Where to put the battery

[spedefreke]

Hi, There is an alternative to battery placement on an ebike. Most riders (I believe) use rear-wheel hub motors which neccessitate a counterbalance on the front. The solution for me is a frame-attached jig which holds the battery pack. My first build (3 years old now) was mechanically attached by bolting an aluminum jig by drilling through the frame wand using stainless steel bolts. A good sturdy frame is needed for this. The battery itself is fixed to an aluminum support with a hook on the back making the battery easily removed. My second build, not yet finished, shown below , has an aluminum jig welded directly on the frame. Any aluminum frame will do. The battery is fixed on to it the same way as build #1 with an aluminum support bracket. Some pics :

 

[spedefreke]

Notice the battery is attatched to an aluminum plate by a dog collar and the battery itself is inside an insulated frozen food bag (insulation removed for better breathability). It is kind of rough looking because I had many issues with the ping bms' but when fully complete, (wires hidden) the appearance is very clean and stealthy-looking. The hook fits snuggly into the jig so there is no movement of the pack when riding.

 

[USAEBIKECO]

In my opinion the battery is best put on a rear rack. It just balances out better than any other way.

 

[spedefreke]

nice looking bike lester. with motor on front wheel, battery probably is best on back. Can't you get it a little lower down? I remember my days of cross country biking in the 80's and a high load on the back made riding less stable.

 

[USAEBIKECO]

Thanks!

We built ebikes with both front and rear motors and front motors tend to balance out the bike better, which is good to prevent rear spokes from popping due to the weight.

 

[dingoEsride]

the best place is centered between the wheels and low down but yours looks like it may be too big for that if you still want to pedal, so that leaves no choice to do like you have done or rear rack, if it works ok for you then fine but looks a little top heavy to me

 

[spedefreke]

Dingo, the battery is in line with the seat and and so all the weight is on one plane. Riding is superb. It could be a little awkward if walking the bike uphill for any appreciable distance.

 

[dogman dan]

:lol: I'm sure the trails are really tough riding in Chicago.

The best place for the battery with either kind of hubmotor is the frame center, about where your knees are. If the crank clearance allows it, along the top of bottom tube is most excellent. If you don't have a triangle, the compromise is to mount saddle bag like boxes to the side of the frame, close to the headset as fork clearance allows.

However, you can get away with doing it wrong if the battery is light enough. I have my 4 pound battery mounted high on a rear rack on my current trail bike. If I carry additional battery, I put it in a handlebar bag so I don't have 10 pounds back there bucking me off.

 

[spedefreke]

putting the battery in the triangle does have its dissadvantages. 1) Less flow-through: a strong wind can off-set you,
2) not very stealthy-looking : try riding in "no motorized vehicle" zones, (appearences are everything),
3) damn crank arms
The low weight distribution of triangle-placed battery has "0" advantages when cruising at any speed except very low speed. The only disadvantage is when walking the bike - a weak person can lose balance.
The front frame-mounted battery also frees-up space in rear for a back-rack.

 

[Ykick]

putting the battery in the triangle does have its dissadvantages. 1) Less flow-through: a strong wind can off-set you,
2) not very stealthy-looking : try riding in "no motorized vehicle" zones, (appearences are everything),
3) damn crank arms
The low weight distribution of triangle-placed battery has "0" advantages when cruising at any speed except very low speed. The only disadvantage is when walking the bike - a weak person can lose balance.
The front frame-mounted battery also frees-up space in rear for a back-rack.

My experience with rear mounted batteries disagrees. Rough sections of road create structural issues, stress and funny load distribution. Slight lean at speed, add in a bump and I can assure you triangle mounting is better than the rear.

Based on experience with frame mounted m/c fairings I can appreciate this form of load carrying. But, few people have the capabilities to execute it properly which would include appropriate suspension spring adjustments if so equipped.

