NEW MotoBatt MFLEX+ batteries!

Tech · Batteries · 2026

One small block. Click a second onto it, a third, a fourth, until you have the cranking power you need. Ultrabatt's modular battery idea was one of the most original things the battery world had seen in years. That idea isn't going away. It's now on the line at Motobatt as MFLEX+, and it came out stronger and lighter.

If you've fitted a lightweight lithium battery to a cafe racer, race bike or custom build in the past few years, you probably know the name Ultrabatt. The multiMIGHTY wasn't a battery, it was a system: no more dozens of case sizes, just identical modules you link together until you have what you need. You built your own battery.

The baton has now been handed over. Order a UB-12400MM+ on Ultrabatt's own webshop today and you're shipped a Motobatt MFX5.0 instead, same dimensions, more cranking power, less weight. Ultrabatt says so on its own product page.

Let's put the two systems side by side.

What Ultrabatt multiMIGHTY was

The brand that brought the modular battery idea to market first.

Ultrabatt was well ahead of the curve. Its first lithium batteries were racing-only, a LITE road version followed in 2010, and around 2013 came the patent on the modular design the brand became known for. That was at a time when the big manufacturers were still churning out lead blocks in dozens of case sizes.

The multiMIGHTY+ came in two sizes:

Both used LiFePO4 cells with a protection board, Ultrabatt called it protecSAFE MOSFET technology, guarding against deep discharge, overcharging, overvoltage and thermal overload, plus a 70A fuse against short circuits. The terminals sat on removable adapters, so modules could be mounted upright or flat.

And then the party trick: linking. You could even mount the modules separately, in two spots in the frame, to spread the weight. For builders that was a gift. A cafe racer with a shortened subframe rarely has room for a standard battery box. Four flat blocks side by side in a shallow tray, or split across the frame, is another matter entirely.

What Motobatt MFLEX+ does

The same principle, built by a manufacturer that has done nothing else since 2002.

Motobatt has made powersports batteries and nothing else since 2002, and now supplies more than 47 countries. MFLEX+ is its take on the modular idea: two models, clickable, with a BMS protecting against overcharge, deep discharge, overvoltage and thermal overload. Mounting orientation doesn't matter, the terminals always end up where you need them.

Linking scales linearly. You simply add capacity and cranking power:

A 4×MFX5.0 pack measures 143 × 156 × 118 mm and comfortably covers big twins, cars, boats and campers. At the other end, a single MFX2.5 is plenty for a light single. Motobatt claims up to 70% weight saving over a conventional battery.

"You're no longer buying a case size. You're buying as much cranking power as your engine asks for, in the shape your frame allows."

Head to head

Same size, more power, less weight.

The large module is a literal dimensional match: if a UB-12400MM+ fitted, an MFX5.0 fits. The small module has actually lost nearly two centimetres in height, in a tight tray, that can be exactly what you need.

A note on the numbers. Ultrabatt quoted CCA, Motobatt quotes CA. Those are two rating standards measured at different temperatures, so treat the comparison as indicative. Ultrabatt itself does describe the MFX5.0 as the stronger of the two.

Why this is good news

The idea stays. The backbone behind it gets a lot broader.

Let's be clear about where the credit belongs: Ultrabatt came up with this. A small, stubborn brand that had an idea the big manufacturers hadn't got to yet, took out the patent and put the first generations on the market. Nothing takes that away, we sold those batteries happily for years.

But a battery isn't bought on specifications alone. You also buy what stands behind it in five years' time. Four things where a global manufacturer makes the difference:

• 1 Stock, year after year. A modular system is only worth something if you can still order one more identical module three years from now.
• 2 A warranty process that runs. A dealer network across more than 47 countries means a claim doesn't land in a single mailbox.
• 3 A serious cross-reference. For each MFLEX+ configuration, exactly which JIS, DIN, EN and BCI fitments it replaces. No guesswork.
• 4 A full programme around it. If your project turns out to be better off on AGM, gel or deep cycle, that sits on the shelf at the same manufacturer.

In short: Ultrabatt's clever idea, with the backbone of a manufacturer that will still be here in ten years.

Worth knowing

Two things not to skim past.

Frequently asked questions

What customers ask us about this.