Antigravity

2- In very cold weather the reason lithium "lags" a little on the start attempt is due to resistance caused by very cold temps within the cells, but the fact is the cells "self-warm" when they express current-flow. So if you bump the starter, not a full start attempt but a little bump of the starter once or twice wait 15 seconds and do it again, then that should warm up the battery so you don't notice much "lag" on the first start attempt because you will have warmed the batteries. So that is a faster method to self-warm it. But you can also just leave your lights on for about 2-3 minutes or so when its freezing. But if you tested in 34 Degrees and the ATX didn't sweat it, you are absolutely fine and good to start it anytime it easily starts a vehicle. You only want to self warm if its seems a little sluggish. If the battery isn't showing signs of strugggling a little in very cold temps then is does not need any warming processes. Also keep in mind that many people are using a super small battery to save the most weight, so they are encountering this issue because they honestly used way to small of a battery in the first place. You should go with a minimum of Ah if you intend to drive in super cold weather. So if your ATX-30 is not struggling then that is pretty good. I don't suggest it for below freezing enviroments because we have to make sure the Customer get a start everytime. But you seem to know how to look after the superlightweight batteries so you are good.

3- It is not recommend that any battery that is FROZEN be charged. When it is 32 degrees that does not mean the battery is frozen... it just means its really cold, but I don't recommend leaving a battery charging when it is below about 25 degrees continually. That is just trying to be conservative. I use our RS-30 when we go to the mountains snowboarding and that is for many days at a time. ITs in a 4.0 Toyota Tacoma and there is no issues. But I still wouldn't recommend it for a Winter in a Work truck... but we have something new coming for that next year.

-nick

Antigravity

To best explain, the Smaller Lithium Batteries that people are using in many Street and Race Cars are based on Motorcycle/Powersports Standardized Sizes in the Motorcycle Powersport Industry.

The Deltran Battery Tender ones are based on the OEM Standardized Powersports Type Case sizes that we (Antigravity) also make....

So Deltran and Antigravity make versions in what I will call the 20 Series for this example. The Antigravity one is called the ATX20-RS.... the Deltran is called the BTL20A360CW. But you can see they state BTL20 as the first part designating a 20 Series battery. I will give them credit, they are now putting the actual REAL AMP HOURS of their batteries now, and its worse than I thought for what they give you.... So as you can see Deltran show a REAL 6.1 Amp Hours for a price of $229.99 for their 20 Series Battery. But the Antigravity 20 Series has a REAL 10.5 Amp Hours... almost TWICE what they offer but it's $90 dollars more expensive.. So that is why it is important to get the real numbers. BUT on the other hand you can use our even MORE compact ATX12 which is 6.4 REAL AH and 1" less wide than the Deltran 20 Series, yet offering just as much power and cost $224.99 which is Cheaper than their 20 Series and also blows them out of the water with the RE-START feature. Then we also have the ATX12-RS-HD (Heavy Duty) which has 8 REAL AMP HOURS... fully 2 more than the Battery Tender and more compact and it cost $259.99 and has the RE-START.

Now to answer your main question of what Battery. I have to be conservative when I'm talking with Customers... I'm not trying to upsell you. I'm trying to clearly state "if you want the absolute correct battery for your car, and it is used on the street and only driven on the weekend, then use this..." Yes I can say our ATX30 would work, but I really wouldn't recommend it because it only has 18 Ah... and I feel a Street Car should be about 24Ah minimum. Then I know if a guy accidentally leaves his lights on, or if he can't get his car started for an hour of cranking that the battery I recommend will do all that. The ATX 30 is great if you have a little time to monitor it, don't have high parasitic draws and really want the a massive weight savings. But that really isn't what everyone needs... often they want a battery they just put in and know it will be there and have the extra capacity that a real Full size auto battery would be best with. And in that case I recommend the RS-30. It's also an 8 year battery. It has different cells in it that have a higher cycle rating. The ATX 30 is about a 5-6 year battery.... both could work well. I just trust one more as the more Automobile oriented battery to handle any situation well.

Let me know if that answered your questions.

