Lithium battery

update: do not try, see end of topic

I installed a lithium battery in the new A110 as I figure if Alpine is going to bend over backwards saving 5 grams per hose clip by making them from aluminium not steel why not save 10kg

Unfortunately (of course) things are not super easy.

It seems the car has a smart charging system of some kind and when idling the battery voltage over the terminals is 12.6v -- the alternator is therefore not running - actually I don't even know whether (And at what voltage) the alternator will kick in or whether it even needs a system reset. Or if it does it via estimating fullness some other way.

Either way, if this is going to be the resting voltage (or less) that it maintains the lithium battery then I'm in trouble as it really needs to rest at 13.6v or so. (4 cells in series) so if 12.6v doesn't get a charge, then it will be held at low capacity.

Anyone know anything about the BMS in the car, if I take it to a dealer will they reprogram it or refuse because it is a lithium battery.

Can I do it at home. It probably uses the same coding system as any Renault with a stop/start, right?

Many cars don’t charge when idling - my 72 stag doesn’t charge when idling and (if I remember correctly) my Saab doesn’t either. Best test the output when the revs rise a little - I’d be interested in what you find

Sorry to be useless but I don't know - but would be facinated to hear how you get on. For what it's worth (certainly not a lot) the stop/start facility only works when the battery is nigh on fully charged - after a long long run - so don't get upset if it rarely, if ever, works with the lithium battery,

How much weight does it acutually save?

[stephendell]

That’s really interesting. From the size and limited capacity of the OEM battery I had assumed it was lithium already. As you say surprising they did not do that with the attention to weight saving. Perhaps as suggested it may be incompatible with stop start. I’ve also fitted a lithium battery but in my Classic A110 not a Modern one. I’d be interested to know which one you bought? I have found the cranking capability was not so good and charging was a pain. I also need to use a dedicated charger with multiplug connector for trickle charge. I would imagine the dealer won’t be helpful and will likely say it is a warranty void.

So I've done a bit more research and know a bit more about things work now in the Alpine stop/start charge system

oh by the way the stock battery is 15.8kg or 34lbs The lithium battery is 2.5kg or 5.5lb

The alternator switches in when the voltage at the battery is approx 12.1v and then EITHER runs for 20 seconds, or stops when the voltage is approx 13.7v (I don't know which).
Then the car continues to drag power out of the battery until the voltage subsides back to ~12.1v. You can hear the impact of the alternator switching in and out on idle and revs.

With the auto-headlights on this takes only a minute to drain the battery back to 12.1v. without the headlights on this takes a couple of minutes max. And so it sits endlessly in this cycle of drop to 12.1v then put some charge back in.

A factor in all this may be the EFB battery that comes with the car has a spec sheet that shows "fully charged" at a resting voltage of about 12.6v. But for a "12v" Lithium battery, full charge is more like 13.7v .. 12.6v resting is only 20% full.

The consequence of this is the lithium battery is probably being held at a low SOC over time? This then means if you return to the car a week after using it things are starting to get pretty low from parasitic drain.

Also I'm wondering what this kind of charge cycle is doing to longevity. The battery is getting amps for 20 seconds then getting drained for a minute, over and over and over. I'm not sure how that impacts lifetime.

Bottom line: I don't know if Alpine/Renault has ANY hidden BMS settings that can help. I don't know if the charging system is working off voltage, or a calculation of amps in, and out, I don't know if, when you start it up at, say, 12v, the alternator will run for much longer and whether or not the voltage over the battery will rise to 13.7v more slowly (getting charged for longer).

Either way. So far it does not look like a 1:1 substitute which is a huge shame as not having so much weight there is in the a110 spirit.

Fine if you have a garage trickle charger and a pigtail and never plan to leave it in somewhere else in a carpark for two weeks. Also all this removing/replacing the plastic trim to access the battery area broke one of the clips. Incredibly weak plastic leg I think.

Thanks for all that, even if the result is mainly negative. It does go some way to explain why the stop/start system (on my car) only ever works after a long run, since, I believe that it will only operate when the battery is 80% charged. Sounds like it will rarely operate , if at all with a lithium ion battery.