 

[23skidoo]

I was surprised that my first bike with the battery in the triangle did not handle that well. The next two bikes have the battery in the backpack and this gives superior handling. It's simple to mount and reduces the pounding on the battery and connections (but still needs to be physically protected). It's more secure because you take the battery with you. It makes charging easier for the same reason. It enables you to interchange batteries for different bikes. It's the most stealthy arrangement. It's easy to disconnect in an emergency with Anderson connectors.

If you use a heavy battery,routinely ride long distances, or live in a hot climate, it's not the best.

 

[spedefreke]

One thing i forgot to mention with front, frame-mounted battery is the superior shock absorbancy. Mounted directly over the front shocks, a heavy battery loves it.
BTW It only cost me $60 to have the jig welded to the frame

 

[dogman dan]

That makes sense to me too, if the rear is hardtail.

The best handling 20 pound battery I ever carried, was in an EV global frame. Two sla's mounted along the downtube. It's max speed was 12 mph, so yeah, it was slow speed handling for sure.

My racing bike had 15 pounds of lipo mounted centered on the top tube of the front of the frame and handled well. Increasing the voltage another 25v, I had no choice but to add 5 pounds to a rear rack. It never handled as good again with that high rear weight.

This was for riding on a racetrack, where handling really mattered. FWIW, I crashed out of the race. Gee, I wonder why?

Basicly, it's not having it so low on the frame that was crucial for a high speed corner, it was having it in the middle, between the two wheels. Not hanging high over the rear wheel.

This is all so frocking obvious, to anybody who ever rode motorcycles. Put your gal on the back behind you, and suddenly the bike handles like shit. Not unable to ride it, but definitely degraded.

 

[spedefreke]

Yes, dogman, my motorcycles are long gone (riding in the Toronto area is suicidal) but you do learn about weight distribution.
During my long distance bicycle riding days where we carried tent, tools, food, stove, clothes etc on our bikes we experimented with different weight distribution configurations. Even putting weight in rear panniers gave the bike an unsteady feel. In the end it was a compromise. But a sturdy frame and fixing packs tightly to the frame was a good starting point.

 

[dingoEsride]

This is all so frocking obvious, to anybody who ever rode motorcycles. Put your gal on the back behind you, and suddenly the bike handles like shit. Not unable to ride it, but definitely degraded.

Not so sure about that one Dogman, it all depends on how she is hanging on but if its a guy it handles terrible

 

[Tommy L]

This is all so frocking obvious, to anybody who ever rode motorcycles. Put your gal on the back behind you, and suddenly the bike handles like shit. Not unable to ride it, but definitely degraded.

Some gals are like RC LiCo and some are like Lead Acid. I prefer the RC LiCo gals! :lol:

Tommy L sends.....

 

[Carlos Dewerchin]

Hi everybody,

I ride a HP Velotechnik E-Scorpion fs and want to install a second battery and a Left - Off - Right three position switch and so double the range of my trike. Theoretically the center of gravity, low and down is the best place to fix them. Is there anybody in the audience who has done it and what recommendations are you willing to share ?
Locating the batteries in the luggage bags is not an option. A picture is most welcome !
Have a nice trip !
Carlos

 

[oatnet]

Hi, There is an alternative to battery placement on an ebike. Most riders (I believe) use rear-wheel hub motors which neccessitate a counterbalance on the front. The solution for me is a frame-attached jig which holds the battery pack. My first build (3 years old now) was mechanically attached by bolting an aluminum jig by drilling through the frame wand using stainless steel bolts. A good sturdy frame is needed for this. The battery itself is fixed to an aluminum support with a hook on the back making the battery easily removed. My second build, not yet finished, shown below , has an aluminum jig welded directly on the frame. Any aluminum frame will do. The battery is fixed on to it the same way as build #1 with an aluminum support bracket. Some pics :

You are correct about the front mount location, I started building bikes with front packs a few years back, and after discovering how much it improves handling over a rear or center-mounted pack, I began evangalizing about front mounted packs on Endless-Sphere. I had difficulty developing the vocabulary to explain why it improved handling and took a lot of flak from skeptics who had not tried it, but many folks tried it and became converts. If you look around, you will find quite a few of builds (both hub-motor middrive) that expanded on my mounting approach and improved it significantly - Gensem and MattyCii come to mind because I was just looking at my Norco thread.

