Walmart Booster Batteries

DAND214 said:
12s4p 44v 16AH 2 miles at 25 less than 1v. 38 miles with 15AH used average speed of 18mph with a fair amount of stop and goes.

CA says if I keep my wh/m around 20 I get 2+ miles per AH or better, crank it up over 30 and it all most cuts it in half


Dan
Click to expand...

Your 16Ah battery is probably 4 x the capacity of the Walmart (realistic) 4 Ah capacity (spec 12). My test run at over 27 lowered my battery 4V vs your 1v. The numbers seem to be in order.

Conclusion: I bought four 4Ah LiPo batteries in a rugged cases, with built in balancers, ac and dc chargers and built in LED lights. All for under $150 and guaranteed for 2 years. I intend to get $138 refunded because they lied on their specs. If available in 2 years, I will buy another set.... $12 for so much fun!

I am completely satisfied because they fit my cycling, exercise, and speed thrill needs.
 
Why 4 sep threads op- whyyyy?
Pretty cool, glad they are working. What kit did you have? I was thinking if they are reliable for safety (bms/charging) and can supply 20a for a basic kit, might be good for a barebone entry level newb build (vs cheaper bare lipo and no potential premeditated 'warranty' claims).

Walmart has some weird battery policies- the 5 yr/ 3yr full replacement on automotive lead is very interesting although I'm thinking the warranty you bought is a little diff.
 
Boyntonstu said:
DAND214 said:
12s4p 44v 16AH 2 miles at 25 less than 1v. 38 miles with 15AH used average speed of 18mph with a fair amount of stop and goes.

CA says if I keep my wh/m around 20 I get 2+ miles per AH or better, crank it up over 30 and it all most cuts it in half


Dan
Click to expand...

Your 16Ah battery is probably 4 x the capacity of the Walmart (realistic) 4 Ah capacity (spec 12). My test run at over 27 lowered my battery 4V vs your 1v. The numbers seem to be in order.

Conclusion: I bought four 4Ah LiPo batteries in a rugged cases, with built in balancers, ac and dc chargers and built in LED lights. All for under $150 and guaranteed for 2 years. I intend to get $138 refunded because they lied on their specs. If available in 2 years, I will buy another set.... $12 for so much fun!

I am completely satisfied because they fit my cycling, exercise, and speed thrill needs.
Click to expand...
That sounds great if that works for you. I just can't see how I would feel comfortable with only 4ah battery.

I will follow this thread to see how it works out for you.

Dan
 
DAND214 said:
Boyntonstu said:
DAND214 said:
12s4p 44v 16AH 2 miles at 25 less than 1v. 38 miles with 15AH used average speed of 18mph with a fair amount of stop and goes.

CA says if I keep my wh/m around 20 I get 2+ miles per AH or better, crank it up over 30 and it all most cuts it in half


Dan
Click to expand...

Your 16Ah battery is probably 4 x the capacity of the Walmart (realistic) 4 Ah capacity (spec 12). My test run at over 27 lowered my battery 4V vs your 1v. The numbers seem to be in order.

Conclusion: I bought four 4Ah LiPo batteries in a rugged cases, with built in balancers, ac and dc chargers and built in LED lights. All for under $150 and guaranteed for 2 years. I intend to get $138 refunded because they lied on their specs. If available in 2 years, I will buy another set.... $12 for so much fun!

I am completely satisfied because they fit my cycling, exercise, and speed thrill needs.
Click to expand...
That sounds great if that works for you. I just can't see how I would feel comfortable with only 4ah battery.

I will follow this thread to see how it works out for you.

Dan
Click to expand...

As per your advice, I ordered a Watt-hr meter I will keep you posted.

Analogy: If you want efficiency, why carry the weight of 18 gallons of gas in your tank if you drive 4 miles or less to work and the gas tank will be automatically refilled to 4 gallons as you work?

How much did your battery cost?
 
batteries were like 250, charger was 100 so about 350.
Now warranty but don't ever to expect to get one.

I never know how far I will go so I always keep extra onboard. I can carry almost 50ah if needed. Makes it heavy but can ride as far as my body can take.

Hope these work out, others will follow if they do. Or maybe have already.

dan
 
DAND214 said:
batteries were like 250, charger was 100 so about 350.
Now warranty but don't ever to expect to get one.

