Is Watt Wagons selling batteries ? Just found 1100wh pack listed on their site.

[onlineaddy]

@bogus regardless of delivery, your concern has resulted in @pushkar improving his battery offerings. Has your goal not been reached? If not, what else are you expecting from this exchange?

 

[J.R.]

I have battery packs the manufacture labels 12Ah. They are 11.6Ah. In the 1980's there were tariffs on motorcycles 700 cc and above. Japanese motorcycles dropped all there 750 cc bikes to 699cc, 698cc, etc... They called them 700 MC's. We need to give ebike manufactures a little break. I wouldn't have a problem if a pack of 950Wh to 999Wh were called a 1kWh pack. All of us can do the math.

 

[vincent]

Agree with JR

you act like WW is the only one doing this

 

[TomD]

@bogus regardless of delivery, your concern has resulted in @pushkar improving his battery offerings. Has your goal not been reached? If not, what else are you expecting from this exchange?

If you read the thread over on ES his orignal concern was that WW was diminishing the effort of others. So no, goal has not been reached.

 

[Bluzrif]

I don't mind holding Pushkar's feet to the fire..He's moving the needle and slaughtering some sacred cows.. And I think he's exhibited incredible responsiveness (so far) to the peanut gallery's suggestions and concerns. Conceptually Id like every start up CEO to handle R&D, marketing, sourcing, shipping as well as service and technology.. perfectly. All while simultaneously manning the website chat and social media. Oh and feeding his family!

I'll bet anyone committed to finding chinks in the king's armor ...will.

 

[J.R.]

I don't mind holding Pushkar's feet to the fire..He's moving the needle and slaughtering some sacred cows.. And I think he's exhibited incredible responsiveness (so far) to the peanut gallery's suggestions and concerns. Conceptually Id like every start up CEO to handle R&D, marketing, sourcing, shipping as well as service and technology.. perfectly. All while simultaneously manning the website chat and social media. Oh and feeding his family!

I'll bet anyone committed to finding chinks in the king's armor ...will.

You forgot cutting and baling the hay.

 

[byunbee]

You forgot cutting and baling the hay.

And that he has a day job.

 

[Mike_V]

Oh tell us more about yourself, Bogus Data Engineer , your work for 'companies' seems vital !

luckily i'm not the vendor. i'm not the seller as well. luckily. just an engineer in completely different area where ALL the real performance data just must be in line with rated values. Otherwise the losses are huge. The companies i'm working for, rather their lawyers, already had some 'issues' with such 'discrepancies' and it ended up with really big numbers.
why WW? Well because i wanted to buy a battery for my FB and that was my first choice. If it was i.e. Luna and i find shitty numbers then i would as Luna why those number. It is as simple as that. I know that forums nowadays are full of sellers, their backers, fake accounts, trolls and some number of real users who want to avoid to be fooled by the rest. The problem is you can not tell who is who so you need to use a common sense, the knowledge, be vigilant, not trust in everything you see, make your own calculations or use your sponsor calculations. Replace 'WW' with any other brand/company. I don't care. I do care what i buy with my money.
At the beginning he was not so keen to make any changes on the web site...

 

[TomD]

I think we could make this discussion more productive and propose a moratorium on flaming in favor of a collaborative and good faith effort discuss how vendors might best advertise capacity. For example, I talked to pushkar about this and it seems like there's no easy solution that will satisfy everyone. Depending on the cells a 52v 21ah pack has varying wh capacities but in real world use the actual ranges are pretty close but with different discharge characteristics (I may be paraphrasing wrong and missed some finer points). Even advertising a pack as 52v 21ah is technically incorrect (no better than 52v x 21ah => 1100wh), but I believe this is how the industry tends to advertise packs and it's probably the most useful for someone comparing battery capacity between vendors without technical knowledge. Let's focus on best practices as opposed to criticisms.

 

[Johnny]

It was probably just a typo. I also think bogus is blowing things out of proportion but even with the margin of error that configuration with 3mah cells are in the range of 900-950 and must not be advertised as 1100wh.

It seems he corrected the information so I think all is good.

 

[TomD]

The issue was some language referring to it as an 1100 watt hour pack. Note the thread title. Presumably you get that by multiplying 52 by 21 and rounding up to 1100. I think many of us naively do this when comparing watt hours on packs so I don't have any particular issue even if in technical terms It overstates things. I asked Pushkar why 52-volt 21 amp hour was more correct than saying 1100 watt hours and he said neither are technically correct but it's common practice to refer to packs this way but if there are best practices he would certainly welcome feedback.