It's probably possible with some fairly simple electronics between the battery and the sensing system, to fool it into thinking that the battery is at 12.1 volts when it's actually at (say) 12,7 volts - but you still have to arrange it that when the battery is above 12.7 volts that the system sees the real battery voltage. It's really pretty straightforward and I'd half expect that there was something on the market that would do it.

I found this https://www.mastervolt.com/replacing-tr ... thium-ion/ which gives some info. They are suggesting that you need to put some fault monitoring into the system , which might be the most difficult bit.

[stephendell]

That was a useful link above and this point seems to be key.

Battery monitoring needs to be shunt (Ah counting) based, not voltage based. Some basic battery monitoring products base the battery status fully on voltage measurement. In case of Lithium Ion batteries this will result in unreliable readings, potentially leading to deep discharges. Only shunt-based monitoring devices that incorporate a Lithium Ion battery type setting should be used.

Would you mind sharing which battery you used?

I used the largest Shorai which weighs in at 2.2kg.

In the new A110 I have often experienced battery drain issues on show cars. The dealers are very conscious of this. You only have to open the doors a few times and the display drains the battery. It’s almost essential to carry a small Lithium jump pack. Orpington had to buy one at the London classic car show. Also when the battery has a deep discharge the gearbox disables and you lose all drive. We had to phone up the technician and go through a reset procedure.

the battery I have in there now is a lithiumax RACE7

after todays experiments went back to check voltage and it has declined to 11.7v so put a lead acid 3 amp charger on it for a few hours. (It is ok to use a lead acid charger on lifepo4 as long as you don’t leave it on trying to “trickle charge” the lifepo4 for days).

stop start on my car with the EFB stock battery was terrible anyway. Often disabled due to car parasitic drain for a week, when it would work, it would barely last a minute off before kicking the engine back. even without AC on.

Lithiumax said a bmw can be reprogrammed with type of battery so it treats it properly, but they have ceased to reply to me about the alpine I think they know the new car designs with switching alternators are screwing up their products.

update

do NOT try a lifepo4 in your a110

took the car out yesterday for a drive with one two hour stop and came home, parked, next day remembered the low SOC issue, went out, car unlocked, opened hood, then all power went off. Battery voltage had sunk to below critical - just from load of opening door.

put charger on and it wouldn't charge because volts were too low. jumped lifepo4 with old battery until voltage crawled up enough for trickle charger to take over.

taking lifepo3 back out of the car this weekend, and sending official query to factory as seller claims they “have had no issue with nissan/renault group stop start equipped cars”.

but it is probably going back i have no faith factory will reply with a technical response. will give them a month tho.

[stephendell]

Standing Battery life is known to be very poor. The Legende on display at Bicester this weekend was unused for 3 days and already needed a jump start.

It is coming up on almost a month and not a peep in reply to the query sent from sales to Alpine in France.

Is this the French way to simply ignore easy to answer technical questions, from owners? I don't think it was an unreasonable question. It could be answered within a few days by a "non!".

Standing Battery life is known to be very poor. The Legende on display at Bicester this weekend was unused for 3 days and already needed a jump start.

That doesn't square with my experience. My car has been unused for at least 3 weeks (probably a bit more) and started absolutely fine. A car on display might well be different - doors opened , lights on and so on.

[stephendell]

Yes as long as you don’t touch it it should be fine, it’s a shame there doesn’t seem be anyway to adjust the auto off timer for the display?

More information.

So the car, as is common nowadays, has a smart alternator system. There is a small module close to the battery (have not gone looking) that is connected to the ECU that measures at least voltage, and perhaps current in/out. This is what drives part of the decision to cut the alternator in and out.

Personally I think it is badly integrated. At least on my car, sitting idling, when the alternator cuts in you can see the idle revs drop but more importantly - the revs stay lower while charging is going on, and the vibrations felt through the engine mount into the car body increase. In addition to that issue, the stop/start system will stop the motor then start it again almost seconds later especially if A/C is on. If it "knew" what was going on, it should not waste time stopping the motor in this scenario.

Anyway the factory got back with a partial answer: disconnect the battery monitor module. This will run the alternator all the time, but will also throw an error light on the dash. So that isn't any good.

For want of single stored value change inside the car modules, one that might allow moving of the "target" SOC voltage up from 12.7v to 13.4v, using light weight batteries with same Ah as the OEM battery, is blocked.