How to Prolong eMTB Battery Lifespan

eMTB batteries are expensive – some are about $1000, so it makes sense to want them to last for as many charge cycles as possible. The two things that you can do to prolong your battery life is to not fully discharge it, and also, perhaps surprisingly, not store it fully charged. For example, this article shows that if you discharge to 40%, their example cell-phone battery will last 1500 cycles until it has 70% of its original capacity still functional. But if you discharge to 0%, it is only 600 cycles. They give further examples of how if you leave the battery in their example fully charged for a year at a 25c temp, it will lose much more of it’s original design capacity than if stored at a lower percent state of charge.

My 2020 Turbo Levo with the 700Wh battery can last a long time, and so I usually only need to charge it every three rides. For example, a typical ride may use 33% of it’s capacity. Charging it every ride to 100% would be bad, as seen on the charts, because that would result it in being stored 100% charged. And only charging it when it completely dies would also be bad, as seen in the other chart from the linked article. So to make the battery last as long as possible, I should ride until it is at 20-40%, and then only charge it to 60-80%. If a longer ride is expected – it is no problem to charge it to 100% before the ride, because it is not being stored at that charge for a long period of time, so for sure, charge to 100% when you need to.

The Giant eMTB has a charger with a button specifically designed for this safer storage – push the button and it will charge to 60%. But what should a Turbo Levo owner like me do? You can buy a timer like this Stanley from Amazon. When using it, my 700Wh battery went from 42% to 64% in one hour – so, 22% gain per hour. This means that if I do a ride, and my battery is at 40% and I want to charge it to about 80%, then I need should push the “2 hour” button on the timer.

Another way to look at is is that a 2-hour charge will cover any of my normal rides, so I just push the 2-hour button most of the time. If I know I want a full charge, then the 6-hour button will always cover it. If you want to know more, read the linked article, or countless others. Or just only fully charge the battery before you need to use it at full capacity and try not to run it too close to empty.

Winter Wheel Set for Turbo Levo

My previous article on an attempt of finding the best tires for my 2020 Turbo Levo only reinforced that there is no one best tire so much as the best tire for the current trail condition, so, I decided to get a second wheel set for the bike so that I could alternate between tire types – especially for winter riding.

I have come to prefer riding a normal MTB in the winter vs a fat bike because I had no luck with riding a fat bike unless the snow was thin and hard-packed. Even then, if I hit a patch of ice, it was super scary. The solution was carbide-studded tires, which are very expensive for a fat bike, but only about $150 a set for a normal MTB if you shop around. I have the Ice Spiker Pro, and like them a lot. They are even great in wet weather and grip wet wooden bridges like nothing else, though they are very loud on pavement.

The 2019 and 2020 Turbo Levo needs 15×110 thru-axle up front and 12×148 in the back with a Shimano driver for the base or Comp and an XD driver for Expert or S-Works. Also don’t get Centerlock brakes as then the wheel sensor magnet won’t mount.

There are various wheel sets on eBay in the $280 to $600 range, but I decided to give my local bike store a chance, and Rockland Cycle in MA offered me a 30 or 35mm internal width 29er wheel set assembled in Florida USA by Wheelmaster (part number 742107) using Ryde Edge M35 rims, DT Swiss 2.0mm black stainless spokes (32 per wheel), and Origin8 MT3100 hubs (36 pawl engagement vs 20 for the stock Specialized hub). It would not come with tubeless tape, valves, rotors, or a cassette, but he said he would put tape on it at no extra charge. I said ok to $269.99 plus tax, and he called me the next day saying they were ready to pick up.

Rim specs

Weight with the tape but no rotors or cassette was 1134 grams front and 1344 back, which is expected since these are rims specifically sold for eMTB, Downhill, Enduro, and Free Ride. Compare this to 1020 grams for the stock front and 1222 for the stock rear. Note that the same wheels with 30mm inner width would have saved 115 grams. So, for the same width, these combined are 120 grams (4.25oz) heavier than the stock wheels. For comparison, a $600-$900 wheel set with double-butted spokes and alloy nipples would be almost 1 lb lighter, front and back combined. Is it worth paying $300 more to save 300 grams? That is $1 per gram. Everyone can decide for themselves, but for me, that makes more sense on a Triathlon bike than an eMTB – especially since I just wanted winter wheels. But, you could get a high-end upgrade wheel set for normal use and keep the stock ones for winter.

