them into the box and close it up with the correct configuration/orientation as the battery holders and interconnections are built-in **

[Hastings]

Can   a 7 KG Samsung 18650 consisting of 130 cells battery can  really  give 30 Ahrs ?
a Ping 20 Ahr  battery using the best pouch cell  is 10 kg.
http://www.pingbattery.com/servlet/the-2/lifepo4-lithium-ion-phosphate/Detail
 Generally pouch cell  need less packing material . Have you tried this ? The producer seems genuine..
I could not see any photos of the BMS they use .

[OCD]

Ping batteries are considered one of the worlds best, although there is a price premium, but his service and quality are backed up by many, many buyers on endless-sphere. Most claims made by Chinese manufacturers are at least somewhat inflated, Ping is one of the exceptions. I have one of those (albeit rectangular) batteries in the link provided, it gives me way more range than my GM batteries, perhaps an actual 27amp/hrs. On my previous build I run two of the flat pack GM batteries in parallel which never gave me more than 18amp/hrs combined when new, now a year later they are down to 12amp/hrs combined. The technology continues to evolve, we're just early adopters.

[Ecobully]

Most claims made by Chinese manufacturers are at least somewhat inflated,

I think they tend to give and advertise their base case scenarios in its most favorable situation. We all know that's just too far from reality. Theoretical limits are not as as good as real world numbers under "normal" usage rather than using our bikes inside a hyperloop (vacuum).

[Bikemad]

Most claims made by Chinese manufacturers are at least somewhat inflated,

Are you trying to suggest that this "300000mAh 20 LED Solar Power Bank Portable Dual USB Battery Charger" does not really contain a 300Ah battery? 



And that this 18650 cell might not have a true capacity of 9.9Ah?:



Surely these stated capacities must be true, otherwise it would be false advertising which is extremely misleading and dishonest!

I was recently very impressed with the charge time for this "100000mAh Solar Battery Charger Power Bank For iPhone iPad Tablets Smart Phones":

Specifications:

Charge time: 60-70h hours for sunshine, 12-15 hours for computer
Capacity: 100000mAh
Input: DC: 5V 1.0A (max)
Output: a. DC 5V 1A ,
             b. DC 5V 2.1A (will charge faster)
Solar panel: 5V, 200mAh
The battery indicator: 4-LED indicate (charging, full of bright blue light)
Size: 121*76*22mm

Charging a 100Ah battery from a 200mA (0.2A) solar panel would take at least 500 hours not 60-70!
To charge it in 12 hours from a computer would require a charging current of 8.34A! I somehow don't think many USB sockets (or USB cables) would be able to supply that amount of current.



I once purchased some 12 Watt MR16 LEDs in the UK (which were probably made in China) and they each (supposedly) contained 4 x 3 Watt Cree LEDs:



I tested them on a 12V supply and although they seemed to be reasonably bright, they were definitely not the stated 750 lumens that I was expecting from these 4 x 3W Cree LEDs.
I therefore decided to measure the current and was very surprised to find that the whole unit was only drawing around 250mA @ 12V which meant I had effectively purchased 3W LEDs instead of the advertised 12W LEDs.

I suspect they were actually made up of 4 x 1 Watt LEDs but the electronic driver unit was only capable of delivering a maximum of 3W output, hence the 250mA current @ 12V.

Alan
 

[GM Canada]

Ping batteries are considered one of the worlds best, although there is a price premium, but his service and quality are backed up by many, many buyers on endless-sphere. Most claims made by Chinese manufacturers are at least somewhat inflated, Ping is one of the exceptions. I have one of those (albeit rectangular) batteries in the link provided, it gives me way more range than my GM batteries, perhaps an actual 27amp/hrs. On my previous build I run two of the flat pack GM batteries in parallel which never gave me more than 18amp/hrs combined when new, now a year later they are down to 12amp/hrs combined. The technology continues to evolve, we're just early adopters.

I find this quite surprising. The GM LiFePO4 flat packs I have are of the highest quality. I have sold a lot of batteries with very few issues. In my personal collection of batteries I have batteries up to 4 years old. None of them show any signs of losing distance. I imagine your batteries are either of the Lithium Ion type or the LiFePO4 type with the cells without the screw on terminal connection. I would be very curious to see inside the packs.

Maybe it is how they are cared for as well. I baby my batteries with slow, warm indoor room temperature charging. Never let them go more them a month without a small charge in the off season. The only ones I had from GM with a short lifespan is the lithium ion ones they still carry. The LiFePO4 packs with the square cells and screw on terminals and very high quality. I don't see anything ping has as being higher quality the what I have.