I never know how far I will go so I always keep extra onboard. I can carry almost 50ah if needed. Makes it heavy but can ride as far as my body can take.

Hope these work out, others will follow if they do. Or maybe have already.

dan
Click to expand...

For comparison:

Bike is a Mongoose Mountain $89 at Target
1,000W rear wheel kit was $189.99 on Ebay
Batteries, chargers, balancer $150
Total under $450 ($138 refundable)

I am 77 and I weigh 184. Without motor, I can pedal 12.
You?
 
Mongoose $80 at a swap meet 6 years ago and the bike 1995 vintage. They were much better than what you get now. I spent more for the motor setup. Mac 8t with 12 fet controller bike about 80 I'm 165 and I'm 65 be 66 in a week. I pedal all the time riding to help range and my health. It's all for fun and something to do.

Dan
 
Boyntonstu said:
Analogy: If you want efficiency, why carry the weight of 18 gallons of gas in your tank if you drive 4 miles or less to work and the gas tank will be automatically refilled to 4 gallons as you work?
Click to expand...

Because gas tanks don't work the same way as batteries. Did you check to see how hot those batteries got from that run?

Make sure to check the voltage sag under load as soon as you get your meter. It will be interesting to see how quickly their capacity diminishes at the load you are presenting. Running them at close to 30mph is going to be more like 20amps+ you are drawing at that voltage. As I have said before in one of your other threads just because they output the power once it does not mean they can do it 100, 50 or even 20 more times before you fry a cell. Please keep us posted with your experiment and good luck. I hope I am still riding an ebike at 77 years old!!!!
 
ecycler said:
Boyntonstu said:
Analogy: If you want efficiency, why carry the weight of 18 gallons of gas in your tank if you drive 4 miles or less to work and the gas tank will be automatically refilled to 4 gallons as you work?
Click to expand...

Because gas tanks don't work the same way as batteries. Did you check to see how hot those batteries got from that run?

Make sure to check the voltage sag under load as soon as you get your meter. It will be interesting to see how quickly their capacity diminishes at the load you are presenting. Running them at close to 30mph is going to be more like 20amps+ you are drawing at that voltage. As I have said before in one of your other threads just because they output the power once it does not mean they can do it 100, 50 or even 20 more times before you fry a cell. Please keep us posted with your experiment and good luck. I hope I am still riding an ebike at 77 years old!!!!
Click to expand...


The batteries were cool to the touch after the 2 mile high speed run. Ditto the controller.

The kit wires are pretty thin gauge and I wonder if they are limiting the current?

At any event, riding at 29.5MPH with the wind in my face is pretty impressive.

I will keep track of the number of recharge cycles.

My other bike uses reclaimed laptop 18650 cells and it has had many recharge cycles.

I am working on a new packaging idea for 18650's. No solder, no weld.

If/when the Walmart batteries fail, I may build a 10Ah 48V 18650 package.
 
Awesome thread. I am thinking of a hybrid gas/electric that would run in town and at low speeds on 24v and commute distance and speed on gas while charging. This looks like just the package, light and simple, just enough power for around town with minimal weight. I can actually use the car chargers to charge each battery off 12v. Keep me informed on how they stand up.

Steve
 
If those cells in your jumper packs fail, just replace them with very good cells. The bms and charger should still be fine. The idea is not bad, we just question how good a cell you got in those boxes. Same thing with top quality cells inside would kick ass.
 
dogman dan said:
If those cells in your jumper packs fail, just replace them with very good cells. The bms and charger should still be fine. The idea is not bad, we just question how good a cell you got in those boxes. Same thing with top quality cells inside would kick ass.
Click to expand...


Thanks.

My challenge is to frame mount them over the front wheel.

I replaced NiCad cells in my portable drills with 18650's. Speaking of kicking ass!

If the cells fail, I will do as you suggest.

I am a happy camper.
 
Today I conducted a battery drain test. I went 8 miles without PA at 20 mph at which point the battery went into the Red zone.

The tank was empty.

The battery went from 51.1 to 41.3 Volts.

I do not know how far it will go with PA at 20.

Fast enough for me.
 