 

[Johnny]

The issue was some language referring to it as an 1100 watt hour pack. Note the thread title. Presumably you get that by multiplying 52 by 21 and rounding up to 1100. I think many of us naively do this when comparing watt hours on packs so I don't have any particular issue even if in technical terms It overstates things. I asked Pushkar why 52-volt 21 amp hour was more correct than saying 1100 watt hours and he said neither are technically correct but it's common practice to refer to packs this way but if there are best practices he would certainly welcome feedback.

We agree. This is a minor wording problem.

Anyone who has experience with lithium based batteries know that you can not really give an exact capacity on these cells. Their voltage drops while draining and the higher rate of discharge the lower capacity one will observe. Yet Ebikes are low C applications and <=1C the capacity should be close to the rated one and imo close is within 10 percent of the rated capacity.

That being said, well known companies are also overrating their packs. Bosch's powerpack 400-500 batteries are in reality less than 400/500wh. Pushkar's offering even at 950wh is cheaper than Bosch's 500wh offering hence a great value.

@pushkar You are doing a great job and you know that I support your efforts. You did a great job by bringing that controller and informing people on how it improves the ride. I also understand that dealing with these kinds of comments can be really annoying so instead I was just trying to shift the focus on the minor and easily fixable detail.

Keep up the good work.

 

[CdnShaun]

I just did a search for massive battery packs and weirdly this came up. https://wattwagons.com/products/titan

Does Watt Wagons sell a big battery too ? I cant seem to be able to navigate to the product from the site - just have a direct link from the search engine.

I have a large triangle and have the jumbo shark pack. This will fit right in. Looks like Titan will be a swap-out without any additional wiring.

Oh, and this comes with the charger included in the price. Incredible. I am ordering one if this is real.

Hey there pennybags,

Just curious - did you end up figuring out a large battery solution for your needs? If yes, what model did you go with?

Cheers
Shaun

 

[pennybags]

I initially bought the Luna direwolf but the fit was too tight (it is a random trapeozoidal shape). I still have it and use it on other bikes. The Luna is panasonic or MJ-1 cells- so it is not a high C rated battery IMO.

After talking to @pushkar I got the Titan with the HG2. I am happy with the pak so far - I get lesser battery sag since the cells are better rated than MJ1. Pushka showed me a way to charge it at (10A) so I am now building a custom charger. I understand that 10A will kill the battery cycle life, but honestly, batteries are not that expensive (well not for me), and if I get 200-300 cycles by using it the way I like, I am happy with it.

Luná and Watt Wagons are the only vendors I would go with for good, genuine batteries locally. I have the UPP packs in the past - they are reasonable too ... but too much of a hassle with new shipping restrictions and they dont always use 30Q /HG2.

My ideal battery is new LJ2 18650 cell that alibaba vendor is sourcing for me - that is the new HG2 replacement looks like.

 

[Explorer-1]

Battery Rating is not as hopeless or as imprecise as many are saying here. First you just have to use numbers that mean something, can be measured, and are repeatable. That means you can't just just 1 number as there are no standard tests to achieve that number, or the test that is being used as the basis for the reported number does not aligned with the test. If you dig into the technical data on manufacturing ratings you will find their test specifications and they will, for the most part, be repeatable. That does not mean you can extrapolate those results to your test (ie. operating conditions).

To get a meaningful Wh rating all one has to do is start at what power does the rating apply, and the cut off voltage. So if one says the rating is 1100Wh, that is not much good. However; if they say the rating is 900Wh with a constant 300W load on our Bike X. That tells you a lot. If they are just selling the battery and they say the Battery is good for 950Wh at a constant 200W load to N.d Volts, then that is more useful in some cases, and less in others as you need to know the cut off voltage of the controller, or maybe the controller or the battery does not enforce a cutoff at N.d V, so after that you don'y know what the battery will deliver.

Now of course the above is a big simplification, because it does not necessarily allow you to figure out what the Wh rating will be if you need something closer to 500W continuous, Is this then back to the same problem... no. The answer is graphs. If the manufacture publishes a Discharge graph with discharge at typical Power ranges, and one graph with several plots between low and Max discharge current, then those two graphs can tell you most of what you need to know. Manufacturers have those graphs for cells, but a professional battery builder will also have them for the battery which includes any management circuitry.

If you want to go further, then you have the more difficult problem of life-span under said conditions.

It may not tell you the range, since those are environment dependent, but it gives you the capacity of the battery interns of power. You can determine the power required for you and your environment, once you know this, you are set to evaluate any batter with properly supplied specification graphs.

Summary
The answers the same as it has been since batteries were invented, discharge graphs based on current, and discharge graphs based on Power. From these graphs you can derive any voltage information that may be needed to meet your requirements (such as speed).