As for 30 vs 35mm, my personal opinion is that most people should get 30mm, but a recent MBTR article said “Many observers believe the majority of riders of all stripes will settle on 2.4 to 2.6 tires fitted to wheels with internal rim widths of 30mm or 35mm, with a lean toward the latter. The Ibis 942 and 742 (35mm internal) rims, for example, outsell their narrower 29mm cousins by 9 to 1.” So, maybe 35mm is in more demand, and there are lots of tires coming out designed for wider rims.

I mounted my Maxxis Assegai and DHR2 tires easily and they inflated without tubes or sealant using just a manual floor pump. After they inflated, I let the air out and added 100ml sealant into each one using a syringe.

For rotors, I cheaped out and got $9 each ones from Amazon, and they are fine. Laser-cut steel is laser cut steel. 200mm ones are needed front and back. Problem is, these were 203mm, and that was enough to make them not fit. I used #10 stainless washers, two under each bolt, to raise the calipers, and that is working well.

For the cassette, I decided not to get another SRAM NX as there are much lighter ones for the same or less money – both the Shimano M8000 11-42 and the Sunrace MX8 seemed better, and either of those looked good to me. I ended up with the Shimano, and it is 435 grams. The stock NX 11-42 is 527 grams or so, so the change was within 1 oz of making up for the difference in wheel weight. You will have to either move the speed sensor magnet, or get a second one.

Once everything was mounted, I did a wet-weather run with the Assegai tire, and then the same route with the Ice Spiker Pro. The Assegai was great on the trail in general, but I could make it slip by testing panic stops on wet wooden bridges. Not so with the Ice Spiker – it was like Velcro ® brand hook-and-loop fasteners even on wet bridges. Shifting stayed indexed on both cassettes, and after some adjustment, either rotor worked with no rub. The same brake lever Deslackinators worked fine as well. I will warn that had I tried to go to a 46-tooth cassette, the chain might not be long enough to continue to work with my 38 tooth chainring.

In summary, these wheels are good for the price, but heavier than wheels that cost 2-3x as much. You can probably get a stock wheel set as a takeoff from someone for the same price, but it is unclear if that is better or worse – especially since this rear hub has more engagement points. They both will have 2.0mm non-butted spokes and brass nipples, and I don’t know which which hubs will last longer. If, however, you want wheels that are an actual upgrade, you should look for something with lighter hubs, and rims made from 6069 alloy. In doing so, it is easy to spend $600 to $900 for better alloy wheels that save about 1lb of combined weight, or you can just lose 1lb of weight off your body.

eMTB Tire Review – DHR2/DHF vs Assegai vs Eddy Current

My 2020 Turbo Levo Comp has 390 miles on it, and am loving every minute of it. While not perfect in every way, everything that I have had an issue with I have been able to address. For example, the suspension was very bumpy, but I solved that by removing the tokens from the forks and rear shock that the factory opted to pre-install. The brake levers had way too much slack, but I fixed that by designing DeSlackinators. The 32-tooth chainring didn’t allow me to pedal much above 20 mph unless I was turning more than 100rpm, so I changed that to a 36 and later to a 38 – and then designed a chainguide adaptor to keep the factory look. Even the 38-tooth ring has been no problem for climbing the steepest of hills, making me wonder why it had a 32 to begin with.

During this time, I learned a lot about tires. I rode the original Specialized Butcher/Eliminator 2.6″ tires for 72 miles and knew that they had to go when they slipped on wet roots more than I think they should (based on my experience with my Nobby Nic Addix that I am happy with on my manual bike). While I don’t ride on wet roots often, it is not the every day case that I need extreme grip for. It is more the occasional scary surface is what I want to be protected from because any tire does ok on normal surfaces. My rule for tires is to always get the best, but the hard part is finding out what is the best, and the best for one riding condition will not be the best for the other.

Some tires I was interested in were Maxxis DHR2/DHF, Assegai, Schwalbe Magic Mary and Eddy Current, and Michelin Wild Enduro. I started by getting the DHR2/DHF in 2.6″ width, 3C MaxxTerra, EXO+. I rode them 272 miles in dry and wet conditions, going for Strava eMTB KOMs in dry, and trying to hit every root in wet. I am 142lbs/64Kg and used them at about 18psi rear and 14 psi front, just like the stock Specialized tires. At this pressure, they were about 2.45 inches wide on the casings on my 30mm internal rims. I could tell right away that they were amazing, and I was not able to slip on the wet roots that caused me trouble before. I also did intentional panic stops on wet wooden bridges, also without any drama. Also, even though the knobs are not massive, I did not break traction climbing the steepest of hills, even when they were sometimes not the most firm dirt. Great all-around tires for sure.