-nick

ATX30-RS cold weather report #1.
34F morning,
13.27-13.3v connected with only a 13mA parasitic drain draw.
12.21v key on, fuel pump priming (solid state dme relay), pdas pump on and pressurizing (lasts ~30 seconds)
12.4v same as above, but fuel pump off
12.65-12.69v same as above, but pdas pump off
12.43-12.5v headlights turned on, this triggered the re-start circuit after about 20-30 seconds
After pressing the RS button on the battery the starter cranked the engine over with no problem.
8.40v cranking voltage (this is with thick 15w50 summer oil still in it)
"abs" "park brake" "red pdas" and "!" warning lights stay on after start along with the chime. I'm guessing that the abs/pdas ecu self tests the cranking voltage and triggers a fault at some threshold. This went away after a few re-starts. Note that when that combo is lit, abs is not functioning (I've confirmed this at autocross).

I repeated the above on another 36F morning, but didn't run the headlights to warm the battery. The starter cranked over the motor just fine. So warming, beyond the pdas and fuel pumps priming, isn't needed down to 36F at least.

Qus 1: How to warm the battery without the RS circuit stepping in? The tip to run the lights for 2-3 minutes just triggers the circuit. A remote re-start button would be a nice addition
Qus 2: Unrelated to the above, is the 13mA parasitic drain enough to self-warm the battery to the point of not "freezing" for charging purposes? Might that drain at least lower the ~25F guideline?

Foxman

Ok, I'll play
Voltphreaks VPR-P6 cold weather report #1:
Temperatures plummeted to 22F here in Boston on Wednesday afternoon, and the winds were gusting. The car sat outside all day in an open garage. A simple turn of the key, and the Voltphreaks VPR-P6 fired the car right up like it was a summer day. Sorry, no voltage readings as I was at the office.
The battery is rated to -22F. I'm looking forward to putting this battery to the test.

apanossi

+1 on antigravity. It's been flawless for over a year.

Peteinjp

Antigravity

Ok cool,

1- First off AWESOME testing data, really appreciate you letting me know what was going on..... for that you are most respected and I might have some stuff for you to test if your willing....

2- I want you to post on Renn for sure, I think its great, but I didn't get a notification of this post, but my employee does review every other day or two so we saw it and now I am responding. So please also email also if/when possible for a more timely response to a question, I don't want to miss them. write to scott@antigravitybatteries.com

3- With your good data I am pretty much certain what has caused the triggering of the RE-START feature. On the ATX-30, being it has a smaller Amp Hour Capacity than something like the RS-30 (18Ah vs 30Ah), it has less OVERHEAD when the electronics are kicking in so will dip lower in voltage than a larger battery like the RS-30. Additionally due to the colder weather it will have more resistance under a load so it will sag a little more in voltage in this environment. Anyway, we have a timed delay before the battery puts to sleep. It should be about 15-20 seconds or so... So if it sees the voltage is below 12.4v for those 20 second it that is will "think" it being over-discharged and put itself to sleep. We put in a limited time so that a person could have enough time to do a longer start attempts if needed, but made it limited so that someone could not keep pulling down the voltage for too long. So apparently it is being drawn on and hitting its timer limit then shutting off because it thinks it is being over-discharged. And because in the colder weather it is having more initial resistance it is going lower in its voltage range than it would at a higher temperature. It was not intended for this use actually, BUT I think we can actually solve it with some additional testing.. but again, I won't necessarily recommend this particular unit for this use being it is more of a Track Car Battery. But I'm game to try, and think it would work in general for someone like you who is willing to work with it a little and test.

4- If your into testing and providing me some good data like above then I would be glad to work with you on this. I have a few Batteries we cold send you so you can get a good idea on what each will do. For example we have something similar to the ATX30 but without the BMS and RE-START feature. Its smaller physically but would probably rip start the car without issue. And you could compare that to the ATX with has all the protections. I also have some new BMSs here for the ATX30 that we are testing that allow a lower drop in the voltage and the timer is set longer also so that would not shut off as soon. So contact me by email at scott@antigravitybatteries.com and we'll get some testing going if you want to. We have a quite a few testing our stuff, but none are really driving a Porsche in the 30s or lower often... So you could be a good longer term cold weather Porsche tester.

