This is the 2700mAH internal battery for the FT-817. One of the accessories supplied with it was a cable to charge it directly - the OPP-817 battery has a socket for direct charging. What I am confused about is whether I must buy the OFC-817 “One Fast Charger” unit to do this, or whether I can trickle charge it without.

For instance, I am looking at this product:


…which appears to have the right connector for the OPP-817 battery, but is also described as a PSU for the OFC-817 charger:


So, is the OFC-817 a luxury item if I need to recharge my 2700mAH pack in 2 hours, or is it a necessity for proper charging of the OPP-817 battery? If slower charging is sufficient, can I just use the wall power adaptor directly? Has anyone much experience of these products?

I am intentionally ignoring the option of charging via the FT-817’s own circuit and via the rear power socket!


In reply to M1EYP:
“I am intentionally ignoring the option of charging via the FT-817’s own circuit and via the rear power socket!”

Why? If you look at W4RT’s advert it clearly states you may use EITHER the Yaesu charger or the OFC-817.


Victor GI4ONL

In reply to M1EYP:

Hmmm… RadioWorld, sniff.

From reading several times you need to provide the One Fast Charger with 17-19V DC and it charges the battery pack. W4RT’s site says the US version of the OFC-817 comes with a wall wart to power the charger but is omitted in export versions. The wall wart you mention is the 17-19V supply the OFC-817 needs. The RadioWorld blurb says the OFC-817 comes with a supply.

However, the question to be asked is why are you fannying about with prehistoric NiMH technology? £72 for a heavy 2.7Ahr battery and £82 for the charger. £72 buys a huge amount of Lithium cells and chargers. A 2.5Ahr cell pack is about £18, and a smart charger is £20. So £80 buys 3x cells + charger and the lot will weigh less than 1 OPP pack.


In reply to GI4ONL:

I think the answer is that the internal charger is designed to take between seven and ten hours. I only use it to check that my external battery is active before switching on.


I’ve already got the OPP-817 2700mAH battery pack, had it for some time. I also have the so-called fast charging cable that came with it, that plugs into the socket on the OPP-817 pack. I also have the modified FT-817 panel so that this can be plugged in without removing that back panel.

I agree that the OFC-817 plus PSU looks expensive, which is why I am exploring whether I actually need them, or whether there is a much simpler way of trickle charging using what I already have, possibly with the addition of the OFC-817 PSU which is only £22.

Rod, the reason I am avoiding using the 817’s power socket and internal charging method is that repeated push and pull on that jack causes wear and tear. An old 817 I have obtained has suffered such wear and tear, and while it can be powered via the rear power socket, the bit that takes charge via that route is damaged. Hence plugging the charging cable directly into the OPP-817 pack (inside the 817) is the desired option.


In reply to M1EYP:

… the bit that takes charge via that route is damaged.

I think mine has failed that way as well Tom as the internal charger will not charge the internal 2700mAH pack. Pity, as it is a pain to take the pack out of the 817 as I have it mounted in a weather-resistant enclosure and it all has to come apart for charging.

73, Gerald G4OIG

Is that an OPP-817 pack Gerald? And how do you charge it?

In reply to M1EYP:

Rod, the reason I am avoiding using the 817’s power socket and
internal charging method is that repeated push and pull on that jack
causes wear and tear. An old 817 I have obtained has suffered such
wear and tear, and while it can be powered via the rear power socket,
the bit that takes charge via that route is damaged. Hence plugging
the charging cable directly into the OPP-817 pack (inside the 817) is
the desired option.

Tom, my first 817 had that problem, when I took the lid off and used a magnifier I found that a section of track had lifted and broken. I bridged across the lifted section with a short length of tinned wire and that cured the problem. I read somewhere (I think on the 817 Group) of somebody who put a charging socket on the lid of the battery box, though looking at it there isn’t much room!



Another consideration influencing my choices is that I am loathe to be disconnecting and reconnecting the tiny Molex connectors. These things have low life cycles even before I get my fat clumsy fingers on them!


In reply to M1EYP:

Is that an OPP-817 pack Gerald? And how do you charge it?

No, its this pack - http://www.g4bee.net/FT817.aspx - actually 2600mAH. I now charge it out of the rig with a constant current charger at around 0.25C.

73, Gerald G4OIG

In reply to G4OIG:

On the g4bee site there is a link to the supplier of the pack. They happen to be selling this, which may be what you need Tom.



That looks interesting. I have emailed that supplier to get confirmation (or otherwise) that this product will charge the OPP-817 and have compatible connectors.

The Radioworld website info on the OFC-817 is really confusing. It goes on about the supplied wall wart plugs, but adds the small print that it needs a 12V supply which is not included! As though the blurb has been copied and pasted from W4RT’s US site in a rather slapdash fashion.

Anyway, I hope to have something fixed up in the next few days.


In reply to MM0FMF:


Used this ‘beastie’ for a number of years now to charge Mikey’s (YYY) excellent selection of no ‘faffing’ about ‘tagged’ NiMh’s - excellent charger. See my QRZ.com page as to the small pouches I use to house 8 or 10 cells.

And as mentioned many moons ago on the Reflector I knew the weakest link on the 817 was going to be the power connector and right from the start kept it in the socket with the power lead held with a ‘P’ clip secured by one of the cover screws and the lead terminated in ‘Raynet - T’s’ http://www.barenco.co.uk/d-c-t-connector-2-pole-assembled-kit-160995

Now over 10 years on without a single DC failure (as long as your ‘ruggedise’ the leads with heat shrink over the individual terminations tags - like all little good Raynet operators would do?). Not a bad track record.


