The Aussie cars have remote central locking, boot release and basic Diahatsu alarm so I'd assume they would have similar standing draw. Does the cobra alarm have some sort of movement sensors ?
The Aussie cars have remote central locking, boot release and basic Diahatsu alarm so I'd assume they would have similar standing draw. Does the cobra alarm have some sort of movement sensors ?
Yes Jez. Much to my surprise, it will set off the alarm if you put your arm through an open window or attempt to get something out of the glovebox when the roof is down. I discovered that by accident.
@Salieri Mine was only standing for 8 days. I then had all the hassle of jump starting it, lowering the roof and going for an hours drive in the countryside. It was a real chore
Maybe because I drive it daily or perhaps I'm lucky but I always drive with... Headlights on Stereo on Subwoofer on and depending on conditions, the heater/aircon/wipers - never had a battery problem, it's the original 8 yrs old - I'm hoping to get another 35 years from it
My aftermarket Cobra alarm senses movement, heat and vibration, it's not connected to the battery though it's independently powered. No remote, it turns off with a live mouse, doesn't beep either it hisses, but nobody has tried stealing my car.
You have to reset all your thinking concerning batteries when you throw LiFePO4 chemistry into the mix. I've got one of these jump starter boxes, claiming to be 68,000 mAh, which is bullshit, of course, but it's normal practice to inflate claimed capacities, which makes no sense, but that's eBay life today. What does matter is that this little box really does work. I proved this by disconnecting the Pb battery and clipping on the jump starter as the only power source. The engine cranked over noticeably faster than it normally does. This doesn't make rational sense, but can be explained by the fact that some LiFePO4 batteries will discharge at up to 200 times their nominal Ah capacity. So a nominal 4 Ah battery can supply up to 800 amps in short bursts. After further research along this line, I have replaced the original car battery with a 7.5 Ah lithium one, which weighs almost nothing, is a fraction of the size, and twirls the starter motor much faster than it's ever gone before. Not only that; I have connected an 83 Farad capacitor (consisting of a string of 6 500F 2.7 volt caps) directly across the battery. These capacitors will start the engine by themselves, but in this configuration, they just take the bulk of the load off the battery, which just has to keep the capacitors charged. An added bonus of this is that the injectors, ECUs, and various other electrical components run much better from this kind of low-impedance power source. A few years ago, this kind of stuff would have been sorcery, or prohibitively expensive at best, but it all cost me no more than the price of a good-quality Pb battery. And the lithium battery is rated at 3000 charge/discharge cycles, so it should last at least 10 years. Probably longer than that with the capacitors, as the battery could eventually become too weak to crank the engine but still able to keep the caps charged up.
Yeah, I did A Level Physics 20 years ago and since then I've maybe wired up a few plugs, sockets, car stereos. I understood 'better battery, lighter, smaller', but I don't understand how exactly I would get that. Questions - What parts would I need to buy? Can we get a pic? Any drawbacks you've noticed or can think of? I can get stuff soldered together no problem, I just have to listen to my best friend talk about his bloody drone batteries while he does it. Sometimes he makes me watch videos of drone racing. :/
The Batteries in those 68000mAh jump starters are probably not LiFePo batteries. The chinese mostly use 18650 LiNiMnCo (Lithium-Ion) cells, which have twice the capacity at the same price. Downside: They are not as sturdy. Interesting setup you have with the 7,5Ah battery, I understand that it can create enough current to start the engine, but I suppose you could not leave the radio or the lights on for too long without the engine running because of the reduced capacity
I wouldn't be too sure about that. These batteries have a lot more reserve capacity than Pb ones, and can be discharged a lot deeper. So, the effective Ah capacity is several times the equivalent capacity of a Pb car battery, which is optimised for cranking current, not long-term current draw. And, Li-ion cells can only discharge at 2-3C, which is not enough to start an engine. Anyway, I measured the discharge capacity of one of these dodgy 68,000mAh units, and it was actually around 4500. Also interesting is that with the new lithium battery, the roof goes up and down no problem at all, with the engine not running. This is how I knew the old battery was on its way out; the roof would stop halfway through the cycle, because the ECU was detecting low voltage and shutting down. What's even more amazing is that since doing this battery swap, my fuel economy has increased by at least 10%. Although, I also stopped using E10 at about the same time, so it's impossible to determine for sure which of these is responsible. But a guy on another forum who did the same thing I did reports the same level of improvement. So, if I'm saving ~$3 per tankful, the battery will pay for itself in a couple of years.
I use Sony VTC4 18650 batteries in my e-Cig, they have a peak discharge current of 15C (30A), 2100mAh capacity and are Lithium-Ion (Manganese) based. I'm 99% sure they use those kind of batteries for jumpstarters, as they are cheap and have a high discharge rating. https://www.amazon.com/Original-Sony-US18650VTC4-2100mAh-Rechargeable/dp/B00LL43I5S LiFePo (also Lithium-Ion, just a different substrate) batteries of the same size only amount to about 1100mAh of capacity at a comparable discharge current. However, they can do a lot more charge/discharge cycles and thus have a longer life. E10 increases fuel consumption quite a bit, so your gain in fuel economy could be that. I understand that Lithium batteries can use a lot more of the Amps compared to Pb batteries now, so a 7,5A should work as you said, thank you for the information. I am very curious to hear from you whether your battery will work!
