Hobby King LiPo Prices

[Boyntonstu]

I see in some threads that folks have purchased HK batteries 50% off the listed price.

For example: http://www.hobbyking.com/hobbyking/..._Multi_Rotor_Lipo_Pack.html?strSearch=10000 4

A $58.39 10C 14.8 10000 batteryfor $30.


And this one: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=18631

A $26.18 20 C 14.8 5000 for $15.00




Is this savings possible and if so what do I need to do to get the discount?

 

[Sunder]

I've gotten some stupidly cheap batteries from Hobbyking before, but they don't have regular specials. Just whatever they have too much of.

So if you're not prepared to check the bargains bin at least once a week and be prepared to quickly figure out a watthour per dollar pricing, then figure the work into rebuilding them into the right sizes, the forget it.

For me, I found some 8s at a ridiuclously low price, but my setup was designed for 12s, and 16s would havd been too fast. So I loaded up, got a BMS for it, and bought a slower winding motor to compensate for the extra voltage. The majority of people wouldn't go to that extent to save a few bucks, but my old motor was getting a worn clutch anyway, so I figured it was worth it.

Someone with more time could have bought 3 x 8s (24 cells total) then rebuilt them into 2x 12s.

 

[motomech]

HK puts selected types of Lipo on sale from time to time. There really is no "rime or reason" to what they put on sale, one just has to keep watching.
A couple of months ago(probably when those links were posted), there was all kinds of Lipo on sale and I scored big-time on some Multistar 6S/ 10K Ah bricks for $50 ea.
One trick @ HK that works on everything they sell is to wait on the page a few minutes and a discount pop-up appears. Grab it then because it only appears once.
You also build up rewards as you buy stuff from them
Lipo @ HK is addicting.

 

[dogman dan]

Once in a while, you can get an incredible deal. Wes likes to talk like you get that price everyday there, you don't.

But,,, hang in there, it might come. And for dang sure, when you are ready to buy, at least leave the page open till they offer a small discount. Don't look too long at a page till you want to buy, and let that discount slip past. They won't offer it again for quite a while.

You can get a pretty decent price on 48v 10 ah,, 14s,,, anytime by buying the 20c stuff. Definitely well under 200 bucks. That's what I usually do. Two 5s and two 2s. I don't really dig the hardpacks. I'd rather have a smaller pack in a home made hard box.


My last purchase I got a great one time deal. I have no idea why they sent me two orders when I paid for one. If they are that stupid, I'm not going to help them out. That made up for nearly as many dud packs I took a loss on over the years. Hey,, I finally broke even.

 

[nutnspecial]

In the last 17mo, I can say it only seems you don't see the good deals at this time of the year. In fact, it seems they tend to be in the late 2nd quarter, early 3rd quarter? Of course there's alot of moving parts to HK pricing though, including their own whims and the public's I imagine.

You were looking for now Stu? Would 4 or 5x of those 16ah 4s multistars for 50$/pc work for you? They should be consistently good for up to 45a draws. We may not see those prices for much longer this season.

 

[Boyntonstu]

In the last 17mo, I can say it only seems you don't see the good deals at this time of the year. In fact, it seems they tend to be in the late 2nd quarter, early 3rd quarter? Of course there's alot of moving parts to HK pricing though, including their own whims and the public's I imagine.

You were looking for now Stu? Would 4 or 5x of those 16ah 4s multistars for 50$/pc work for you? They should be consistently good for up to 45a draws. We may not see those prices for much longer this season.

Decisions, decisions. I like having to mount 4 batts not 5.

I now have four 3s in series of the weak 3-4 Ah boosters,

They workn OK and I now have about 1,400 miles on them.

The four 16ah 4s multistars for 50$/pc would be nice but I would have to replace the controller the throttle, and a pair of 8s chargers.

The more I think about it, the more convinced I have become to stay with 48 V.

I could do it with two of these and a pair of 6s chargers:
http://www.hobbyking.com/hobbyking/...Multi_Rotor_Lipo_Pack.html?strSearch=10000 6s

 

[wesnewell]

Sign up for their news letter if you want to know what's on sale fast enough to get in on it when it happens.

 

[nutnspecial]

Stu, if you are thinking of staying @ 12S, you could also get (3) 4s 16AH for 160, instead of 10AH for 200!

It's never fun or that good of an idea to always be disconnecting and reconnecting packs to charge, plus balance chargers are weak/expensive and completely unncessary for most, imo at least. A few battery medics and decent MW power supplies will do awesome, fast, cheap, reliable. 'Bulk' charge.
2 of these will do up to around 62v so you can use them for other configs too.
http://www.ebay.com/itm/MEAN-WELL-HRP-300-24-NSFP-HRP30024-/391476933389?hash=item5b25d7f30d:i:391476933389

Here's a picture of my pack. I wrapped in a cut-up plastic box and taped everything well, added balance extensions, saran wrapped, vetwrapped, and placed in a 'handlebar' bag. 12s 16ah 45a weighing 9lbs.

 

[Boyntonstu]

Stu, if you are thinking of staying @ 12S, you could also get (3) 4s 16AH for 160, instead of 10AH for 200!

