I like Chalo's lathe. :thumb: It's a perfect example of what I'd recommend for hobby use. I've actually used the same brand in the past.
Lightweighting and aerodynamic optimization of a subcompact car.
- Thread starter neptronix
- Start date
Hey all.
I've been without a shop for a few years now but still continue to improve on the car's efficiency.
Recently i bought a scanguage II, calibrated it, and confirmed that the car's fuel economy meter has been lying to me this whole time.
The car's fuel economy meter will always clip the fuel economy at 170mpg even if you are idling at 60mph ( this would amount to ~500mpg with such a small engine ). It will also count time that you are decelerating as 170mpg despite the fuel injectors being turned off, and you achieving infinite miles per gallon ( scanguage considers this '9999' mpg )
Because of this clipping feature, my fuel economy is within a 1% of the scanguage's count if i stop hypermiling ( esp. being in neutral ), but if i hypermile, the difference in readings can be as large as 25%.
So at some point, i *have* broke 70mpg, i just didn't know it.
But it's winter, so i wouldn't know what peak fuel economy looks like with the new count :?
..anyway, i decided to duct tape the upper half of the grill to see if i could increase my winter fuel economy, which normally takes a big hit.
As a result, i created a warm air intake due to how air is channeled in this car.
My average fuel economy during a 5 mile run that starts at below freezing improved from 45mpg to 55mpg, and the car warms up in half the time now, which is great because when hypermiling, you make very little waste heat to warm up the car, so the cabin remains cold for a long time.. not anymore.
duct tape FTW :lol:
I've been without a shop for a few years now but still continue to improve on the car's efficiency.
Recently i bought a scanguage II, calibrated it, and confirmed that the car's fuel economy meter has been lying to me this whole time.
The car's fuel economy meter will always clip the fuel economy at 170mpg even if you are idling at 60mph ( this would amount to ~500mpg with such a small engine ). It will also count time that you are decelerating as 170mpg despite the fuel injectors being turned off, and you achieving infinite miles per gallon ( scanguage considers this '9999' mpg )
Because of this clipping feature, my fuel economy is within a 1% of the scanguage's count if i stop hypermiling ( esp. being in neutral ), but if i hypermile, the difference in readings can be as large as 25%.
So at some point, i *have* broke 70mpg, i just didn't know it.
But it's winter, so i wouldn't know what peak fuel economy looks like with the new count :?
..anyway, i decided to duct tape the upper half of the grill to see if i could increase my winter fuel economy, which normally takes a big hit.
As a result, i created a warm air intake due to how air is channeled in this car.
My average fuel economy during a 5 mile run that starts at below freezing improved from 45mpg to 55mpg, and the car warms up in half the time now, which is great because when hypermiling, you make very little waste heat to warm up the car, so the cabin remains cold for a long time.. not anymore.
duct tape FTW :lol:
Chalo
100 TW
How did you keep the tape from flapping/buzzing/shredding? Did you back it up with anything stiffer?
CONSIDERABLE SHOUTING
10 kW
- Joined
- Jun 15, 2019
- Messages
- 809
Hey, neat thread! I've been making a home shop like yours for some time now, and I've wanted to do something similar with a kit car like a better Lotus 7/Locost. Their aero is so bad they get unstable even above 70mph, a Cd close to 0.40 is terrible for a 1,400lb sports car!
One thing I picked up since you mentioned you hope to get a TIG welder, is to invest in some coverings for your tools when you TIG OR an "area" where you can isolate your welding. The smoke, gasses and splatter that's created goes further than you think, and with lathes dirt and dust will just naturally gather in the oils and grease over time; I use old, used shower curtains that I replace every few months and I feel it really helps keep everything clean.
As for the car-
One thing I picked up since you mentioned you hope to get a TIG welder, is to invest in some coverings for your tools when you TIG OR an "area" where you can isolate your welding. The smoke, gasses and splatter that's created goes further than you think, and with lathes dirt and dust will just naturally gather in the oils and grease over time; I use old, used shower curtains that I replace every few months and I feel it really helps keep everything clean.