Glad to hear this experiment is working out for you. Sounds like that battery may be a hair more than the expected 3-4ah. Will be interesting to see how many cycles you get out of it. Did it get hot at all? What kind of voltage sag were you seeing at heavy load? Can you split one of the cases so we can see what kind of cells are in there?
 
ecycler said:
Glad to hear this experiment is working out for you. Sounds like that battery may be a hair more than the expected 3-4ah. Will be interesting to see how many cycles you get out of it. Did it get hot at all? What kind of voltage sag were you seeing at heavy load? Can you split one of the cases so we can see what kind of cells are in there?
Click to expand...

No heat. It was about 68* today in Florida.

I will dismount the batteries and look inside when I build my over the front wheel frame mount.

If Ebay will replace the DOA Watt meter, I will be able to see the Volts.
 
With moderate pedaling, you should be getting between 1.5 and 2 miles per ah. Pedaling should be about 20% better, or around 10 miles.

Looking a lot like they actually deliver about 4 ah to me.

20 mph without pedaling tends to take 400-500watts on flat ground with little wind.

Though not cold at 68 degrees, you should see a bit of improvement come summer, once it's closer to 90F. The battery will perk up.
 
dogman dan said:
With moderate pedaling, you should be getting between 1.5 and 2 miles per ah. Pedaling should be about 20% better, or around 10 miles.

Looking a lot like they actually deliver about 4 ah to me.

20 mph without pedaling tends to take 400-500watts on flat ground with little wind.

Though not cold at 68 degrees, you should see a bit of improvement come summer, once it's closer to 90F. The battery will perk up.
Click to expand...

I see advertisements for electric bikes that cost thousands of dollars and they don't tempt me to shell out multiples of my $450 project,

I note that none of the specs list the maximum speed. Mine goes 30. However, it may be a legal issue because 20 mph is max.

Here are a few interesting comparisons: https://www.electricbike.com/watt-hours/

The Faraday Porteur inspired me to design the front wheel frame rack battery holder. (Not quite there yet.)

Their battery replacement costs are quite revealing. For another $150 (Money back after 2 years) I would double my Ah and go all the way up to 8Ah. :roll:

8 Ah would make a 20/20 bike, 20 mph for 20 miles.
 
Love to see a photo of inside the case. 4AH total makes sense, they claim 12AH because they added the capacity of all the cells together, but since they are wired three in series the amp hour capacity is cut by that factor, 12/3 is 4AH.

To get the engine starting current from a pack that might be 3S2P would require fairly high C rate cells. Of course 6 cells is far short of what most ebikes come with. The ebike pack I recently ordered has 112 high quality cells. So it is under $5/cell. This Walmart pack is $40 for 6 cells, or $7.50 per cell. Not all that inexpensive. It is just a very small pack. Most ebike riders are not content with such limited range. With four packs there are 24 cells which gives 8 miles range, and it adds a lot of plastic weight and volume to the bike, and it won't fit easily in favorite places like the triangle.
 
"$40 for 6 cells, or $7.50 per cell. Not all that inexpensive."


Max. 12,000 mAh lithium battery
Emergency jump starter - 11.1V starter, 400 amp peak current

If you include the BMS, the ac and the dc charger, the USB charging port, the LED on/flashing light, charge indicator, and the 2 year money back warranty plan, is it expensive?
 
The Luna pack includes a balancing BMS and voltage readout at the under $5/cell pricing. Cheap chargers and USB regulators are not very costly, and having to deal with four chargers is not a savings. 112 cells at a price differential of 2.50 per cell gives $280 to spend on such things just to reach the same total cost. Additionally the 112 cells are higher capacity (and known quality brand name units) than the Walmart cells, giving even greater range and reducing weight.

The value of a 2 year warranty is harder to monetize. A good pack won't need any warranty in a 2 year period, so no value. An unreliable pack will be replaced but will fail again, so not much value there. So at worst it has zero value, and at best it would replace a 1.9 year old pack with another 1.9 year life pack which would give it the same value as a no warranty pack that lasted less than four years. I can't assign a lot of value to that as most quality packs will last more than 4 years (at some reduction in capacity). What do you want, quality or warranty?

Also you have to add the costs of fiddling with the mounting, the bike packs have that all worked out, often including convenient key locks and bottle or rack mounts. The pack I mentioned includes a triangle pack to put it in in that cost.

