Like the title says. Is it possible to install LiFePO4 batteries in the Evolve GT? As much as I love this board, the voltage sag is ridiculous and the only board I know that uses LiFePO4 is the Boosted Board. How would this affect range/performance? Would the board even work or would the BMS fail to work?
The BMS wouldn’t work and it wouldn’t be safe to even use it since it would be charging at a higher voltage compared to LiFePO4 cells.
You’ll be getting less range for sure in the same space.
I am pretty sure my Boosted Board doesn’t say that much and my DIY board with the same battery as my Boosted didnt sag much either.
Shoot. I wonder how much it would cost to change the battery and have a new BMS+ESC. I really like the integrated deck concept of the GT - haven’t seen anyone else do it. Carbon fiber is a pretty awesome material.
I would be interested in what you experience and feel when the voltage sag is present. And do you also have that issue with the street setup? It also would be interesting which kind of cells they use.
Board I Use: Evolve Carbon GT
Battery They Use: 360Wh(36v10ah) 10s4p Li-ion
My Experience: Part 1 - 100% Charge: When you’re charged up to 100%, the voltage sag makes no difference in the performance of the board. The only reason I could tell the battery was sagging was because the percentage on the remote dips heavily. However, after reaching max speed or cruising speed, the battery percentage goes back to normal. Until you fall below 50% (12ish miles) you can floor the board and ride it as hard as you want with no issues. This is all in GT mode by the way. Part 2 - 50% Charge: However when you fall below 50% its a completely different story. The board will be fine, but you won’t be able to use GT or FAST mode for very long as the battery sags below 20% and switches to ECO mode. This is a safety feature as Evolve doesn’t want the board turning off on you sending your face into the pavement. If you stay in ECO mode for the rest of the ride, you’ll be fine. That really is the only issue caused by the voltage sag. Oh, and the fact that the battery percentage indicator is pretty much useless.
In short: I still love the board.
A lot. Basically a whole new build except for the motors and deck.
A new intelligent BMS is going to be like $100 like Raphael Chang’s BMS.
A new set of ESCs will be around $200-$400.
I can’t believe Evolve is using a simple voltmeter for remaining battery capacity… it is a $1500+ board lol.
So basically you can only have fun until the battery gets to 50%? Then you can’t even climb a hill?
Pretty much. You’ll be able to climb a hill, but fairly slowly and maybe about 20% grade at most at a snail’s pace. Honestly a board that costs $2K should’ve been better designed. The real appeal for me was the integrated enclosure - that was pretty much 100% my selling point. But I can say for now, that if you want a prebuilt board from an established company, Evolve is the best.
I think the more relevant questions are firstly; what are the dimensions of the CGT battery compartment, and secondly - what are the alternatives for configuring LiFeP04 cells and a BMS within that enclosure to give you less voltage sag with equivalent (or better) performance?
I just unscrewed the board to measure it out and here are the rough measurements for the compartment:
Length: 59cm (23.2 in.) Width: 13.5cm (5.3 in.) Height: 2cm (0.78 in.)
So just based on height, A123 26mm cells won’t be a possibility(Boosted cells). I guess you could go LiPos?
Have you ever tried another evolve CF GT to compare battery sag experience? Or another evolve battery in your deck, if you have any local esk8 to test with.
I don’t know anyone else with an electric skateboard - much less an Evolve board . But based on what I read online, the voltage sag is a common issue - in fact its common among all boards that use Li-ion cells but you can really tell on Evolve because of the powerful motors combined with the battery meter on the remote.
Aren’t LiPos unsafe? I also feel like charging them would be more complicated and annoying.
How about these?
I know they are 18650, but would the fact that they are LiFePO4 make a difference?
You should check out my latest 4wd build. I use wood, which is more flexible (not a lot of flex, but enough to absorb some road vibrations) and more durable than carbon fiber. Chaka’s free ride deck uses the same idea (I got some of my ideas from his deck). I should have hollow core decks ready for sale in the near future for sale. And I’m working on a complete also.
With my 4wd hub motor board, I can climb 20% grade hills at speeds above 20 mph… This is the kind of power my completes will have. Everything on the market right now is a toy. But 2017 is going to be a big year, power we’ve never seen before will become available to the public.
In terms of making an equivalent battery with that type of cell, the A123 cells you have noted are lower capacity cells (1100 mAH as opposed to 2500mAH), and they are lower voltage (3.2 as opposed to 3.6v), so a rough calculation should indicate that If you made a battery of the same dimensions as your existing CGT battery, it would be at a lower voltage and smaller capacity (in watt hours).
Wow, that’s not even half the capacity. Do you think it would be worth the trade off for the increased output?
I would assume carbon fiber is a lot more durable than wood? I mean wood may feel more solid but from what I know, carbon fiber is used in high end cars for a reason.
Your board sounds really cool and read your post on the importance of redundancy. I’d love to see pictures of it! Maybe when I get more money I’ll buy your decks as I am still a high school student working part time. The Evolve Carbon GT was a really big expense (almost all my money in fact) and I’m very low right now. As for hill climbing - I live in Ohio so I don’t have to worry about large hills as many are 10-15% at most and the GT accelerates up those hills up to 22mph without breaking a sweat.
To get the best bang for your buck at higher discharge rates, I would go for pairs of 5S Lipos and wire them in series and then parallel.
Maybe wire in a 10S BMS for simplified charging (evolve charger compatible?) It really comes down to $.
I’m just scared of the potential hazards that come with having LiPos. Just for the sake of having the option - if cost wasn’t an issue, what would you recommend? 26650 A123 LiFePO4 cells are ruled out because of their width being more than 0.7in.