As for the car-
- Maybe something like a rallycross mirror for better side visibility?: https://www.amazon.com/Rally-Panoramic-Rearview-Mirror-Panel/dp/B0061OZT9Q
- You want to keep the safety, but you've removed the headrests. This is a bad idea- headrests are critical in an impact to prevent coup-countercoup injuries, without them the head can hyperextend backwards and allow the brain to bounce around within the skull. Headrests act like a stop to prevent that hyperextension which can cause neck and cervical spinal injury.
CONSIDERABLE SHOUTING
10 kW
- Joined
- Jun 15, 2019
- Messages
- 809
Also to add onto Chalo's comment, Duct tape doesn't like UV light and dries out quick. Not sure what to replace it with- aluminum tape for HVAC?
JackFlorey
100 kW
There are several flavors of gaffer's tape that work very well in those applications. Lately I have been using Welstik, a brand of gaffer's tape that is unusually strong.CONSIDERABLE SHOUTING said:
Chalo said:
Didn't need to to for the upper grill bits, they're nice and narrow and the duct tape just kinda caves in. Somehow it survives highways speeds too.
CONSIDERABLE SHOUTING said:
Given that it's a modification that lasts 3 months, i'm OK to just re-duct tape it instead of build something sturdier.
Ideally i'd like some custom cut foam inserts painted to the color of the car that i could pop in in mid november and remove by February.
I ended putting back on the original passenger side mirror because 90% of my driving is city driving lately, it's kinda not worth it.. one day i'll go for smaller mirrors though.
The headrests are still removed except for the driver and passenger side ones because i have a 3rd passenger maybe once a year.. just dead weight at this point. I know a lot about orthopedics and understand this is bad.
Been a while..
Generally speaking, all the easy/cheap weight that could be removed without compromising safety, is removed.
Current yearly average is 45.2mpg with a lot of 10 miles and under trips, maybe 5% is highway, so in these conditions, i wouldn't benefit from any additional aerodynamic improvements right now.
Tires and battery are both due for replacement, so this is a great time to address their weight.
Scenario A:
If my math is correct then i'm expecting a 1.3mpg gain in city-ish driving conditions, better front-rear balance, slightly better acceleration, and better ride quality due to the lower unsprung weight.
Scenario B: i use 2006 era Mini Cooper wheels which come out to 12lbs each, so i have a wheel weight loss of 32lbs instead.
32 * 3 = 96lb + 21.5lbs ( battery loss ) = 117.5lbs or 5.1% effective weight loss during acceleration and possibly 2mpg gain in this kind of driving.
The Mini Cooper wheels are said to have a 56.1mm bore whereas the Mazda 2 has a 54.1mm bore, but i can use a hub centric ring to make up the difference. Offset and bolt pattern match, so it seems a fit, except for aesthetically.
Rims in this weird size also don't get any lighter unless i'm willing to accept significantly wider tires and lose some of this extra efficiency to tire friction. That goes against the idea of building the best hypermiling machine i can. Therefore, there's no scenario C.
If the math for Scenario B is correct, then i'm embarrassed i didn't think of this earlier!
Time to scrounge on ebay
Generally speaking, all the easy/cheap weight that could be removed without compromising safety, is removed.
Current yearly average is 45.2mpg with a lot of 10 miles and under trips, maybe 5% is highway, so in these conditions, i wouldn't benefit from any additional aerodynamic improvements right now.
Tires and battery are both due for replacement, so this is a great time to address their weight.
Scenario A:
- Swap out the 20lbs 16" rims for 15" aftermarkets which weigh 15.5lbs, saving a total of 18lbs also freeing up some torque due to lower rotational mass/diameter of the rim.