5- I do not have any data on testing that a low milliamp draw will reduce the freezing of a battery by mildly warming it. I do not feel it will because a true warming effect needs a higher PULSE DISCHARGE to effectively bump the temperature up in the battery. Like some short stabs at the Starter but not full start attempts. I understand you concept, but I don't think it will work because he current dis-charge input is low.

6-.We are super conservative in our battery recommendations. I don't prefer to see the ATX- 30 used as a daily driver in cold weather but more as a Track Battery.. but from your testing so far I think its a great exercise to see if some BMS changes will make is work fine. We are have another lithium technology that I might like you to try that should not have any issues with cold at all...

Antigravity

Good ideas...I thought of doing the Bluetooth reset by phone...but we are currently doing some bluetooth testing on the batteries...for a product coming out next year. The Bluetooth is pretty cool to see the status of the battery.. but I realized the first time I forgot my phone that I don't want to have a phone linked to the battery. So we will keep the resets as exterior and physical units.

So for the here and now we are making this type of product for remote access to the frunk or Jump Starting Lead/Acid Batteries without opening the trunk... it about 8 weeks out. This is the mock-up I made for the GT3... its a harness that our MICRO-START products can connect to that allows you to energize you system to unlock the frunk or to jump start if you have a lead acid battery. It will also remotely reset an ATX version of our battery, but not the RS30.. Anyway it route to below the windsheild and hood juction and you just plug a MICRO-START or other mini jumpstarter into it and energize your car or to open the frunk or jump start it. The blue plug you see will have a cover and just tucks under the edge of the hood when not in use. I accidentally locked my self out of the RS the first day I got it when I put our RS-30 into it and forgot to turn it ON...I thought that going under to the fuse panel and energizing the system was really dumb so I made this Harness so if it ever happened again I could easily get in the frunk.

Sword_of_the_Spirit

-nick

Down to 18F this morning, and not driven within 12hrs. Worth mentioning, I run 0w40 mobil1 for the winter months. At 0-40F temperatures, thin weight and low zddp isn't a concern for a few months! Also, after being off the charger for an hour, the voltage is right around 13.35v. For some reason it's hard to find a published 90-100% charged voltage range.
1) 13.23v before getting in the car. I gave it a quick starter bump to thaw the battery as a precaution and the starter sounded a little sluggish.
2) Let it rest a second, then cranked it over to fire. Starter was a little sluggish again and cranking voltage showed 7.63v(!). It caught easily but then stalled, which is how it's always behaved at these temps (vac leak? always seemed like it could use more after-start fuel enrichment at these temperatures).
3) Cranked it over again and gave it a little help with some extra throttle to avoid a stall, and was able to hold it steady at about 1600rpm to warm it for a minute before slowly lifting off the throttle for it to idle on its own.
4) Charging voltage is always very near 13.80v for me. It can go as low as 13.40v with headlights, fog lights, heater fan, stereo, heated seats, windshield wipers all on. I suspect that my replacement Bosch alternator is not performing perfectly, though it has been consistent for the past 5+ years.

Uniquely C4 stuff: Interesting to me, the pdas didn't complain about this low voltage start. Maybe because it was driven 12hrs prior, the hydraulic pressure was decent and the pump didn't need to run very long. Too bad there is no good documentation on the pdas logic and self-diagnoses. Possibly the startup self-test triggers the warning lights if 1) the pump has to run for more than 90 seconds before reaching working pressure, or 2) the pump runs for more than 45 seconds and the cranking voltage is less than 9v (numbers are just guesses).

Anyway, I'd say the antigravity battery is a solid performer in the cold! Parasitic drain hasn't been an issue at all. Over the holidays it sat for 16 days and only dropped from 13.35v to 13.10v. I don't know what effect temperature has on the amp-hour reserve, but this was a fairly mild stretch of weather with lows not much below 32F.

Scott, I'll send you an email and am happy to help with winter testing. One feature that I would like- for the trickle charger to have a low temperature cut-out. I'm worried that I'll forget and leave the charger on overnight and have the battery freeze while it's being charged. From what I gather, the only ways to kill one of these is to charge it while frozen, or to charge it with a bad voltage regulator outputting 14++ volts.