Mobile e-bike charging station

[via]

I would like to make a bike trailer that can do quite a bit of e-bike charging (10+ kWh/day?). I have a super heavy duty Surly Bill trailer with a crate box built for this purpose. This rig's job will be to charge 3-5 e-bike batteries while riding, probably at a charging speed of 4-5 amps each.

Since I intend to charge the rig at vehicle charging stations, I thought it might actually be logical to use a plug-in hybrid vehicle battery. Perhaps from a Chevy Volt with capacity ~17 kWh. Does anyone know if these batteries will operate independently of their car computers? Or if I am barking up the wrong tree with that idea.

 

[floydr]

Might be ilegal to charge a trailer at a public charging station. Charging an ebike at a public charging station might be ok
You would replace the Battery pack's BMS with one that could communicate with the EVSE (charging staion). A Chevy volt battery pack is around 435lbs your trailer has a 300lb weight limit. A better plan would be to look here or here for a lower weight battery that fits your needs. I would go with the 9.8 kWh LG 51.2V nominal battery add a BMS and a 48V inverter. You could have two of the LG packs and perhaps be right at the weight limit of your bike trailer. Add a 2000/4000 watt 51.2V(120/240VAC) charger to charge the battery packs.
Later floyd

 

[via]

Thanks a lot, especially for that tip on a battery vendor. I have a support vehicle so it probably makes sense to move the battery charging rig into the pickup truck, if we are talking about a 150 lb battery + 50 lbs of other electronics. I can technically tow all that with my BBSHD + Phaserunner, even up mountains, it but it will make the riding less enjoyable.

 

[Grautuefel]

Not to be that guy, but a small almost silent honda genset would achieve the same result for 1/10th of the weight and 1/10th of the cost. What's the goal of using an intermediate battery in this case? Especially if you have a road vehicle nearby in any case.

 

[via]

I will certainly use a gas generator if I feel I have to! It is technically a way to give e-bikes crazy range, it just breaks the spirit of solar touring somewhat. But if battery options are too expensive I will do it.

 

[Hillhater]

I would like to make a bike trailer that can do quite a bit of e-bike charging (10+ kWh/day?). I have a super heavy duty Surly Bill trailer with a crate box built for this purpose. This rig's job will be to charge 3-5 e-bike batteries while riding, probably at a charging speed of 4-5 amps each.

??.. i am puzzeled as to why you would use one large battery pack to charge multiple ebike packs WHILST RIDING ?
..why not either just hav multiple ebike packs already charged, .….
..or just use the one large pack in the trailer to power the ebike directly ?
Also battery to battery charging is not a simple process and can be very inefficient.

 

[amberwolf]

, it just breaks the spirit of solar touring somewhat.

So does using a charging station.

 

[amberwolf]

Some thougths below, from someone relativley experienced with very heavy loads, big trailers, etc.

Yes, that's a piano.

I would like to make a bike trailer that can do quite a bit of e-bike charging (10+ kWh/day?). I have a super heavy duty Surly Bill trailer with a crate box built for this purpose.

How much weight can it carry, under the specific riding conditons you have for all of your riding?

How much load can the hitch take, under those conditions? Meaning, how much of a jerk or pull, or shove or slam, can it take from the mass of the trailer against the bike?

How much load can the bike frame take at the hitch point under those conditions?

If the loading on the hitch itself, or the mounting point to the bike, exceeds the capabilities of any part of these things, you could lose the trailer (best case) or rip the bike apart (worse case) while losing the trailer.


How much weight / load can your bikes' rear wheel handle? It's going to see some of the load on it under various conditions, and a lot of it under certain conditions.

How much braking capacity and traction does your bike have? (the trailer has no brakes of it's own, so it's all up to your bike to handle all the forces of braking as well as the actual braking).

capacity ~17 kWh.

How much does that weigh, including power conversion and current limiting / charge control electronics to get it's power into the ebike batteries?

I'd make a rough guesstimate that it's probably around 25lbs / kwh (casing, protection, waterproofing, main-pack-charging electronics, ebike-pack-charging-conversion electronics, etc). Going with that, 17kwh x 25lbs = 425lbs.

The surly bill Bill Trailer | Large Flatbed Bike Cargo Trailer | Surly Bikes is rated for max of 300lbs.

Assuming you aren't carrying anything but the battery on it, then at that rate you could have 300lbs / 25lbs = 12kwh (actual kwh/lb of your setup will determine actual capacity you can carry).

If you need to carry your ebike's extra batteries on it , or other supplies, that weight takes away from the capacity of the recharge-system battery you can carry.

 

[via]

So does using a charging station.

Lol. Not gonna argue that. Let's just leave it at "the heart wants what it wants".

 

[via]

??.. i am puzzeled as to why you would use one large battery pack to charge multiple ebike packs WHILST RIDING ?
..why not either just hav multiple ebike packs already charged, .….
..or just use the one large pack in the trailer to power the ebike directly ?
Also battery to battery charging is not a simple process and can be very inefficient.

Basically because there are 3-5 bikes to charge over 3-5 days. It would be a really large number of packs to have pre-charged. It's even a lot of batteries to charge, like in a hotel or something. Doable but not super reliable, and probably has me waking up in the night to swap batteries onto the chargers.

Ideal to have the charging happening all day long, and always in the correct place (with us).
The 175W solar bike trailers are actually contributing quite meaningfully to this end, since they charge the bikes themselves and do it all the time (weather permitting - region is Southwest).