It's never fun or that good of an idea to always be disconnecting and reconnecting packs to charge, plus balance chargers are weak/expensive and completely unncessary for most, imo at least. A few battery medics and decent MW power supplies will do awesome, fast, cheap, reliable. 'Bulk' charge.
2 of these will do up to around 62v so you can use them for other configs too.
http://www.ebay.com/itm/MEAN-WELL-HRP-300-24-NSFP-HRP30024-/391476933389?hash=item5b25d7f30d:i:391476933389

Here's a picture of my pack. I wrapped in a cut-up plastic box and taped everything well, added balance extensions, saran wrapped, vetwrapped, and placed in a 'handlebar' bag. 12s 16ah 45a weighing 9lbs.

View attachment 1

Good thinking.

My 4 battery install fits my bike well. I could use 3 of these and place the controller in the fourth position.

How do you balance charge?

[youtube]y6MAb-vjwpU[/youtube]

 

[wesnewell]

The Mongoose Ledge 2.1 is my main ride also. But you'll get a much better ride on pavement with 2.125" street tires. I just replaced the whole wheels on mine and use 2.4" Cyclops tires.

 

[wineboyrider]

I paid $50 for 4s 16000 mah multistars like Nutspecial has. They were all very good cells and I only paid $350 for 1400 wh's of batteries.

 

[nutnspecial]

You could probably rig up 3 batteries and controller in a similar design. The biggest part with lipo is protecting them from puncture and damage, and making them more water resistant (balance leads and ends of batts) if you want to ride in the rain.

How do you balance charge?

You should almost never have to. The checkers are used before and after ride to confirm proper cell levels, and while charging as well. If a pack needs some balance, they have the ability to bleed off high cells during charge or after, but that is rarely necessary with a happy healthy pack. I set the MW to somewhere around 4.15-4.17v per cell (50v total). A typical nearly full 16ah charge should take about an hour with the MW hrp's I linked. I always charge supervised, it's a good practice with this chemistry. https://www.youtube.com/watch?v=J_oKpOSzJpo

You would likely want to run a voltmeter http://www.ebay.com/sch/i.html?_odkw=voltmeter&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR1.TRC0.A0.H0.Xvoltmeter+100v.TRS0&_nkw=voltmeter+100v&_sacat=0 during the ride to gauge the average cell levels by total pack voltage. A controller limit is nice too, but not absolutely necessary especially on lower draws where there isn't much sag happening. On 12s 16ah multistar and ~25a draw you might find you like your 'end' SOC works best at or above 42v, or perhaps 43v. With larger (45a) draws, they would be happiest with more like a 45v cutoff.

 

[Boyntonstu]

The Mongoose Ledge 2.1 is my main ride also. But you'll get a much better ride on pavement with 2.125" street tires. I just replaced the whole wheels on mine and use 2.4" Cyclops tires.

My tires are 1.95 front and rear. The Nylon threads are just beginning to peep through the rear.

I will take your advise and replace with 2.125.

Interesting to note that my kid's 20" MB is a hard-tail with softer front shocks. It gives a much smoother bump-free ride than the Mongoose Ledge even with the rear spring adjusted to minimum or possibly free. Is it possible to adjust front shocks?

I don't see building a new wheel around the motor in order to go from 2.125 to 2.4 tires.

Could I cram a 2.4" tire onto a rim that has 1.95" tires on it?

 

[Boyntonstu]

You could probably rig up 3 batteries and controller in a similar design. The biggest part with lipo is protecting them from puncture and damage, and making them more water resistant (balance leads and ends of batts) if you want to ride in the rain.

How do you balance charge?

You should almost never have to. The checkers are used before and after ride to confirm proper cell levels, and while charging as well. If a pack needs some balance, they have the ability to bleed off high cells during charge or after, but that is rarely necessary with a happy healthy pack. I set the MW to somewhere around 4.15-4.17v per cell (50v total). A typical nearly full 16ah charge should take about an hour with the MW hrp's I linked. I always charge supervised, it's a good practice with this chemistry. https://www.youtube.com/watch?v=J_oKpOSzJpo Great Video!

How about this for voltage monitoring? http://www.ebay.com/itm/272294986987?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

You would likely want to run a voltmeter http://www.ebay.com/sch/i.html?_odkw=voltmeter&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR1.TRC0.A0.H0.Xvoltmeter+100v.TRS0&_nkw=voltmeter+100v&_sacat=0 during the ride to gauge the average cell levels by total pack voltage. A controller limit is nice too, but not absolutely necessary especially on lower draws where there isn't much sag happening. On 12s 16ah multistar and ~25a draw you might find you like your 'end' SOC works best at or above 42v, or perhaps 43v. With larger (45a) draws, they would be happiest with more like a 45v cutoff.

 

[nutnspecial]

Great Video!

It's one of the first ones I saw, and thought the same. You would likely not have any in parallel, and they would stay in series in pack / on bike, so it's as simple as plugging in the mains, and either checking a few times with one medic, or using a set of them to monitor/ discharge any cells over 4.1, 4.15, or 4.2v as you wish. Running conservative with levels and discharge rates will most likely have the cells all within .01 to .02v in the charge/discharge cycles, with no need (or very rare need) to balance.

How about this for voltage monitoring? http://www.ebay.com/itm/272294986987?_

Sure, that's pretty nice how they integrated it right into the throttle!