Jack (;>J

In reply to M1EYP:
The internal charging circuit of the 817 limits the charging current and all you can adjust is the charge time. You can charge these bigger packs this way but you will need something like two or three cycles of the 817 charge regime. You are limited by how much current that crappy connector will carry (which is why they double up on pins for the current carrying wires)which is why there is the modification to the battery door to connect to a built-in socket on the high capacity battery pack.

I had one of these battery packs - bought from another company of cowboys in Essex - and a charger came with it. Provided you can supply the battery with a current of 10th of its capacity you will charge it but the fast chargers push current into the batteries at about C/3 hence the reason you can turn them round in short time.

My experience of this battery is that I got about a year of use while activating (then it failed) and I still needed my Lithium Ion battery to ensure I didn’t run out of steam. I certainly would not buy another one of these overpriced, and in my experience, dubious quality batteries (YMMV) preferring to modify the alkaline battery holder to take rechargeable NiMH and use a lithium ion battery back for the main pack.

Barry GM4TOE

In reply to MM0FMF:

£72 buys a huge amount of Lithium cells and chargers.

As in “787 Dreamliner”?


Wlat (G3NYY)

In reply to GM4TOE:

That charger will do 300mA or 600mA charge rates. So for a 2700mAhr pack, the 300mA rate is a tadge more than the C/10 rate. You’d be looking at a 12-14hr charge time then. At the 600mA rate you’d expect 6-7hrs charge time.

However, from experience (both as an amateur and professional career) series charged batteries are more prone to life shortening issues when fast charged. I’d expect a decent life from the pack if charged at the C/10 rate. In an ideal world you’d charge the cells in parallel and that’s how I charge AA NiMHs. I have some 1800mAhr AA NiMH cells which are now 12years old and still working well.

I chose the same connector Jack (and Raynet) before I knew either used them. It seemed like a robust connector which can’t be reverse connected and was up to the peak currents LiPo packs can give. The self-cleaning wiping nature of the terminals ensures reliable mating and contacting. In my case, part of the selection process came from the fact I had a bag of them acquired after a clean out in the lab of a former employer. I knew they’d be useful one day. I just didn’t expect the day to be 11 years after I left their employment!


I bought some Duracell AA 2400mAh NiMhs and made a copy of the internal battery pack. I wired a separate charging jack and fitted it next to the battery door, so I can use my smart (neg-delta-V) fast charger. No wear and tear on the rear power socket. Cost of battery - less than £15. Very rare that I run out of power on a hill. When it dies I can just make another…

That component shop charger has just arrived. It is now charging the OPP-817 pack on the 300mA rate, which I will leave on for a few hours. The charger has a green light indicator for fully charged.

Interestingly, the charger came with a few unanticipated features. Like a car cigar lighter plug as an alternative to the 3-pin mains plug. Also an adaptor going to crocodile clips instead of the plug.

So it looks like I now have the facility to recharge the 817 in the car - and my SLABs - if it all works. At little over a tenner I didn’t really mind taking the gamble. I will probably swap the croc clips for an Anderson Powerpole connector in the fullness of time.

I’ll report back with how things have gone some time later or possibly tomorrow.


Well it didn’t work.

Periodic checking of the 817 last night showed the voltage indicator creeping up gradually. But to my surprise, the green “full charge” indicator would keep coming on after about 30 minutes of charging (set as 8 cells / 300mA rate), even though when you turned the 817 on, it was far from fully charged.

On one check, the voltage indication had dropped somewhat from the previous check!

With the voltage showing 9.6V - far from ‘full’ but enough to do a short activation - I quit charging last night and planned a test activation for this morning - Thursday 18th July 2013.

I was on the summit of The Cloud G/SP-015 just before midday in blazing heat. After setting up the SOTAbeams MFD high on the SOTA Pole, I turned on the FT-817. It immediately turned itself off again. And again when I retried. There was absolutely nothing in the OPP-817 battery pack. It would appear that a long period of not being used has killed this battery pack; it must be discharging itself as soon as it is taken off charge.

So I am now wondering what to use, that will meet the following criteria:

  1. Must fit inside the FT-817 battery pack compartment, like an internal.
  2. Must be able to be charged directly - I know that charging via the rear jack of this 817 does not work, even though it can be powered for ‘now’ use that way.

I do have the battery tray for this FT-817. Has anyone had much success with any particular brand/capacity of rechargeable AA batteries? These would be easy enough to charge up externally, and tick the box for being ‘interna’ on activations.

So what did I do on summit?

Well, I had popped Jimmy’s BNC-SMA adaptor into my pocket, “just in case”, so I was able to connect my VX7R to the MFD antenna. My first seven contacts of the activation were all S2S! Baz 2V0YVX/P, Steve MV0VFR/P and Mickey 2V0YYY/P were all on Shining Tor G/SP-004. Neil 2W0TDX/P and Karen 2W0XYL/P were on Plynlimon GW/MW-001. Allan GW4VPX/P was on Pen y Garn GW/MW-004, while Steve MW0BBU/P was on Foel Cwmcerwyn GW/MW-011.

Eleven more QSOs took the tally for the activation to 18, all on 2m FM. And then it was time to go home.


In reply to M1EYP:

Sorry to be a bit short today, Tom. There was s2s coming in from all over the place and I was finally working some DX on HF. Nice to get St. Thomas in the US Virgin Islands and Puerto Rico. The first time I’ve worked Barry N1EU, Charles AE4FZ and Rich N4EX for an age.

Nice days radio.

73 Mike