Ebike charging at work options

SwampRodent

Finding my (electric) wheels
Jun 19, 2019
9
2
Hey all, how are you commuting types changing your bikes up at work?
Originally I had a removable battery that I could take into the workshop and charge on the bench, however these days the battery it permanently attached to the frame so I have a cable that runs out to the works cycle shed with a blue industrial socket on the end, inside the building I have a 3Amp circuit breaker and a time switch for those times I get called away preventing the battery overcharging.
Now, the issue I have is that the company is due to move premises, a brand new building is currently under construction but unfortunately this is not a staff focused company and they refuse to spend a single bean on anything that might benefit the staff out of principal so whatever charging system I come up with will have to come out of my pocket including any liabilities.
I have a few options;
  1. Build a 30Ah battery pack so I can do the full 25-28 mile commute (longer commute in winter) on a single daily charge, I don’t want to discharge the battery below 50% as this will drastically shorten its life. This will be expensive, heavy and I will have to build another charger with a higher current to charge in a suitable timescale.
  2. Charge a lead acid battery at work daily and carry it out to the bike shed and charge with a DIY 12V to 42V charger as I do at home. Perfectly do-able but a bit of a faff and I will have to shell out for a deep discharge lead acid battery and a charger (which always get stolen!).
  3. This one is my favourite. We have a 1.2Kw solar tracking array in the car park that is currently grid tied, if this is to become redundant I want to convert it to a solar ebike charging station. The company is a green company and have daily visits from international VIP’s and I feel as they are running a fleet of fuelcell cars a solar charging station with at least one bike on charge would be perfect for showing off the companies green credentials, however I put this to the management and they are not interested, I think they will likely put the array on ebay when they move. There was a visit from NASA a couple of years back and they were standing around the bikeshed in a semicircle pointing at my bike….that rates pretty high on my cool scale! J
I will have to do some research and find out if there are any government incentives that I can use as a lever.
This would be a professional looking charge station not some Heath Robinson affair, there is also a redundant 3Kw wind turbine on the roof that would work awesomely in the winter months, how cool would that look! Actually I’m getting all fired up now I might put some designs on paper :)

This is the array and my bike how it was 4 years ago.
 

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Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
504
94
72
Hey all, how are you commuting types changing your bikes up at work?
Originally I had a removable battery that I could take into the workshop and charge on the bench, however these days the battery it permanently attached to the frame so I have a cable that runs out to the works cycle shed with a blue industrial socket on the end, inside the building I have a 3Amp circuit breaker and a time switch for those times I get called away preventing the battery overcharging.
Now, the issue I have is that the company is due to move premises, a brand new building is currently under construction but unfortunately this is not a staff focused company and they refuse to spend a single bean on anything that might benefit the staff out of principal so whatever charging system I come up with will have to come out of my pocket including any liabilities.
I have a few options;
  1. Build a 30Ah battery pack so I can do the full 25-28 mile commute (longer commute in winter) on a single daily charge, I don’t want to discharge the battery below 50% as this will drastically shorten its life. This will be expensive, heavy and I will have to build another charger with a higher current to charge in a suitable timescale.
  2. Charge a lead acid battery at work daily and carry it out to the bike shed and charge with a DIY 12V to 42V charger as I do at home. Perfectly do-able but a bit of a faff and I will have to shell out for a deep discharge lead acid battery and a charger (which always get stolen!).
  3. This one is my favourite. We have a 1.2Kw solar tracking array in the car park that is currently grid tied, if this is to become redundant I want to convert it to a solar ebike charging station. The company is a green company and have daily visits from international VIP’s and I feel as they are running a fleet of fuelcell cars a solar charging station with at least one bike on charge would be perfect for showing off the companies green credentials, however I put this to the management and they are not interested, I think they will likely put the array on ebay when they move. There was a visit from NASA a couple of years back and they were standing around the bikeshed in a semicircle pointing at my bike….that rates pretty high on my cool scale! J
I will have to do some research and find out if there are any government incentives that I can use as a lever.
This would be a professional looking charge station not some Heath Robinson affair, there is also a redundant 3Kw wind turbine on the roof that would work awesomely in the winter months, how cool would that look! Actually I’m getting all fired up now I might put some designs on paper :)

This is the array and my bike how it was 4 years ago.
I like your thoughts and ideas, and I thought that I might mention a few small details that might assist you further:-

1) Rewiring a cheap 24 hour timer, so that the tiny motor gets its power from AFTER the switch, and not as normal from before, simply means that it switches itself off. But does does in some cases, also require a manual on off switch so you can restart it again when needed. I have used such a design for battery charging for at least 30 odd years, well before e-bikes. And made many more for friends too. They cost only a few pounds each to buy new!!
Make sure you have the right type of screwdriver, as some use security screws nowadays!

