EcoFlow RIVER 3 Plus Smart Extra Battery (EB300)

Double the runtime of your RIVER 3 Plus

The EcoFlow Smart Extra Battery (EB300) is an add-on battery for the EcoFlow RIVER 3 Plus. It holds 286Wh, the same as the RIVER 3 Plus itself, so stacking the two doubles your stored energy to 572Wh. If your RIVER 3 Plus gets you through most outages but runs flat during the long ones, this is the simplest fix. You don’t replace anything; you add to what you have.

It sits in our portable power stations range, part of our wider power and backup section.

What the EB300 does

Adds 286Wh with no cables

The RIVER 3 Plus sits on top of the EB300 and connects through pogo pins, spring-loaded contacts that meet when the two units are stacked. Locking clips hold them together. There are no cables to lose and no screws. Once stacked, the pair behaves as one larger power station, so the RIVER 3 Plus’s AC outlets, USB ports and switchover all work as before, just for longer.

How far you can expand

With one EB300 attached, the RIVER 3 Plus holds 572Wh. EcoFlow lists 858Wh as the largest RIVER 3 Plus system, which it reaches with its larger 572Wh extra battery. You stack one extra battery at a time.

A 140W USB-C port of its own

The EB300 has its own USB-C port, rated up to 140W in both directions. Lift it off the RIVER 3 Plus and it works as a large power bank for a laptop, phone or tablet. The same port also charges the EB300 on its own from a USB-C charger.

LFP cells rated for 3,000 cycles

Like the RIVER 3 Plus, it uses LFP (lithium iron phosphate) cells. EcoFlow rates them for 3,000 cycles to 80% capacity and around 10 years of daily use.

Size and weight

It measures 234 x 224 x 110 mm and weighs about 3.5 kg. The footprint is almost the same as the RIVER 3 Plus, so the stack stays neat on a desk or shelf.

How much extra time does it give you?

To estimate runtime, take the capacity in watt-hours, reduce it by about 15% for losses, and divide by the load in watts. These figures are estimates.

• RIVER 3 Plus alone running a laptop and router at 55W: 286 x 0.85 / 55 gives roughly 4.5 hours.
• With the EB300 stacked, 572Wh: 572 x 0.85 / 55 gives roughly 9 hours.
• A desktop PC, monitor and router at 150W: from roughly 1.5 hours to roughly 3 hours.

On its own as a power bank, charging a 45W laptop from the USB-C port, 286 x 0.85 / 45 gives roughly 5 hours of laptop power.

Compatibility

The EB300 works with the EcoFlow RIVER 3 Plus. It does not fit the standard RIVER 3 or older RIVER 2 models. The USB-C port charges most USB-C laptops, phones and tablets. To get the full 140W, use a cable rated for it, such as the UGREEN 240W USB-C cable. A lower-rated cable still works, just more slowly.

Setting it up

Place the EB300 on a flat surface and set the RIVER 3 Plus on top so the pogo pins line up, then close the clips. Turn on the RIVER 3 Plus and check the screen or the EcoFlow app, which should now show the combined battery. Update the firmware if the app offers it. To use the EB300 alone, open the clips, lift the RIVER 3 Plus off and plug a USB-C cable into the EB300.

Who it suits

It suits RIVER 3 Plus owners who find the battery runs out before the power comes back, home workers who want a desktop to last through a long afternoon outage, and people who want a big laptop power bank for travel days. It is not for you if you don’t own a RIVER 3 Plus, or if you need to run a fridge or kitchen appliances. For that, a DELTA model is the better buy.

How it compares

If you don’t have a power station yet, buying the RIVER 3 Plus first and adding the EB300 later spreads the cost. If you already know you need around 1kWh and more output, the EcoFlow DELTA 3 Classic gives you 1,024Wh and 1800W in one unit. For a laptop power bank alone, the EB300 is heavy. It earns its place when it spends most of its life stacked under a RIVER 3 Plus.

Full product details are on EcoFlow’s official site.

Looking after it

Keep the pogo pin contacts clean and dry, and wipe them with a dry cloth if dust builds up. Store and use it somewhere cool and out of direct sun. If you separate it for a long time, top it up every few months so it doesn’t sit flat. Avoid dropping it on the contacts.

Frequently asked questions

Does it work with the standard RIVER 3?

No. It is made for the RIVER 3 Plus only.

Do I need any cables to connect it?

No. It connects through pogo pins when the RIVER 3 Plus sits on top.

What total capacity do I get?

572Wh with one EB300 on a RIVER 3 Plus.

Can I use two EB300s together?

EcoFlow’s system stacks one extra battery at a time. For 858Wh, it pairs the RIVER 3 Plus with its larger 572Wh battery.

Can I charge a laptop from it directly?

Yes, through the 140W USB-C port.

Does it have AC sockets?

No. Used alone, it has only the USB-C port. AC comes from the RIVER 3 Plus.

Buying from Encom Digital

Everything we sell is genuine EcoFlow. Prices on this page exclude VAT, and every order comes with a KRA-compliant VAT invoice, which your accounts team will need if you are buying for a company.

We offer same-day delivery within Nairobi and deliver to the rest of Kenya. You can pay by M-Pesa, card or bank transfer. If you are fitting out an office, a school or an NGO, ask us for bulk and corporate pricing.

Call or WhatsApp us on +254 714 962 072, email us, or visit us at Rehema House, 4th Floor, Standard Street, Nairobi, Monday to Saturday, 8AM to 6PM.