New Project. Smart Aux Battery

Wieviel Hundert Ladegeräte sind bei Renault in die Tonne gewandert bevor der berühmte 12 Volt Fehler
von Seiten eines Forumsmitglied entdeckt und eine adäquate Reparaturmöglichkeit gefunden wurde.
Gott sei Dank lassen sich Menschen wie @twizylover
nicht von Fortschrittsverweigeren zurück halten weiter zu machen.
Es gäbe keine Alu Bremskolben, Sitzschienen, Bremsscheiben, Bremssättel hinten wie vorne, Zusatzlader, neue Akkukapazitäten und und und.
Oja, Anhängerkupplung, LED Scheinwerfer diverse Seitenscheiben, eingetragene Breitreifen, Gehäuse für andere Akkus.
Sollte ich was vergessen haben bitte nachtragen.


How many hundreds of chargers ended up in the trash at Renault before the famous 12-volt fault
was discovered by a forum member and an adequate repair solution was found?
Thankfully, people like @twizylover
don't let those who resist progress hold them back from moving forward.
There would be no aluminum brake pistons, seat rails, brake discs, rear and front brake calipers, auxiliary chargers, new battery capacities, and so on.
Oh yes, trailer hitches, LED headlights, various side windows, registered wide tires, housings for other batteries.
If I've forgotten anything, please add it.

Berthold schrieb: @twizylover
I am trying to understand your project. My thoughts on it.

The Twizy has two energy storage devices. The drive battery 11000Wh (new cells) and the auxiliary battery AGM with 12V x 14ah = 168Wh. So 98.5% of the energy is distributed in the drive battery and 1.5% in the auxiliary battery.

Now you want to increase the size of the auxiliary battery,for example, 12V x 40Ah = 480Wh. This would allow the Twizy to carry approx. 300Wh more energy. With the Twizy's consumption of 11,000Wh/100km, that is 110Wh per km.
The additional range would therefore theoretically be a maximum of approx. 2-3 km.
Is it worth it?

It is true that the AGM battery wears out quickly. However, there are replacements available, e.g. sodium batteries (from Hakadi), which are resistant to low temperatures, have a high cycle count and are inexpensive at 40€.
Is the conversion you are considering worth it?

Hi Berthold;

Mmm, here there is a misunderstanding, this project is not about increasing range of mileage. Its about upgrade the twizy 12V line, to isolate it from 52V -nominal- line, so the main charger becomes with no SPF on the 12V section. The 2-3km that you are talking will be a free upgrade but it is not the target of the project. The goals of this porject is about no change of the 12V battery in whole life of the vehicle. (More than 4000 cycles), and with x3 capacity of the oem battery so you can plug extra devices or systems of 12v Even, we are focused on not using at all the oem charger.

Talking about quemistries, a few weeks ago we were studying the LTO option with 20000 cycles or more, but we don't have enough room on twizy battery place, so we finally go with LiFePO4 as the best overall quemistry option.

I hope this helps. Best regards.

Twizylover schrieb.

Its about upgrade the twizy 12V line, to isolate it from 52V -nominal- line, so the main charger becomes with no SPF on the 12V section.

please confirm:
The plan is to increase the size and durability of the 12 V battery and have two new separate chargers. One for the drive battery and one for the 12 V battery. Have I got that right now?

Berthold schrieb: please confirm:
The plan is to increase the size and durability of the 12 V battery and have two new separate chargers. One for the drive battery and one for the 12 V battery. Have I got that right now?

Yes.

This battery has a dioded output, so no energy at all can go into the new aux/service battery system from the actual 12V line, even if the oem charger wants to do that by his design.You can only go into the new service battery via the 230v line with his own automotive grade rectifier and automotive grade BMS.

The french engineers of Renault think that mix both lines 12v an 52v for a very different purpose in the same charger was a good idea, they think that permanently charging the 12V battery on the go was a good idea too -when you always must charge your traction battery from AC-. We are not agree with them... and this project is our tech alternative.