- Braille B2618 battery is 18.5lbs versus the stock Group 35 battery at 40lbs, saving 21.5lbs. It's 26AH versus the stock 50AH, but cold cranking amps are equivalent, so this should work, given i don't let my car sit for longer than 2 weeks ( this is OK )
If my math is correct then i'm expecting a 1.3mpg gain in city-ish driving conditions, better front-rear balance, slightly better acceleration, and better ride quality due to the lower unsprung weight.
Scenario B: i use 2006 era Mini Cooper wheels which come out to 12lbs each, so i have a wheel weight loss of 32lbs instead.
32 * 3 = 96lb + 21.5lbs ( battery loss ) = 117.5lbs or 5.1% effective weight loss during acceleration and possibly 2mpg gain in this kind of driving.
The Mini Cooper wheels are said to have a 56.1mm bore whereas the Mazda 2 has a 54.1mm bore, but i can use a hub centric ring to make up the difference. Offset and bolt pattern match, so it seems a fit, except for aesthetically.
Rims in this weird size also don't get any lighter unless i'm willing to accept significantly wider tires and lose some of this extra efficiency to tire friction. That goes against the idea of building the best hypermiling machine i can. Therefore, there's no scenario C.
If the math for Scenario B is correct, then i'm embarrassed i didn't think of this earlier!
Time to scrounge on ebay
You won't need the 'concentric rings'. The tapered lug nuts are more than sufficient for centering the rims. BTW, my 88 Toy Corolla SR5 has the same 4x100mm lug pattern.
Re: lathes
The Atlas 10 (and smaller) lathes are doable if tight tolerances and high accuracy isn't a concern because the beds suffer from lack of rigidity, exhibiting too much flex. If you can find an older South Bend 9 thats been reasonably cared for, they are excellent. One proviso: The SB9 was available in 3 basic models: A, B and C. Model C (the budget version) doesn't have the highly desirable 'quick change' gearbox (but can be adapted by simply drilling a couple of mounting holes). It needs to be emphasized however... it isn't the lathe itself that's the wallet burner... it's the tooling!
Last edited:
Hillhater
100 TW
I am guessing you are just talking of the wheel RIM weight ?…excluding the tyre ?
If so, i am sure you realise that the tyres themselves will weigh more than that (20-25 lb each) and have a much greater dynamic inertia effect as their weight is mainly on the perimeter.
have you investigated different tyre options for both weight and low rolling resistance ?
i believe some of the tyres designed for EVs have special compounds and such for low RR And narrower sections to minimise wind resistance also.
maybe a set of rims and tyres from a Prius or similar will fit !
Re:lathe comments, i'm in an apartment, so purchasing machinery is out of the question at the moment.
Yes, excluding tire. Because the weight of a little taller sidewall is a lot less than an equivalent amount of rim. So the idea is to get the heaviest part closer to the center.
I did:
- No major sellers list tire weights :/
- On the original, 185 wide, non-low rolling resistance tires, the wheels would slip fairly often, and we also have occasional heavy rain, snow, and ice, so i decided to stick to regular tires instead of low rolling resistance ones.
- Car tire punctures are more frequent out here than anywhere else i've lived. So i don't want to emphasize picking the lightest tire i can get, i want a totally average one.
So unfortunately i'm giving up some addl. gains in the name of traction, which isn't great to begin with.
I considered that but recently found a few weights on them, and all of them seem heavy, including the little Prius C.
Sort of makes sense, because a Prius is significantly heavier.
Yes, excluding tire. Because the weight of a little taller sidewall is a lot less than an equivalent amount of rim. So the idea is to get the heaviest part closer to the center.
I did:
- No major sellers list tire weights :/
- On the original, 185 wide, non-low rolling resistance tires, the wheels would slip fairly often, and we also have occasional heavy rain, snow, and ice, so i decided to stick to regular tires instead of low rolling resistance ones.
