Voltage while riding. How do I know how much juice I have left?

[jigs]

I just got my Luna a couple days ago. KHS1000 with BBSHD motor. I LOVE this thing already aside from how the battery is mounted. 3 skinny zip ties holding it to crappy multi-layer glued rubber? Really? On a $3000 bike? And who's kid is cutting the stickers? Do you guys wan't me to machine a sheet metal stencil to trace with the razor? I'm serious, I'll send you one. Anyway, with my last bike and dashboard there wasn't much to see. This one has the 750c dash which tells you how much wattage you're pulling at any given time, which is great. Do I shift, do I put more leg into it, etc.

The battery meter however is completely unpredictable. I was out yesterday and at one point I had it almost half way down. "crap" I thought. I better head home (lots of big hills here). The battery meter started coming up on the way home and by time I got home and let it sit for a couple minutes it was back to 50 volts.

Is there any way to get a better idea of how much battery you have left? I have the meter set to volts as instructed by a tech at luna, not %

[paxtana]

You could wire in a batt-man between the battery cradle and motor for more accurate representation of power consumption. For the battery maybe switch to metal zips? Not sure if done on that model but at least previously we put neodymium magnets at the base as well to help with rigidity.

[paxtana]

We are sold out so it might be autohidden.

https://lunacycle.com/gauges/batt-man-ebike-amp-hour-fuel-gauge/

[g725s]

OK. Do you assume since Luna has sold them before but now they are sold out that Luna is planning on getting more of these in stock?

[paxtana]

Yes we will definitely have it restocked but it could be several weeks.

[calfee20]

That sounds like normal battery sag. If you are pulling a lot of amps the voltage can drop quite a bit especially on smaller amp/hr batteries. The voltage will come up somewhat when you let the battery sit.

As far as the bike itself, Luna is a small group of enthusiasts that are putting bikes together that are not available anywhere else. http://lunacycle.com/blog/luna-cycle...y-buy-from-us/ I was working on a Radcity for a friend and had to fabricate a bracket just to mount a water bottle. The spacing was to large for any water bottle bracket I have ever seen.

You are trading power and performance for a little bit of fit and finish. You could also buy a $5000 factory bike and then get blown away by some ebayer who managed to get a good battery and controller.

[ykick]

52V Shark pack powering BBSHD whenever I see about 46V UNDER LOAD I know that to be quickly approaching empty. Somewhere around 40-42V under load you’ll find the “cliff” and a cell group will touch ODDV (over discharge detection voltage) which causes the BMS to cut power.

Full power BBSHD (30A) can sag 14S4P GA cell shark pack 5-6V easily and perhaps more if the pack isn’t conditioned and balanced correctly.

People can calculate pack DC IR (internal resistance) rather easily using a color display. Take note of the resting voltage - let’s use 58V. Dime throttle for 10s (seconds) then note of the peak Watts and the lowest volt meter reading. Somewhere around 1550W @ 52V is basically 30A.

Subtract 52V from 58V = 6V drop @ 30A. Do Ohm’s law - divide 6V drop by 30A x 1000 = 200mOhm total DC IR.

Now, since current is the same through each series group divide 200 by 14 (number of series wired cell groups) = 14.3 mOhm. This value is “fraction” of an Ohm. 14 mili-Ohm isn’t bad IR for 4qty 18650 GA cells in parallel group like the shark pack. In this example each cell is exhibiting about 57mOhm IR.

DC IR is a good number to know in the beginning of a battery pack and useful for comparison later as the pack/cells age and also during colder weather and lower SOC (state of charge) these numbers will go up. Sometimes dramatically.

$3000 IS a lot of money but when you add up all of the parts along with the bike IMO it’s fairly remarkable how it can sell for only $3k...

[HIGHVOLTAGE]

A lot of misconception from people thinking these are full production bikes similar to something from Kickstarter or an brand name E-bike like Stromer. These are custom builds based around high quality brand name bikes like KHS & Giant. A large portion of the pricing comes from the actual bike value itself (Seriously, look up the value for some of these bikes, Giant Anthem, KHS 1000/500 etc etc), which if you tried to build one yourself using the same components, you actually wouldn't save yourself that much more money and it would be a ton of extra labour & skillsets involved that for some would end up just being far more expensive than just buying our builds.

