Battery Reading Variance

I'm a new Evolve rider and came from a boosted. Liking the improved range already and the AT tires are a nice bonus. I know the % indicator while riding can fluctuate a lot depending on the speed/load you are putting on the board. I have not yet drained the battery completely, but want to know what number to trust. I've seen the reading hit into the single digits while under load but back into the 20-40% range at rest. Which number should I more pay more attention to?

 

Seems to be more susceptible to dropping into the red under load than the bigger carbon battery. Even at 50% I can drop to 4% then back up on BGT. Doesn't happen on the CGT.
People agree? it's a annoying as its already a smaller battery and then it cant handle load half way through its kilometres of potential range.

 

Now that I've gone out a bit more on it I am noticing that as well. I can get it to 0-6% and it keeps going then will go back up to over 50% after that. It's going to take a while to get used to how far the range is based on usage. Today my trip to work was cold, slightly uphill most of the way, and with a strong head-wind. Seeing it drop so far so easily made me worried about making it the 8km. Got here no prob, just hard to base things off of.

 

I also noticed battery indication quickly dropped in red. After around 12-14km it was below 20% and even further down to 9% when I switched to fast. Back to eco it went up to 35-38%. So difficult to read the true range still to be available.

As the board is new (this will be the first charge cycle) would the battery also need a little time to give maximum capacity?

Will do AT setup tomorrow and see what is does on range

 

I need to switch to street to get more range I think. I'm a heavier rider so the larger AT wheels are probably making it exponentially worse. I'm a fast rider. The idea of putting it on eco pains me. I was setting it to GT after 5 minutes of riding and I don't see myself changing it from that.

 

I ride the same way ;-)

 

I personally GT all the way. You can use the same amount of current if you go the same speed and feather the trigger if you are conserving juice.
Eco is a waste because even a head wind slows you down and fast can't get up hills adequately. Might as well stick to GT and reduce the variables.
Do you know you can fit a 10ah battery in the bamboo case dimension wise. You have to get it made with higher capacity cells though which is expensive.

 

Has anyone actually got 'Bat drain' to come up on screen when under load? I mean when they know the battery has over 30% left but they see it drop over 30% into the red? I just tested a few times. It gets to 0% but didn't cut out. Maybe we just shouldn't look at the remote so much!
See vid

 

Just done 3km with at setup few small Hills and on fast. 60% on the remote as indication.

 

Do you know the capacity of each stock cell? Have people managed to swap them out?

 

I've seen the pack rated at 6.5Ah online, and I've seen pics of the pack marked 7Ah. I have also seen it, though not officially, to be a 10s3p or 30 individual cells. I'm no expert, so someone please correct me if I'm wrong, but this puts each cell at between 2166 and 2333 mAh, or perhaps 2200 to 2400 mAh. I don't know if something is lost in building a pack, LMK.

Anyhow, if a similar sized pack was built with 3400 mAh cells then, perhaps, we could see a pack at 10.2 Ah (or 10) similar to the capacity of the CGT. If so, then I'd suspect the same range and performance the CGT has. I'd love to have the benefit of improved range and less voltage sage, if this is possible.

Who can clarify all, or any, of this? If this type of scenario is possible, who could build a pack for me and make it available to me here in the United States?

I prefer the look, size, and feel of a bamboo deck to the carbon. I originally ordered a Bamboo, but changed to a carbon after considering the range. I will be using AT almost exclusively due to poor quality Houston roads and sidewalks, or lack of sidewalks. I'm also a bit of a heavier rider at just under 90kgs or 200Lbs. So, I'd gladly pay the difference between the CGT and the BGT to get a battery that provides CGT performance on a BGT.

Now, I have no idea what's possible for upgrading the CGT battery, but if it's amazing, well, I might consider a CGT with upgraded pack the ultimate. Anyone know, or have a good guess at the battery pack configuration of the CGT and what possibilities it might allow for with upgraded cells? If an upgraded pack in a CGT can could get me about 50 kilometers or 30 miles a charge on AT (and even less voltage sag) I'd be all over that! Especially if it could be done for around $500 USD or less.

