Anti gravity lithium batteries

[ZeroGravity58]

Figured Id give some input on someone else who maybe buying one of these. I picked up the antigravity lithium ion H6 size battery 40ah, It's 1500 ca. I've had it in my truck for a couple weeks with surprising results. I don't run glow plugs and it cranks over much faster then the single leadacid battery. Granted this is also a much bigger battery but it's a 1/4 of the weight. For those of us running a single battery I think it's well worth the investment after you get over the price.... Here a few pictures I took. If you go from a stock dual battery setup to a single lithium battery you can drop 70lbs pretty easy.

 

[2004LB7]

how do those tolerate the cold while charging? LiFePo4 are known for having lithium plating issues below freezing temperatures. does the BMS manage this?

 

[Chevy1925]

I’d assume it’s more geared toward a race vehicle than a daily. I’m contemplating one in my tracker to drop the weight

 

[ZeroGravity58]

I did a bit a research before hand. The batteries do not accept a charge when. The internal battery temp is below 32 degrees. By using the battery you will heat up the cells, also the BMS will not allow the battery to charge until the internal temp is above 32 degrees. Being under the hood still it shouldn't be hard to get the internal temp up to 32. The only other thing they say is when below freezing to put a load on the battery to create some internal heat before cranking, that shouldn't be hard if you are still running glow plugs and let them cycle. I just turn the key on and let the lift pump run for 20-30 seconds before cranking

 

[ZeroGravity58]

The reason I also went with antigravity is i know a few local bmw guys that run these in DD's with no problems. Im in Maryland so the lowest temps may get into the teens a couple nights a year

 

[2004LB7]

looking at those specs again I find it hard to believe the 1500 CCA. that is some crazy high C rates for lithium batteries. just over 37 C. most high output lithium such as the LiFePo4 which that battery most likely uses is normally limited to 10 C. some can do up to 20 C for short duration but 37.5 C seems risky form a business standpoint. they are probably banking on the fact that the resistance of the wires, starter, grounds, etc will limit the current to something more reasonable and no vehicle will actually pull 1500 amps

 

[Bdsankey]

looking at those specs again I find it hard to believe the 1500 CCA. that is some crazy high C rates for lithium batteries. just over 37 C. most high output lithium such as the LiFePo4 which that battery most likely uses is normally limited to 10 C. some can do up to 20 C for short duration but 37.5 C seems risky form a business standpoint. they are probably banking on the fact that the resistance of the wires, starter, grounds, etc will limit the current to something more reasonable and no vehicle will actually pull 1500 amps

It's CA not CCA listed in his post, they are two different measurements. CCA is measured at -18°C/0°F and CA is measured at 0°C/+32°F. The picture below also is pulled directly from their website.

 

[2004LB7]

It's CA not CCA listed in his post, they are two different measurements. CCA is measured at -18°C/0°F and CA is measured at 0°C/+32°F. The picture below also is pulled directly from their website.

View attachment 106721

regardless of the temperature 37 C is extraordinary for lithium chemistry. and if you look at the photo posted it says CCA so that's what I based it on

 

[2004LB7]

thinking about this further, I would bet substantially that they employ a bank of super capacitors to give the cranking amps even when cold. I've been using a similar setup in my previous LB7 and currently in my TDI. I have 6x 3k F caps in series for cranking and another 4x 38120 headway cells rated down to 14°F for a little more capacity. the BMS only manages the lithium cells for lower current charge and discharge but the capacitors handle the cranking power. mine is rated at max CCA of 1900 with a short circuit current of 9300 amps. and because this all fits into the old gutted battery I would bet they did something similar. and not to brag (but I really am ) mine was less then $200. unfortunately it is only about 10 AH capacity vs the 40 AH of the antigravity one. but I could have increased it if I needed

 

[ZeroGravity58]

I'm not gonna cut it open to find out what is in it yet lol. I found the battery on sale for a good discount but I did have to wait 2 months to get it. I don't need batteries for my lbz yet but if it works out I'd consider buying one to replace the two in there. Cost wise it wouldn't be that much of a difference. Only time will tell how long they last...

