Where to mount battery & which battery to buy?

[BatteryMan]

So this is what my bike looks like *not my actual bike, just used as a reference*:

I'm thinking of going with a 1500w kit from here:

https://www.aliexpress.com/store/product/Passion-Ebike-48V-1500W-Bicicleta-Electric-Bicycle-Bike-conversion-kit-Rear-wheel-motor-kit/1088910_32476876343.html?spm=2114.10010108.1000023.2.XKRxF1

My question is regarding the battery, where should I mount it? Anyone have any good ideas? I have a rear rack but it is connected to the rear seat post with a max weight of 25 pounds, and I would rather not put it there because it will have horrible weight distribution with the rear electric motor not to mention it will limit how much weight I can put into my panniers and rear bag.


Here is a crude photo of where I would like to put the dolphin battery. Any thoughts on this location?

dsc_1980-edit


And here is the battery I am thinking of going with due to it's small size (14.5 x 3.5 x 3.5 ") :
48v Panasonic 11.5ah or 13.5ah Shark Pack
http://lunacycle.com/batteries/packs/48v/48v-panasonic-11-5ah-or-13-5ah-shark-pack/


However, I was told that it's not a great battery for a 1500 watt kit, so do you think I should just get a 1000watt kit? Would the battery above be a great battery for a 1000watt kit?

 

[LewTwo]

Try making a cardboard template .... worked for me.

 

[dogman dan]

Wow,,, the ol mongoose blackcomb is back. Of the cheap Y frame bikes, that was a good one. I still have two at the house, one worn out and junked, the other still ridable.

here is how I mounted lipo packs on one. This was a 72v 10 ah setup.

Mounting enough battery on that frame to run a really powerful motor is a problem for sure. Less than 8 pounds can be tolerable on a rear rack, for moderate dirt riding or street. For high performance riding you will need to somehow mount the battery in the middle, without putting it where it will get you in the balls each and every ride. Especially if the weight is getting towards 15 pounds.

 

[nutnspecial]

I agree, and imo only lipo will be a good fit for that bike. An adequate can cell pack will be big and expensive. If you don't want lipo and want to consider a 1kw hub instead, check with the manufacturer for recommendations at that power level.

Top tube mount as pictured is possible, but also thought the same with modular packs in a top tube pannier style pack. That's what I do, with lipo as well. The 11-ish lb 250-300$ pack is good for over 80a. There's some pics/vid in my build.

Imo a 1500w hub is on the heavy side for light offroad bikes. What is your desired usage and speeds? Maybe you'll find a nice geared hub (or middrive) will suit the bike better and be better match to a small premade pack? For the 26a a 1kw hub uses, I'd much rather have a 26a middrive, or geared hub for that bike.

 

[d8veh]

Both Em3ev and Luna do Dolphin batteries (09 case) that can easily supply 1500 watts. A Luna Mighty Mini at only 3 pounds can power a 1500W BBSHD. Its in that saddle bag. 18650 cell-packs are much better than lipos. They're smaller and lighter:

 

[999zip999]

You sure made it a challenge for battery space and controller. What type of riding you doing. What range ? Plus where do you live.

 

[nutnspecial]

18650 cell-packs are much better than lipos. They're smaller and lighter:

Yes, the better 18650's are better for size/weight per capacity.
They're typically known as a less volatile chemistry too.
But they're not better for discharge/ charge capability (for size/weight/capacity), nor price.

I use lipo for the superior discharge and charge capability at the cost of range in the same size pack. The modular packs are also the best fit for my FS, and are better to experiment and customize voltage for me.

If a dolphin pack can reliably do (35-40a?) for this 1500w build then that's a very viable option. It's in fact the only way to go (practically, imo) for this build if OP isn't interested in lipo.
I do really appreciate the construction and ease of use on the little 25a 48v LG pack and charger I recently got to play w/ a 1kw hub.

 

[d8veh]

18650 cell-packs are much better than lipos. They're smaller and lighter:

Yes, the better 18650's are better for size/weight per capacity.
They're typically known as a less volatile chemistry too.
But they're not better for discharge/ charge capability (for size/weight/capacity), nor price.

I use lipo for the superior discharge and charge capability at the cost of range in the same size pack. The modular packs are also the best fit for my FS, and are better to experiment and customize voltage for me.

If a dolphin pack can reliably do (35-40a?) for this 1500w build then that's a very viable option. It's in fact the only way to go (practically, imo) for this build if OP isn't interested in lipo.
I do really appreciate the construction and ease of use on the little 25a 48v LG pack and charger I recently got to play w/ a 1kw hub.

