Walmart Booster Batteries

^^^Agreed. Boyntonstu, you really need to get a power meter if you care to learn much more at this point in practice. Hopefully you can get the broken one you purchased replaced soon.

You are likely running around 350+watts at 20mph and 950+watts on your 30mph runs which would be more than 5c continuous while you are holding that speed. All of this is our fairly accurate napkin math until you get a power meter. We all just use SWAGS from spending many hours calculating our builds, looking at the simulator, and comparing the numbers we have obtained from experience.
 
20 mph takes between 400 and 500w, (electric) depending on slight grade or wind. but of course it can take less if downhill, or downwind. And you can pedal hard enough to reach 20 mph with only 250w, but likely you are like me, and pedaling is only about 75 watts rather than the typical younger mans 100-150w.

You see other numbers for watts and speed on pedal only bikes, since they don't lose watts in controller, wire, and motor heating.

Lots of scoffing here, but for you it's working. You only need a short range, and it was cheap. For most, a larger battery with 20+ miles of range is needed.

Definitely clear you aren't getting the 12 ah out of it, more like 4 ah so far, but likely you could get a bit more. It might even go 6 ah, which is not too bad for 150 bucks.
 
Do you have any torque arms/plates on that hog?
 
Those of us that have spun an axle or two wish you the best of luck! Make sure you check your nuts regularly or you might rack the other set! haha
 
ecycler said:
Those of us that have spun an axle or two wish you the best of luck! Make sure you check your nuts regularly or you might rack the other set! haha
Click to expand...


I am following in wesnewell's footsteps. He has gone 15,000 miles with the same bike, same motor, more power, and no torque arms.

Am I missing something?
 
Only if you develop a loose nut will you have any problem. It's true, the cheap bikes have a pretty sturdy horizontal steel dropout. It's very deep too, so the axle is not going to jump out.

In addition, the bolt on derailleur mount is actually a torque arm. But what I like to do is weld the derailleur mount to the frame for some extra strength, and to make the reinforced slot deeper. This insures the entire washer and nut is supported.

So the idea is, add metal to the tip of the hanger, so the slot is deeper, and the thing becomes a very stout torque arm. One good TA on one side is all you need, and the cheapo derailleur provides that.

If your bike cost more, and has a shallow vertical dropout and a derailleur hanger, then you do need a TA.
 
2-1/2 month update. Everything working fine. Go for a ride, enjoy the Walmart Booster battery power and fast acceleration, come home, plug in the four chargers for a few hours.

I have not run the batteries down beyond the 50% yellow range.

Do it again the following day.

It has become routine.

I will update if anything changes.
 
I bought one of these at the local wallyworld as it was considered a seasonal item and was on close-out. It has a fairly bright led flashlight built into it (0.5 watt) and if I am figuring right, it could run that on a full charge for about 5 hours. It is touted as "12,000mah max", but I have tested it on 2 different meters and it has only about 3 to 3.5 Ahrs available. As far as high amps for short bursts, I think this might be pretty good for what it was designed for. Probably 200 amps would be possible for a total of 50 seconds, enough to start most cars if it wasn't too cold outside. It even uses "EC5" connectors on it and some very heavy gauge wire. I haven't opened it up yet. Nice USB port--2 amp max output. On a 250 watt hub motor, 3 of these could be used to overvolt a 24v hub and 4 could be used to overvolt a 36v hub.
 
I went 15 mph for 13.5 miles using PA and the battery LVC prevented any further motor power.

I calculate 3.5 Volts as the discharged state.

I can only pedal to 10 mph and the motor provided the extra 5 and then some into a strong headwind.

The bottom line is that my bike range limit using the Walmart booster batteries is 13.5 miles at 15 mph.

Not too shabby.
 
I see the point about availability, return warranty (but still to be established) and value...
But , unless the warranty trick works, the "value" is not too good.
For $56 you can get a bigger capacity (5.2Ahr) 12S set up of HK Multistar 10/20C packs !
These would be smaller, lighter, and plenty of discharge potential for your use.
Plenty of $$$'s to spare for chargers and even more capacity too !
 
Hillhater said:
For $56 you can get a bigger capacity (5.2Ahr) 12S set up of HK Multistar 10/20C packs !
These would be smaller, lighter, and plenty of discharge potential for your use.
Plenty of $$$'s to spare for chargers and even more capacity too !
Click to expand...

Don't forget that the HK batteries would then have no BMS whatsoever, and a proven track record of house fires. A little savings could get pretty expensive pretty quickly.
 
Chalo said:
Hillhater said:
For $56 you can get a bigger capacity (5.2Ahr) 12S set up of HK Multistar 10/20C packs !
These would be smaller, lighter, and plenty of discharge potential for your use.
Plenty of $$$'s to spare for chargers and even more capacity too !
Click to expand...

