Breaking new ground: Making Synch e-bike batteries in the UK

This piece first appeared in the March edition of BikeBiz magazine – not subscribed? Get a free subscription.

South Coast-based Synch is an e-bike business with a difference. We talk with co-founders Chris Mooney and Matt French, and Danson Joseph, from battery manufacturing partner, Danecca, about sourcing e-bike batteries from a UK supplier – which is believed to be an industry first.

Let’s open the conversation with an overview of Synch bikes, giving readers some wider context.

Matt French: I’d start by saying that, in the big picture sense, we’re looking at e-bikes being what we consider to be part of the overall environmental story in this country. 

We wanted to do our bit. Synch is here for these reasons.

We have a cargo bike frame made here in the UK, whilst importing another model which has its frame manufactured in China – both are our design. 

We do paint, assembly, QC, and distribution from here in the UK. 

We’re completely open, honest and transparent: The best way, and, as far as we’re concerned, the only way.

With this in mind, we did an extensive search of UK battery manufacturers only to discover that there weren’t any – as far as we could find – for electric bikes.

Now, moving batteries back to the UK has two underlying reasons: Reliability comes first – we’ll explore this a little more in a moment. The second element is transport and carbon footprint – we don’t want to be shipping these kinds of products around the world. 

So, to the hot topic: You’ve initially sourced batteries from mainland China, or the wider Southeast Asia region, and then run a project to identify how you could source batteries from the UK.

Chris Mooney: Yes. One of the major elements of the cost of e-bikes is the batteries. Added to this, although they were Samsung cells, and the batteries were all fully certified, we were never entirely happy with those we’d previously used. We had good, quality certified, batteries but we weren’t happy with their overall performance.

Clearly, the UK does have a nascent automotive electric battery manufacturing sector. We talked with two battery manufacturers, and went with Danecca, based at Silverstone Park. 

They’ve got a wealth of experience in battery manufacturing, which, from the initial meetings, gave us a lot of confidence. Danson Joseph and the team were very willing to work on a project like ours, seeing the opportunity to break into the e-bike battery manufacturing sector.

We’ve been through the whole prototyping process with them. So, yes, we’ve now got fully approved, certified, UK-manufactured, lithium-ion e-bike batteries – the main certification,  UN 3480, is transport-focused.  

We think we may be the first in the UK.

We couldn’t find anyone who had a comparable product or a substitute product that we could use, which meant we had to go from scratch with the UK manufacturer. 

Going through the whole approval cycle took us from August 2024 until now, and we’ve just received our first batch of production batteries which are going onto the bikes that we’re building this week. 

One question immediately springs to mind: Are your new batteries backwards compatible with older bikes? 

Yes. One of the non-negotiables we gave Danecca was that we wanted to use the same mounting system as our current batteries. 

Simple reasoning here: Imagine you want to get a new battery for your bike that you’ve had for five, six, seven, years. We don’t want to change all that – customers would, quite rightly,  have been very unhappy if a replacement battery didn’t work with their bike.

So Danecca uses the same base mount and standard shell. This means they had to fit their technology within the shell – quite a tight fit when they’ve also improved the output.

I mean you can tell by it’s a very dense battery now, very well made, housed within the same casing as our previous batteries. 

Danson, could you give us an introduction to Danecca?

Danson Joseph: I’ll start at the beginning: Whilst Danecca is based at Silverstone Park, we’re not a motorsport company. However, our location does enable us to tap into cutting-edge technologies our customers often require.

We work on a wider variety of projects and applications of battery technology – be that automotive, aerospace, off-highway, grid, marine, micro-mobility or anywhere else requiring custom-engineered battery packs and modules. 

Ultimately, we have the knowledge and experience to help develop a project from concept through to industrialisation.

Can you share an example of how your battery expertise and industry insight informs decisions you’ve made?

We’ll start with some fundamentals of our Synch project.

In the volumes we’re working at now, there’s nothing special about the exterior of the battery – these parts are actually from the same supplier that Chris used previously. They’re a very standard format, called down-tube enclosures, available in a standardised range of thicknesses, heights, and lengths, that make up the various bike batteries you can buy on the market. 

Our component sourcing rationale for casings comes in two parts: 

1) There’s no way to add significant value to the battery enclosures. 

2) The cost element – these parts are where the tooling costs are really expensive. 

In comparison, the distinction we have is the use of commercial cells. LG M50 cells are used in automotive environments. These are cells developed with applications such as mobility in mind. That last part is really important. 

You’ll be aware that there are a plethora of excellent Chinese cell manufacturers servicing every imaginable application and sector. What we need to be sure of is that we source appropriate components for our specific application. 

Where might this approach not be the case – do you have an example?

What you don’t want is to buy from someone (a business) who has, for example, taken a brilliant cell for, say, a vape, and thought, “I can buy these vape cells at a really low price –  I’ll put them into a collection, call it a battery, and sell that cheaply.” 

