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The eBike thread
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As Mad_Lad said, first port of call is check voltage of battery. When the BMS on mine kicked in (and stopped supplying charge), I measured and it was down to 34V (but a day later this had gone up to the resting voltage of 36V)
Fully charged you should be at about 42V, so if it is significantly less after charging, most likely the charger is faulty
Chargers are only €3 including shipping from Chinaland
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Deleted User wrote: »I would think if this is a 36V battery then it should have about 42V hot off the charger.
Indeed. But at 40V the pack still has a state of charge of about 80%. This should be plenty to get the motor going. Unless the BMS refuses to play ball - because of maybe 9 batteries in the series are close to 4.2V and one is below 3V or whatever the threshold is. And when the battery charger is connected, the controller gets the voltage it needs directly from the charger no matter what the BMS wants. A way to test this (it will be a bit tricky) is to use max throttle for a second (using an extension lead). If the power comes from the charger the acceleration will be lethargic as the charger only provides 2A or something like that. Not like the battery that can provide 13A or so
My theory at the moment!Deleted User wrote: »I would connect the charger over night and see if this makes a difference to the battery, it may be a case where the cells are very out of balance and could take 24 hrs or more to balance them, this happens when the battery gets old and normal over night charging might not balance the cells properly. Just a theory at the moment.
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Indeed. But at 40V the pack still has a state of charge of about 80%. This should be plenty to get the motor going. Unless the BMS refuses to play ball - because of maybe 9 batteries in the series are close to 4.2V and one is below 3V or whatever the threshold is. And when the battery charger is connected, the controller gets the voltage it needs directly from the charger no matter what the BMS wants. A way to test this (it will be a bit tricky) is to use max throttle for a second (using an extension lead). If the power comes from the charger the acceleration will be lethargic as the charger only provides 2A or something like that. Not like the battery that can provide 13A or so
My theory at the moment!
Yep you pretty much got it, total pack voltage doesn't tell the state of the cells.
I had a LiFeP04 battery I got back in 2009, 48V 20AH from pingbattery.com, it had led's which would illuminate when cell balance had complete, an excellent feature !
Of course today you wouldn't use LiFeP04 on an Ebike, too large and heavy and not so good energy density but fantastic life, good for storage.0 -
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Deleted User wrote: »I had a LiFeP04 battery I got back in 2009, 48V 20AH from pingbattery.com
How much did that pack set you back?
I'm a bit annoyed now that both my packs are depleted and I'm waiting for a charger and cables from China. Dying to do some speed and range testing...
Have high hopes for these little packs. And they were incredibly cheap. Was tempted to buy a cheap Chinese 72V 2000W continous power pure sine wave inverter for about GBP110 this evening. Throw it and the batteries in the boot of the EV when I go for a dodgy trip and if I completely run out of juice in the middle of nowhere they should give me 3km of additional range in about 20 minutes. Enough to get to the nearest 3 pin plug so I can use the granny cable (or with luck a slow or even fast charger)My ads on adverts.ie:
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How much did that pack set you back?
I'm a bit annoyed now that both my packs are depleted and I'm waiting for a charger and cables from China. Dying to do some speed and range testing...
Have high hopes for these little packs. And they were incredibly cheap. Was tempted to buy a cheap Chinese 72V 2000W continous power pure sine wave inverter for about GBP110 this evening. Throw it and the batteries in the boot of the EV when I go for a dodgy trip and if I completely run out of juice in the middle of nowhere they should give me 3km of additional range in about 20 minutes. Enough to get to the nearest 3 pin plug so I can use the granny cable (or with luck a slow or even fast charger)
The battery inc shipping was 668 Euro's.
Today that Would cost 730 Euro's with upgraded BMS and 5 Amp charger, a joke really, costs should have fallen a lot.
20 Ah of Lipo would cost me less than half that !
You can get more power out of your existing controller, jsut put some solder on the Shunt, this will allow more current which will = more torque and if you want more speed add more voltage but you need to know the FET's in the controller and look them up and see their max voltage and current limit, this will be the peak, exceed it and you will have smoke, how do I know that ? haha I fried a few and had to get herself to pick me up on a few occasions miles away ! :rolleyes:
A little bit of solder on the shunt at a time.
When tinkering, it's good to get a watt meter, can be got for about 15 pounds on Amazon.
https://www.amazon.co.uk/gp/product/B07M5XD4G9/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
I got this to monitor the power I'm using from the battery with my Radio Transceiver but it will do the job for the ebike just don't exceed the voltage which is the voltage hot off the charger.
Down the road you can get what's called the cycle analyst, pretty much the same thing only much more expensive, but other models can plug direct into some controllers which you can limit acceleration and speed, it works great.
