topic Re: Battery Backup in Broadband & Landline

Battery Backup

GDog3 — Tue, 27 Oct 2026 17:34:37 GMT

I ordered the battery backup unit (BBU) to power the ONT and EE Smart Hub Pro.

Problem is that it powers the ONT, but as soon as I plug in the Smart Hub it flashes red and shuts down power to both.

My Hub is the Smart Hub Pro 7. Anyone know if this is supported?

Wait time for support is currently over one hour.

Re: Battery Backup

JimM11 — Tue, 27 Oct 2026 17:52:37 GMT

@GDog3 Yes it is supported, correct BBU and correct cable to match the EE Smart Hub Pro version, just try the units individually to see which has the issue with current draw. 1st the ONT it takes very little current, then try the Pro it will draw a lot more, then finally them together, and assume you have the batteries fully charged on the BBU unit.

Re: Battery Backup

GDog3 — Wed, 28 Oct 2026 06:08:54 GMT

Many thanks Jim

i tried your suggestion but it didn’t work. Maybe I have a faulty one.
ill call EE

Re: Battery Backup

JimM11 — Wed, 28 Oct 2026 08:58:55 GMT

@GDog3 That is all you can do, The two parts as below so you see the BBU and the cable for the ONT/Pro hub.

BBU Plus (Digital Voice)
Specifications
Hub compatibility BT/EE Smart Hub 2, EE Smart Hub Plus, EE Smart Hub Pro
Manufacturer Part Number 5061061580004
EE Article Code 400023335
https://ee.co.uk/products/battery-back-up-plus-digital-voice

EE Smart Hub 7 Pro
Specifications
Compatibility EE Smart Hub Pro (SH40J)
Manufacturer Part Number 5061061580042BBU
EE Article Code 400023338
https://ee.co.uk/search?q=battery%20backup

Re: Battery Backup

GDog3 — Thu, 29 Oct 2026 08:38:21 GMT

Thanks Jim

New BBU being sent out. See if that works.

Re: Battery Backup

JimM11 — Thu, 29 Oct 2026 09:07:29 GMT

@GDog3 Look carefully at the power connector for your PSU and the one on the cable supplied with your new BBU, those plugs are three pin type so not easy to test like the other two units, but the supply is still 12V D.C. for the Pro Hub. Hopefully it is just a bad BBU that has been sent and it's shutting down due to the current draw on itself.

Re: Battery Backup

GDog3 — Thu, 29 Oct 2026 10:06:45 GMT

Thanks Jim

The plug that goes to the Pro Hub does seem a bit of a snug fit. Maybe that is the issue. I'll report back when the new one arrives.

Re: Battery Backup

JimM11 — Thu, 29 Oct 2026 10:19:53 GMT

@GDog3 Yes the Pro hub is the odd ball connector that is in use, and there are three connector cables in use by EE, one to cover the 6+, one for the BT SH2, and the final for yours the 7 Pro version.

Have never seen a Pro live to look at so would be worth you taking the look see for your original connector to what EE sends with the BBU. The 7 Pro is the most powerful for current draw due to the mass frequency supported and it's power brick PSU standard socket connecter is rated 48W with a 4A current draw whilst all the others are 50% off that rating. You for sure are the first to post as using but by now others must have tried it on a 7 Pro hub but it does appear the BBU is protecting itself from what you describe as happening. The only other thought is the new cable has the polarity flipped by mistake and if so just be careful when connecting it back up again.

Re: Battery Backup

GDog3 — Thu, 29 Oct 2026 17:27:12 GMT

Thanks Jim

Not a very good pic sorry. I can't tell at the moment what exact version it is. I'll look tomorrow if there are any clues on it.

Re: Battery Backup

JimM11 — Thu, 29 Oct 2026 18:47:01 GMT

@GDog3 Does look like the EE one from the link above.

Battery Back Up Plus Connector Cable for Smart Hub 4 Black | EE

Re: Battery Backup

Denzel99 — Thu, 29 Oct 2026 22:16:58 GMT

I'm not sure what the issue is that you are trying to resolve here, but if it is the size of the plugs then I can confirm that the BT Smart Hub 2 is 3.0 mm x 5.5 mm. 3.0 mm is an unusual size. More of an American thing, I think.

Incidentally, you can use a set of metric drill bits as gauges to measure the internal diameter. If a 3.0 mm doesn't fit try a 2.5 mm. If that doesn't fit but a 2.0 mm does then it will be a 2.1 mm etc.

Re: Battery Backup

JimM11 — Thu, 29 Oct 2026 23:28:20 GMT

@Denzel99 Special 3 pin connector barrel socket on the EE Smart Hub 7 Pro version, with 2 GND connections and 1 +12V D.C. centre and outer are Gnd's with the inner part off the round barrel having the positive on it, never seen on but would be very hard to check without getting a socket plugged on it for pin access.

Re: Battery Backup

GDog3 — Fri, 30 Oct 2026 06:47:21 GMT

Hello Denzel

The issue is outlined in my original question.
Best wishes

Re: Battery Backup

Denzel99 — Fri, 30 Oct 2026 14:27:07 GMT

@JimM11 Centre positive is fairly normal. If it’s the pin diameter, you can find a plug that fits it and then measure the hole in that plug and deduce the pin diameter etc.

@GDog3 Fair enough. I was just going by the plug in the picture. As I said, I wasn’t sure what you were after. Sorry I couldn’t help.

Re: Battery Backup

JimM11 — Fri, 30 Oct 2026 14:46:36 GMT

@Denzel99 The EE Pro is NOT centre positive that is as far as the EE Pro manual documentation is showing, will link the page. See the section plug polarity also @GDog3 if you need the look see.

ee-smart-hub-7-pro-user-guide.pdf

Re: Battery Backup

Denzel99 — Fri, 30 Oct 2026 22:07:19 GMT

@JimM11 Yes, I see what you mean. That is a peculiar design.

Re: Battery Backup

GDog3 — Sat, 31 Oct 2026 14:33:40 GMT

I'm beginning to suspect they were out of stock and sent what they had, as the replacement still hasn't been shipped...

Re: Battery Backup

JimM11 — Sat, 31 Oct 2026 17:05:02 GMT

@GDog3 Could be the case, also may be waiting on a returned unit to send to you also, do you know if getting both again the BBU and the 7Pro cable set? Trouble is it's working connected to the ONT but the power is just so low on that unit would last forever time wise protecting that alone, the 7 Pro hub is a way different animal pulling a few amps out of the BBU, but as you have said as soon as that is connected on it's own the BBU shut's down, thinking it is either protecting itself from current draw, or maybe the batteries in the BBU are goosed.

You could do the BBU on the ONT by itself, once fully charged pull the mains cable off it and see how long it runs.

Re: Battery Backup

GDog3 — Sun, 01 Nov 2026 16:27:05 GMT

This is getting interesting...

New BBU arrived but without cable. A different model number...

Connected up and this one now reports E5 which suggests it doesn't like the hub.

Re: Battery Backup

JimM11 — Sun, 01 Nov 2026 17:36:03 GMT

@GDog3 Is the E5 in the display for the unit? and does it look ok when connected to the ONT for operation.

Would assume E5 is an error code to display, any manual or paper document with it, the vodafone unit is the same BBU but unfortunately no document on there site either to say what E5 is. Found the linked info BT site.... LOOK very carefully at the BBU splitter cable for the Pro connection, you should i think see a cable pin bang centre off the plug and make sure it looks that way and is not pushed away to the side..... If the cable is wired wrong you may get a HUGE current draw for wrong polarity also.

Problems with Battery Back Up | BT Help