Great cells used in an application they’d not been designed for won’t deliver the desired outcome. Sounds obvious but isn’t always considered. 

It’s also why the cells we buy are at least three times more expensive than the cheapest options: Application-appropriate components – over spec if anything, given the auto industry requirement.

Your insight and experience inform and influence component and manufacturing decisions.

We start with the LG M50 cells and apply our experience to integrate them in a way that is much more performance and durability-enhanced. 

The welding process we use – ultrasonic wire bonding – allows us to individually connect the cell to what we have as a PC board.

Getting into more detail, we have a PC board that is both the sensing and the conducting element for the battery. Then we connect it to a standard bike Battery Management System (BMS) which is, at this point, also the same as was previously used. Again, quality and cost efficiencies make this a smart business decision, and the right decision for the end user.

Now seems like a good point to tackle the elephant in the room: E-mobility, lithium-ion batteries and bad press – what’s the story here? 

When you look at e-bike and e-scooter fires, a lot of those come from the welding process which joins the cells to the busbars, creating the electrical path.

So, we’ve got a document from a tear-down that one of our clients did, exploring a variety of battery fires in India.

When they then tore apart the different batteries made by different companies, the upper-end units that were being used were made by companies like Ola in India. Batteries from Ola had a more robust assembly – they’re doing similar to what we are in terms of construction and manufacturing. 

However, the ones that were more prone to failures were where people had taken nickel strips and used resistive welding or MicroTig welding. A lot of companies in the UK still use these techniques because they operate as job shops using hobby equipment.

The problem with this method is that you can’t be certain of the contact, and, as a result, if it will work as you put it together: You’ve got no determinant of the fact that you’ve actually welded through onto the tab – because if there are any obstructions, anything like that, there’s nothing that gives you an indication the weld is sufficient. 

For comparison, with our automated welding processes, as it places a piece of wire aluminium – and the wire is half a millimetre thick –  onto the terminal …  it does a little tug. This is, in effect, non-destructive testing. It also measures the individual deformation of each of the two wires that go onto each cell. Then the machine bonds onto the PC board with the same process, in so far as it measures the deformation of the wire. 

The consistency of the deformation is an indication that you’ve got the quality you want.

And this is why Synch came to your door and decided to work with Danecca

Danson Joseph: You’d have to ask Chris and Matt that, but, without speaking for them, I’d say, in short, ‘Yes’.

Our approach is ‘How do we use the best available components, but then add to it in a way that is unique to the UK?’ You’ll hear Chris call this “shared value of local production.”

And that’s where we’ve got our own PCB in the Synch battery. Now this is combined with the LG M50 cells that we put in, and our means of wire-bonding onto the PCB, and then a very simple connection onto the BMS – which is also the same unit the Synch previously used: A quality item. No change needed. 

So, this new Danecca battery has exactly the same interface as with previous, pre-Danecca version. Chris mentioned earlier, that this is critical to ensuring existing customers are benefiting from progress and being supported in long-term ownership.

How does this impact the person buying and using the bike? 

Danson Joseph: For end users, what we’re saying is that because of the slightly different architecture and the choice of appropriate cells, we achieve a higher range. 

Chris Mooney: We’ve got effectively what is the same amp hour battery as we previously had but the range is, on average, somewhere between 10% to 15% more.

So the battery is less lossy, in effect?

Chris Mooney: Correct. Yeah, absolutely.

Having talked about both Synch and Danecca, and heard about the battery development, how do see the next 12 to 24 months going? 

Matt French: We’re keen to expand our dealer network, adding to a committed bunch who already have our bikes in their stores, giving Synch bikes floor space. 

Just as we’ve worked with Danecca to manufacture British-made e-bike batteries, we’ve also found a UK manufacturing partner for our Cargo bike frame. 

We’re in Poole. They’re a boat builder, just around the corner from us. Lots of high-end design and manufacturing experience. We’re the first business they’ve made a bike frame for.

Our powder coating’s done 200 yards from where we are now. We’re lucky to be on quite a big industrial estate. So, we’ve got most of what we need not much more than a stone’s throw from our front door.

One area where international supply is, currently, unavoidable: E-bike motors. 

We’ve specced Bafang because of the product, the support, and the growing name recognition – you’ll have seen the EMBN factory visit content on YouTube. They’re a business that develops and manufactures product, gets brand, and understands service. 

We’ve always done as much as we can in-house, and when not possible we turn to recognised experts.

If you’re a UK retailer, or UK bike shop, looking for a mobility-focused e-bike brand with character, and like the ethos and expertise behind Synch, we’d love to open a conversation.

Retailers keen to explore this conversation in more detail can contact Chris Mooney chris@synchgo.com or Matt French matt@synchgo.com or call the Synch head office on 01202 133 433