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Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

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Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#151

Post by conjecTech »

oppositelock wrote: post #118

Modern cars with keyless entry typically draw ~50mA@12V when "off", this power is used to power the receiver, keep ECU state for such things as learned fuel maps, blink the alarm-on indicator, etc. 45Ah capacity gets you a bit over a month to drain down the battery, while 10Ah gets you a bit over a week. This isn't good, you'd have to keep it on a battery tender if you're not driving the car for just a week. I can al…

Co-founder here: The capacity isn't set in stone. You might be right, if we need to increase it we can - or just offer a couple different options, but so far we haven't seen any issues and a number of our beta users are only using their cars once every few weeks.

The capacity quoted on lead-acid is also a bit deceptive. There amount of current you can draw drops pretty heavily with state-of-charge. You might have trouble starting your car even with 50% of charge left. So if Ohm doesn't work for you, you'd likely be having trouble with a lead-acid as well.

As far as the low-voltage cutout - it's definitely not trivial, but it's been done in other applications previously. I'd be a bit ashamed if you were able to come up with a solution of the cuff though, it took us a lot of work to get it working! It does involve some energy injection, but not enough to cause problems.

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#152

Post by Dylan16807 »

thrownaway2424 wrote: post #105
conjecTech wrote: post #75

Earlier quoted context omitted.

No worries there. Everything is right around the 12V level. We can boost the voltage on the capacitors some, but we never exceed anything that the alternator is spitting out.

But a car alternator's output is nominally 13.8V.

13.8V is around the 12V level and is not high voltage.

What are you objecting to?

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#153

Post by toddkazakov »

> With that in mind, Ohm is focusing on the performance car market first. Those are the guys that’ll rip out their passenger seats to gain a tiny performance gain on the track

Give me a break. With 10 amp hours my car will probably not be able to make through a single engine start.

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#154

Post by URSpider94 »

gscott wrote: post #128

Recently my wife's car batter died, end of life. When a new battery was put in it the car ran poorly. Apparently when the battery dies something in the car resets and the car "figures" out the settings again and runs rough at idle. We called a repair shop and they said to just wait a few days and it will fix itself. Which was true, runs fine now. The moral of the story is that with a new car if the battery dies, weir…

Yup, I've experienced this.

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#155

Post by mycelium »

blueintegral wrote: post #147
dmitrygr wrote: post #111

1. put this into a modern car 2. do not drive for a month 3. car's slow but steady draw drains battery to where it self shuts off 4. attempt to enter car 5. realize that it is a modern car, and without electricity from the battery you cannot even open the door 6. ... 7. profit?

You should get a bit longer than just a month of disuse before it shuts itself off. Are there modern cars that don't even let you use the key to open the door? I know Tesla has the thing where the handle is flush with the door, but are other cars doing that too now?

I have a 2015 VW Golf that has no keyed entry, just the fob buttons.

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#156

Post by blueintegral »

sandworm101 wrote: post #27

(1) Those nasty things inside car batteries are easily recycled and in fact are recycled more often than not (like 95%+) (2) Car batteries do not last only 3-4 years as per the OP. Car batteries can last decades. There are many variables, but the car in my battery is far older than 4 years. (lol) (3) Replacing an easily-recyclable product with a less-recyclable one is no step forwards. (4) XX addressed by OP comment,…

Oh, one other thing I wanted to add: The 3-4 year lifetime of lead acid batteries is the average lifetime. There are certainly outliers, but if you go to the store and buy a lead acid today, the warranty is about 3 years.

The BMW thing is interesting. The reason they do that little "ritual" is because they want to program the ECU to use a particular charging profile for your battery, and it needs to know the age of the battery and the type (AGM or not). That's to try to extend the lifetime of the battery. We don't really need to worry about that, since we handle all the charging profiles internally. One of our testers drives a BMW, so we're making sure that we can handle that and similar cases.

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#157

Post by fredkbloggs »

sliverstorm wrote: post #115

One challenge in going after the enthusiast market is going to be, the enthusiast market already has options. Back when I drove a fast sporty little car, I got one of these: http://www.amazon.com/gp/product/B0002ILK6I $100, 4 pounds. Proven technology. I can buy it today. Half the cost, 60% more capacity, and 2/3 the weight of this "Ohm". Smaller too, from the looks of the "Ohm". I'm not trying to rag on you guys, bu…

You would choose the Ohm because Ohm is a startup, and... startups! YEAH! Tech! Oh yeah! And stuff...

Like so much else out there, they want you to think it's better when in reality it's at best a niche offering that's going to be worse for most people. But there are a lot of people out there who are happy to spend 2x or 5x or even 10x on something that a "fellow startup" is making, just because it's novel or made by another small company, regardless of its actual merit. As they've said forever, a fool and his money are soon parted.

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#158

Post by fredkbloggs »

blueintegral wrote: post #50
sandworm101 wrote: post #27

(1) Those nasty things inside car batteries are easily recycled and in fact are recycled more often than not (like 95%+) (2) Car batteries do not last only 3-4 years as per the OP. Car batteries can last decades. There are many variables, but the car in my battery is far older than 4 years. (lol) (3) Replacing an easily-recyclable product with a less-recyclable one is no step forwards. (4) XX addressed by OP comment,…

You're right! Lead acid car batteries are one of the great recycling success stories. What's interesting is that the volume of lead acid car batteries in the world is so high, that even at that high recycling rate, that still leaves 24 million pounds of lead each year from car batteries that don't get recycled. There's also been some problems recently with lead recycling plants contaminating the environment [1]. You'…

If your device had an equal market share, what fraction of it would be recycled? What core charge would a new buyer be expected to pay for that recycling cost?

Re: Ohm (YC S15) is a smarter, lighter car battery that works with your existing car

#160

Post by facetube »

gscott wrote: post #128

Recently my wife's car batter died, end of life. When a new battery was put in it the car ran poorly. Apparently when the battery dies something in the car resets and the car "figures" out the settings again and runs rough at idle. We called a repair shop and they said to just wait a few days and it will fix itself. Which was true, runs fine now. The moral of the story is that with a new car if the battery dies, weir…

I've experienced this too. On a year 2000 Toyota with a couple hundred thousand miles on it, battery removal literally makes the car not know how to move for 10-15 minutes. The manual says that the car adapts to "driving style" and engine age/performance; it apparently gets to relearn all of that in a hurry after a reset.

TL;DR: The car wakes up with amnesia and has to discover for itself that it's old.

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