I like your new approach of welding the plate to your aluminum frame. How did you heat-treat it after the welding made the aluminum in the headtube soft and weak? That is what has kept me from welding a plate on... I have considered drilling a few holes in a headtube, and using a combination of epoxy (like Gensem) combined with bolts to add a mechanical bond. Another consideration - I can't tell if your battery will be floating loosely in the front bag, or if the bag is just concealing a firmly-mounted front pack; I did find that any slop allowed a front battery to move, it added its own steering inputs, usually when I least wanted them.

Below are pics and links to a few of my front-pack builds... The Norco/front mounted pack thread is pretty long, so the link is to the middle of the thread, where we sorted out why it improves handling; like balancing a broom upside down, it works because the mass on top of the broom requires smaller corrections at the bottom of the broom to stay balanced. In addition, steering inputs to the battery mass don't need to be translated through the frame. On an ebike, this translates to faster, more precise transitions. OTOH the rider needs to be fully adjusted to using smaller inputs before they encounter their first panic maneuver - it is very easy to overcorrect if you are used to a normal ebike.


Norco A-line:
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=34230&start=100#p521699

Specialized Enduro Comp:
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=24329

Snow Bike
http://endless-sphere.com/forums/viewtopic.php?f=4&t=48521

Tidalforce

 

[docnjoj]

Hi everybody,

I ride a HP Velotechnik E-Scorpion fs and want to install a second battery and a Left - Off - Right three position switch and so double the range of my trike. Theoretically the center of gravity, low and down is the best place to fix them. Is there anybody in the audience who has done it and what recommendations are you willing to share ?
Locating the batteries in the luggage bags is not an option. A picture is most welcome !
Have a nice trip !
Carlos

Hello Carlos and welcome to E-S. I ride a Steintrike Mad Max and have the A123 pack split into 2 x 6s Amp 20 below the seat in a lexan holder. Handling is fine this way since the batts are right below my butt. Putting the batts on the rear rack really makes the handling terrible, and my rack is rated for 50 kilos! Solid steel and made by the same folks who make the trikes. The trike is in my Sig but if you want more details I'll post a few pictures.
otherDoc

 

[Jolly Jumper]

I dont´ like these front mounted battery´s.
I guess ist about 12-14kg including the case and mount.

We all know the brake-power a front brake on a fast e-bike have and must have.
In a emergency brake situation where u need front brake you have some more meters brake way becouse your backwheel will lift much earlier with a 12-14kg in this position.
In addition you have more stess in the head-set-bearing and tube and the stearing is more sluggish.

For ebikes that drive not faster than 35km/h it would be OK...

 

[oatnet]

In a emergency brake situation where u need front brake you have some more meters brake way becouse your backwheel will lift much earlier with a 12-14kg in this position.
In addition you have more stess in the head-set-bearing and tube and the stearing is more sluggish.

For ebikes that drive not faster than 35km/h it would be OK...

Obviously you have never ridden a front pack, and are armchair engineering - do a search and you will find many builds that might convince you otherwise. Since the battery is behind the front hub, extreme braking drives the mass down the forks, into the front wheel, and improving contact, so braking is actually a bit better than a rear pack that can make the front wheel skid.

The Norco A-Line pictured above does 80+ km/h, and I have many thousands of miles on front packs, and I have not experienced rear wheel lifting under extreme braking. I do have a problem with the front wheel lifting under heavy acceleration though :lol: despite the battery mass up front - I can accelerate much harder with the pack helping to hold the front end down. OTOH many folks (especially offroaders) prefer wheelie machines, so the front pack is not a good choice for them.

Since the top heavy mass of the front battery requires smaller movements (like the broom example earlier) and steering inputs do not need to be translated through a frame (the battery is between your hands, basically), steering is more responsive, regular bikes end up seeming sluggish. Yes there is more load on the headset, that is why I build on sturdy downhill frames that were designed to take shock loads far greater than a mere 28lbs - like 220lbs of man and machine going off a 10' drop at 25mph.