- Car tire punctures are more frequent out here than anywhere else i've lived. So i don't want to emphasize picking the lightest tire i can get, i want a totally average one.
So unfortunately i'm giving up some addl. gains in the name of traction, which isn't great to begin with.
I considered that but recently found a few weights on them, and all of them seem heavy, including the little Prius C.
Sort of makes sense, because a Prius is significantly heavier.
So i bought scenario A rims ( 15.5lb ) and new tires to accompany the downsizing..
Plan to get the 21lb braille battery, which is 31ah, and i imagine, much more reliable during the winter.
Of interest, i looked into solar chargers, and how big of one i could put on the rear deck, and then i see this battery tender rated for 15w:
Doing the math, assuming i'm getting actually 10 watts out of the 15 watt panel:
The battery is 372 watt hours. Given 8 hours of sunlight @ 10 watts, i can generate 80 watt hours, or charge the battery by 21%.
Perhaps i don't need such a big solar panel. A 7.5 watt would do, and assuming i'm getting 5w, the big braille can recharge up to 10.5% in a day.
Sanity check: any downsides to this idea? does a solar charger have any kind of negative effect on a battery long term?
Here's something more off the wall..
A number of people who have done alternator deletes ( involves running some heavy deep cycle batteries and recharging by hand ) on ecomodder say they can see a 10% improvement in fuel economy.. this is pretty wild and has been interesting to me because i have a feeling it frees up some horsepower; very useful on a car with a putzy motor
My car's alternator is rated for 100A, which is around 1300w of power, assuming 80% efficiency we could say it can probably rob the car of 2 horsepower at the most.
According to stackoverflow, losses on a typical alternator are extremely high:
This lends some credence to the idea that you could see at least 10% better fuel economy. A very aerodynamic car will cruise at around 15hp or less on the highway, and 1200w at around 3000rpm is about 1.5hp.
OK, so the alternator is rated 100A in my car, right? That's about 1300w at most, which means, the pulley could handle about 2hp of power being pushed through it. So with something like an RC motor where the alternator is sitting, i could be pushing 2hp instead of losing 2hp, which is theoretically good for a 20% boost in fuel economy and a small increase in acceleration. If this RC motor could also do regeneration, then we can keep our battery charged, and now we have a very mild hybrid.
This idea seems pretty awesome, but too involved considering i have no garage at the moment.
Supposedly a lithium battery, thanks to it's higher discharge and charge efficiency, reduces alternator load somewhat, while also being lighter than the braille lead acid at the same time.
Braile has a 8.5lbs 20ah car battery for $664.99. This seems to be a good choice if i also pair it to a 10w solar charger to make up for the small capacity during long stretches of not using the car.
Braille G30S GreenLite Extra Capacity Lithium Automotive Battery
I think this is the sanest option because i get lightness and extra efficiency in one. The only concern is starting in cold temperatures, which i could probably remedy with a small battery heater ran off the battery itself.
I'm thinking this lithium car battery or one similar to it could be the ticket. What does the crowd think?
Plan to get the 21lb braille battery, which is 31ah, and i imagine, much more reliable during the winter.
Of interest, i looked into solar chargers, and how big of one i could put on the rear deck, and then i see this battery tender rated for 15w:
Doing the math, assuming i'm getting actually 10 watts out of the 15 watt panel:
The battery is 372 watt hours. Given 8 hours of sunlight @ 10 watts, i can generate 80 watt hours, or charge the battery by 21%.
Perhaps i don't need such a big solar panel. A 7.5 watt would do, and assuming i'm getting 5w, the big braille can recharge up to 10.5% in a day.
Sanity check: any downsides to this idea? does a solar charger have any kind of negative effect on a battery long term?
Here's something more off the wall..
A number of people who have done alternator deletes ( involves running some heavy deep cycle batteries and recharging by hand ) on ecomodder say they can see a 10% improvement in fuel economy.. this is pretty wild and has been interesting to me because i have a feeling it frees up some horsepower; very useful on a car with a putzy motor
My car's alternator is rated for 100A, which is around 1300w of power, assuming 80% efficiency we could say it can probably rob the car of 2 horsepower at the most.
