# Bike Trailer + More Batteries = Long Range (E)Bike?



## mirrorinthewall (Sep 8, 2019)

Hi Forum, this is my first post!

I was reading on here about creating DIY EV cars or another site and they said if you add more batteries, you increase range. I didn't see much online about adding extra batteries to an ebike to improve range, and could not find any pages arguing for putting some extra batteries in a bike trailer to dramatically increase range. The range of a lot of ebikes looks like 10-50 miles, which honestly to me seems small and like you might as well just physically bike the extra mileage than rely on electric assist (in fact a lot of cyclists seem to argue for that). If someone wanted to ride a "century" (100 miles) or double century (200 miles) on a (e)bike, how would they go about making that happen?

If you put extra batteries in to a trailer and hook them up to an ebike, could that help to get you to a 200 mile range? How can a long range ebike be created? Should such a bike also have a motor on one of the trailer wheels, and should they be activated along with the bike, or separately (like, you could run out the battery on a trailer wheel motor, then run the batteries out tied to the ebike, or should you have both motors running at once?). Would you want motors on both wheels of a trailer and/or both wheels of the bike, or should you choose one side or the other of the trailer, or front or rear of the bike to have a motor on it?

Will you need stronger motors on both because the bike is heavier now?

Should a cargo bike be used that is a bit heavier?

Does this kind of design get too heavy at some point where pedaling becomes useless and you need to just switch to an EV-motorcycle? (Is this why I don't see designs online that add extra batteries to a trailer, or has it just not been done much yet?)

I appreciate any thoughts on this topic, I thought an ebike would be able to travel further for less than an EV-car or EV-motorcycle as it is lighter, so I was kind of thinking how an EV-car's electrical design could be adapted to an ebike for longer range.


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## Ebike man (7 mo ago)

Hi My first post also 
Shame nobody has any thoughts on this 
I will attempt to build my own trailer with 200ah of lead acid to charge on the go through a dc to dc converter 
My bike is 63v 15a currently around a 30 mile range on throttle only at 25mph. 
I hope to get atleast 150 miles out of 8 car battery's wired together in 2s 4p configuration to give me a trailer battery of 24v 200ah. 
I will use a dc to dc boost converter to step up the voltage to 63v to constantly provide power to the charging side of my battery already on my bike 
I'm using around 8-900w on the flat at 25mph so if I put 300w from trailer I should triple my range to 90 miles continuous riding. 
Then I'd have to stop and wait a few hours for my battery to charge back from the trailer side. 
I could just run at 15mph (around 300w then I could potentially run till my bike and trailer are empty together giving a mega range of over 400 miles but at 15mph 
Also I haven't taken weight into account on the range.

If not hilly terrain I wouldn't think it would matter when riding for long times with minimal stopping 
(I travel the full 30 miles of my bike and only stop and start once or twice as I'm riding in country lanes with no junctions) 
In city I would think that there's no point with battery trailer as power points are everywhere or just have spare battery at home charging.


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## remy_martian (Feb 4, 2019)

So, rather than an electric motorcycle, you plan to build a lead-acid abomination to block traffic as you abuse your prostate for four hours?


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## kennybobby (Aug 10, 2012)

Weight is not your friend when you are pedaling a bicycle

i think when you *do* consider weight in your planning that 8 lead acid car batteries will be much too heavy. The frame of the trailer will need to be strong enough to carry the 8 without collapsing, so the trailer will have quite a bit of weight also.

What type of battery does the Ebike currently use--is it lithium? How much does the bike with battery weigh, and then what is the weight with biker and any luggage?


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