Another way to look at it is watt-hours per dollar. The Walmart pack is 11.2V * 4AH = 44.8 watt hours for $40 which is just over $1 per watt hour. The Luna pack is 52V * 20AH for 1100 watt hours for $540 which is just under 50 cents per watt hour. So the Walmart pack is twice the cost per unit energy as the Luna pack. Smaller packs to tend to cost more per unit energy, buying a larger pack gets you longer range and it also gets longer life since the reduction in capacity still allows useful range if there is extra to start with. 8 miles is very short range, and as the pack ages it will be 7, then 6 miles. On a very cold day it might only be 5 miles due to thermal characteristics of batteries. Additionally, drawing the battery deeply will negatively impact its life as well. A larger pack drawn halfway will last far longer than a small pack fully drained each usage cycle.

The Walmart starter pack is a good value for a car starter or for temporary 12V or USB power (I might get one for that use), but they are not really all that cost effective (or size or weight effective) for a good ebike pack at $160 (for 44V 4AH) not including a mounting system, and you have to provide series wiring as well.

Enjoy your ebike, I'm glad it is working for you. DIY allows us to configure our systems as we wish. I particularly like being able to buy bits separately and spread out the costs, on the hardware installment plan. Shelling out $2000 to $6000 at once for a factory bike would be much harder to do.
 
112 cells at a price differential of 2.50 per cell gives $280 to spend on such things just to reach the same total cost.

My bike was 99 at Traget
Rear hub motor 190 Ebay
4 batteries 150 Wamart

Total build cost was under $450 for everything.

You paid about $100 more for just the battery pack.

Since I never go more than 8 miles (I am 77), and I always pedal for exercise, the range is suitable for my needs.

If I had to go 20 miles, I think that with PA, I could do it at about 12 MPH.

I have pedalled 6 miles with the motor turned off.

Drawing the battery deeply? In my drain test they went down to 3.44 V per cell.

Is 3.44 V too far down for battery longevity?

I usually drain them to 3.92 V and that should be fine.
 
Discharging the batteries is not just about what voltage you take them to - it is also about how fast you discharge them. This is a factor of the current and capacity called the C-rating. If your battery has a capacity of 1amp and it is rated to discharge continuously at 5amps or 10amps peak, then it's relative ratings are 5c and 10c. This is one of the reasons why on your first build you did not hit your calculated top speed, because your recycled batteries could not output the power your motor/ESC were demanding to draw. It is also why I keep asking if the batteries are getting hot and why I keep indicating that you may burn up a cell sooner than later or lose capacity very quickly.

You can't always believe the ratings. You can buy expensive batteries on the market rated at 20c and soon learn that they are really only good for 2-3c and that running them at anything above that will show that they not only output way less than their rated capacity, but will permanently diminish and/or destroy the cells. That is why a lot of us go to great lengths to learn about and obtain and build the batteries we run.
 
ecycler said:
Discharging the batteries is not just about what voltage you take them to - it is also about how fast you discharge them. This is a factor of the current and capacity called the C-rating. If your battery has a capacity of 1amp and it is rated to discharge continuously at 5amps or 10amps peak, then it's relative ratings are 5c and 10c. This is one of the reasons why on your first build you did not hit your calculated top speed, because your recycled batteries could not output the power your motor/ESC were demanding to draw. It is also why I keep asking if the batteries are getting hot and why I keep indicating that you may burn up a cell sooner than later or lose capacity very quickly.

You can't always believe the ratings. You can buy expensive batteries on the market rated at 20c and soon learn that they are really only good for 2-3c and that running them at anything above that will show that they not only output way less than their rated capacity, but will permanently diminish and/or destroy the cells. That is why a lot of us go to great lengths to learn about and obtain and build the batteries we run.
Click to expand...

Thanks, good information.

My Walmart batteries did get me to 30 MPH for 2 miles and they discharged to 3.925 V. That ride was wicked!

Estimating that my bike needs 250 Watts to go 20, at 50 Volts it would draw 5 A.

My 4Ah pack is discharging at 1.25C. Correct?
 
Boyntonstu said:
Estimating that my bike needs 250 Watts to go 20, at 50 Volts it would draw 5 A.
Click to expand...

My estimate of your speed using conservative assumptions about weights, bike style, motor efficiency, and rider size suggests that you'd be doing well to make 15mph from 250W electric power.
 
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