Still, I could not leave well enough alone, and was dying to try the Eddy Current because they were said to being designed without regard for rolling resistance. That is bad right? Yes. But, I figured they used a really soft compound that would give them amazing traction in exchange for that added rolling resistance – and since it was an eMTB, I would only give up battery life and not really any speed. I got the 2.6 inch front and rear. They also measure about 2.45″ casing width at the same pressures. As of this writing, I have 46 miles on them, and I learned something interesting: The open block tread pattern feels weird on roots and solid rocks. You can sometimes feel the knobs snap off the root, and that is an unpleasant and sometimes scary feeling. And the same time, that large open tread has got to help on mud and sand – perhaps making them great winter tires. But for me, the wet root thing was still on my mind – I didn’t like these tires for where I rode, and decided to go back to Maxxis – but not before I tested rolling resistance.

There is a website which I love – but I asked the author if he could review more tires like the DHF and Eddy Current. He explained that people who buy aggressive treads just don’t care about rolling resistance so he was focusing on tires designed for efficiency. I took this to mean that people care about tire weight, but not the much more important rolling resistance – probably because it is hard to measure and quantify. So how could I find out which tires rolled the best? In general, when reviews say a tire “rolled well” or “did not roll well,” I don’t trust that they even can tell.

So I devised a test and rode a pre-planned trail-ride with the Maxxis and Eddy Current, both at 100% assist, and with me trying to end with the same segment time. I wanted to see how much battery the bike used up for each tire.

The test was successful. The DHR2/DHF won the rolling-resistance test. As far as I can tell, it rolls better, and there is certainly no evidence that it rolls worse! So, good job Maxxis with that tire that is also plenty grippy.

Now I wanted to test the Assegai, and went all out and got them in MaxxGrip with the DoubleDown casing. While the Assegai had an astonishing amount of grip on the forest floor, they were actually slipping on wet roots, even though they are MaxxGrip, so they were not infallible either. I also almost crashed when the front hit a minor patch of shallow mud – I bet the Eddy Current front would not have blinked at that. I am thinking I prefer the DHF MaxxTerra to the Assegai MaxxGrip, all things considered (price, weight, grip, rolling resistance).

Other factors to consider was that Maxxis installed really easily – I could probably do it without tools, which would be helpful for field repairs. The Eddy Current were the opposite – I broke a tire lever and needed to use a Pedros lever to install them – and even then, at great difficulty. A function of the super-tough sidewalls, so perhaps for the extra effort you get durability. I have seen people tear the Maxxis EXO+ sidewall on their Turbo Levo rims and don’t see any chance of that happening with the Eddy Current. In fact, I hit a hard object and my rim edge did put a hole in my DHR2 that I later patched from the inside.

So what will I do going forward? I think the DHR2 or Eddy Current (rear or front) are great rear tires. For a front tire, I will stick to the DHF 3C MaxxTerra EXO+ after I use up the Assegai. I will skip the Assegai MaxxGrip DD due to the extra energy required and weight, as that makes my 700Wh battery behave as if it were a 630Wh. I am about to test Magic Mary, and will update this when the results are in.

Making “nylon-like” Resin

Most resins are hard and can crack when dropped. There are some great “tough” resins such as Siraya Blu and eSun Tough, but what if one doesn’t want clear? I needed a white. I tried adding white opaque pigment to Siraya Blu, and it was promising, but the blue color was evident and it was just not white enough.

Elegoo white is often on sale for $38 per KG at Amazon with an extra 5% off if you buy several, but it is a normal modeling resin, which is designed to be hard and detailed – and my part was cracking the first drop at one meter onto a hard floor. I decided to see if adding in Siraya Tenacious would solve that.

Tenacious is a clear and flexible resin that when used by itself, can form flexible rubber-like parts such as watch bands or tank treads. When used for thicker parts, it behaves more like a urethane from skate-board wheels and feels solid. The nice thing about mixing in Tenacious is that the exposure happens to be the same as Elegoo White, so the same settings work for any ratio – though optimally another second or two is best, and base-time can be lowered.

I tested Elegoo white dropped from 1 meter, and it failed first drop. I then repeated with another sample, and that also failed on the first drop. With 33% Tenacious, 10 drops were not a problem. Now we are getting somewhere.

The color does turn into a warm/yellowish white, but I am happy enough with the look, and recommend 33% Tenacious mixed with a hard resin for an affordable nylon-like blend. This is a simple 2:1 ratio, so easy to mix up with whole bottles.