I am still heavily in the LiFePO4 camp. Not jumping back to the Lithium Ion camp yet. These newer high energy 18650 cells are half the life cycles and less safe.  I can't in clear conscience sell the new lithium ion batteries to people and say "Yah their great, they don't last half and long and are not as safe as liFePO4, but their great!"

Gary

[GM Canada]

Just buy 18650 cells, and toss them into the box and close it up with the correct configuration/orientation as the battery holders and interconnections are built-in **

Man that method of just tossing them in the box sounds fantastic, How far can you toss them from

You also have to ensure you are getting real cells that wont burn your house down. That is the real challenge

Gary

[OCD]

These newer high energy 18650 cells are half the life cycles and less safe.  I can't in clear conscience sell the new lithium ion batteries

Not sure why you think they're less safe, I haven't read that anywhere on the 'net. I don't think anyone believes they last as long either. To greatly increase the lifespan you can use the adjustable chargers from ebikes.ca or Luna cycles.

I am still heavily in the LiFePO4 camp.

Funny you mention weight, I personally would rather have 30amp/hr from my 15 pound battery rather than 45lbs of LiFePo4 for the same capacity, even if it had a shorter lifespan.

In my personal collection of batteries I have batteries up to 4 years old. None of them show any signs of losing distance.

I use the same GM charger that came with my batteries as everyone else, could be that I simply burn through the lifecycle of the battery faster than you by commuting/charging 250 days a year to work. 

[GM Canada]

This is the go to chart for the People in the NMC camp with the new 18650 cells. If you look at the cool graphics you can see they rate the NMC as a higher in specific energy but lIfFePO4 is rated higher in specific power, life span and safety. http://batteryuniversity.com/learn/article/types_of_lithium_ion

As for weight, certainly if you have a 30 amp pack that is a substantial weight for liFePO4. By far though the vast majority of people only have about a 10 amp battery. So really is less than a 10 pound difference at that size. Does it really make that much difference if a combined bike and rider weight is 200 lbs or 210 pounds. not really. I carry 30 amps on a few of my bikes and it doesn't bother me in the slightest. But its spread around on the back of my bikes. Occasionally I have been known to through a case of beer on top on my way home from work as well. I am not a daredevil rider either, just a street legal speed guy motoring around.



As for the ride numbers we are pretty much the same. Being in Canada likely closer to 200 rides a year to work for the last 5 years.

[Ecobully]

Sourcing genuine cells has been made difficult with knockoffs. There are a few reputable resellers that cater to the needs of battery pack builders. LG/Samsung/Sanyo all seem to have some great high drain cells rated at 3500mah right now priced at around $5-6/cell. I guess Endless-Sphere threads has made it easy to find good sources (and bad ones, too).

A123 LifePO4 pouches and cans were once considered a hot commodity in the ebike world, but most have moved along and over to 18650 cells. The lightweight, and highly durable cells allow users to charge/discharge quickly and if they last 2-3 years, one can then enjoy newer technology that comes about which will probably yield even

I use LiFePO4 cells in my RV and enjoy it over my older SLAs. I also use Sony VT LiMn cells that have been bullet proof and in balance for the past 5 years without a BMS. I keep my LiPo packs and single cells in a bunker inside my fireplace--no fires, but I don't trust them while unsupervised. This type of uneasiness has not been extended to the newer 18650 cells (I use Panasonic/Sanyo 18650GA cells). Prices have dropped significantly and capacity along with C ratings have risen quite a bit with each coming year.

BTW, those older Headway 15A LiFePO4 cans were made into 4S10P banks for my RV and are doing quite well paired with my solar panels. They used to ride along behind me on my bike, but I moved onto lighter higher capacity packs.

I write this not to place a dark cloud over LiFePO4, but to offer different options and their respective pros/cons. If I were to sell these packs and carry liability for my advice, I may play it safe with IFR for the time being. Again, just another option

[GM Canada]

In re reading my last few posts it sounds like I am against new battery technologies. This is not true. I'm all for it. Believe me I consider getting into the new stuff on a daily basis. But at this time for me when it comes to warranty and liability issues its best to stick with the safer and longer lasting batteries at least for the time being. Getting double the lifespan for basically the same money makes sense to me and to a lot of my customers. At this point I still have trouble keeping batteries in stock even in the off season. In the past few months I have had a major rush on batteries and completely ran out. So a lot of people are still on board with lifepo4. Also the fact I have almost zero battery warranty issues to deal with is a big bonus for me and my customers.

Gary