Ideas for replacing lead acid with 18650 battery bank ?

ng.sa

10 µW
Joined
Apr 3, 2017
Messages
5
G'Day from downunder

I have been searching the web & this forum for any ideas about the best way to replace my lead acid battery with a 18650 battery bank.

I know that my 4x4 needs about 14.4V to crank it over.

I'm not certain of the amps ?

I have approx. 40 x 18650 old & new ones & I would like to have the dimensions of the battery bank to be less than current battery.

Length (maximum): 306mm, Width (maximum): 171mm, Height (excluding terminals): 201mm

Any suggestions of how to wire 2 x serial - 5 x parallel or combination etc. ?

TIA
 
you'll need 4S probably 3S won't cut it....

let's assume CCA (cold cranking amps)is somewhere around 650Amps for a 4wd (can check online but I am lazy) good cells can deliver peak 20amps, that's 33P... even if you assume they will deliver 30Amps each, that still 22P

you might be able to get away with less (like 10P) but you'll really be stretching the capability of the cell and will impact on it's lifespan

Thoughts?

Andy

P.S Where downunder are you? I'm Far North QLD downunder.
 
If I'm reading you right this is for weight reduction yes? What kind of motor is this? If it's a 4cyl you can probably make do with a couple LiFePO4 motorcycle batteries in parallel. I ran a single 3lb LiFePO4 battery in my Jetta 2.0T FSI for over a year before it kicked the bucket and that thing was WAY too small.

If not for weight reduction, just stick with lead acid for now.
 
G'Day Andy

Animalector said:
you'll need 4S probably 3S won't cut it....

Thanks for the heads up :)

Animalector said:
let's assume CCA (cold cranking amps)is somewhere around 650Amps for a 4wd (can check online but I am lazy) good cells can deliver peak 20amps, that's 33P... even if you assume they will deliver 30Amps each, that still 22P

Apparently a 'Rolux' is 850AMPs for cranking !!!

Animalector said:
you might be able to get away with less (like 10P) but you'll really be stretching the capability of the cell and will impact on it's lifespan

I got these 18650s as freecycle so I will try 20 for my WR450 dirt bike as a experiment & see how that goes, this is a real learning process as I want to eventually move up to a DIY PowerWall as the 240v feed in SA is sxxt ( very expensive & unreliable ) & I want to get some control.

Animalector said:
P.S Where downunder are you? I'm Far North QLD downunder.

I was born in rocky, but now live in SA
 
Thanks for the reply :)

marcexec said:
Second the use of LiFePo4 - ran Headway 38120P (1p4s) in a bike just fine.
Look for the newer 38120HP

Any idea what these 38120HP are worth, I cannot see from the web site the prices ???
 
ng.sa said:
Thanks for the reply :)

marcexec said:
Second the use of LiFePo4 - ran Headway 38120P (1p4s) in a bike just fine.
Look for the newer 38120HP

Any idea what these 38120HP are worth, I cannot see from the web site the prices ???

No idea where you are based, headway headquarters or eclipse bikes come to mind.
 
G'Day Marc

marcexec said:
No idea where you are based, headway headquarters or eclipse bikes come to mind.

I'm in Oz ( SA ) & I have been chasing up the sourcing of 18650s for a while & find all kinds of issue purchasing them.

I bought 20 even though the Ad. said 5000, from my research & what I had read they can never be more than 3400-3600, but when I weight them they were less than the other that easily out performed them.

So its a steep learning curve, my golden rule now is if the seller will not tell you the weight of each of them, dont buy them !!!
 
ng.sa said:
G'Day Marc

marcexec said:
No idea where you are based, headway headquarters or eclipse bikes come to mind.

I'm in Oz ( SA ) & I have been chasing up the sourcing of 18650s for a while & find all kinds of issue purchasing them.

I bought 20 even though the Ad. said 5000, from my research & what I had read they can never be more than 3400-3600, but when I weight them they were less than the other that easily out performed them.

So its a steep learning curve, my golden rule now is if the seller will not tell you the weight of each of them, dont buy them !!!

Just had a little check and couldn't find a good source for the cells for Australia - unless you want to order from Europe.
Maybe look at the A123 26650 instead, there are at least some on Aliexpress.
 
G'Day Cycleops

cycleops612 said:
I ran that (common one would think - why use anachronistic cells in car batteries?) query by a a tech i know, & he said "fine, but u need a new $800 dollar alternator", or some such.

not sure i trust the advice, but there it is.

I dont see a $800 alternator being used here -> https://www.youtube.com/watch?v=GUXM1XuLUIs

Yes I understand that boostpacks are not 18650s but as I said I'm asking for ideas for replacing with 18650s
 
Back
Top