According to stackoverflow, losses on a typical alternator are extremely high:
This lends some credence to the idea that you could see at least 10% better fuel economy. A very aerodynamic car will cruise at around 15hp or less on the highway, and 1200w at around 3000rpm is about 1.5hp.
OK, so the alternator is rated 100A in my car, right? That's about 1300w at most, which means, the pulley could handle about 2hp of power being pushed through it. So with something like an RC motor where the alternator is sitting, i could be pushing 2hp instead of losing 2hp, which is theoretically good for a 20% boost in fuel economy and a small increase in acceleration. If this RC motor could also do regeneration, then we can keep our battery charged, and now we have a very mild hybrid.
This idea seems pretty awesome, but too involved considering i have no garage at the moment.
Supposedly a lithium battery, thanks to it's higher discharge and charge efficiency, reduces alternator load somewhat, while also being lighter than the braille lead acid at the same time.
Braile has a 8.5lbs 20ah car battery for $664.99. This seems to be a good choice if i also pair it to a 10w solar charger to make up for the small capacity during long stretches of not using the car.
Braille G30S GreenLite Extra Capacity Lithium Automotive Battery
I think this is the sanest option because i get lightness and extra efficiency in one. The only concern is starting in cold temperatures, which i could probably remedy with a small battery heater ran off the battery itself.
I'm thinking this lithium car battery or one similar to it could be the ticket. What does the crowd think?
Last edited:
marty
1 MW
Car makers are thinking the same as you. Back in the beginning of cars when diagnosing a charging / starting problem. Here is how I do it. Charge battery all night. Next morning remove charger. Battery's are like beer. They foam a little when they get excited. Let battery sit for 5 minutes or so. So the foam settles down. [Joking about the foam]. Measure voltage. Start car. Measure voltage again. Write the two numbers down. Voltage with car off and voltage with car on. Looking at those two numbers will tell you if the alternator is charging.
Now with my 2019 Honda Fit, things are different. Alternator only charges when battery needs to be charged. If I remember correctly there is only one purple wire going to the alternator that tells it when to make electricity. This is to save on gas.
Read here how I made this discovery.
endless-sphere.com
I copy:
Off 12.8V
Running with everything off 12.3V
Running with parking lights on 12.3V
Running with parking lights on and heater on 1 speed 12.3V
Running with parking lights on and heater on 2 speed 12.2V
Running with parking lights on and heater on 3 speed 14.3V
Running with parking lights on and heater on 4 speed 14.3V
Running with parking lights, headlights on and heater on 4 speed 14.3V
Off 12.6V
Note change from 12.3V to 14.3V that's when alternator is charging.
To make a older car work like this you would need a newer alternator that can be switched off and on and a computer to tell it when to make electricity.
Driving with all lights off at night would also save gas because alternator would not have to work as hard. Also turn heater blower off and yea no AC.
Now with my 2019 Honda Fit, things are different. Alternator only charges when battery needs to be charged. If I remember correctly there is only one purple wire going to the alternator that tells it when to make electricity. This is to save on gas.
Read here how I made this discovery.
$$$ Headlights on with ignition $$$
2019 Honda Fit LX This is a continuation of topic List of small hatchback cars Start reading on page 5 Problem: I leave headlight switch in the AUTO position all the time and keep a bottle cap on the photocell so that I don't have to remember to turn headlights off or on. I like all lights on...
endless-sphere.com
I copy:
Off 12.8V
Running with everything off 12.3V
Running with parking lights on 12.3V
Running with parking lights on and heater on 1 speed 12.3V
Running with parking lights on and heater on 2 speed 12.2V
Running with parking lights on and heater on 3 speed 14.3V
Running with parking lights on and heater on 4 speed 14.3V
Running with parking lights, headlights on and heater on 4 speed 14.3V
Off 12.6V
Note change from 12.3V to 14.3V that's when alternator is charging.
