EBME Forums Forums Maintenance Technical Assistance Replacement batteries (Medgraphics)

The thing is Richard most of these Smart cell's are standardized they have similar numbers to your standard AA, AAA or PP3. When you pick a smart cell instead of having it built to your requirements you pick you from a set of standards that fit your requirement.

You need to check to see if the device manufacturer has picked a standard battery or custom, most times companies are going to pick standard since one of the advantages of smart batteries is standardization and proven (although new) technology, the battery has probably be used in many similar curcumstances and there's probably less chance that sometime down the line it's going to cause you problems.

What you should be doing is go back to the device manufacturer and finding out if they are using a certain product number of smart battery and ask why such a large market up. It's what was done here and a discount soon followed!

Looks like I might need to invest in a Smart Battery Reader, then, Chris.

For anyone interested in digging deeper into this stuff, the MAXIM site looks like the place to start. Try this .pdf, for example. Catch you later!

Not sure you got my point(s) about programming of the standard smart batteries to the OEM requirements or the reasons why compatibility between the smart battery, battery management units and the medical device charger itself is so important.

Despite the battery fitting in the slot and apparently working how do you determine full compatibility with the charger, that the SoC and SoH are working as they should be (as the medical device manufacturer intended)?

It seems to me, from what you've posted, you feel it's valid to ignore that issue, make assumptions, take a chance, and go ahead and purchase something that's standard with the same form-factor and electrical specification (but not necessarily the same battery management) anyhow. Not an attitude to be encouraged given guidelines on battery management from the MHRA.

I do in fact, contrary to popular belief, have plenty of "hands-on" experience and know for a fact that some "standard packs" supplied by 3rd parties for use with M3 monitors can cause problems because they're not fully smart-compatible. By standard do you mean the 3600mAh NimH or 7200mAh Li-Ion used in these type of monitors??


It's a fact newer batteries are life-cycle and age limited and degrade over time irrespective of supplier, whether they're custom or standard and whether they've been abused or not. This must be factored into the lifetime costs.

We should expect replacement of up to 2 packs using newer battery technologies over the lifetime of a medical device that uses them and should therefore factor this into the purchase price, get a one-off discount on the purchase to cover a pack replacement, or arrange replacements when required, FOC, contractually. It can be done, should be done and it's a forward-thinking approach; it has been tried where I work.

Li-Ion, for example, give about 150-250 useful cycles, degrade more quickly at higher operating and storage temperatures and when stored fully charged - they have a 3-5 year shelf-life that's more or less fixed dependent upon the quality (consider you get what you pay for) and the countdown is from the day they're manufactured.

Don't know how you got hold of that notion, Richard! I would have thought that popular belief would have it the complete opposite!

Interesting what you say about battery changes per equipment life. So you reckon three, then? Over a ten-year life span, I presume.

And yes, "forward thinking" indeed. Get the batteries written into the initial purchase order (ie, at today's prices), and just call them off as you need them. Yes, that sounds like the way to go!

Depends on the number of charge/discharge cycles and the projected lifespan of the medical device I suppose Geoff. For Defibrillators that are kept on charge on crash trolleys then I'd expect it depends more on their age rather than the number of cycles. Unless the crash trolley is located in a geriatric ward, A&E or CCU that is.....

For monitoring used on inter-hospital or intra-hospital transfers then I suppose it comes down to the number of discharge/charge cycles and whether battery reconditioning is used (hence the importance of smart battery compatibility with charger/conditioner). Most importantly whether the packs are abused or not.


Something like this was arranged for our new defibrillators that use Li-Ion smart battery packs and we received about £3500 of spare MnO2 packs (non-rechargeable 5 year shelf-life I think), FOC, for our AED "first-responder" defibrillators, recently, on our site alone.

Of course we have arranged that operators get discount on battery reconditioning units and tried to make certain that our crtical care areas have acccess to them for the smart transfer-monitor batteries.

It's my personal belief that if batteries are operator accessible then they should take responsibility for managing and replacing battery packs that they use/abuse. Operators instructions include battery management guidance.

H'mmm. The notion of user servicing (as in servicing by the user). Now, that takes me back a bit, I must say. It was an idea that was officially promoted in British Military Hospitals (remember those, anybody?) thirty years ago. "They" were even meant to fill in simple record sheets to declare that the tasks had been carried out (not that a scribbled signature proved much, of course)!