So don't think that's just cause it's a $3k that it means it's a luxury bike. Many luxury bikes will sacrifice performance & power for features & usability but that's not really been our philosophy here. We love speed & power and sometimes you gotta make sacrifices to keep the pricing fair. You're free to modify the bike & improve it's design to your hearts content if you wish though. We love seeing all the different solutions our customers come up with to remedy these small issues.

[jigs]

A lot of misconception from people thinking these are full production bikes similar to something from Kickstarter or an brand name E-bike like Stromer. These are custom builds based around high quality brand name bikes like KHS & Giant. A large portion of the pricing comes from the actual bike value itself (Seriously, look up the value for some of these bikes, Giant Anthem, KHS 1000/500 etc etc), which if you tried to build one yourself using the same components, you actually wouldn't save yourself that much more money and it would be a ton of extra labour & skillsets involved that for some would end up just being far more expensive than just buying our builds.

So don't think that's just cause it's a $3k that it means it's a luxury bike. Many luxury bikes will sacrifice performance & power for features & usability but that's not really been our philosophy here. We love speed & power and sometimes you gotta make sacrifices to keep the pricing fair. You're free to modify the bike & improve it's design to your hearts content if you wish though. We love seeing all the different solutions our customers come up with to remedy these small issues.

I was just joking about the stickers and didn't mean to offend anyone. And as far as the zip ties go I just doubled up with some more heavy duty ones. The battery sits tight now. I'm a sarcastic person and need to remember you people don't know me and my sarcasm would be lost in text. I was actually going to buy a second battery.

The problem is the bike is totally useless to me now. It's been in my basement with a clicking charger for 3 days, I've had it for 5. 38 miles and I have a dead bike. I hope someone is going to send me a new battery or charger or whatever the problem is. Joel was great on the phone and explained a lot to me and I believe he opened a ticket as well, but this is ridiculous. I shouldn't have to open a ticket for a bike that I JUST purchased and lasted two days and 3 or 4 charges. If you're that busy you are NOT a small company.

I went with you because you build off good bikes. I love the KHS 1000 and I thought the custom battery was great, that's why I bought The bike. I also liked the fact that I had more control over the bike with YOUR controller, but if there was a cut-off or something you removed that would kill my battery I should have been made aware of that. The bike came with zero documentation about batteries that you guys are making. It was recommended to me to spend the extra money on that charger. A lot of good that did me.

And if they are built off other bikes, where are all those parts? Shouldn't they be mine? This bike is completely useless to me now and because of the custom battery I'm stuck with nothing. I can't even stick in a regular battery or use it as a regular bike short of cutting out the battery.

My real name is Phil Abrahamsen if anyone cares to look into this

[calfee20]

I sincerely hope you have opened a trouble ticket with Luna. I am sorry you are having this problem which is almost the worse one. If it were me I would get an advanced charger ASAP regardless of what Luna will do for you. You should always have a spare charger. One forum member with the clicking problem mentioned that he got a deal on an advanced charger. If you get an extra battery you will want two chargers anyway.

[paxtana]

Hi Phil we have marked to send you an adapter that will fix the issue with the clicking charger. Should be able to send it out within a few days.
If you prefer to exchange it for one of the standard chargers we can do that as well and might be able to get it to you a little faster. We would cross ship the replacement and refund you the price difference. Just email support and say this was authorized by paxtana.

Please email support next time you have a problem that needs troubleshooting, phones aren't really meant for that and Joel can only do so much because there's no paper trail on a phone call and we need to be able to keep track of everything said and done in order to properly address an issue. As well as being able to exchange links and pics, none of which is possible with phone calls.

[commuter ebikes]

My extra charger has saved me in at least one critical situation. I bought it in anticipation of a future charger failure. The anticipated charger failure did eventually occur, and I used my spare charger while the replacement was being shipped. I don't own a car and I don't ever plan to buy one, so I need to keep at least one ebike operable for commuting to work.

BTW my batteries and chargers are all interchangeable for all four of my ebikes. It is nice to be able to use any battery for any bike and any charger for any battery.

[jigs]

I apologized in the other thread and in PM to ykick about being a loudmouth ass on the board. I was very frustrated. It's no excuse but it happened. Sorry to muck up your threads, gentleman

[commuter ebikes]

We have all been very frustrated at times with our experimental vehicles. It is definitely worth it once you get over the hump.