Lipo noob shopping list help!

[Scoot440]

I am building a very conservative commuter (I have always run SLAs before now) and the list of variables for Lipo is quite large. Please offer any advice.

The bike:
steel frame cruiser, no suspension
Heinzman geared/brushed hubmotor 26" rear
generic brushed 36V 30A controller
26x1.75 commuter tires

The commute:
9.8 miles round trip, virtually no hills, but high winds and high temps are very common
250lb rider who plans to pedal a lot
would be very happy with 16-20mph

Thinking of running 3 of these ZIPPY Flightmax 5000mAh 3S1P 20C in series
http://www.hobbyking.com/hobbyking/store/__16786__ZIPPY_Flightmax_5000mAh_3S1P_20C_USA_Warehouse_.html

This charger: HobbyKing ECO6-10 200W 10A 6S Bal/Dis/Cyc Charger
http://www.hobbyking.com/hobbyking/store/__15167__HobbyKing_ECO6_10_200W_10A_6S_Bal_Dis_Cyc_Charger_w_acc_USA_Warehouse_.html

Power for the charger will come from a deep cycle SLA 100Ah 12V (fed by a Harbor freight 45W solar kit).

Where I would like advice is for voltage checkers/LVC alarms, pre-made charging boards and wiring harnesses, and other accessories you would choose to make this system feasible but relatively inexpensive. I would prefer to purchase items from ES members rather than Hobby King where it makes more sense. The bike and motor are not variables, but I am pretty flexible on everything else.

Thank you in advance for any advice!

 

[wesnewell]

Typical lipo 36v packs are 10s, but most 36v controllers will handle 12s fine. And you can get 5ah of 12s for about the same price as 5ah of 9s using 3 of these when they are in stock.
http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html
The only other thing you really need is a volt meter to monitor pack voltage and these work great.
http://www.ebay.com/itm/Waterproof-Digital-Voltmeter-DC-15V-To-120V-Red-Led-Voltage-Digital-Panel-Meter-/170846310527
Don't use the motor when voltage drops below 42V and you should get at least a couple of years from it. At 20mph, range should be about 10 miles at 20mph. Pedaling at 16mph you could expect to double the range easily.

 

[cal3thousand]

I don't think 9S1P is going to get you very far unless you plan to go slow and pedal.

Here's my logic:

9S1P = 3.7v * 9 = 33.3V
33.3 V * 5000 mAh = 166.5 Wh
166.5 Wh * 80% (safe use margin) = 133 Wh

133 Wh / 9.8 miles = 13.6 Wh/mi.

To maintain that low use over that distance without charging in between (and keeping your batteries happy), you would have to keep at below 15mph and pedal too.

 

[Scoot440]

So, a more realistic starting point for me would be 4 of these ZIPPY Flightmax 5000mAh 5S1P 20C (or similar) to create 10S2P?
http://www.hobbyking.com/hobbyking/store/__8581__ZIPPY_Flightmax_5000mAh_5S1P_20C.html
HK has these in stock.

 

[Scoot440]

Following cal3thousand's math, that would give me:

10S2P = 3.7v * 10 = 37V
37 V * 10000 mAh = 370 Wh
370 Wh * 80% (safe use margin) = 296 Wh

133 Wh / 9.8 miles = 30.2 Wh/mi.

So, this should barely tax the battery pack and give me some wiggle room if I want to make a side trip or two.

 

[wesnewell]

So, a more realistic starting point for me would be 4 of these ZIPPY Flightmax 5000mAh 5S1P 20C (or similar) to create 10S2P?
http://www.hobbyking.com/hobbyking/store/__8581__ZIPPY_Flightmax_5000mAh_5S1P_20C.html
HK has these in stock.

Well that will certainly work, although it will cost $160 compared to $75 for 3 4s packs that will also work just fine.

 

[Scoot440]

Okay, so playing with the math (and looking at my budget)

12S1P = 3.7v * 12 = 44.4
44.4 V * 5000 mAh = 222 Wh
222 Wh * 80% (safe use margin) = 177 Wh

177 Wh / 9.8 miles = 18.1 Wh/mi.

And depending on what is in stock when I order, 3-4S packs or 4-3S should do the trick.

That does sound much more feasible. Wes and Cal, thank you for helping me not to make a big mistake on this!

One last question, what hardware would you recommend for charging all 3 (or 4) packs together?

 

[wesnewell]

The easiest way to get 5ah of 12s is with 2 6s packs in series. It will cost a little more than using 3 4s packs, or 4 3s packs, but makes charging options a lot easier. These are in stock if it meets your budget. Wait for discount box to pop up.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16804
I'd recommend this charger for any 12s pack.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw
If that's too much you could use any cheap 6s charger if you don;t mind splitting the packs to charge.

 

[dogman dan]

10s for "36v".

I'd say wait a bit, which sucks, to order. Stock is crappy low now, and shipping from china for batteries is not an option anymore for me. Get 10s 10 ah, in simple to use 5s packages.

For alarms, I just got some of these, (they had to come from china) and am liking them better than the pack voltage ones I have used before. I'm still running them a bit, before I actually post a review. I like the cell level lvc alarm, cell level v readout, and adjustable lv alarm setting.
http://www.hobbyking.com/hobbyking/store/__18588__Hobbyking_2_8S_Cell_Checker_with_Low_Voltage_Alarm.html

Get a cellog 8 as well, for quicker checking, and more accurate checking.