Can't see that catching on in today's NHS hospitals, Richard (more's the pity). Although, let me stress, personally I'm all for the units taking total responsibility for their equipment, and calling upon the biomeds for service only (ie, rather than assuming that the biomeds are taking care of everything). How many nurses (users)? How many biomeds?

I wouldn't go as far to say servicing by the operator, I'd call it operator replacement as necessary, which is the case with any other accessory or consumable, such as ECG leads, air-filters, etc. When all's said and done the manufacturer has provided instructions and designed battery management, i.e. the use of operator accessible batteries, SoH and SoC, for the operator.

Not sure we're in a position to recondition smart Li-ion packs every 60-90 days or so (as is recommended) to recalibrate SoC indicators in batteries using a battery reconditioner, for example, thus prevent significant tracking errors in battery gauges. I'd expect someone in the clinical area to take responsibility for this in an ideal world (I said it -doh).

Perhaps a new topic called User Tasks (or whatever) is called for here, Richard. I'll have a trawl through the archives later on (hopefully, Huw will beat me to it).

My take on things is that, in many ways biomeds have been, over the years, their own "worst enemy" in their eagerness to provide service excellence (understandably, of course). Meanwhile, many of the user staff have been only too happy to just sit back and let it all be done for them. What we in the trade generally refer to as "hand-holding", I think. In these days of so-called equality, with many users drawing a higher salary than the techs, a re-appraisal of the situation is well over-due, wouldn't you say?

H'mmm so if some one like Omron sold a MN1400 with a Omron shelve on it Richard would still buy his batteries from Omron?

It's a bit like purchasing Yaesu batteries, if you know that a particular companies battery is a Yaesu I can't see any point in purchasing from the manufacturer far better getting it from EuroEnergy. In the same line if you know that a company uses a particular model of Moltech smartcell it's far better to get it direct.

The "cant see any point" statement tells me a lot the Chris - looks like I've "got a live one" as they say. As you're no doubt aware, maybe not, wards can buy and replace their own MN1500s for literally pennies each - NHS logistics buy in such quantity it's not worthwhile getting EBME involved - the batteries are operator accessible. As I posted earlier:


Anyhow I thought we were discussing smart batteries used in safety-critical medical applications? That's actually what I've been discussing all along.

Since you've raised the issue, Chris, is that a commercial or domestic grade MN1400, i.e. PROCELL (ZnMnO2) or DURACELL (ZnMnO)? The specifications are quite different you know - for a start one has an internal impedance that's double the other so it has significantly steeper discharge curves versus load current, i.e. voltage drop, with higher currents. This impacts on peak available current and effective capacity thus operating time (a la bunny).

However, I'm glad you raised the issue, it simply illustrates that you get what you pay for where batteries are concerned - you're paying for the chemistry and quality in manufacture to achieve the performance required. Not sure if you're aware, Chris, probably not, that sealed Gel LA batteries come in two varieties at least - for standby or cyclic use. Plus the specifications can be rated at different discharge rates and currents depending upon the manufacturer/grade.

Irrespective of cost it's the performance in critical applications I'm interested in - no point saving £10 on a £35 OEM battery pack in a critical care ventilator backup system if the cheaper cells don't perform as well and have to be changed twice as often. Then you have the fact that in the past Japanese Yuasa LA batteries supplied in OEM devices used to beat the apparently identical UK sourced/manufactured ones hands down on performance and longevity.

So I disagree that a battery is a battery is a battery, irrespective of whether the numbers on the side of it appear to be the same. The simpler the battery, e.g. LA or NiCd the more you have to look at where they're being manufactured and physically whether the performance and manufacture is up to it, how it's been stored and maintained, etc, etc - irrespective of whether the number on the side says it's "standard". Smart packs just complicate the issue.

All these manufacturers are not playing about when they produce specifications for their "standard" batteries.

Saying this you can probably get away with sourcing from 3rd parties if you know exactly what you're looking for in the specifications, based on experience you can tell performance of the 3rd party is equivalent or better and you are certain that there is no difference, i.e. the cell is a like for like swap-out. But in my experience with LA, NiCd, Alakaline cells and the occasional smart pack, I've had problems with cheaper "equivalents" and prefer not to "experiment".