When you are in a combustion car, you don't have any other way that charging the service battery on the go with the alternator, so you never need to go to an AC outlet. In an EV its a little bit different. For a strange reason, that we don't really understand, these engineers wants to "emulate" an alternator, when its no needed at all if you charge your service battery at the same time that you charge your traction battery. Doing that, the life of the battery increases, because you are not doing microcycles or charge in a travel of 10 minutes, you charge with a bms that charges all the battery in the most convenient way for each kind of cell, and many other advantages, like you always know the SoC of your aux battery, and always its on 100% after a traction battery charge, so you never happen again the "motorcycle battery case" when you often do short rides the agm battery always go down a little and you need to suppot your battery with an external ac charger.

What do you think now?

i hope this helps. Regards.

twizylover schrieb:

Berthold schrieb: please confirm:
The plan is to increase the size and durability of the 12 V battery and have two new separate chargers. One for the drive battery and one for the 12 V battery. Have I got that right now?

Yes.

No. I think there is a misunderstanding. You have 2 seperated Chargers, one "new" 12V-only, somehow conected to the 230V Input line, and the original Renault Charger for the Main Battery, who's 12V Output is not longer in Service for the Lead Battery.

Which voltage will your smart aux battery provide when it's charged at SOC 100% ?
I suppose ~12,8V ?
Am I right?

twizylover schrieb: This battery has a dioded output

Snorre schrieb: Which voltage will your smart aux battery provide when it's charged at SOC 100% ?
I suppose ~12,8V ?
Am I right?

I see where this is going

Two nice to have Features i thought of and want to share:

Emergency-Backup: Monitor vehicle state (CAN-BUS), 12V-Internal SOC and high current draw. If vehicle is off(parking), below 20?% SOC and current is drawn, shut off the output and only allow a restart via Bluetooth Command or every 15 minutes for 15 seconds. This will save me from being stranded because of a faulty Hazards Switch or power-hungry ODBII acessory.

Emergency-Jumpstart: Allow reverse charging via USB-C PD, so you can jumpstart the Twizy with your phones Battery. I have involuntarily tested that use case: www.twizy-forum.de/probleme-twizy/92292-...oses-phaenomen-twizy-geht-nicht-mehr-aus

I would be more willing to purchase a two-module solution: Battery + Bluetooth-Gimmick-Charger Box. This way, everyone could use her/his preferred Sodium/Lithium/Lead-Acid/... Battery.

Snorre schrieb: Which voltage will your smart aux battery provide when it's charged at SOC 100% ?
I suppose ~12,8V ?
Am I right?

Voltages with current selected cells:

The range will be from 14.6V 100% to 10.0V 0%.

This is from 3.65V to 2.5V each cell

I hope this helps.

Berthold schrieb:
No. I think there is a misunderstanding. You have 2 seperated Chargers, one "new" 12V-only, somehow conected to the 230V Input line, and the original Renault Charger for the Main Battery, who's 12V Output is not longer in Service for the Lead Battery.

That is perfectly right. Thanks.

FlipFlop schrieb: Emergency-Backup: Monitor vehicle state (CAN-BUS), 12V-Internal SOC and high current draw. If vehicle is off(parking), below 20?% SOC and current is drawn, shut off the output and only allow a restart via Bluetooth Command or every 15 minutes for 15 seconds. This will save me from being stranded because of a faulty Hazards Switch or power-hungry ODBII acessory.

I think this feature is nearly covered by the anti-theft feature, because you can off the battery mains. For long storage periods, for anti thief purposes or even for your use case. Monitor can to check 20%SOC of traction battery and in parking mode -no insert key-, and only on via the anti-theft unlocking wireless procedure. But for high drawn accessories perhaps the solution could be better with a indendent 12V accesory line, that isolates himself for the standard 12V line. There we can connect these hungry devices an get more metrics about power consumption an posible workarounds. So you can off all the accesory line without interfere with the vehicle normal operation. We'll think about that.

