Pel

Its just tyres and weight, if in the 930 im not sure I would hang with Nigel & yourself. We must try it though

Pel

Paul, could the 3.2 see its first outing June 25th??

996tnz

Hi John. Don't do plain LiPo unless your barbeque insurance (house and car?) includes modified cars. LiFePO4 (Lithium Iron Phosphate) is the much better way to go as they are stable. Probably either a Deltran Battery Tender (eg 480cca), if you can find them in NZ or a willing overseas shipper; or else a Shorai. Been offered a NZ group buy on the Shorai 405 of $385 inclusive, plus $80 incl for the trick (Deltran branded in this case) charger they need to keep them healthy.

There has been some discussion about alternator charging current versus that typically usable by these but they seem to work fine in the cars.

Hopefully someone with more time on their hands will be able to source a good LiFePO4 and charger cheaper somewhere else but maybe a quick poll already of who may be interested here for potential group buy numbers?

LiFePO4 battery interest:
John
Walter

964X33

http://www.motozone.co.nz/products/h...batteries.aspx

What you say echoes my research to date Walter.

964X33

Are there any issues with the terminals? Do they have or can you get standard terminals? At the group but price I could be interested.

Found a 964 user...

https://rennlist.com/forums/964-foru...batteries.html

John McM

I'm keen but is 405CCA is enough and are we sure that the car's charging system won't cause issues?

A DIN66MF is 17kg and the Shorai 540CCA is 2.25kg. That is one heck of a weight saving. The Lead Acid Battery isn't that cheap either so there isn't a huge extra cost (only a Porsche owner can think like that).

Kiwi Carguy

I put a Shorai in my Buell. Awesome little batteries!

kiwi 911

No. Scarlett is a Sunday driver and not dialled in for track.

I'm out for Taupo.

964X33

Trying to make sense of CCA figures.
The HC20 which has been a great battery states CCA at -18C of 230A, a PHCA at 27C of 680A.

For the Shorai 540 I can only find a general statement of CCA of 540 but with no other details.

Anyone understand electricity beyond electrons holding hands?

floatingkiwi

A LiFePO4 battery can be safely overcharged to 4.2 volts per cell, but higher voltages will start to break down the organic electrolytes. Nevertheless, it is common to charge to 12 volt a 4-cell series pack with a lead acid battery charger. The maximum voltage of these chargers, whether AC powered, or using a car's alternator, is 14.4 volts. This works fine, but lead acid chargers will lower their voltage to 13.8 volts for the float charge, and so will usually terminate before the LiFe pack is at 100%. For this reason a special LiFe charger is required to reliably get to 100% capacity.


I understand all this stuff fairly well, give me a pm if you need.
Basically it sounds like it'll go fine in a vehicle, you just (as always) will never charge it 100% and will need a special LiFeP04 charger to keep it topped up. You can use a normal charger on it but it wont charge it to 100%.

floatingkiwi

liPo4 charger:
http://www.ctek.com/au/en/chargers/LITHIUM%20XS

996tnz

Yes, it gets a bit involved. Discovered that CCA for lithiums is usually extrapolated from their measured performance at higher temps or so as they don't measure very consistently at very low temps like -18C. If I was planning to park overnight at winter skifields with a small one fitted I'd maybe take along one of those little portable jumpstarters just in case, taking that inside for the night. Funnily enough, if the car doesn't start immediately with one one of these batteries, some advice is to turn on the headlights for about a minute to warm the battery pack before turning them off and trying again.

So you gain some performance and/or fuel economy from the weight loss, and reportedly gain some battery life too (most say they outlast conventional batteries by 3-5x, though our big lead acids seem to last well anyway).
They're good at providing starting current (a 120 would probably start our cars) but don't hold much total power.

And on the flip side they have a lower total stored capacity ie AH, so you may lose the ability to leave the car unattended for a few weeks and just start her up again - unless put on a LiFePO4 specific maintenance charger, assisted by a booster pack or a battery cut-out switch is used - and even if running frequently, every now and again you'll want to put her on that fancy charger to balance the cells or else battery life shortens.

Some not overly technical background here: http://autotrailusers.nz/ForumFiles/...20in%20RVs.pdf

Cold temps still actually don't hammer them near as much as they do conventional (AGM) batteries:

Shorai straight from the freezer:
https://www.batterystuff.com/kb/arti...buse-test.html

John McM

I'm still keen, especially for Herman, which is more of a weekend warrior and sometimes track rat than a ski field transport (I would like to run the snow in 4WD though).

Question still in my mind though is whether we go up to the 540CCA level? Sure it's more money, but over the life of the battery it's not that much. I suppose we also need to work on some engineering for the battery holder. With this in I reckon I can get a full size spare in the frunk.

996tnz

I don't really think it makes any difference to its starting ability when charged, but it would give you maybe another (WAG) 3-7 days of parked standby time. Maybe more in your case as I imagine the 964 draws less resting current than the 996 and later.

Macca

https://rennlist.com/articles/gte-sp...ce-racing-911/