Costco Jumper Batteries? Crazy?

[akrenits]

Hello, ES

http://www.costco.com/.product.100230151.html?cm_sp=RichRelevance-_-itempageVerticalRight-_-CategorySiloedViewCP&cm_vc=itempageVerticalRight|CategorySiloedViewCP

Is it insane to hook 6 of these up to make an 8Ah, 72v battery? The continuous amps certainly seem capable and its the cheapest form of battery I've found so far. How would I go about that?


Also,coes linking batteries in parallel double their continuous amperage output AND their AH?
For example can I link two of these and expect them to create a 12 AH battery that can pull 40 amps, 2kw no problem? http://lunacycle.com/batteries/packs/52v/52v-mighty-mini-cube-ebike-battery-pack-panasonic-pf-6ah-affordable/

If I do this, do I then need to be concerned about balancing between the two packs?

If you have an equally priced/cheaper/simpler option for a ready-made pack that can support 40 amp continuous draw with as high a voltage as possible, please link it

 

[jimw1960]

In short, yes, you can do that. Parallel would give you twice the AH and discharge current. You'd probably want to put some diodes on the positive power output wires to prevent one pack discharging into the other when they are not at the exact same charge. You'd also want to separate them for charging. Maybe build a small junction box to hold the diodes, fuses, and paralleling connections that you can quickly unplug the batteries from when charging.

 

[Jon NCal]

If you need high power, low cost, why not use lipo?

 

[akrenits]

I honestly can't find a good cheap source for them. Ideally I'm looking for 10Ah at 72v, 30-40 amp continuous draw. I am also on my first build so I am hesitant to wire my own packs up. I am willing to learn, but if anyone has any ready-made solutions for around $500, let me know.

 

[spinningmagnets]

Before you jump in with both feet, I would recommend buying one unit and opening the case to see what cells are being used. This might actually be a great product, at a low introductory price, so "get it while the price is good". On the other hand, the performance specs may be wildly overstated, and you might end up deeply disappointed by the purchase.

So..."take one for the team" and buy one unit immediately, crack it open (voiding the warranty) and post pics of the carnage.

 

[akrenits]

So..."take one for the team" and buy one unit immediately, crack it open (voiding the warranty) and post pics of the carnage.

I definitely will, but before I even spend that $60, could you explain the logistics of what I would be getting myself into? how intensive is the build process for a battery like what I'm looking for? what extra costs would the project incur? Is there any other solution for my needs that you could recommend?

I''m all for contributing to the wealth of knowledge here, but I have a very tight budget for my first build and cant afford any mistakes

 

[Chalo]

Those are not 8Ah batteries. It's customary (deceptive) practice for the manufacturers of such batteries to add up the capacity ratings of the cells as if they were in parallel, when in fact they're in series. They also call them "12V" batteries when in fact they're 3S, so nominally 11.1V by more conventional designation.

Thus, what you see there is most likely an 11V, 2.7 Ah pack. If so, it's not a bargain in terms of Wh/$.

There are a few threads lately about starter batteries from Walmart. User Boyntonstu reports what he considers satisfactory performance from his setup using them. User Alan B posted test data in the link above.

 

[Jon NCal]

In the $500 range, and 40A, I would get the 52V 12.5Ah Samsung 25R triangle battery from lunacycle.com, 8.2lbs, 50A continuous and ships from California (vs. China, which can be harder to get customer service).