 

Hey Thom with amp hours! (...Username)
The batteries need to be able to cope with an millisecond instant discharge of 80a I have been told. Even though the GT is only putting 12a or so to each motor.
So the problem with the higher capacity cells is they can't possibly handle the current draw needed and may trip the power and may not last as long as well.
I am definitely not an expert on this, but have been trying to interpret the experts who are 'currently' making my battery. There is a lot of info I am just taking on board but not really understanding properly.
I made a bigger deck so I could extend the battery, but they recommend not joining old cells with new cells and can't match the stock ones so we are doing one large 15ah or so for my maple GT.
We are using 60x ur18650nsx 2600mah (20a) and just more of them which will extend the range by over double.
We could use a higher capacity cell 3000 or so which had only (10a) load. But I wasnt going to risk it cutting out all the time for the extra capacity.
I think this makes sense?

 

Thanks for sharing. "a h" username, funny.

The amp load capabilities of the pack wasn't something I had even considered. So you'll have 20c3p? Will you have a different BMS too? Also, I assume you then need to make, or have made, a custom shell for the electronics and larger pack, right? Do you have a build thread going somewhere? I'm curious as to who's doing the pack, and other work. If you'd share that'd be great.

I did find some 18650 cells with 3000mah capacity and 20A capability (Picture attached). Is price a restriction to using these, or something else I haven't considered?

How is the discharge of a pack calculated relative to it's configuration? If each "P" or group of cells is essentially one larger capacity cell with the same discharge amperage characteristics, does that mean a group of 3 20A packs will be able to handle only up to 60A? Or, is there some other math I'm missing. I assume your new pack is capable of 80A discharge, but is it more (or less) capable than that? Is there any reason to build more capability than 80A into a pack if that's the max the BMS allows?

What about charging Amps? If more, or more capable, cells are used can they be charged at higher amperage with less ill effects? I know the standard GT charger is 2 amps and the fast is 4. I've read that the quick charger is worse for the battery pack, but don't know how much worse, or how a pack like yours might be effected differently, if at all. I assume with twice the capacity would come twice the charging time.

I really like the sound of what you're doing. I really want to ride all day on AT. Street wheels on my other boards just don't cut it here. I'd love to find a way to maximize my range on a compact, flexible, sensored, AT setup. If I've asked too many questions, I apologize. I'll gladly take a link to any resources you might know of which would allow me to find my own answers to the configuration questions. Or, contact information for an "expert" who'd be willing to build me a pack of my dreams.

 

I was at first planning to make my own board but then got the boosted, wasn't happy, so got the Bamboo GT. Before I changed my mind from DIY I had managed to collect over 400 18650 battery cells (my work throws out a lot of laptops with batteries in great condition). I don't really want to mess with the internals of the evolve but it's tempting.

 

I think it will be 6 lots of 10 cells.
Or 5 if 6 won't fit in the enclosures we using.
So I think that means 120a or 100a peak available.
If we used the 15a cells and could only fit 5*10 then the total would only be 75a. Trying to get the 80 to be sure we don't get cutouts. Not even sure about the 80a. It could need more so playing it safe.
I have been assured that the stock bms will handle the upgrades specs. Fingers crossed or I am stuffed, up for a new evolve stock battery plus $700 AUD out of pocket for this new battery. Hmmm
I am not sure why we didn't use the 3000 20a. But have sent him an email to confirm.
I can also try to get a few of your other questions answered.
Well be able to answer in a few weeks when it's done and working and I can breathe a sigh of relief and double my range and hopefully not get that voltage sag... fingers are crossed.

 

Could you explain the math on how 6P to 5P drops you 45a to 25a? Also, what does the stock 10s3p battery provide? Seems like it almost have to be less than 80a unless they're using 30a cells. But, it seems 30a cells wouldn't allow for a 6Ah pack.

I really look forward to seeing more of your project's progress. Did you make the maple board yourself?

 

Just did another ride. It's crazy how much it varies. Started the trip at 90% and got to the store with 70%. There is uphill sections both ways so it should be a fairly even trip. On the way back up the hill it was at 0% for the steepest part. Stayed at 0% for 100-200m. At the top it came up a bit. When I was done it was at 50%. It makes it impossible to judge how much battery there is unless you are at a stand still.