What Are The Pros & Cons Of These 2 Battery Systems?

Hi all,

I have a quad with electric assist from a company called ZZ Merck on order. I've been waiting for a long time for this quad to be shipped. It's been delayed for months now, and hopefully it'll finally ship soon.

It should be this quad: https://www.zzmerck.com/products/recumbenttrike/TrikExplor/4WDSportUtilityQuad.html

However, it seems ZZ Merck has changed the battery system for that quad, and the above listing shows it has a 48v 14.5Ah lithium battery with Panasonic cells.

The batteries we came to a decision on for my quad, and that are listed on my Invoice, should be the batteries this other quad comes with: https://www.zzmerck.com/products/recumbenttrike/2017-10-12/400.html

Those are the 2 batteries with reflectors attached under the rear rack, which you can see in the last photo. They are 48v 20Ah lithium batteries, so the total should be 40 amp hours in that setup. I'm assuming they aren't made by Panasonic, although I don't know what company makes them.

What are the pros and cons of each of these battery setups?
Obviously 14.5 Ah is a lot less than 40 Ah, but the smaller battery has Panasonic cells, which I understand are very good.

I'm wondering if I should go with the 40 Ah battery setup I originally signed up for, and that we agreed to, or if I should ask ZZ Merck for 2-3 of the smaller Panasonic batteries, and swap them out as needed, since the design for my quad seems to have changed.

I also need to clarify the difference in the rear racks, other than that the second one holds the 2 batteries underneath it. The rear rack on the skinny tire quad seems like it may be lighter (and it doesn't show a bag, which is also in my Invoice), but I'm not sure of the differences just going by the photos.

What are your thoughts?

Thanks.

Can't really advise as there is no real detail, but generally speaking...
You are generally better off with a (or2) larger battery than two smaller ones. For a given amp draw, you are stressing a smaller battery more, and if you have a deep discharge before you swap them this is also taxing on the smaller battery.
But we don't know the cell type in the larger option. They could be OK or junk-i guess junk is unlikely in a product of this caliber (id hope so)
There can be some minor benefits-weight on short trips etc. But I reckon this vehicle will chew a bit of juice.
Do you have a choice? given they are completely different battery cases, also location and mount are different.
Does this help? Not even sure if I've got the question right :?

You make it sound like you have no idea what you'll use the quad for, or how much energy a given task will take. The second one is forgiven but what is not, and needs to be corrected at once BY YOU is to say what you want the quad to do (how far, how fast, how much cargo, what terrain, etc).

Like the other guy said one big battery is better than several small ones. Why would you want to swap out and manage several batteries, inconveniencing yourself for no gain, when it's completely unnecessary?

Bigger is almost always better.

Ask them what cell's in the 20ah though, you need to know.

500w is pretty weak for a motor. I'm sure it would be nice and easy on the 20ah battery, even if it contained the junkiest of cells. A pair of 20ah batteries would run forever and a half on a recumbent with a 500w motor.

The motor also seems to be a mystery motor. Not a good sign. Maybe buy the thing unelectrified and build it yourself or ask if they can clarify what the heck is on there.

Another bike they sell uses a dapu motor, and i'm not sure if that company is exactly known for quality. ( lotta shitty motors of that size out there )

I'm thinking about going with the 40 amp hour setup, and that's what we agreed to. I'll ask about the specific cell type.

I'm wondering how much heavier the 2 batteries and that rack are, compared to the 14.5 amp hour Panasonic battery and other rack, so I'll ask about the weight difference as well.

I know the motor is a 500 watt Bafang unit with a cadence-sensing pedal assist and throttle. I wanted a 750 watt motor, but the rep said it would be expensive for them to order just that one part, whereas they order 500 watt Bafang motors in batches, if I remember correctly.

I suppose if I really want to upgrade to a 750 watt motor in the future, I'll just have to do that myself, but hopefully the 500 watt motor will suffice. I know a customer who has their big fat tire quad: https://www.zzmerck.com/products/recumbenttrike/4wdoffroadrecumbentq/recumbentquad.html who said this, "500W seems very powerful", although that quad only uses a throttle for its electric assist system, and doesn't also do cadence-sensing pedal assist. The big fat tire quad also doesn't use a Bafang motor, and has some custom motor from another company, if I remember correctly.

Good canned cells are under 14 lbs / nominal kwh. So even with packaging you're at 3x lbs for a ~2kwh nominal battery. That's less than a single lead acid car battery.

Also, I finally looked at the link for the quad itself and that thing is ridiculously expensive with underwhelming specs to say the least. So the more pressing question is why anyone would pay over 7k for a thing like this with a really really lame 500w motor? For the money you can do better. It doesn't really make sense unless you're rich, and if that's the case the forum will suggest a much better quad. You can disregard that at your own peril if you're rich but old and infirm and prefer to go slow.

FWIW, paralleling two small batteries is easy, and give you the same result as one big one. Lower sag, longer range, less stress on each cell.

The only hassle is unplugging to charge them separate, which aint much hassle, and being sure both are actually charged full before reconnecting to ride.

I finally got a response from the Sales Manager at ZZ Merck. Here's what he said about the specific battery type in my quad, which apparently has just finished being built. I'm supposed to get photos today of the build, and he mentioned we'd discuss shipment next week.

He said, "The battery on your quad is 2x 48v 20ah with our domestic brand 18650 cells. Each cell is 3.7v 2.6ah.", so it seems like a Chinese battery Make & Model, which I'm assuming isn't as good as the Panasonic battery, but on the other hand has much higher capacity since two 20 Amp Hour batteries will give me 40 Amp Hours total versus 14.5 Amp Hours for the one Panasonic battery.

Any thoughts?