The guy has a BBSHD. The Luna Mighty Mini with 14S2P 18650s can handle that motor and it's controller. A Dolphin packwith 13S4P would have double the capability. The cells can provide 60 amps, though, IIRC, the Dolphin pack has a 40 amp BMS.

SAMSUNG 30Q or GA 18650 cells cost double what lipos do for the same volts and Ah, but they last twice as long, so the cost is the same in the long term; however, they have half the weight, which gives them a massive advantage. Lipos are now old school. Time to move forward and embrace the new technology.

 

[Antenor]

Like those dwg

Enviado do meu SM-G850F através de Tapatalk

 

[motomech]

Make a box that attaches to the bottom of the square main tube out of this;

http://www.njsupply.com/10-Wht-Vinyl-Downspout_p_66233.html

Fill w/ 2 of these;

http://www.hobbyking.com/hobbyking/store/__27187__Turnigy_nano_tech_5000mah_6S_65_130C_Lipo_Pack_US_Warehouse_.html

Need more capacity, 2 more bricks in/on a rear rack, less than 4 pounds.

 

[nutnspecial]

Time to move forward and embrace the new technology.

Ok, so how would you go about a pannier mount similar to mine, and how large would it have to be for reliable 80-100a? How much are you derating the C rate? It's my impression that if you want any cells to last you should derate to 1/4.

Cans are neat but honestly seem like alot of unncessary expense and complication against 1 or 2p of lipo (which can be 5-20ah modular packs costing as little as 30$ for 4s 5ah 25a and 50$ for 4s 16ah 40a) . . . What do can's cost in comparison? Besides having to put the damn things together! And when both are derated, seems to me cycle life is comparable enough.

I'd be the first to get into spotwelding for the fun and productivity aspects, but I am not sold that it wouldn't be a waste of time and money. If I want cans for a small pack, I think the 14s 4ah tool batteries are WAY better in cost and usability @ 50-100$/pc w/individual bms/modular.

For an easy and cheap huge battery I'd prob go lipo 20s 32ah w/ easily ~100a discharge (2p 16ah 10/20c multistar). That would cost about 550$ w/ a few balance parallels and shipping . . . it would weigh 28lbs.
How about cans for that?

 

[999zip999]

eTrike eTrike was this rant aimed at Luna Cycles ? Why is Eric in your sights again. Both use high quality cells offered at good price. Opening more of the world to ebikes and ect is what E.S. is about. Carry on.

 

[boisrondevens]

Both Em3ev and Luna do Dolphin batteries (09 case) that can easily supply 1500 watts. A Luna Mighty Mini at only 3 pounds can power a 1500W BBSHD. Its in that saddle bag. 18650 cell-packs are much better than lipos. They're smaller and lighter:

I Wouldn't say 18650's are lighter and smaller then lipo's. Safer definitely YES

 

[nutnspecial]

Safer definitely

Actually I'm not so sure. There's a saying about making things more fool proof and ending up with bigger fools . . . . If the user isn't smarter than their equipment (in this case a bms) the results can be just as bad as failures in manual monitoring and maintenance we often do with small lipo packs. I don't like how most can' packs don't allow easier self monitoring at cell level.
Lipo is definitely a more 'volatile' chemistry when it has a lower thermal runaway threshold. That's only ~ 20-30F tho (of around 200f range) iirc, and there are definitely reported issues of thermal runaway with both 18650 and lipoly/lico.
A lipo user is typically also more personally responsible in applying proper protection for the cells from physical damage . . .

I like education and responsibility > relying completely, blindly on tech that can/does fail.

The batteries themselves still even have a degree of unpredicability it seems, (more than equally hazardous gasoline imo) - so having to trust a bms with no easy way to self monitor on a cellular level is not the best idea for the portable energy industry, to me. Also a standard maintenance pamphlet should be included to aid education and proper use/maintence. Some of the threads here hint on how much the major populace have to learn.

That's not necessarily a knock on cans w/ bms's in general- I like them and perhaps with the proper maintenance and educated users they are safer - but let's not forget the above quote as it may apply to the industry, and think about how to mitigate those undesirable results.

As far as anchors in boats, we all have opinions and as long as things are civil and not personally dirogatory I see absolutely no problem in discussing these opinions.

 

[999zip999]

We need competition and more innovators pushing forward this will bring down the price of cells and Battery Technology will go forward. Plus I'm happy to have a California base company Luna cycle . I have very dealing with Paul em3ev. More options.