Don't forget that the HK batteries would then have no BMS whatsoever, and a proven track record of house fires. A little savings could get pretty expensive pretty quickly.
Click to expand...

House fires? What is the story on that?

The Walmart Booster comes with the BMS and the charger.

The case seems pretty robust.

I use a 2 hour timer to prevent overcharging.
 
lipo fires ... :roll:
many reported, much discussion, not much conclusion,..
even all te best tech brains in the world could not solve the root cause of the Dreamliner fires !..
... but the finger is frequently pointed at the RC lipo pouches.
RC guys burn their batteries most often, because they run them hard into the ground, both physically and electrically
however, the last serious Ebike fire reported was actually on a 18650 pack with a BMS installed ! :eek:
Many of the fires are most likely attributed to operator error / poor pack design/ abuse? over charge /over discharge/ shorting/etc etc etc
only one that i can recall was apparently a unprovoked ignition of a new pack.
Many of us simply dont trust a BMS and prefer to rely on the " Human BMS" and check their packs before and after use for balance , temp, connections, swelling, etc.
Thats easy with RC lipo, ..... but hard to do on a fully sealed commercial pack.
..And , i would not keep any type of Li Ebike pack in my house !

everything is a compromise ! :(

EDIT:- Has anyone ever opened up one of these type battery boosters to see exactly what cells may be in there ?
I think we assume there is possibly 6 x 18650's being worked to the limit......but there just could be 3 Lipo pouches of high C rate instead ?
 
Hillhater said:
lipo fires ... :roll:
many reported, much discussion, not much conclusion,..
even all te best tech brains in the world could not solve the root cause of the Dreamliner fires !..
... but the finger is frequently pointed at the RC lipo pouches.
RC guys burn their batteries most often, because they run them hard into the ground, both physically and electrically
however, the last serious Ebike fire reported was actually on a 18650 pack with a BMS installed ! :eek:
Many of the fires are most likely attributed to operator error / poor pack design/ abuse? over charge /over discharge/ shorting/etc etc etc
only one that i can recall was apparently a unprovoked ignition of a new pack.
Many of us simply dont trust a BMS and prefer to rely on the " Human BMS" and check their packs before and after use for balance , temp, connections, swelling, etc.
Thats easy with RC lipo, ..... but hard to do on a fully sealed commercial pack.
..And , i would not keep any type of Li Ebike pack in my house !

everything is a compromise ! :(

EDIT:- Has anyone ever opened up one of these type battery boosters to see exactly what cells may be in there ?
I think we assume there is possibly 6 x 18650's being worked to the limit......but there just could be 3 Lipo pouches of high C rate instead ?
Click to expand...

At 3.5 Volts cut off, moderate acceleration, cool to the touch after each ride, it is my opinion that the Walmart boosters are not being worked hard.

You asked about the inside, a good question. When I remove the packs, I will open one up and take photos.

My Li Ebike is kept in my attached garage with some space around it and an attic above it.
 
I wish there were verifiable specs for these batteries. They seem wholly untrustworthy ("12,000 mAh", yeah right), but probably safe. And it seems like they have self-sufficient BMS. Both those things are worth money even if the batteries are not great performers.

I have a use for safe, BMS equipped batteries that can withstand brief 180A peaks without self-destructing. They'd serve as replacements for SLAs in an eGo scooter I've had mothballed with a bad battery. All the batteries I've found so far that will endure the peak load I need are either bigger and more expensive than I want, too risky to consider, or SLA. Boo.
 
Hey, it is working. 8)

But it does appear like at the rate he's discharging, which is VERY low, the capacity is nowhere near 12 ah to his stopping point. But I think he's got quite a bit more meat on the bone below 3.5v too.

My guess is there is 5 or 6 1c 18650 cells in there. Cheap ones like I have in my Alibaba pack. FWIW, that pack is putting out only 80% of rated capacity after 6 months use. New, it put out 90%.
 
dogman dan said:
My guess is there is 5 or 6 1c 18650 cells in there. Cheap ones like I have in my Alibaba pack.
Click to expand...

If that were the case, then the pack would be of no use whatsoever for starting a car. But I assume they're of at least marginal value in that role, because that's what they're for. That's the only reason I'm curious about how well they could replace SLA in a high peak current application.

For the eGo scooter application I have in mind, assuming Alan's assertion of 44Wh is correct, these starter batteries would cost approximately twice as much per Wh as SLA bricks. But they have their own chargers--which also needs replacing in the eGo-- and they would weigh a fraction as much. They might have better cycle life. In a 4P arrangement, they'd only have to be able to push bursts of 50A to be adequate for the job.
 
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