2) Assuming that when you say 50% of the capacity, you mean 50% of the "usable" 100% of the battery (Li-ion batteries are never run "empty", as that ruins them!), then you are being a bit too careful not going below 50%. I always run my batteries to empty (not the real empty of course!), and for my last e-bike, bought secondhand, I ran it for over 6 years and the battery was still good when I gave it and the bike away!!
My guess is with a good solar panel, plus using more of the batteries usable capacity, you don't need the mains!

Let us all know how you get on with recharging!
regards
Andy
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
2,133
541
Basildon
None of what you say makes sense. You're thinking of building a new bigger, heavier, more expensive battery because you're worried that using your present one to its full capability might shorten its life by a few charges!

I used to do a 30 mile hilly commute with an 8 Ah battery and a motor the same as yours running at full power all the way, but with a 15 mph cut-off. Your battery looks a lot bigger than 8AH, so should do that journey without any problems unless you can't pedal.

What about replacing your battery with a removable one that can take in and charge without any hassle?
 

SwampRodent

Finding my (electric) wheels
Jun 19, 2019
9
2
I like the timer idea, the way I charge the bike at home is to charge a big lead acid battery from a 200W PV panel during the day and then use a DC to DC converter to step the voltage up to 42V to charge the bike, an Arduino microcontroller then monitors things, displays Ah and time as well as terminating the charge when the current falls to 200mA. I use a 240V timer to switch everything off at 10:30just to be safe incase the Ardino freezes.

Admittedly 30Ah is on the large side I kind of realised that after I wrote it, maybe 25Ah would be better.

I probably should have given a bit of background but didn't want to make the post too long. This is a custom built bike for some serious hill climbing and off road commuting, my homeward ride is an 800 foot climb often into a pretty savage Easterly wind as I ride through a wind farm about 1000 feet above sea level. Also I am crossing ploughd fields, meadows and thick sticky mud where I can easily be wheel spinning for a solid half mile, this is stuff you cant even stand up in hence the moniker SwampRodent! This is partly why I cant have a removeable pack as it is constanly covered in wet mud so the locking mechanism just wouldn't work.I also run my front and rear lighting of the battery pack, trust me I'm pedaling hard, some of the climbs are getting on for 20% so have to stand, the cut off is slightly above 15mph so I'm spending quite a reasonable time running at full current, in the summer I'm using balloon 26 inch balloon tyres, in the winter knoblies. The motor has 250W on the rating plate I suspect it might be slightly higher.

My Ah use on the home run is around 8-10Ah depending on wind strength, the battery is (was) 17Ah (10S5P), once the battery failed to charge at work as the charger tripped out and I made it home by the skin of my teeth luckily the low voltage cutout didn't trip or I would have lost lighting so there is no way I would ever consider doing the hole trip on a single charge. The battery has now gone through 1100 charge cycles which I think is pretty decent, the bike has now done 22,000 miles in 4 years.

I have a plan that will get me a workplace charge in the short term, I have an old Lifepo4 pack that I can charge inside work in the afternoon then charge the bike with it the following morning, however I still want to build a solar charging station at work.

I hope this now makes a bit more sense.
 
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Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
504
94
72
I like the timer idea, the way I charge the bike at home is to charge a big lead acid battery from a 200W PV panel during the day and then use a DC to DC converter to step the voltage up to 42V to charge the bike, an Arduino microcontroller then monitors things, displays Ah and time as well as terminating the charge when the current falls to 200mA. I use a 240V timer to switch everything off at 10:30just to be safe incase the Ardino freezes.