FlipFlop schrieb: Emergency-Jumpstart: Allow reverse charging via USB-C PD, so you can jumpstart the Twizy with your phones Battery. I have involuntarily tested that use case: www.twizy-forum.de/probleme-twizy/92292-...oses-phaenomen-twizy-geht-nicht-mehr-aus

Mmm, could be interesting, an additional usb-c port for charging at PD... we consider it, but will increase the cost. input pd port, electronics, sealed connector... when if you have an AC 230v outlet near you can solve too. And remember that with the new design its very more difficult this use case than in oem design, so perhaps don't need it at all.

FlipFlop schrieb: I would be more willing to purchase a two-module solution: Battery + Bluetooth-Gimmick-Charger Box. This way, everyone could use her/his preferred Sodium/Lithium/Lead-Acid/... Battery.

Its currently a three module solution. The case, the electronics and the cells. The battery case has something like a drawer where is placed the bms an all the electronics isolated from the cells. So you can choose what you want. As you know the bms should be as near as possible to the cells so its difficult, we'll think about it.

Many thanks for share your ideas. Regards.

twizylover schrieb:

Berthold schrieb:
No. I think there is a misunderstanding. You have 2 seperated Chargers, one "new" 12V-only, somehow conected to the 230V Input line, and the original Renault Charger for the Main Battery, who's 12V Output is not longer in Service for the Lead Battery.

That is perfectly right. Thanks.

So the 12V battery is not charged while driving. It is only charged when the Twizy is plugged into the mains.
This means I have to keep an eye on TWO batteries if I want to reach my destination.

The range will be from 14.6V 100% to 10.0V 0%

Startet der Twizy überhaupt mit 10 V?

Goldbacher schrieb:

The range will be from 14.6V 100% to 10.0V 0%

Startet der Twizy überhaupt mit 10 V?

Wenn die halbwegs stabil anliegen und nicht auf 5V zusammenbrechen ja.

Berthold schrieb:
So the 12V battery is not charged while driving. It is only charged when the Twizy is plugged into the mains.
This means I have to keep an eye on TWO batteries if I want to reach my destination.

No. You always can do it but it is not needed.

With 40Ah you will always have enough aux battery capacity until the next traction battery recharge, even with an XL Battery like 11.1 kwh or more. In an use case with 15kwh traction battery, which its about 200km as max range, so in 200km you don't have enough time to drawn the 40Ah capacity. And at the end of this 200km, you need to recharge for the next trip, so your aux battery will be at 100% again.

In other words, you don't have time between traction battery recharges to empty the aux battery so you have not to worry about two capacities, also, you have new metrics where you can check your aux battery consumption and different status provided to the canbus via the BMS.

Furthermore, this is our bet against Renault engineers like i said in previous posts, we believe that in an EV you don't need an alternator if you have enough capacity between traction battery charges, also, as some of the new features, if 12V accesory line is drawing off the battery we can cut this line off and you always can reach your destination while the system keeps feeding the oem 12V devices.

I hope this helps. Regards.

twizylover schrieb:
Furthermore, this is our bet against Renault engineers like i said in previous posts, we believe that in an EV you don't need an alternator if you have enough capacity between traction battery charges, also, as some of the new features, if 12V accesory line is drawing off the battery we can cut this line off and you always can reach your destination while the system keeps feeding the oem 12V devices.

If the 12V battery is large enough to cover the worst-case scenario, this will work.
However, for safety reasons, the DC/DC converter (you name it alternator) from the OEM charger is still included in the Twizy and ready for use.

By the way…-
Many car tuners are going in the opposite direction.
They are trying to make the 12 V battery as small as possible in order to improve the car's power-to-weight ratio. Here is an example.
Akku tunnig Porsche
Theft protection via app is also cited as an advantage.