Battery Case Specs E-PCASE09

[sbeck90630]

Looking to build a custom battery and need to know how much room is inside one of these battery cases

http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2015-47-JKHT.457DR

Im looking to stuff two HobbyKing lipos in there and wondering how much room I have to work with inside of the case.

If anybody has pictures of the interior of the case or pics of something similar, it would be greatly appreciated.

Thank you

 

[sbeck90630]

And I see the specs on the website for the outside dimensions but I need to know what they look like cracked open.

 

[friendly1uk]

I couldn't get anything to fit. Thought I have lost the dimensions, It's also called a dolphin battery I think, but more commonly the 09 part of the prefix is used. An aliexpress seller had them open and measured, I think they just called it the new bottle battery

Some food for thought though, if you do buy one: http://endless-sphere.com/forums/viewtopic.php?f=3&t=64667&hilit=battery

 

[sbeck90630]

Thanks for that awesome link. Its a good read. Ill keep researching and decide if its worth my time.

 

[thetimmy]

I was considering doing the same thing. My SSR SandViper utilizes the 36V 10AH battery and I'm quite happy with it, even thou this is my first eBike. The battery is rain-proof, locking, and easy to detach for charging. I wanted to purchase the empty case with the hopes of adding 18650 laptop cells to build a 48V battery. Does anyone have advice for me?

 

[speedpower99]

laptop cells are never good in this application due to low current discharge 1-2C.
You can fit 10s5p, 12s4p or 14s3p inside. so you better use high power cells.

 

[d8veh]

The case can take 52 18650 cells when packed in a square format. You might get more in if you packed them diagonally. Recycled laptop cells is a great idea, but a complete waste of time. You need equipment to test them, then it takes ages going through charge/discharge cycles to sort them out, only to end up with an over-weight, saggy battery. Take my advice and buy a ready-made one with branded cells.

 

[thetimmy]

Thank you for the advice. After looking at the incredible amount of specialized equipment I would need to build a battery right, I think purchasing a pre-built battery would be the best option. Thou building it has a certain appeal...I wanted to immerse myself in the field of battery technology as I plan to buy an RV and install solar panels so that I never have to tie into shore (electrical grid) power. This means plenty of batteries and how to manage them effectively. I was only 5 credits away from getting my Electrical Engineering degree so at one time this topic was rather familiar to me, but its been several years since I graduated (computer science) and I really need to brush up.
I currently live in an urban area with a high crime rate, (saving $2000/mo) so security is a top priority for me. Does anyone have a recommendation for a locking case or any other way to prevent the battery from being stolen?

 

[d8veh]

Making a battery with used laptop cell teaches you a lot about batteries. That's really the only reason to do it.

 

[thetimmy]

Making a battery with used laptop cell teaches you a lot about batteries. That's really the only reason to do it.

Could you point me in the right direction towards purchasing the proper equipment needed to test the batteries, charge them, and even assemble them into a larger battery. I know I need a multi-meter to test the batteries, but I don't know if I would need a special unit designed to handle high current. I know I need a battery charger and that I will likely need the ability to adjust the voltage and current, but the only experience I have with such devices was in college and I remember hearing those adjustable power supplies were $2000.

I don't mind investing in the equipment as it will be necessary for converting my RV to run off solar & batteries.

 

[d8veh]

The cheapest way to test the cells is with a lipo charger for which you'll probably need a separate 12v power supply. The imax charger is about the cheapest. Get it from Hobbyking. There's a lot of cheaper counterfeit ones around that aren't as good.

You then should make a 6S charging jig out of wood/MDF for which you need spring contacts ar one end. I took mine from an obsolete AA battery charger. You can now charge and discharge 6 cells at a time and observe their voltages. You should do them in groups of the same designation. You need to study the datasheet for each cell designation you have so that you know what the normal capacity is. A BC168 charger is much quicker and better at balance charging, but it's more expensive. It's not so good at discharging though because it won't show which ones went down the fastest unless you observe in realtime.

Once you've sorted out good cells, you have to find a way of joining them. You can solder them with wire, but there's a danger of damaging them, you really need a spot-welder that you can find on Ebay or Aliexpress. The metal joining strip is fairly expensive.

Finally, you have to add a BMS. You can do without one and charge your pack like you would do with lipos, but bulk charging through a BMS is a lot more convenient.

 

[docnjoj]

I've soldered a lot of batteries over 50 something years of electric model flying and ebike stuff and it works for me. That being said, the cells that Tumich sells in the New For Sale section are the best deal going. Spotwelded by the best Bosch can buy and reasonably priced too. New cells. Check it out as I have no interest in the company other than as a satisfied customer..
otherDoc