To make a older car work like this you would need a newer alternator that can be switched off and on and a computer to tell it when to make electricity.
Driving with all lights off at night would also save gas because alternator would not have to work as hard. Also turn heater blower off and yea no AC.
Last edited:
marty
1 MW
Also think alternator works more when car is coasting.
Read:
endless-sphere.com
I copy:
12.4V Driving with foot on gas pedal.
14.4V Coasting with foot off the gas pedal.
Read:
$$$ Headlights on with ignition $$$
2019 Honda Fit LX This is a continuation of topic List of small hatchback cars Start reading on page 5 Problem: I leave headlight switch in the AUTO position all the time and keep a bottle cap on the photocell so that I don't have to remember to turn headlights off or on. I like all lights on...
endless-sphere.com
I copy:
12.4V Driving with foot on gas pedal.
14.4V Coasting with foot off the gas pedal.
Hillhater
100 TW
Yes.
Most modern cars are fitted with these “Smart” alternators to improve fuel mileage.
they work in conjunction with the ECU to prevent the alternator charging when the engine is under load, and as marty said, mostly charge when coasting or off throttle.
I doubt you could replace your alternator with one of the smart units as you would need the comparable ECU and firmware..but anything is possible.
In anycase, your alternator is only going to charge when the battery voltage drops below a set level, ( internal voltage regulator) so you might think that a bigger high capacity battery could be better at holding its voltage under load from accessories ?
I have a 140 AH LIFe battery that holds 13+ volts until it is 80% discharged …but it needs a special charger to get it back to 100% as a standard alternator 14.7v wont get it there.
Last edited:
Interesting stuff, Marty & Hillhater.
I think Honda learned some things from the VX/HX models of Honda Civic that they are still applying today based on these findings on the Honda.
Interesting thought that my alternator may also be optimized in a similar manner. In this case, it's possible that a lithium battery doesn't provide significant benefit.
But my car battery has kicked the bucket recently so i'm out of the time window to do measurements.
I notice a lot of makers of lifepo4 car batteries are shy on quoting what the cold cranking amps is. I think this is because the internal resistance reduction versus dropping temps is much worse for lithium versus lead acid. So that's a red flag for lifepo4 unless it's significantly oversized.
Of alternative interest, Toshiba has a SCiB car battery. No prices listed, must beg them over email to buy it, but.. it would probably have super badass starting power deep in the winter.
12V/24V Automotive Starter battery | SCiB™ Rechargeable battery | Toshiba
Overall i'm thinking the 21lb braille is the way to go, pretty safe bet, and only 2x the price of a lead acid replacement, versus 5-10x that for lithium, so it's next on the to-order list.
I think Honda learned some things from the VX/HX models of Honda Civic that they are still applying today based on these findings on the Honda.
Interesting thought that my alternator may also be optimized in a similar manner. In this case, it's possible that a lithium battery doesn't provide significant benefit.
But my car battery has kicked the bucket recently so i'm out of the time window to do measurements.
I notice a lot of makers of lifepo4 car batteries are shy on quoting what the cold cranking amps is. I think this is because the internal resistance reduction versus dropping temps is much worse for lithium versus lead acid. So that's a red flag for lifepo4 unless it's significantly oversized.
Of alternative interest, Toshiba has a SCiB car battery. No prices listed, must beg them over email to buy it, but.. it would probably have super badass starting power deep in the winter.
12V/24V Automotive Starter battery | SCiB™ Rechargeable battery | Toshiba
Overall i'm thinking the 21lb braille is the way to go, pretty safe bet, and only 2x the price of a lead acid replacement, versus 5-10x that for lithium, so it's next on the to-order list.
