Lithium Car Motor Start Batteries.

[BiGH]

Hi everyone,
I did a bit of a search and couldn't find any information on this so I thought i'd ask the question. A few places for example; http://lithbattoz.com.au/index.php?page=battey-packs and http://www.yesa.com.hk/ offer motor start batteries to replace your old lead acid batteries. What does everyone think of these? on the lithbattoz site they make some statements that you can get better fuel econ etc with lithium etc?

opinions?

i open the floor and go to sleep

 

[HAL9000v2.0]

I did something similar few weeks ago. Still working in my Car...

 

[liveforphysics]

Fantastic work Hal! Such a nice neat job! I just strung 4 headways together in a string and called it a day. You did a heck of a nice neat job!

 

[HAL9000v2.0]

We have dicussion over here what type of BMS is best for car battery. My opinion is that only balancing is what It realy needs. everithing else is in the car. overvoltage protection is in alternator, undervoltage is in Ecu and if you go with enough C you can not kill it with to high charging amp...
I am looking for good 4S balancing shematic...

 

[heathyoung]

Its spelled 'peak' BTW - but cute design...

 

[bigmoose]

I am also interested in suitable balancing solutions downstream of a 60 to 90 amp output alternator.

 

[spinningmagnets]

I think its good to have smaller and lighter car batteries. If these become more commonplace, mass-production might turn them into an affordable source for breaking down into E-bike/E-scoot batteries...

I hope this isn't too much of a thread drift, I read a few years ago about how in Russia and Canada, the winters were so brutally cold that engine starter batteries often are replaced-by/or paralleled-with a very large capacitor. I wondered how the capacitor output was throttled instead of suddenly dumped into the starter motor. Anyone with any ideas how?

 

[TylerDurden]

... in Russia and Canada, the winters were so brutally cold that engine starter batteries often are replaced-by/or paralleled-with a very large capacitor. I wondered how the capacitor output was throttled instead of suddenly dumped into the starter motor.

I doubt they choke the capacitors. The inrush current draw of motors can be many times the running current; the cap would help reduce the resulting voltage sag.

 

[HAL9000v2.0]

Its spelled 'peak' BTW - but cute design...

yeah, I see..musr install Corel spelyng cheker...

 

[liveforphysics]

I wondered how the capacitor output was throttled instead of suddenly dumped into the starter motor. Anyone with any ideas how?

A load only feels the voltage across it. All the caps in the world in parallel with something holding 12v, or just something holding 12v makes no difference in the current the load draws. The caps would only make it easier to avoid voltage sag than needing a larger battery.

So I guess to answer your question, it would be winding resistance and BEMF that limits the current. Just like every other starter motor.