Admittedly 30Ah is on the large side I kind of realised that after I wrote it. I probably should have given a bit of background but didn't want to make the post too long. This is a custom built bike for some serious hill climbing, my homeward commute is an 800 foot climb often into a pretty savage Easterly wind as I ride through a wind farm about 1000 feet above sea level. Also I am crossing ploughd fields, meadows and thick sticky mud where I can easily be wheel spinning for a solid half mile, this is stuff you cant even stand up in! I also run my front and rear lighting of the battery pack, trust me I'm pedaling hard, some of the climbs are getting on for 20% so have to stand, the cut off is slightly above 15mph so I'm spending quite a reasonable time running at full current, in the summer I'm using balloon 26 inch balloon tyres, in the winter knoblies. The motor has 250W on the rating plate I suspect it might be slightly higher.

My Ah use on the home run is around 8-10Ah depending on wind strength, the battery is (was) 17Ah (10S5P), once the battery failed to charge at work as the charger tripped out and I made it home by the skin of my teeth luckily the low voltage cutout didn't trip or I would have lost lighting so there is no way I would ever consider doing the hole trip on a single charge. The battery has now gone through 1100 charge cycles which I think is pretty decent.

I have a plan that will get me a workplace charge in the short term, I have an old Lifepo4 pack that I can charge inside work in the afternoon then charge the bike with it the following morning, however I still want to build a solar charging station at work.

I hope this now makes a bit more sense.
A lot more! Thanks.
You appear to treat your battery in a very similar and careful way, just as I do, except for the 50% bit! I always try to run mine close to empty.
Sadly I have never counted the recharges on an bike, but the first e-bike, all secondhand, was used every day except when snow or ice was around, though snow was not much of a problem really. Only came off once.
Second bike, not yet fallen off!!!
There are people here that apparently do not believe that generally speaking, a charger must be completely powered off once full charge is achieved, but they also do not get the life out of their batteries that we do!!
Each to his own!
With regard to bike lighting, I found out the hard way that the lighting went off when the battery cut out, and since then I have secondary front and rear lights, with rechargeable batteries in them, very cheap and very bright! And I use them quite often in the winter, and the charge lasts quite a long time, several weeks, but not actually measured exactly....
Also, the extra rear light is fitted under the saddle, does not get wet, has several programs and a loud alarm for when anyone just touches the bike, probably a brown stain on the underpants is the result!
Comes with remote control as well! In the UK,just over 10 pounds on ebay, and runs as an alarm alone up to 3 weeks on one charge (USB).
I was thinking that if money is no object, what about you carrying a second, maybe slightly lower AH battery with you, and some sort of cable to allow either one or the other to be used...That way you will get home easily.....Just a thought.
I have two batteries for that exact same reason....
have a great weekend
Andy
 

robincooper

Just Joined
Sep 10, 2019
4
1
29
London
That's interesting Robin, how much current is the solar panel able to supply? Do you find is supplies just a small top-up of the battery or a more substantial charge during a sunny day?
One time charge. But for me it's easy when I ride my bike in a sunny day a just put a solar charger on a backpack. That's why when I go from South to North it charges.
Hope I understood your question right.
 

ebiker99

Esteemed Pedelecer
Feb 17, 2019
359
118
One time charge. But for me it's easy when I ride my bike in a sunny day a just put a solar charger on a backpack. That's why when I go from South to North it charges.
Hope I understood your question right.
I was think more about when the bike is parked up at work and on the solar charge all day, does the battery voltage go up by just a small amount or a substantial amount on a sunny day?
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,713
5,735
The European Union
I would only need 15 Ah to do that distance (there and back), are you throttle only? In that case buy an electric moped, they have better range...
 

SwampRodent

Finding my (electric) wheels
Jun 19, 2019
9
2
My system at home works an absolute treat, I use a 180W 14V panel to charge a lead acid battery all day then when I get home I use an Arduino based charger to give the 42V / 2A to charge the bike which takes about 5 hours. I use it all summer but at this time of year (mid September) it does struggle to harvest enough power to charge the bike every day, in the winter I generally get 1 charge per week so have to use that dirty grid power stuff :)
I'm aiming to replicate this system at work but it looks unlikely we will even get a cycle shed, the very best I can hope for is a toast rack which is less than ideal to mount a metre long PV panel to. It might be a case of charging a battery some ware on the site and carrying this to my bike.
 

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