Networking with the EPAX X1 LCD-SLA Printer

The EPAX X1 is capable of networking using hardwired ethernet. To set this up, first install the latest firmware from here:

To install, put both files onto a USB memory stick, insert the stick into the printer, and power on the printer. You will hear a series of beeps. Wait until they finish, and then check the version using the Info screen to make sure that it updated.

Now unscrew the four screws on the back side of the enclosure, and plug in an ethernet cable (the green cable in the photo). Plug the other end into your router or switch.

Using the front panel control, enter the network setup area:

Now toggle the network type. While WiFi is shown as an option, there is no WiFi hardware inside the printer, so you must use a cable. Push the switch in the upper left of the touch-screen to enable the ethernet connection. If you see an IP address fill in, it is working. A green LED should now be illuminated where the cable plugged in.

Now load the latest version of ChiTuBox, version 1.4.0 or newer, and slice a file. You will be presented with the option to save the sliced file, or send it to the network.

Select “Network Sending,” and you should see all of the EPAX printers that you have connected to your network. If this is your first time, you may need to select the refresh icon.

Note that you can click on the pencil icon and rename what each IP address is called.

Now press the send button. You should see it showing the progress where it says “Send file to the printer…”

When the sending is complete, it will ask if you would like to print the file. If you say OK, then it will start printing. If you hit Cancel, then the it won’t print, but the file will now be on the printer’s SD USB memory card for you to later start it manually from the printer’s touch screen.

If you would like to make the machine wireless using WiFi, you can probably make it work using a wireless bridge. Here are some untested referral-link examples:

I hope that helps get you up and running without resorting to the sneaker net.

On the difference between DLP and LCD based SLA printers

Laser, LCD, and DLP are three distinct methods of exposing a light-sensitive resin in layers to cause a cross-linking of liquid polymers, curing the liquid into a solid object. All of these are used within SLA printers, a term used to refer to the stereolithography process. There has been a disturbing trend to refer to LCD printers are “DLP” printer that started when lower price-point manufactures began to use the already-taken “DLP” term for marketing purposes and claiming it was ok because their LCD does light processing using digital signals. Doing so, however, is like calling a gasoline-engine car an electric vehicle – something that it is not – just to confuse consumers into thinking that they are getting something often seen as more desirable but at a lower price.

Laser, (originally L.A.S.E.R as an acronym for Light Amplification by Stimulated Emission of Radiation) uses galvanometer scanners to direct a light beam via vector and raster scanning. The process is fast for smaller object, but get progressively slower when it must draw out more objects. The advantage is a smooth surface finish and compatibility with resins high in polymer content for the strongest resulting parts. An example of desktop laser-based SLAs are the Peopoly Moai and the Formlabs Form-2 printer.

LCD is a variation of SLA that uses a Liquid Crystal Diode display, the same as in most laptops and mobile phones, as a mask. It is also known as MSLA, or masked SLA. A light source is placed on one side, and the resin on the other. Because the entire layer can be exposed at the same time, they are generally faster for printing more or larger objects. Example of LCD-based SLA printers are the Anycubic Photon, Wanhao Duplicator 7, and the EPAX-3D 1X. One reason why LCD still remains on the low end, because the fact that they can simply be manufactured for less cost, is that there is a limited amount of light that can pass through the LCD panel before it overheats and self-destructs. This limits the speed at which printing can take place. To help make up for this lower amount of light exposure, the resin makers increase the monomers and photo-sensitive initiators, with a resulting increase in potential for shrinkage and weaker parts. In reality though, due to advances in resin such as Siraya Labs Blu (the strongest LCD resin I have tested) and eSun Bioresin (the strongest solid-color LCD resin I have tested), some very strong parts can be made – just as strong, if not stronger, than PLA and ABS parts on FDM printers.

DLP uses a digital micro-mirror device in which light is reflected through a projector lens and onto a tank of resin. Because this matrix of mirrors can be well cooled, a lot more light can be directed than with LCD, thus making it the choice of larger, faster, and more expensive printers that can still make use of less sensitive and stronger resins normally reserved for laser. The downside being a higher price point, taller printer size, and sometimes lower resolution because DLP chips tend to max out at 1080P.

But you may ask – why is it not ok to refer to my LCD-based printer as “DLP” when the manufacturer says it has light processing and is digital? The answer is because the term DLP was already taken for a digital micro-mirror projector device, and there would be no distinction between the technologies, both of which are used in resin printers, if you used the same term for both.

Here is a video showing a DLP chip in action:

This is TI explaining their DLP reference design. Notice how it does not make use of an LCD:

Examples of some DLP printers are:



Milkshake 3D:



G3D T-1000

FlashForge Hunter: