Anyone looked into trying a Lithium Ion battery?

[Scottd]

They last longer, massive weight saving and about half the size. This is about the only sensible thread I found on the subject -

http://forums.seloc.org/viewthread.php? ... pid5951748

These ones are supposed to be safe and at £200 delivered it’s hard to see the down side?

http://www.shorai-eu.com/products/produ ... X27L3-BS12

[robin]

Yes, I looked at doing it DIY using a bunch of high-C cells I could source pretty cheaply. Not a cost-effective DIY solution, though, by the time you've designed all the electronics you need and they can carry the 200A starting current ....

Those Shorai batteries look OK. Note that contrary to what the chap on the SELOC thread says, they will require battery maintenance if you propose to store for any length of time unused. I would use their charger solution as it's clearly designed to do exactly the right thing.


The battery will have a cut-off voltage of around 7.5-10V - i.e. if you discharge below that, the battery will just go open circuit, like you removed it from the car.

That means that your alarm will go off, and the klaxon battery will start to discharge - if it goes completely flat, it will resist being recharged.

If you then leave the lithium battery for a further 6 months or so after hitting the cut off, the cells will destroy themselves (prismatic, ion, polymer .. it really doesn't matter, they all behave similarly).

Also these cells have a cycle life which lead acid batteries don't (really). So even if you keep the battery in good health, each time you discharge it by leaving the car parked for a few days, then crank the engine few time, you reduce the capacity of the battery when it recharges. So eventually you will need a new one.

Lead acid batteries don't survive deep discharge either, but they are really cheap

So unless you need to save the weight (and unless you're racing, you don't) then I cannot see what advantage of the Lithium-* battery really is?

Cheers,
Robin

[Scottd]

Well you don’t need to be racing to want to save weight, but yea there’s a cost versus gain. It’s just annoying that with all the improvements in battery technology that none of it has fed into cars, although I still think this is pretty close.

Though there’s no guarantee that I can find for these, theoretically they should last maybe twice as long as lead acid which would bring them closer to being economical. It’s rare for my car to sit a week without getting used so it should stay healthy.

A big thing for me is how much easier it’d be to replace, I’ve replaced the battery about 3 times and it doesn’t get any easier! Still takes about two hours.

I'm still tempted, probably a little bit pricey though.

[fd]

Perhaps drop an email to Allan McDonald, he's a bike racer/hillclimber/good guy and sells litium ion batteries to the hillclimb/sprint community.

Not sure he would stock the capacity you need for a big fat road car (;-)) but worth an email.

http://www.skyrichbattery.co.uk/

Fd

[robin]

I think the 043 battery from local motorfactors is about 30 quid. On an S2 you swap it in 10 minutes, tops So you can buy and fit a lot of lead-acid batteries before you've bought one of these.

Agreed on the S1 it is a total ball ache, so makes more sense to fit something that you can replace more easily.

But, if you plan on replacing it at all, it's a pretty expensive item to replace, I would say ... cheaper to invest in some technology that means you don't have to replace it at all. E.g. a battery isolation switch ... that will be what your LiIon battery does when it reaches the cut-off voltage anyway and your lead acid battery will last years if isolated when not in use.

Cheers,
Robin

P.S. You do have to be doing motorsport to care about 10-20kg. Or just have some sort of weight-OCD

[Scottd]

Cheers Fergus, would be good to see what he thought, probably along the same lines as Robin though.

I was talking to the guy from that SELOC thread, he says it was brilliant, started the car better than the lead acid, until... the car didn’t get used for a couple of months and his SatNav ran the battery right down. So no cut-off switch apparently? Which seems mad, every mobile phone has one. So that was it, completely dead, he said he couldn’t get it re-charged. He’s gone back to lead acid

10-20kg I’m holding down through the front to the bottom of the car, with one arm, for an hour as I try and prise it past the wiring loom I’ve just had to cut all my lovely zip ties from. I’m OCD about trying to avoid that every two years.

[hiscot]

I use a AGM westco battery , as it is smaller lighter yet powerful battery ,I have had it for over 5 years its still as new however whilst it takes a long time to discharge it also takes overnight + to recharge ( care says from 3 days see care link on mx5 parts ) ( trickle charge ) and you cannot jump start and expect this type of battery to recover as a normal lead acid

http://www.mx5parts.co.uk/westco-batter ... p-635.html
note its recommended to have a isolation switch . I don't however mine is left on a auto trickle charge I also sit a strap underneath in order to lift it out


DSC01445 by hiscot, on Flickr

[Scottd]

Getting a dry battery had crossed my mind before being distracted by the £200 Lithium Ion one.

At £100 your Westco battery is possibly my new favourite option. That space saving would certainly help a lot! I read a few negative reviews but again they’re about people not using the car regularly which hopefully doesn’t apply to me. Having said that... my annual mileage is below 4k these days, so my previous battery issues are possibly a lot to do with the journeys not being long enough.

Thoughts Robin?

[robin]

The lead acid bat in my Toyota is original. 18 years old and works fine.

If you know you will run flat you should look at marine batteries. Hawker genesis rings a bell.

If you are not running flat (is you never need jump leads or charger) then something else is breaking your bat. Possibly overcharge due to faulty regulation.

The best solution is remove klaxon and use bat isolation switch. Make sure you recharge at least every 6 months. Will last a lifetime.

[Scottd]

I went with Bob’s MX5 dry battery, barely a few grammes lighter sadly but at least I wont have to dismantle half the car to get it out. Mark my words tho, in a couple of years time we’ll all be 10kg lighter with lovely new cheap Lithium batteries

Klaxon!? I blew that thing up years ago - thank god, it was just a pita anyways

I ruined the last battery because a couple of years ago I’d gotten rid of the 90’s CD player – put on the lovely long dash panel – and put in a blu tooth receiver (£8) and a mini amp (£24). Sweet setup actually, just play everything off the phone and no sign of a stereo. Plus saved a few KG’s for those race days lol

The problem was, I had two power sources, one was on all the time, one was only on when the ignition was on. And I wrongly had the blu tooth receiver always on and the amp only on when the ignition was on. Obviously I realise now thats the wrong way round, because the amp only draws power when it’s used where as the blu tooth receiver will use power all the time. Albeit a tiny amount, still enough to drain the battery after a few days.

[robin]

Both those devices should be on ignition switched power. The amp will use some "quiescent" current even if not making sounds.

Cheers,
Robin

[Scottd]

Ah ok, cool!

So how come I had these two power sources after disconnecting the stereo? It’s so long since I did it I can barely remember what was going to what. I'm sure it'll come back to me heh!

I’d like to get it powered up correctly so I can put the long dash back on, I’ve been driving about with out it and it's not pretty. Kinda looks like I've broken in

cheers Robin

[robin]

Hi Scott,

The permanent live is there for radios to maintain time of day clocks and possibly to support memory functions on the radio (though modern radios surely store channel lists and other settings in non-volatile memory).

You should just tape the permanent live up and ignore it, splicing both the bluetooth module and the main amp into the ignition switched circuit instead.

Cheers,
Robin