s-petersen
100 mW
Next good day I will give it a more thorough test, The new seat is not here, but the 30A fuses and tiedowns arrived.
Building my first e-bike, questions
- Thread starter s-petersen
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s-petersen
100 mW
Rode it 7 miles, and it works great! Battery was at 75% when the ride was finished, My only pedaling was on the steep hills, and it wasn't bad. I wanted to test out the system worst case, by me doing the least, top speed was 26mph, I have the "road legal" wires connected, and amperage limited to "20 amps" according to the controller, but I think it is still putting out more.
Pedal assist is not hooked up yet, I have to get the tool from a friend of mine. What level should I charge it? 100% before a ride, or less after a ride? New seat soon! (below), my butt is too big for the original one! Edited for clarity.
Pedal assist is not hooked up yet, I have to get the tool from a friend of mine. What level should I charge it? 100% before a ride, or less after a ride? New seat soon! (below), my butt is too big for the original one! Edited for clarity.
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Chalo
100 TW
That seat is more than adequate even for a giant butt. You can't expect to be comfortable immediately while doing something you have no conditioning for. Fine tune the angle and give it a few rides. It's as likely to be too big as it is to be too small.
s-petersen
100 mW
That is the replacement!
MUCH has been written here on ES about maximizing Li-Ion battery longevity by not charging to 100%, nor discharging to 0%. You can search around here a bit to get a feel for it.
Easy rule of thumb for you at first: Limit charge to 80-85% before a ride, don't discharge below 30%. No need to charge immediately after riding-- the battery does better stored at 50% or less (say 35-50%). NEVER let the battery sit at 100%.
My own experience with flat culprits is (in order):
- Glass shards
- Bits of wire (as if from a wire brush)
- User error (pinch-cutting the tube when using tire spoons sloppily)
- Screws, nails, etc.
s-petersen
100 mW
"which caused an immediate exciting blowout." certainly don't need that... I have also heard low tire pressure, and curbs will do it
s-petersen
100 mW
Drove another 11 (18 total) miles without charging, down to 64% Blew the 30a fuse 2x properly in the middle on tough hills, I set the controller to 15a,(p14 on the controller) and it seems to make no difference, still getting 900+ watts (36V) with full throttle. Controller still says 100% battery, I think it is set for Li-on batteries, instead of Li-fe , I don't think that can be changed. Fuse holder and fuse is not really hot, but the 30a Chinese fuses may be the issue. I dunno...
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Is this that customer-return kit? Maybe the problem is that the display isn't sending data to the controller or controller isn't receiving it. In that case, no changes you make to the settings will be saved to the controller, so it will just run at whatever it's power up defaults are. Does it change behavior in any way, based on assist level changes? If not, this is a likely problem. Some systems give a comm error (E30, etc) in this event, but some only do that when the display can't read the controller, not when the controller can't read the display.
It can also be that the display has the wrong firmware for the controller it's paired with, so that it's data is the wrong format or the wrong values, so the controller ignores it. That's less likely since the display is providing you with the watts (which has to be calculated by the controller, or is based on amps that has to be calculated by controller).
I have a Lishui-based system with Kingmeter display, IIRC, that always reads as if it was LiFePO4, and all the Lion batteries read full even when they're not until they're much less than full because it expects a lower voltage total.
If yours reads full even at only 64% for a 12s LiFePO4 battery, it's probably not using the right battery voltage range or is set for the wrong battery voltage entirely. Your battery should be at about 3.2v x 12x = 38.4v. Is that the voltage you see at this point?
A LiIon battery at that SoC is probably around 3.8 per cell, at 10s, so around 38v, so even if your display's meter was set to LiIon it should still show about right for your battery.
If your display is set to 24v battery, then it would show yours as full all the time, even when completely empty.
If the fuse holder or fuse are increased temperature under normal operation, something is wrong--either the parts are defective, or insufficiently capable for the current flowing thru them.
Also, keep in mind that fuses are "precision" parts, in that the fuse wire itself must be exactly the right metal composition and the right thickness / length / etc in order to correctly blow for a specific current rating.
If you look at the spec sheets for fuses such as those at Eaton / Bussman / etc, you'll find a chart in them that shows you how long a fuse takes to blow at a specific current. That is so that a fuse can be properly specified for a system, so that it will blow before wire / etc damage occurs, but will *never* fail under normal usage. It takes a certain amount of time
To pick the right fuse you need to know how much current you will have in that normal usage, *and* how much current will damage your wiring that the fuse is protecting (all the wire beyond the fuse point, which is typically right up at the cell block inside the battery, so that any short circuit that could cause a wiring fire instead blows the fuse without damaging any wiring). It
So the smallest wire in the battery + or - wires (the current path) is the weakest point, and whatever current it is meant to handle is the limit to pick the fuse for--the fuse should always be picked to blow before that current is reached.
But the fuse should be picked to never blow when normal usage current is reached and sustained, "forever".
If the fuse keeps blowing, then one of these is typically the problem, in the order they usually are seen in:
--a wiring fault exists (intermittent short, damaged insulation, etc)
--fuse is sized too small for the load it must handle
--fuseholder is not holding the fuse right and causing so much heat it melts the fuse; this always causes wiring insulation damage and usually causes melting of plastic parts nearby.
--fuse is defective or poorly manufactured
docw009
10 MW
If you can do 100% before a ride, no one will complain. If you do it after a ride, that hurts longevity, but it's LiFEPO4 isn't it. I thought those lasted for thousands of cycles with most any charging scheme.
s-petersen
100 mW
Yes it was the customer return, It looked like it was never used, except for the shipping damage. The controller "works properly", in that the settings are saved, and when I mistakenly set the wheel size to 20 inch, the bike got real fast. The pas is set at max, but the sensor is not installed yet, so it is inactive. My battery voltage rating on the label is 39.6v at 364 wh and tops out at 42.5v at full charge. The controller is set to 36v. The controller is rated for 26a according to the sticker, and the default setting in the controller. I installed 30A, because it is not supposed to blow at currents below that level. Unless the amp rating is average current, there should be no issue. Last time the fuse blew I set the controller current limit to 15a and it still output 900+ watts and the fuse blew again later. There are no shorts, no chaffing wires, and great performance,si I don't think much is wrong. There is one thing, I just thought of, is to disconnect the electronic braking, it may affect something, as I installed the wires to the board.
My battery is 12s, and the display on the battery is configured for that. top charge for LiFe is 3.65v which is 43.8v
so the battery meter on the pack is pretty accurate, my charger cuts off to a trickle at 42.5, unless I leave it on for an extended time, but I am not comfortable leaving it unattended. The fuse holder does not get excessively warm.
Likely
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