 

[buick455]

How well would these hold up to an engine startability issue though, like loss of fuel or communication to the ECM? How long would they survive cranking and if they did it once how many times could they do it? Any known longevity testing of these in not ideal starting situations, even say like with a new fuel system build when it's dry?

 

[TheBac]

$1000 for a f****** battery?!?!? Are you guys absolutely nuts?

 

[Cougar281]

$1000 for a f****** battery?!?!? Are you guys absolutely nuts?

Well, if you only need one to replace the two lead acids our diesels need, and it lasts at least 4x as long.... But I'd be concerned about using them where it could freeze... As previously mentioned, most lithium chemistries don't do well below freezing - charging more than discharging. LTO is the only one that I know of that tolerate below freezing temps, but it's not very energy dense.

Sent from my Pixel 5 using Tapatalk

 

[2004LB7]

How well would these hold up to an engine startability issue though, like loss of fuel or communication to the ECM? How long would they survive cranking and if they did it once how many times could they do it? Any known longevity testing of these in not ideal starting situations, even say like with a new fuel system build when it's dry?

if it is 40AH I calculate best case 16x 30 second crank intervals at 300 amps each. likely less due to voltage drop and lower battery efficiency at higher draws. if it uses super capacitors then it would probably only have a few seconds worth of cranking then you would have to let it rest for a bit for the lithium cells to charge the caps back up for another go. not sure how the BMS would manage that aspect

 

[2004LB7]

here is my version of the "Antigravity" battery for less than $200. don't mind the cardboard spacer as it was used for "rapid prototyping" but it's been in prototype stage for about 8 years now . you can see the lithium cells on the side in one compartment. these feed the Maxwell 3000F capacitors through a resistor to limit the current to a few amps. the BMS is rated for 30 amps but the surge of current during starting would likely trip it each time I started the engine if I didn't put the resistor between them

 

[ZeroGravity58]

I'm not that electrical savvy to try and build my own....I guess I will see how well it works. My truck doesn't get driven and whole lot but it does sit in a non heated garage. I got the 40ah battery for 650, if you shop around you can find them at a decent price. I did buy it back in oct but it was on back order. Just received it about 2 weeks ago. I do know that running the single Bosch after it sat in the cold for a couple weeks if the truck didn't start in the first 15 seconds I was giving it a hot shot. I'll see how this one does one night when it's cold out.

 

[2004LB7]

would you be willing to disable the injectors and see if you can get the full 30 second crank?

 

[ZeroGravity58]

I could give it a shot one day

 

[Harshman]

here is my version of the "Antigravity" battery for less than $200. don't mind the cardboard spacer as it was used for "rapid prototyping" but it's been in prototype stage for about 8 years now . you can see the lithium cells on the side in one compartment. these feed the Maxwell 3000F capacitors through a resistor to limit the current to a few amps. the BMS is rated for 30 amps but the surge of current during starting would likely trip it each time I started the engine if I didn't put the resistor between themView attachment 106722

I would like to know what BMS and what resistor you are using.

 

[2004LB7]

I would like to know what BMS and what resistor you are using.

4S 30A BMS LiFePO4 12.8V With Balance Function Free Ship from Indiana | eBay

4S 3.2V LiFePO4 Protection board. 30A Output current. From Indiana. Includes balance circuit. Release: 3.60±0.05V. Current: 20A (MAX). Detect delay: 145S. Detect: 2.1±0.08V.

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Amazon.com: LM YN 50 Watt 2.5 Ohm 5% Wirewound Resistor Electronic Aluminium Shell Resistors Gold (Pack of 2) : Industrial & Scientific

Amazon.com: LM YN 50 Watt 2.5 Ohm 5% Wirewound Resistor Electronic Aluminium Shell Resistors Gold (Pack of 2) : Industrial & Scientific

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the resistance is not too important. as long as its in the range to pass less amps then the BMS can handle and within the wattage range of the resistor. I think mine was 5 ohms