What is the difference between different 'Silverfish' batteries?

[BigDykeWithABigByke]

If I buy a bike that takes a silverfish and I want to get a second battery, what to I look out for to make sure it will be compatible? I would assume the main thing would be the voltage and the cell brand, anything else?

 

[BigDykeWithABigByke]

Which bike do you have?

None yet, just wanted to know as I want to get a second battery with what ever bike I get. Say for the sake of an example I want a Nakto Super Cruiser and I want to get another battery for it.

 

[harryS]

I doubt that any of the favored battery sellers on this forum sell Silverfish packs, so you probably won't hear about brand name cells, but if your seller offers them, great. The Silverfish design has been around for around 10 years, and is now only used on low end ebikes these days. You find then on ebay for around $200. They will be around for a long time. Lots of inexpensive ebikes still use them.

In fact, I just bought one last month from UPP on ebay. It was a 36V18AH, $265 shipped from a US warehouse. The original ebike was $700. I think UPP is a little bit above the junk $200 packs, but who knows.

Anyway, with regard to criteria, I compared outside dimensions and verified that the output terminals were the same polarity.

 

[BigDykeWithABigByke]

True, but to be fair, there still is a market for silverfish battery, such as Nakto, very entry level ebike.

I am not sure if Nakto (or similar) owners would expect state of the art battery.

Good to know that they aren't the top end anymore, should show how much I know. I just want to know that if I plug in the battery it won't blow up the bike in a literal or metaphorical sense you know?

 

[Explorer-1]

The original silver fish battery had a tail, the current generations do not. i think there may be some of the second versions (no tail) that are slightly taller than others with the same no tail design. The hight can affect weather they can be looked into the mount without adjusting the latch hole, because true silverfish have the on/off and locking integrated into one key system, if you can't lock the battery into the mount then you can't turn it on. They are ways to adjust things on many bike to get around this if there is just a height issue.

 

[harryS]

I bought a second silverfish because my old one failed after 27 months. When I took the old one apart, I found it to be better constructed than some of the other batteries I own. The cells were mounted in a plastic form, covered on all six sides with a stiff fiberboard, and shrink wrapped. No glue. No tape. The cells are then pushed into the metal tube that forms the case of a SIlverfish, and they're padded with rubber. Pretty solid for a $200 pack, and I doubt it cost that much to make..

One surprise was that the ON/OFF switch is a heavy duty unit that actually switches the power from the cells. Most packs I've taken apart use a low current switch to toggle an on/off circuit in the BMS. That means the BMS has been always turned on, and it draws some residual power.

 

[Explorer-1]

I bought a second silverfish because my old one failed after 27 months. When I took the old one apart, I found it to be better constructed than some of the other batteries I own. The cells were mounted in a plastic form, covered on all six sides with a stiff fiberboard, and shrink wrapped. No glue. No tape. The cells are then pushed into the metal tube that forms the case of a SIlverfish, and they're padded with rubber. Pretty solid for a $200 pack, and I doubt it cost that much to make..

One surprise was that the ON/OFF switch is a heavy duty unit that actually switches the power from the cells. Most packs I've taken apart use a low current switch to toggle an on/off circuit in the BMS. That means the BMS has been always turned on, and it draws some residual power.

Yup, I agree. I love how my silverfish switch out the batteries there is no parasitic drain, the batteries can be properly stored for years at the correct level. One or more of the major cell manufacturers had input into the design of the original Silverfish and they got all the certifications for transport.

Unfortunately since that good design, people have worked to just make cheaper and cheaper designs or more and more proprietary designs. All are s*it though when it comes to parasitic drain.

 

[Explorer-1]

Alternatively, you can just build your own ebike with Silverfish battery.

....

Although very hard to get original SF batteries.