NOOB LiPo Shopping list. Did I miss anything critical?

kiwipete

100 mW
Joined
Nov 13, 2013
Messages
45
Am looking to convert my MTB (strictly commuter no offroad) with a MAC kit (yet to purchase) but after a lot of reading have decided that the best battery option (for now) is to go LiPo.

Yes, I've read a number of the horror stories (member Floont comes to mind) and my wife is already not that happy with the money that I'm about to spend, let alone risk burning the house down..

So as part of the risk mitigation process I will build a small vault out of lightweight, aerated concrete in the garage where I will store and charge the batteries, as well as fitting a decent smoke alarm. The concrete vault will allow the smoke and fumes to come out (don't want pressure build up) but will contain any potential fire and heat.

I have only a short commuter trip so don't need a big pack and would like a nice stealth install of the batteries like the member 'Headwind' has done:

IMG_0004_zpsf23fb71f.jpg
IMG_0001_zps1bef09cd.jpg


So this is what is on the shopping list :

- 2 X Turnigy 5000mah 6S 20C lipo batteries, to give me 44.4 V at 5aH
- Icharger 106B with matching powersupply
- parallel charging harness
- parallel balance lead
- 2 Hobbyking 2-8S Cell Checker with Low Voltage Alarm (that will act as my lvc)

I will only (parallel) balance charge the packs so that should take care of over-charging and will leave the Cell checkers permanently on the batteries (whilst not on the charger of course) to make sure none of the cells go under-voltage.

As per dogman's sig, will discharge to 3.65v minimum and charge to 4.1v maximum.

Also will buy a small aluminium enclosure that the two lipos will (snugly) fit in, to make sure there is little chance of physical damage.

Have I missed anything critical so far?
 
Welcome to the Ebike world--I reccomend some decent cell level monitoring, and pack level monitors.In addition to your low voltage alarms...

1) the cell-log 8, about 16 dollars, nice device that reads cell voltage via the balance wires accurately.
the cheap low voltage alarms break easily and can be inaccurate,but still necessary for rookies, but the cellog is good to spot check your cells say during a ride or pre charging or post ride. more precise than cheap alarms

Use the low voltage alarms only when you ride, do not leave anything connected to battery like low voltage alarm they get their power from a cell or two and will drain and imbalance or even kill your battery if left connected for days.

a watt meter will show you how much energy you get from your batteries,
this is must know" info for noobs or your flying blind, if you are using 12 series 5 amp hours , two bricks, then you should get ten miles but maybe only 8 maybe 12, - this watt meter will let you count up the amp hours used, you should probably only use 4 of 5 amphours available, It is chea accurate and you only need to use it at first to learn about the batteries then later you will use it intermittently.

links
http://www.hobbyking.com/hobbyking/...Voltage_Monitor_2_8S_Lipo_USA_warehouse_.html

http://www.hobbyking.com/hobbyking/store/__10080__Turnigy_130A_Watt_Meter_and_Power_Analyzer.html
 
Thanks for that BikeFanatic.

I'll add the Turnigy watt meter to the list.

The alarm that I listed (http://hobbyking.com/hobbyking/store/__18588__Hobbyking_2_8S_Cell_Checker_with_Low_Voltage_Alarm.html) according to the description does pretty much what the Cell log8 does:

"This unit also features a handy built in LED display that will show the voltage of each cell followed by the over all voltage of the pack"

Or do you think that this alarm/cell voltage reader is hopelessly inaccurate?
 
They can be pretty bad for accuracy. But they are so cheap, you can go ahead and get some. I have a few like them, and I use them only when I plan on a ride that might take cells below 3.5v. Left on the pack all the time is a bad idea, they will actually unbalance the pack. But I will use them when I will do a long ride I know will 100% discharge one of my packs.

Do get a more accurate cell checker, such as a cellog 8. The cheaper non logging one will allow you to carry one to use as you feel the need to.

Example, you planned on not running down the pack so low, but a mile from home you realize you are pretty low. A quick check with the cellog, and you find you can easily still ride home slow, rather than pedal it.

I would recommend adding some kind of handlebar mount voltmeter. Particularly with a pack that small, you should be easily able to see when your pack is desperately low and you should stop, if that should happen when you aren't home yet. There are some very cheap voltmeters out there on ebay, look for the ones with only two wires, that run on any voltage battery. With a simple voltmeter, you get a feel for how fast the voltage drops in normal use, then when you see it start to drop fast, you just passed about 3.6v.

Two little lipos in the garage is not a huge storage problem. They sell fireproof lipo bags plenty big enough to store two packs. You could double that up by putting the bag in some kind of metal box, like a cheap toolbox. Then of course, don't put the box on top of or very close to flamables.

Lastly, to protect the lipos when you carry in the bag, lots of easy to use materials can make a stout box to prevent abrasions and punctures. I like coroplast, but also easy to get and work with is plastic from storage boxes. Walmart often has a pencil box that perfectly holds two lipos.

Another good option might be three of the hardshell 4s packs.
 
A 12s charger isn't that expensive. It will make things easier.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw
If you buy cell checkers, don't leave them hooked up. They will drain power from the batteries. There's really no need for them. A simple voltmeter hooked to the controller side is all you really need since you will be balance charging the pack with every charge.
http://www.ebay.com/itm/Waterproof-Digital-Voltmeter-DC-15V-To-120V-Red-Led-Voltage-Digital-Panel-Meter-/170846310527
Don't run voltage below 44V (resting) and you won't have a problem. Most 48V controllers have an LVC of 42V. Ona 12s packs that's 3.5V per cell loaded, which I consider perfect. Allows you to use up to ~95% of your batteries power, and will keep a balanced pack at a minimum of ~3.6V per cell.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=47294
 
Change your battery plan so a different number of series ..10 13 14v or 17 ..I know..weird numbers but that is what Paul sells...and then you have safety net of a bms

http://em3ev.com/store/index.php?route=product/category&path=42
 
for 14s..get 2 7s packs instead of the 6s

http://www.hobbyking.com/hobbyking/store/__21374__ZIPPY_Compact_5000mAh_7S_25C_Lipo_Pack.html

http://www.hobbyking.com/hobbyking/store/__21384__ZIPPY_Compact_5800mAh_7S_25C_Lipo_Pack.html

http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?cwhl=XX&idCategory=86&v=&sortlist=P&LiPoConfig=7&CatSortOrder=desc


He sells chargers too

http://em3ev.com/store/index.php?route=product/category&path=37
 
The joy and the dilemma of running the RC lico packs is that there are so many right ways to do it. Only a few wrong ways, and the sparks when you connect let you know then.

Anyway, just two 6s packs, It just is so small and simple that charging by swapping them from 12s to 6s won't be that big a deal. Even the crazy slow 50 w chargers might be ok for him with a pack that small. But I would recommend a 150-200w one. Get it done in an hour so you can go to sleep.

Really guys, it's two lico packs. Not 8 or 12 or so on.

I have 15 ah of 14s, an I am charging the dangerous way, but in a safe place, with a bulk lithium charger set for 14s. I balance at most every 60 days because I run a discharge routine that does not unbalance the pack. I cut safety to enhance convenience, but the price I pay is moving the packs to that safe place to charge every cycle.

I don't feel a need for a bms, but I also know I could start a fire any charge. Using an RC charger and the balancing setting every cycle has got to be safer.
 
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