Could this be a lead-acid battery?

[rogermunns]

I have acquired a second-hand bike with a dead battery. Apparently 7 - 8 years old. I have bought a new Li Ion battery which is very similar in appearance to the old one. The question is because the new one weighs 2.7kg while the old one weighs 4.9kg. This seems a very big difference ..... any thoughts?

 

[KirstinS]

Lithium has changed a lot in 8 years. You can get far greater capacity in a single cell these days compared to back then

So you need fewer of them to make the same Ah and voltage battery.

 

[vfr400]

It's impossible to say without more details.

 

[rogermunns]

vfr400 - what sort of details?

 

[sjpt]

Pictures of the two, especially any labels they have which may give more info about what's inside them.
Or if pictures are awkward, what any labels say.

 

[KirstinS]

It's impossible to say without more details.

Yeah for 100% I guess you're right but I cant see how a 36v lead acid could ever get down to 4.9kg (each 12v pack being c3kg)

I'll eat my hat if this isnt a matter of improved lithium tech or a reduction in Ah or both. So not lead acid vs lithium

*leaves quickly to purchase a chocolate hat*

 

[Nealh]

Show us pics of the old one and it's charger it may be a Lithium phosphate aka lifepo4 celled battery, hence the weight difference.

 

[KirstinS]

Pictures of the two, especially any labels they have which may give more info about what's inside them.
Or if pictures are awkward, what any labels say.

Or indeed the bike you have

 

[KirstinS]

Show us pics of the old one it may be a Lithium phosphate celled battery, hence the weight difference.

Ahh good point

 

[vfr400]

What's the output voltage of the charger - written on the label?
Which bike is the battery used on?
How much capacity did the original have?

Another possibility is NiCad or NiMH for the original, but without details, all we can do is guess. Time to kick yourself Kirstin. I'll want to see the vid of the hat being eaten! If it's a chocolate one, I want half.

 

[flecc]

At 4.9 kilos possibly an NiMh battery as VFR says. For example when Ezee bikes were offering an overlap choice of NiMh and Li-ion for a while, in the identical battery case, they weighed 4.2 and 2.5 kilos respectively.

I'm sure only Heinzmann used NiCad more recently than the last 15 years, so that's less likely
.

 

[KirstinS]

Time to kick yourself Kirstin. I'll want to see the vid of the hat being eaten! If it's a chocolate one, I want half.

Maybe ! But not until OP comes back to us

*leaves to bribe OP via DM *

Ps I'm banking on old school prismatic cells vs newer tech. Based on zero info

 

[Nealh]

I think Alan has posted on the wrong thread unless he has decided he no longer wants to be rogermunns .

 

[flecc]

Ps I'm banking on old school prismatic cells vs newer tech. Based on zero info

Could be. This 36 volt Li-ion from a bit over a decade ago weighed over 4 kilos:

 

[KirstinS]

vfr400 - what sort of details?

The suspense is killing me Roger , please put me out of my misery !

 

[KirstinS]

Could be. This 36 volt Li-ion from a bit over a decade ago weighed over 4 kilos:

View attachment 32484

Yes I had one similar and had that in mind

 

[rogermunns]

Hello again all. Mystery solved with the pic by flecc a couple of posts ago. I have only just seen this, pardon me.
Last night I slit the aluminium (english spelling) with a dremel. It had been totally impossible to push out the contents (after unscrewing the ends). As I slit along the 39cm length of ali sleeve I found out why the internals were fixed so tight. Because as I cut, the ali split along, such was the force being exerted by the metal insides.
Now for the pics. Sorry they are big, I couldn't find how to reduce their size.
First; the split-apart case plus the internals (one cell had been snipped off for separate photo)
Second; one of the 10 cells with a DVD to show scale
Three, four, six; the bike SWIFT Zoom 4
Five; the charger.

Again, sorry for delay, us 74y.o.s are very busy!

 

[rogermunns]

It might be thought 'of course, they are Li-Ion 'because the charger' says so. But the widow of the guy who had the bike told me she wasn't at all sure that the charger belonged to THAT bike, because he had others and it might have been for one of them . The bike I have was in a garage even more messy than mine, with many electronic bits all over the place.

 

[vfr400]

They're Philyon lithium cells, the same as was were in the early Ezee batteries and many more similar ones. It's a standard silver fish case, so your modern one will be OK. Just check that the terminals are the right way round. it's best to check at the controller connector before connecting that the red is the plus in case there's any cross-over anywhere else.

Looks like Kirstin doesn't have to eat his hat after all. Blast!

 

[rogermunns]

Thank you. I suppose the Philyons are beyond recall? Maybe 6 years since they were last used. Out of the single one is coming 0.3volts.