That motor should be good for 5 Kw, 60 volts and about 83 amps peak ( battery current) . I had a blast, looks like a similar motor, although I just remembered, you got front motor and that's a no no above maybe 1 Kw max.
The 72 controller won't work with your 36 volt battery or do u have 2 of them ?
That would be 27 Amps battery current for 2 Kw , I wouldn't do it in a front wheel setup, chances are the little torque washers would pop out or break spinning the axle breaking the wires and they are a pain to replace, believe me.
I told you anyway to get the rear motor because it won't be long until you want more power lol. 0 -
I'm not talking about a 72V controller. It was a 72V DC to AC pure sine wave inverter that I could use my little hoover board battery packs in series to provide AC power to my granny cable to charge my EV
I'd say my fork would be toast very quickly even with a 1kW motor. The setup I went for is just right. If I want more powah (indeed quite possible) I will sell the bike or the kit or both and get me something else. Probably going to cost me more money than I'm willing to spend though.Deleted User wrote: »The battery inc shipping was 668 Euro's.
Are you sure? That really wasn't too bad at all back then, quite surprised about that figure for a 1kWh battery (20Ah * 50V). I have a figure in my head that the original Nissan Leaf 24kWh battery cost Nissan USD20k to procure back in what year was it, 2010? So USD833 per kWh. Which is more than you paid. Which doesn't make sense!
My own batteries are a combined 8Ah * 40V so about a third of a kWh. €90 including all shipping so comparable to about €270 for a kWh My ads on adverts.ie:
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I'm not talking about a 72V controller. It was a 72V DC to AC pure sine wave inverter that I could use my little hoover board battery packs in series to provide AC power to my granny cable to charge my EV
I'd say my fork would be toast very quickly even with a 1kW motor. The setup I went for is just right. If I want more powah (indeed quite possible) I will sell the bike or the kit or both and get me something else. Probably going to cost me more money than I'm willing to spend though.
Are you sure? That really wasn't too bad at all back then, quite surprised about that figure for a 1kWh battery (20Ah * 50V). I have a figure in my head that the original Nissan Leaf 24kWh battery cost Nissan USD20k to procure back in what year was it, 2010? So USD833 per kWh. Which is more than you paid. Which doesn't make sense!
My own batteries are a combined 8Ah * 40V so about a third of a kWh. €90 including all shipping so comparable to about €270 for a kWh
I still have the paypal receipt.
Jun 15, 2010 15:22:10 PDT
Description Unit price Qty Amount
48V 20AH V2.5 LiFePO4 Battery Pack
Item# $642.00 USD 1 $642.00 USD
Subtotal $642.00 USD
Shipping and handling $160.00 USD
Total $802.00 USD
Payment $802.00 USD
Charge will appear on your credit card statement as "PAYPAL *PINGPING227"
From amount €667.15 EUR
To amount $802.00 USD
Exchange rate: 1 EUR = 1.20212 USD
Yeah shame they're more expensive now.
How much charge do you think you could put into your car with those tiny batteries ? 0 -
Deleted User wrote: »How much charge do you think you could put into your car with those tiny batteries ?
The batteries are 0.34kWh. Given some losses and usable capacity let's say I can get 0.3kWh or near enough into the battery using my granny cable and the car set to the lowest level of charging: 860W. Doing this for 20 minutes at 2.5C will not be very healthy for my pack, but it should get me out of a hole and give me near enough 3km range when driven handily
But would I ever need to use it? Probably not.My ads on adverts.ie:
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The batteries are 0.34kWh. Given some losses and usable capacity let's say I can get 0.3kWh or near enough into the battery using my granny cable and the car set to the lowest level of charging: 860W. Doing this for 20 minutes at 2.5C will not be very healthy for my pack, but it should get me out of a hole and give me near enough 3km range when driven handily
But would I ever need to use it? Probably not.
Pure curiosity question. 2.5 degrees Celsius? How do you control for temperature?0 -
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The batteries are 0.34kWh. Given some losses and usable capacity let's say I can get 0.3kWh or near enough into the battery using my granny cable and the car set to the lowest level of charging: 860W. Doing this for 20 minutes at 2.5C will not be very healthy for my pack, but it should get me out of a hole and give me near enough 3km range when driven handily
But would I ever need to use it? Probably not.
I wouldn't waste the money on the inverter then lol.0 -
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A Chinesium 72V inverter would only be about €100, but yeah. Probably not going to use it. In the process of adding home attached battery storage, with an emergency supply for when the grid is down (that is very rare in Dublin) so don't need it for that either.
Ah u don't need emergency power, not like you got Well pumps and septic tank pumps to worry about 0 -
The last time we had a serious power outage lasting several hours was about 12 years ago. I was the only one on the road with a gas stove, so I was warming up baby milk for the whole road
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![[Deleted User]](/applications/dashboard/design/images/defaulticon.png)
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