2015 Battery rules change

[Dylan Edmiston]

The AC limit of IC4.6 does not apply to OEM charging systems designed for a DC voltage which is <60Vdc.

No surprise with this, just thought I'd let everyone know that there is no worry with your stock system.

[Mumpitz]

In my experiences, lead acid cells should also not be over charged or over temped as well. Lead acid batteries when overcharged or over temped tend to release flammable hydrogen gas and spew sulfuric acid if it comes unsealed. Sometimes when charging, they'll outright explode... I guess now that all of the common lithium cells are protected by the BMS only teams with a shorted lead acid battery will burst into flames.

I've seen me do it. I was standing right next to it in the dyno cell. 1/4 of the battery shrapneled out puking corrosives.
On the other hand I've been working with LiFePO4 cells, building my own packs, since 2010 without issue. My experience is admittedly a pretty small sample, Kevin's experience is clearly a valid counter example. I'd love to see an impartial DFMEA comparing lead acid and LiFePO4 batteries.

Kevin, did you/the ECU team determine what caused the antigravity battery fire?

Gotta love the US Army's method of testing "we shot it 47 times and it didn't blow up"
https://batteryworkshop.msfc.nasa.go...pl_DCarmen.pdf

[apalrd]

No surprise with this, just thought I'd let everyone know that there is no worry with your stock system.

I got a similar response:

Andrew,

The intention of IC4.6 is not to apply to OEM charging systems designed for a 12Vdc system voltage. It is acceptable to run the OEM generator/regulator that came with your engine even if the voltage is >25Vac between the generator and regulator.

Dan B

I wonder how many other people asked the same question.

[Kevin Hayward]

Kevin, did you/the ECU team determine what caused the antigravity battery fire?

Unfortunately not. We will not have a chance to find out definitively either. I would say a physical knock of some sort in transit (battery shipped to and from the UK) or a charging fault. Either that or it was caused by my general allergy to electrons.

We have since implemented a number of control measures for the team to follow.

I am confused if the RC says there are plenty of suppliers of legal lithium batteries for 2015, but no one has found any yet.

Kev

[Some Guy]

Here is an example we were given by the rules committee that meets the requirements. It's close to $1k and quite a bit larger than the pulse battery we have been running. Our team probably won't have funds for something like this, so we will most likely be switching back to lead acid. It's worth noting that only some of the batteries these guys sell come with protection circuit.


http://lithiumpros.com/shop/12v-lith...pack-with-bms/.
.

[Adam Farabaugh]

How much would you guys be willing to pay for a battery like this?

I might be interested in starting a small company if the money is there

[Some Guy]

We have been pay $210 for our Pulse battery, which uses a123 cells. I think 350 would be a reasonable number. Given the EarthX price point.

[DanielH]

We've been using shorai batteries for the last 2 years and they work great.
I asked them if our batteries had the protections required by the rules and this is their response:
"We are not offering that on our batteries until approximately Q-1 2015 (all that you require will be in there)"

The shorai MSRP is $159 for the batteries and $85 for the charger. LFX14A2-BS12. Although the price may change with the addition of a internal BMS.
http://shoraipower.com/batteries-c41


I also did a quick google search and found a company which offers batteries with the required protection. I called them up and all of their "UltraStart" batteries have a BMS. They have 2 temperature sensors in the batteries and over/under-voltage protection and short circuit protection.
http://www.starkpower.com/spnews/starterbatteries/
The stark power batteries are listed at 169$, charger included.

There are some reasonably priced batteries with the protection required available. Has anyone found any other options?

[bobochacha]

Totally agree! found one custom batttery for 500USD!

[Dylan Edmiston]

Upon further review of IC4.4.4, and after talking with a number of battery manufacturers. We will allow LiFePO4 based lithium batteries which do not meet IC4.4.4.b, as long as IC4.4.4 a and c are met.