VARTA Mempac 3/V150H Rechargeable Battery for Potterton EP2000 controller

[Johny B Good]

As per the title, I've been shopping around t' internet for pricing and availability of a replacement 3 cell 100mA NiCd battery (no solder tags required).

The best VAT inclusive price I've seen so far is just over a fiver for a 150mAH NiMH equivilent from Cell Pack Solutions The correct 140mAH is the more usual AH figure quoted by most other suppliers so I'd hope the modest 40% capacity boost is because they went for an ultra low self discharge cell design - NiMH equivilents to NiCd are usually 100 to 200% greater in capacity.

I haven't checked out the postage, perhaps I should... Well, that's a case of TANSTAAFL if ever there was one! A whopping £3.99 for RM 1st class recorded 1-3 working days! Once you've accounted for the pre VAT price of £4.25 plus postage and 20% VAT, it comes to an eye watering total of £9.89.

I guess I've now got a target price point for my local suppliers to try and undercut. I suspect there's f*ck all chance of making a cheaper purchase locally but I thought I'd seek out some opinions in regard of there being any less greedy suppliers out there to which I could turn.

Incidently, I'm not above resorting to using a smaller round cell version of this battery (same length and diameter as the original - hopefully cheaper and more available).

The Potterton has a high quality battery compartment which will easily keep a secure grip on the smaller battery. I say high quality because, when it came to cleaning the white fuzz of chemical deposits from the positive battery contact, all it took was a few seconds under the cold tap with a toothbrush to return the contact surface to a pristine condition. Pretty good considering it's probably been furred up like that for the last 10 or 15 years of the battery's 25+ years of service.

[JimK]

What do you want to pay?

Is the difference worth your time?

Nah Just spend the whole tenner & move on ffs?

Jim K

[Johny B Good]

Well Jim, that was one thought I had at the back of my mind, along with another thought that I could just simply carry on running without a backup battery as I have done for the past 10 to 15 years and save the money for better things. :-)

[The Natural Philosopher]

There comes a point where I calculate that to actually get in the car and drive to a shop that carries most items costs me around £5...I don't baulk at £3.95 postage at all, and if you spend more than an hour finding a cheaper alternative you have in fact wasted at notional rates another tenner.

[The Natural Philosopher]

Yes.

YES.

Its like the video card fan in this machine which has been dead jammed and silent fr at least 3 years. yer man said 'refanning that would cost as much as a new card' and although the temp monitoring software says its getting up to 80C or more, its rated to 90C..

Now when it comes to de-coking the aga, its an hours work to save £100 and that IS worth doing. That's a week of groceries, that is.

[Martin Brown]

Depends how often you have power cuts. Where I live it would quickly drive you crazy if the boiler clock reset to midnight every time (like the blasted cookers do and then refuse to play until you set the time).

Regards, Martin Brown

[The Natural Philosopher]

In which case less than a tenner is value innit?

[Johny B Good]

That's the key thing. Apart from one 3 hour outage over 20 years ago and a period of modest brownouts about ten Christamases ago, my UPSes have never been called upon to 'save the day'.

The mains has been so reliable that ever since the batteries on my big 2KVA UPS failed nearly two years ago, the only UPSes still protecting anything are the BackUPS500 protecting the NAS server box[1] and my first UPS ever, an Emerson AC30(?) which is meant to protect the supply to the VM Superhub.

This last unit provided power to a lamp stand, with a 15W CFL fitted, strategically located on the first half landing to illuminate the toilet (where the kids could complete their homework assignments for the evening of that 3 hour outage) as well as provide some illumination for the stairs and hallway.

The mains had failed just before I was going out to an amateur radio club meeting so I was able to move the little UPS from its usual location to set up some strategic lighting to save the XYL and sprogs from being left totally in the dark, apart from a candle or two and some torches.

By the time I returned, some three hours or so later, the mains had been restored just prior to my homecoming. The UPS had managed to run the 'emergency lighting' for all of that time without exhausting its battery.

Getting back to the issue of the Potterton controller, it would still be nice not to have to 're-program' it every time I felt the need to shut the power off for maintenance jobs. As things stand, I'm loth to do so which means any such maintenance tends to be put off indefinitely.

Since mains outages are so very rare where we live, I can afford to take my time over finding a replacement so have the luxury of keeping my eye out for any suitable 'donor' NiCd (or NiMH) packs I might spot in a flea market stall or junk shop. The original mempac uses oval shaped cells (oval as in 'racetrack oval, that is!) which could easily be substituted with round cells of the same diameter and length so my choice of a donor battery is quite wide. :-)

[1] Mention of which, I've still got an outstanding firmware update that was issued, literally, 4 calender months ago. The server is now showing almost 208 days of up time. It's high time I updated the firmware and used the opportunity to check the condition of the battery in the BackUPS 500. It's been quite a few years since I last ran an endurance test on this unit.

[Johny B Good]

This is all too true. :-(

I suppose it depends on how much value you place on the benefit of having a functioning Mempac battery fitted into the controller. In my case, it's not so critical for every day operation with the mains supply proving, thus far, to be as reliable as it has been over the past 30 years or so where I live.