One of my lady friends' husband who is a car mechanic told me the bulk of the fuel economy improvement is probably due to ditching E10. He says E10 is worst thing ever invented; makes the ECU think the mixture is too lean, so opens up the injectors more.
Ethanol has less heat value than petrol, i.e. you need more fuel to compensate. Its good that you don't use it anymore, because Daihatsu did not allow using it for Copen built before mid-2008
@Vin Petrol The battery I've got is actually a motorcycle one; 7.5 Amp-hours. The capacitors can be found on ebay, 500 Farad 2.7 volts. You have to connect 6 in series to use in a 12 volt system. That gives you a capacitance of 500/6 or about 83 Farads. It's very important to not exceed the 2.7 volt rating on any individual capacitor, so it's safest to buy a balancing PC board, which also provides a secure and convenient mount for the capacitors. Best to put the whole assembly in an enclosure of some sort, as an accidental short circuit could have bad consequences. The capacitors are wired straight across the battery, with 10 or 12-gauge wire. When you start the engine, the capacitors supply most of the grunt for the starter. Theoretically, you could eliminate the battery altogether, because the capacitors are quite capable of starting the car on their own; but you would need, at the least, some way of charging them up in case it didn't start first go, or the charge leaked away over time. Also, you wouldn't be able to use the radio or any accessories without the engine running. A very small Pb battery would be enough to keep the capacitors charged. I haven't tried it this way over any length of time, because I'm so impressed with the LiFePO4 battery, and in my case, the capacitors just take much of the load off the battery, which should make it last longer. But they should extend the life of any Pb battery as well. The capacitors cost about $AU 5 on ebay, but I've found that some of them tend to have excessive self-discharge and can't be used for this application. To test them, I charge them up individually to 2.7 volts and leave them overnight. Next day I measure them, and if the voltage hasn't dropped below, say, 2.4 volts, then they're ok. I found that out of 6 new capacitors, at least one usually has too much leakage, so it's best to buy a few extras so you can select the best ones. As the photo shows, I had to pack the battery holder with blocks of wood and layers of foam, because the battery is so much smaller than the Pb one. I don't think there's any need for the usual sort of battery clamp; this battery weighs next to nothing. The capacitors are not shown here; I've got them sitting on top of the battery and held down with a clamp I made from a piece of aluminium. I'll try and take another photo and add it here.
It would be impossible to do it that way in Germany, the people at Tüv or Dekra would not be happy about the missing mounts or the way the battery poles are connected I looked up the battery, its quite cheap at around 100€. Do you reckon it could be used in a car without the capacitors?
I connected it that way in case I wanted to put the original battery back. I don't think I will. The capacitors are not really necessary, it starts the engine by itself no problem at all. The roof goes up and down easily without the engine running. The capacitors are maybe a bit of overkill, though I think they should make the battery last longer. Although, my mechanic friend says the low impedance power source will be welcomed by the injectors, coil packs, etc., resulting in better performance. Also, the alternator doesn't have to work as hard. Charge acceptance of the lithium battery is a lot better than Pb.
I live in the UK and both my 1.3 Copens have had battery problems in the winter. I have a Cobra/ Hatcham alarm/mobiliser fitted and even when it is not 'armed' it takes about 200ma. In 10 days or so the main battery - even when new - is flat. I now keep it on a trickle charge in the winter which 'solves' the micro battery problem. (I'd hate to leave it at airport car park for 3 weeks though...)
Well, the lithium battery has been in for about 6 months now, hasn't missed a beat. There are some issues with LiFePo batteries and cold weather; you're not supposed to charge them if it's below freezing. That's not an issue here, I can't remember the last time I saw frost on the ground, it was a lot of years ago. Also, they must never be allowed to go dead flat, it kills them. I'm going away overseas in a month or so for 4 weeks, and I've never left the car idle for that long before. I'm going to put a little solar panel in the back window where it will get a bit of sun every day, feed it into a regulator and clip it across the battery. I still don't know what the static drain is, but I don't have any extra alarms or anything, so I don't think it's much. But some of the many ECUs are powered up all the time, so it can't hurt. Here's the photo I said I'd upload 6 months ago. The capacitors are in the white box (6x 500F). The clamp holding everything down is made from an old Seagate hard disk lid. The capacitors are connected straight across the battery. I think these wouldn't be a bad idea no matter what kind of battery you have. Theoretically, you could use a small 6Ah burglar alarm battery along with the capacitors as long as you never left the ignition on without the engine running. Actually, you could leave the battery disconnected and only have it to charge the capacitors if necessary; the capacitors will easily start the engine by themselves. I was going to do that before I got the lithium battery. @ Salieri Note: I haven't changed the connections; my mechanic was pretty curious as to what all that was there for, but didn't suggest there was anything wrong about it.
Are you not anxious your insurance company might have a problem with this? Suppose 'something' happened and there was a fire? Surely they would use this an excuse not to pay?