-JD


PS -I keep forgetting to post my pictures from a trip to Amsterdam earlier this year - I was stunned to see how many normal bikes had been outfitted with front racks, and the heavy loads (children, groceries) the locals were hauling around on front racks... IMO Amsterdam is a population of expert cyclists, and if front racks have evolved to such heavy usage, it's probably because it works.


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[heavymetalthunder]

I have a front motor hub and mounted my lipos in the front by building a box, because I have large panners, during my night rides home may batteries are moved to the panners and a night time headlight is installed in the front box to add to my day time running lights. I really haven't noticed much of a handling difference as my bike is a bit heavy either way I go.

 

[torker]

Oatnet I "have" to see the snocat/ er bike in action..

 

[Jolly Jumper]

In a emergency brake situation where u need front brake you have some more meters brake way becouse your backwheel will lift much earlier with a 12-14kg in this position.
In addition you have more stess in the head-set-bearing and tube and the stearing is more sluggish.

For ebikes that drive not faster than 35km/h it would be OK...

Obviously you have never ridden a front pack, and are armchair engineering - do a search and you will find many builds that might convince you otherwise. Since the battery is behind the front hub, extreme braking drives the mass down the forks, into the front wheel, and improving contact, so braking is actually a bit better than a rear pack that can make the front wheel skid.

The Norco A-Line pictured above does 80+ km/h, and I have many thousands of miles on front packs, and I have not experienced rear wheel lifting under extreme braking. I do have a problem with the front wheel lifting under heavy acceleration though :lol: despite the battery mass up front - I can accelerate much harder with the pack helping to hold the front end down. OTOH many folks (especially offroaders) prefer wheelie machines, so the front pack is not a good choice for them.

Since the top heavy mass of the front battery requires smaller movements (like the broom example earlier) and steering inputs do not need to be translated through a frame (the battery is between your hands, basically), steering is more responsive, regular bikes end up seeming sluggish. Yes there is more load on the headset, that is why I build on sturdy downhill frames that were designed to take shock loads far greater than a mere 28lbs - like 220lbs of man and machine going off a 10' drop at 25mph.

-JD


PS -I keep forgetting to post my pictures from a trip to Amsterdam earlier this year - I was stunned to see how many normal bikes had been outfitted with front racks, and the heavy loads (children, groceries) the locals were hauling around on front racks... IMO Amsterdam is a population of expert cyclists, and if front racks have evolved to such heavy usage, it's probably because it works.


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Doesn´t wanted piss on your doormat
But even a blind person would agree that you have much more problems when you are forced to a emergency brake @80km/h with the battery mounted like you have.

Here i have drawed the forces who make your backwheel lift when braking realy hard on front wheel. The battery there makes it not look better!


Obviously you was never being in the situation of a real emergency brake wher every cm brake way counts.
And yes i have self tryed multiple wights 2-12kg on this position and more than 2-4kg i would not recommend for fast ebikes!

 

[dogman dan]

A heavy rear hubmotor does go a long way to keeping the rear down in a panic stop. In that picture, that looks like 25 pounds of clyte there to me. But I suppose there would be an ideal maximum weight for a front mount battery. I certainly don't think 10 pounds up there is so bad. I carry that much now in a handlebar bag when I need long range. I did learn to mount it as tight to the headset as possible.

Of course, experienced riders never ever allow themselves to be in a situation where panic stops are required. That's just riding a suicidecle. Often as not, the real life saving maneuver is not standing on the brakes. It's more like a touch of brakes, and a 15 to 90 degree change in direction. Generally its touch brakes, then grab all the throttle you have. Threading the needle works, locking up brakes and doing stoppies is just going to have you hitting the metal.

But again, it all starts with not putting yourself in that vulnerable situation. You know that car is going to turn into your path unless you are asleep at the wheel.