Car battery for Ebike?!

Post anything about batteries here. Lead acid, rechargeable, whatever.
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Joined: Thu Feb 23, 2017 7:41 am

Car battery for Ebike?!

Post by Ensnaturae » Thu Feb 23, 2017 8:25 am

I read the article ... ... .php#thumb
And it sounds truly fabulous!
I'm going to try to connect my ebike to a much more powerful SLA ... Leisure, or car battery.
This won't be easy, possibly, as I have never attempted anything like it, before...
Does anyone have any thoughts on this idea?
I read this morning, on another site...that it is IMPOSSIBLE.. to connect a car battery to an ebike ..
(I have a good trailer to carry a heavy lead ebike is a cheap Chinese bike, that runs on a LEAD battery, not the lightweight kind, Lithium)
My son recommends ..(since I have a trailer, and can't travel more than 25kms..on one at present HAVE to carry a second battery...weight total 20 KGS) a 16kg car battery, that in his opinion will keep going for over 50 kms, plus.
I must use heavy duty cable, that works with a car battery, I think..
But the gears etc of my ebike...currently, are lightweight cables..
What would happen? Will they melt if connected too a car battery?
Its easy to dig out the wires on the bike, where they connect to the supplied battery station..
I imagine..just adding a metre and a half of some kind of wire...and connecting all the ebike a car battery, SLA if possible...fixed securely in my bike trailer...
It be a problem free idea....but...
Why do some people say...IMPOSSIBLE?!!!!
MY BIKE IS A BASY WAYSCRAL 315 FROM NORAUTO. THE ABSOLUTE BOTTOM OF THE RANGE...BUT IT GOES VERY WELL FOR ANCIENT PEOPLE, AS I am. It just needs to manage much longer distances...and I am very hard up! Like many ..I hope to find the very best, economic, low budget, solution..that might be useful for everyone like me!!! Thanks very much for reading this message!!!!

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Re: Car battery for Ebike?!

Post by hi_tech_guy_18 » Thu Apr 20, 2017 12:01 pm

more weight means more tork you motor need to put out to move you + extra weight
using more watts and drawing more amps

if Therese too much weight the motor will draw too many amps go beyond spec and just burn out )at the same time if amprage goes beyond battery spec it will force the voltage to 0v and screw up your battery's (call it the curse of ohms law and internal resistance oddly it the same thing destroying your motor )

But you can convert a lead acid bike to lipo / lifePo4 bike
its very easy find battrry plug on bike CUT off Put on new battery pack plug that fits new lifePo4 battery pack and your done
these do come with a BMS (battery management system)
that prevent you over discharging or overcharging the pack

you can even make you own custom pack just remember to add a BMS

the BMS makes lifePo4 compatible with old lead acid gel/agm chargers but they work better with lifePo4 chargers due one of the states the bms does on full battery is disconnect battery form charger leaving the lead acid charger open circuit and some don't like that being prolonged (lifepo4 ones do due they put themselves into sleep mode and wait for the bms to emit a connection to battery state )

nice thing with lipos / lifePo4 they have no memory
there more effiant to charge (unlike lead acid that wastes 50% of the input amps) it also make them much faster to charge up
it also allow them to dish out more amps (they remain voltage stable at hight amp draws witch is vital for cool running battery's) even take more amps in charging even on low amp charge the times impressive fast
the alo can store a lot more Ah and not have lead acids dead lead weight

lifePo4 if you full charge them they will keep there chrage if you abuse them for a year on the shelf
[lead acid if you do the same are flat in 6 moths and very much need a full change to try and bounce them back if they bounce back]

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Re: Car battery for Ebike?!

Post by techman » Wed May 03, 2017 10:44 am

My bike mileage was doubled with the added lead acid battery pack. I was using two alarm backup batteries so the extra weight was not much really. And the bike was designed to have a second battery pack installed anyway.

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