Elektroroller-Forum.de

Hallo!

I hope that it is OK to ask my question in English.

I am from The Netherlands and I was wondering if it would be possible to install the new Emco 2.0 Lithium batteries in a old Emco Novax (Lithium model).

New Emco battery:



Emco Novax S4000:

Will not work easily. The new Accus have an integrated Batterie Management System (BMS).
As far as i know the BMS in the Novax are assambled in the Scooter,
so you have twice of them. Will not work together properly.

But this is a question for a Dealer with lot of experience, like Herby.
Also I am interested in the answer, cause i get my used Novax next Monday,
hoping the Battery is still alive and will work.

Emco is able to deliver a new Accu, but it is ridiculous expensive, up to
2900 Euros inclusive assambling, my local Dealer told me.

Mechanically, the Novax is not designed to accommodate Emco's new portable batteries. The shape and size of these batteries differs from the one of its built-in battery. Furthermore, the high power consumption of the Novax requires the battery capacity to be at least equal to the one the scooter was shipped with (60 Ah), which means that you will need to install two batteries. This makes it even more complicated to find a place where they fit in.

Electrically, the new batteries should not cause any problems. When installing two batteries, however, you will need some kind of "split box" to connect both batteries in parallel. It is not recommended to connect the batteries directly without the split box. Especially when the batteries have different states of charge, connecting them directly will lead to unwanted high compensation current flowing from the battery with the higher state of charge to the one with a lower state of charge. The split box is also needed to charge both batteries simultaneously.

Regards

Michael

The Novax was sold in diferent Kind of Battery Power, there was 40 and 60 Ah Accus with 48 Volt (different to Novum with 5 kw 60 Volt)

The 60 Ah model is the newer one. Emco stopped selling the 40 Ah model in 2012.

With the 40 Ah battery, the maximum battery discharge rate was very high (4000 W / 48 V = 83,333 A -> more than 2 C). It would be even higher when using one single 37 Ah battery. To retain battery health and to reduce voltage drop under high load, I recommend installing at least 56 Ah (2 x 28 Ah).

Regards,

Michael

Thank you very much for the valueable information!

We would be interested to upgrade the capacity of a 2016 Emco Novax to 74Ah (2x 37Ah). If it would require to remove/modify the plastic under the buddy seat that would not be a problem.

We currently own a Emco C2000 with 56Ah (2x 28Ah) and a 2012 Emco Novax with a broken battery (just 3400 km old). We would be interested to install the almost new original battery in the old Novax, sell it and share the portable batteries between the C2000 and the Novax. This would make the scooters more economical for us.

@Michael In regards to the integrated BMS in the new batteries. Do you know of a solution to make it work with the Novax controller?

I have read on this forum that the Emco Novax Lithium batteries are a special type designed for e-racing (LiNiCoMnO2). It appears that the new batteries are LiFePo4. Could this be a problem or does 48V simply mean that it will provide the energy demanded by the motor?

viewtopic.php?t=2041

The new batteries are LiNiCoMn as well. LiFePO cells are bigger than LiNiCoMn cells with the same capacity. They would not fit into compact battery packs like the new ones from Emco.

The new batteries and their integrated BMS will work fine with the Novax' controller, if you connect them via the mentioned "split box". Emco uses split boxes in all their scooters that can be equipped with two portable batteries, namely Novi, Nova and Novantic. In these scooters, the split box also implements overcurrent protection. However, I'm afraid the split box cannot be used for the Novax, because the Novax' motor has much more power (4 kW instead of 2 kW). You will need to build your own split box using components that can take higher current.

Unfortunately, I don't know the split box' design, because the split boxes used in Novi, Nova and Novantic are moulded in epoxy resin, making it impossible to look inside. The split box looks like this (never mind the red arrow, it just points to a screw):


The simplest way to achieve a split box function would be inserting diodes into the minus lead of each battery, according to this (simplified) diagram: The plus connector of each battery is used as a common connector for charging & discharging. To split discharge current only, diodes must be inserted into the "minus discharge" leads. If you want to charge both batteries simultaneously, additional diodes must be inserted into the "minus charge" leads.

Pin assignment of 7-pin Weipu connector is as follows: For use in the Novax, the diodes should be capable of 100 Ampere current and to prevent overheating, they will need some kind of (passive) heatsink. Note that diodes will cause voltage loss of about 0,5 to 0,7 Volts. This results in a maximum power consumption of 42 A * 0,7 V ~ 29 W per discharging diode with both batteries connected and ~59 W with only one battery connected (it is not recommended, however, to operate the Novax with only one battery). To reduce voltage loss, use mosfets instead of diodes. Unfortunately, I don't have a diagram for such a circuitry.

Depending on the charger you want to use, each of the diodes used for charging must be able to take at least the maximum charging current, which is 15 Amperes when using an Emco quick charger.

The nominal voltage of the new batteries (48 V) is the same as the one the Novax runs on. So this should cause no problems. After removing the old BMS, you can connect the new batteries (via split box and overcurrent circuit breaker) directly to the controller's input.

Regards,

Michael

In Poland we have one just like this with 2 removable akus.