So... how about a simple NC (normally closed) reed switch (or momentary toggle SW) on the accelerator pedal, or throttle linkage somewhere under the hood -- coupled in series with the alternator's field excitation lead? Switch closed (charging) when idling... open (no charging) as soon as you begin accelerating. Doable for city I would assume, but you'd likely need another simple circuit to detect low battery voltage and overide the throttle switch on extended travels.
The throttle pedal on my car ( 2018 model ) has 7 wires, so it would be complicated to optimize after the fact. Would be worth measuring at least, using Marty's findings as a baseline for what an optimized alternator scenario looks like.
Much more interesting is an alternator-less, solar powered setup though
Had a good call with the braille sales dude, really friendly and informative. He advised against a lithium battery because this is a daily driver and if the lithium goes flat, it's possibly toast. The G30S would be the right choice for my car though, for daily driver duty.
Took his advice and ordered the 21lbs lightweight AGM battery. Maybe the next time i buy a battery, we'll have LTOs on the market, but for reliability reasons, i'm uninterested in being a guinea pig since this is a daily driver and not a race car.
Much more interesting is an alternator-less, solar powered setup though
Had a good call with the braille sales dude, really friendly and informative. He advised against a lithium battery because this is a daily driver and if the lithium goes flat, it's possibly toast. The G30S would be the right choice for my car though, for daily driver duty.
Took his advice and ordered the 21lbs lightweight AGM battery. Maybe the next time i buy a battery, we'll have LTOs on the market, but for reliability reasons, i'm uninterested in being a guinea pig since this is a daily driver and not a race car.
Last edited:
Chalo
100 TW
To be honest, I don't know how much of a project it would be to strap together five of these:
add a balance board, and mount it in a foam lined box. I'm waaaay too apathetic about cars to do any such thing to my own household mule, but if I didn't hate it, I'd probably hack out a battery like that.
Hillhater
100 TW
He is BS ing you .
All the commercial Li 12 v batteries i have checked, all have a built in BMS with under/over voltage protection, ..and overload , overcharge etc.
the 140 AH , 10 kg, LiFe that i use has more useful capacity than the 200Ah , 25 kg, AGM deep cycle that it replaces.. and it only cost Au $450 ( us$300)
there are many very good Youtube video reviews of these 12v Li batteries to show you which to avoid (many !) and which are best for your application
Hint :… if you go with a small battery, no alternator set up, you may want to consider carrying one of those emergency jump starter packs that fit in your pocket but will still start a car many times before recharging. !
Last edited:
He stated that they don't have BMSes, they have some kind of cut off circuit that is even safer, at the expense of bricking the battery.
The batteries are designed for race applications and all out low weight, and not daily drivers.
I don't think he's yanking my chain. The guy could have sold me a dramatically more expensive product.
The batteries are designed for race applications and all out low weight, and not daily drivers.
I don't think he's yanking my chain. The guy could have sold me a dramatically more expensive product.
Damn, those are cheap. But i only have one car and i use it for business, so i'm a lot more risk adverse about a car than a bike. Especially since it can get insanely cold out here.
It sounds like a worthwhile experiment though. Supposedly LTO is very fire resistant, so an unknown Chinese brand sending you some cells with poor construction quality, is probably a lot less risky than the ticking timebomb that some cheap Chinese non-lifepo4/LTO chemistry batteries can be. LTO has some self-balancing characteristics, so it may not even need a BMS.
Hillhater
100 TW
You need to find a better battery supplier if that is the level of his advice and knowledge !
Li starter batteries have been factory fitted in some european cars for over 10 years !
And why dont you check yourself ,.. a simple google search will throw up dozens of replacement 12v Li car batteries !
This is just one example, but there are many other cheaper options
iTECH1420CA Lithium Car Battery 12V Stop Start 1420amp 60Ah
and this shows the presence of BMS and temp protection in even the cheapest 12v battery
(note.. this is only a 100a discharge battery )
Similar threads