How to charge best is a hornets nest you kick. But you will want at least one regular RC charger, for single cell charging and balancing packs if nothing else. If you wish to bulk charge, EM3 ev has an interesting one. Mine is about to arrive any day. The interesting feature of this lithium charger is a three position switch to allow 50% 90% and 100% charges. I think top of charge will be adjustable, but I won't know for sure till I get mine.

Another interesting charger is (thunder power?) 12s charger. Not sure I have the name right. It charges up to 12s through the balance wires, so each charge is a perfect single cell charge, x 12. Just like 12 chargers each one charging one cell. It's getting good reviews lately. I'd have bought one, but lately I'm running 14s.

 

[Scoot440]

Hi Dogman, thanks for joining in!

Is this the charger you are referring to?
http://www.hobbypartz.com/75p-t6-multi-charger.html
I do like the idea of charging mulitple packs with accurate balancing. I also like the multi-level bulk charger. I look forward to your review.

Patience is rough - school is out and the streets are so much more bike friendly right now - but I keep seeing my budget needing to increase as I see all the options. The 4S hardcase packs that Wesnewell posted ( http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html ) look like the best deal going until you read the comments about how rarely they are in stock.

What I am learning:
There are lots of different configurations to build packs with the same capabilities and most of them cost about the same money. The biggest limiting factor seems to be what is in stock at HK.
9S1P would get me to work, but I'd need to charge at work, which sounds like a terrible idea with Lipo.
So, it looks like 12S1P and 10S2P are more realistic for my needs. 12S1P will run about $100-120 for the battery packs, 10S2P will run closer to $160.

A Thunder charger plus gages and accessories will be $100-130. Lesser 6S chargers are much cheaper but the charging process is much less convenient.

I have toyed with the idea of building the bike as a 24V system, but I tend to find higher voltage/lower current to be less damaging and more reliable than the other way around.

Thanks again to the three of you for your input! I feel much better prepared now to make a good choice.

 

[pixelzpusher]

Scoot440,

Here is what I have been using on my ebike for over a year and it has worked great for me. I commute 30 miles a day to and from work round trip. I charge at work and at home, carrying 12s lipos total 20 amp hours. The commute uses about 1 amp hour per mile, giving me lots of reserve in the packs.

Lipo source:
www.haiyinstore.com
- I've been flying rc electric airplanes for over 8 years. Between myself and my buddies, we've tried all sorts of lipos on the market from Thunder Power, Flightmax, Turnigy, Gen Aces, to Haiyinstore. For the best bang for the buck and reliability, Haiyinstore lipos are hands down the best. All my electric flying buddies have switched over to Haiyinstore.com lipos. They have a Nevada warehouse so batteries arrive to me in LA within 3 days of ordering. Just make sure you specify the Nevada warehouse when placing your order.

Lipo charger source:
http://www.valuehobby.com/power-systems/chargers/lipo-balance-chargers/gt-power-xdrive-6-4x60-watt-6a-6s-balance-charger.html
- I have 3 of these. I know it's more than your $30 charger you want, but all the guys at the rc airfield I go to use this one, or a similar one under another label. It charges 4 lipos at once, up to 6s packs. It's also a smart charger that will balance and prevent over or under charging in case you're not paying attention. I would recommend spending the extra money for the safety and speed of charging your lipos. In addition, this charger charges SLAs, Nimhd, Nicad, and lifepo4 batteries.

Charger power source:
- Convert an old desktop computer power supply, minimum 250 watts, into a DC/AC power convertor. Google it on youtube.com and you'll find tons of videos on how to do it. This option is better than buying a $60 power supply. You get more power for less money if you just put a little leg work into it. I had 2x $60 power supplies that I purchased before doing this and neither of them held up as good as the one I made from an old computer power supply.

Lipo balancer
- You can balance from the charger I recommended or if you don't get that, use one of these:
http://www.ebay.com/itm/3-in-1-RC-2s-6s-Lipo-Li-Fe-Battery-Balancer-LCD-Voltage-Meter-Tester-Discharg-er-/360723868009?pt=Radio_Control_Parts_Accessories&hash=item53fcd16969

These are sold under different labels, but they all do the same thing. I have 4 of these.

Regarding lipo usage, if you take care of them and do not over discharge beyond 3.7v per cell, you will get a lot of use out of them. My lipos have lasted 17 months, over 400 cycles. I commute 20x to and from work a month, 40+ cycles on the lipos per month in 17 months. I do not discharge beyond 3.7v most of the time, but have done so by accident a few times by grabbing a discharged pack thinking it was charged. Total capacity of my packs are still 3500-4500mah out of 5000mah total in the packs after 17 months of daily use. Some people discharge them all the way all the time and that will shorten the lifespan of the packs. I used to discharge my packs 100% during my early electric rc flying days and wondered why my lipos didn't last so long. Ever since I learned not to do that, all my lipos have had over 3 years of shelf life, discounting bad cells of course.

 

[pixelzpusher]

Scoot,

Here are my lipos charging at work right now.