Comparing 36v 12Ah SLA with 24v 8Ah Li-on

[skrivener]

My friend gets 55 minutes at 15mph with light pedal assist from his 8Ah 24v Li-on. A 6½ mile max range seems disappointing

I believe lead acid batteries are not directly comparable, but might I expect a 36v 12Ah lead acid model get me a bit further if I was only looking at distance when comparing.

Thanks

 

[torrent99]

My friend gets 55 minutes at 15mph with light pedal assist from his 8Ah 24v Li-on. A 6½ mile max range seems disappointing

I believe lead acid batteries are not directly comparable, but might I expect a 36v 12Ah lead acid model get me a bit further if I was only looking at distance when comparing.

Thanks

Just doing a bit of analysis on the battery energy content:

For the 24v 8AH Li-on (ROAAR! sorry 20 month old baby in the house)
That amounts to 24*8= 192WH of energy.
Your friend get 6.5 miles from that 192WH which is 29.5WH/mile (about right I get about 36 with no pedalling)

Your lead acid:
36V 12AH = 432 WH
And if your friend were to pedal it that would theoretically last:
432/29.5 = 14.6 Miles

Looks good doesn't it?

BUT.... unfortunately you can't get ALL the energy out of lead acid batteries...
flecc knows best but I'm seem to remember its only about half...i.e. 6AH

So 36*6 = 216WH ----> 7.32 Miles

So yes you would probably get a longer range from the lead acid.

But not by much. And to top that his LiIons will last more cycles before they need replacing and are much lighter to lug around....

 

[flecc]

Yes it is only about half the content that is usable from lead acid.
.

 

[rog_london]

Yes it is only about half the content that is usable from lead acid.
.

Also, if you're commuting, it's a VERY good idea to have a spare charger at work - so you can recharge at each end of the journey. That will make a huge difference to the eventual life of SLA batteries.

It may be beneficial on other battery technologies too, but nowhere near as much as it would be with SLAs.

Rog.

 

[skrivener]

Thanks Torrent, appreciate how valuable time gets with a 20 month baby in the background.

So might hope for roughly 12% extra distance with the 36v 12A Lead Acid over 24v 8A Li-on.

The extra weight would presumably loose a bit of that, but it's unlikely to be worst for the same distance.

Tempted, as the lead & steel is 60% of the alloy frame / li-on & it would make an interesting comparison between the 2 bikes.