My main hope in posting my query was that someone else in this group may have already dealt with this issue in a remarkably economic way and would jump at the excuse to disseminate their hard won knowledge. :-) If you don't ask, you'll never find out so it's worth a punt before wandering off into the wilderness of commercial reality.

[Martin Brown]

Doesn't RS do them for ~£6 and at a local trade counter for cash they probably won't ask too many questions. I can't recall what their minimum order value is for mail order or try RapidOnline.

Regards, Martin Brown

[Johny B Good]

Thanks Martin. I've just checked out the Rapidonline site and the price, delivered, works out to a total of "£10.67". This is for the solder wire tagged version (I can easily remove the tags if they don't list the tagless version as seems to be a common failing with a lot of these suppliers). A more careful search for "VARTA Mempac 3/V150H" only reveals the tagged versions.

Mind you, I haven't yet tried the more obvious Sheds like B&Q, Plumb Centre and Wickes so I think it's time to confirm my worst fears and take a peek.

Well, I've just checked out that list of "Usual Suspects" and I have to say, with disappointing results (i.e.none!). However, I have noticed the obscene pricing by Wickes on their 4 x AA NiMH cell packs at a staggering £7.99 !!!

Sadly, they all met my expectations for disappointment so no surprises there. :-(

[Johny B Good]

Well, for the benefit of those who like "Closure" and didn't spot my response to the "Coin Battery" thread started just 2 1/2 hours prior to my last post above, CPC got a mention as a supplier who do free deliveries on orders that meet their minimum 5 quid order value on card transactions.

I posted a query to the group as to whether or not they sold that Varta Memtec battery on account the site was down for maintenance when I tried to check it out in the wee small hours yesterday. I'd posted the question as a reminder to myslef as much as expecting someone else to "Do My Homework For Me".

Sure enough when I downloaded the latest batch of news postings and caught myself back up with the "Coin Battery" thread, reminding me to check out CPC, it turns out that they sell the solder tagged version for a mere £3.94 +VAT. Not too surprisingly, the tagless one, for which the controller is designed to accept, was more expensive ("Supply & Demand" effect), staggeringly, almost double the price which took it well over the 5 quid minimum for free delivery.

Since it's fairly trivial to remove the spot welded solder tags off the cheaper battery, I ordered that along with a couple of other useful items to pad the price up to £5.53 +VAT (allowing for the VAT about £1.50 cheaper than if I'd bought the tagless battery on its own).

In the end, I was able to source the battery (along with a couple of other useful items) for a total of just £6.64 delivered, over 3 quid cheaper than any of the other suppliers I'd found!

It might seem a trivial saving to most but I'm not exactly awash with spare cash so it was worth the wait for, as Mr McCawber might well have said, "Something (better) is bound to turn up." which indeed it did. :-)

[Grimly Curmudgeon]

Done similar; when I couldn't find the exact battery (or at an exhorbitant price) I made an external pack and encased it in a similar surface-mount unit to the controller. Looked fine, and not out of place.

[Dave Plowman (News)]

The days of RS only selling to genuine trade customers are long since gone.

Rapid have a minimum charge too.

CPC, because of their low minimum charge and free postage are *generally* the best bet for small value orders. Once you've gone beyond a minimum charge and gone high enough to get free postage, Rapid are pretty close. Depending on just what you're buying. Farnell are also worth a punt too. I recently wanted a new (old) Antex iron, and Farnell had the best price anywhere - and by quite some margin. RS tend to be my last resort for things I can't get elsewhere.

[Johny B Good]

That's it for me too. I wasn't desperate so I was prepared to just keep my eye out for either an old battery pack's worth of canditate cells with 'goodish' ones I could canabilse or something in better nick that would fit the bill.

As it happened, I discovered the solution in CPC's minimum (pre-VAT)

5 quid order facility with free postage on card transactions so problem solved. :-)

[Johny B Good]

And, the parcel arrived in the midday post yesterday. It took me less than ten minutes to remove the battery tags and dress the spot weld pips with a file to add another three quid's worth of value to it. :-)

I've installed it into the controller and verified it allowed it to maintain the time when switched off at the mains. I'm leaving it switched for 24 hours or so (I haven't turned the boiler back on - still waiting for the winter season) to recharge the battery which was showing 1.25333v/cell before I started adding value to it.

I came across the invoice for the Bosch 40W E14 oven lamp this evening and saw that it had cost me nearly 6 quid! (VAT inclusive price). Making up the order value with a 40W E14 oven lamp cost me just one fifth the price of the Bosch sourced one. The 60p audio lead I had to add to get over the 5 quid minimum order hump will _probably_ come in handy sometime in the next decade or so I'm sure.

All in all, a very satisfactory resolution to my quest (and possibly a useful hint to others in need of a cheap replacement controller backup battery).

Now all I have to do is gird up my loins to tackle that awkwardly placed Honeywell diverter valve. :-(