I discovered the Lithium Ion 9 volt rechargeable batteries a couple of months ago and can endorse everything that has been said in praise of them on this website. It takes a little while for stuff to come over here to the UK from the USA, so I'm not too sure how long they've been around here, but I see entries dated from 2003 in the USA. For radiomic users here who haven't yet come across them, I'll summarise their advantages: this applies to use in an Audio 2020 UHF transmitter.

They last longer than Duracells. I've managed to squeeze 8 hours out of them, but I note in one past post on this site that it is NOT recommended to drain them completely.

The little charger than comes with them charges them in under 2 hours, four at a time simultaneously.

The charger is mains (US and UK) or 12 volt with a car adaptor supplied. For the truly obsessive, you could fit a Hirose plug and charge from your NP1 adaptor in your mixer while you shoot!

Cost for four + charger is about £80. They are made by i-Power US and I got mine from Richmond Films. Use them about 10 times and they've paid for themselves.

Size wise, I've had no problems with them fitting in the battery tray.

For those who have had them for years in the UK, sorry to break old news! But there must be a few like me who haven't heard of them until now and it really is worthwhile getting them if you use radiomics a lot.

Nick F.

£80's quite a lot and will buy you many PP3s for your Sennheiser G1 sender and receiver - by which time you may well have bought an AA fed Sony or G2 system.

And do the Li-ions give 9 volts proper? the Ni-Cad PP3s were always 7.2 volts, so pretty useless.

tom.

£80 is lot, but I'm using rechargeable Ni-MH which (in non-video related equipment) give me 20 hours per charge, and I'd like double that, so this alternative might be useful.

My Mi-MH 200mAh PP3s apparently are 8.4V

Yes, these Li-Ions give you a solid 9 volts, unlike Ni-cad or the others.

£80 will buy you a lot of PP3s, of course, but if you are in it for the long run the Li-Ions make financial sense. If you bulk buy PP3s you can get them for something like 50 for £80, maybe less if you are shrewder that I am. That means using each of the four Li-Ions you get for £80 (and that includes the charger, don't forget) 12.5 times puts you at break even point, the rest is profit. If you don't buy your PP3s in bulk, then the break even point comes earlier, at the 8 times mark if you buy from the corner shop! Then there is the point I made about Li-Ions lasting longer, so one Li-Ion is worth one and a half PP3s in time and that brings the break even point even lower, because you are changing them less frequently.

If you charge the client for batteries consumed, it is up to each person's individual conscience whether they continue to make a charge while using rechargeables!

Nick F.

ok, I'm not a mathematician, but -

I have twelve rechargeable NiMHs, six in use, and six being charged, changed twice a week, 26 weeks of the year. I don't charge my clients according to the battery type, but I can't see that using non-rechargeables would be sensible, either financially, or environmentally. Having looked at the specs of these Li-ion batteries, I would need to try one to see if it would power my equipment (for recording bats) for four days without discharging completely (actually, they record overnight on a timer, and at present I get two and a half nights recording time). It seems that if they discharge completely a few times, then they do not recharge properly. I also need to know how they fare if left unused for six months - because I'm not very good at remembering to charge things that aren't actually being used. Otherwise I'm better off with the NiMH rechargeables which don't seem to suffer by being neglected in this way.

Annie, I think you are quite right. For your usage stick with what you are doing. Unfortunately NiMH batteries are of little use to power things like Audio 2020 radiomic transmitters (people sized) as even when fully charged they don't give the oomph needed. But I guess as in so many other ways, nature photography and recording has its own rules!

Nick F.

I don't know anything about powering radio mics, but the 200mAh batteries give me several hours more recording time than the 170mAh.

I discovered the Lithium Ion 9 volt rechargeable batteries a couple of months ago and can endorse everything that has been said in praise of them on this website. It takes a little while for stuff to come over here to the UK from the USA, so I'm not too sure how long they've been around here, but I see entries dated from 2003 in the USA. For radiomic users here who haven't yet come across them, I'll summarise their advantages: this applies to use in an Audio 2020 UHF transmitter.

They last longer than Duracells. I've managed to squeeze 8 hours out of them, but I note in one past post on this site that it is NOT recommended to drain them completely.

The little charger than comes with them charges them in under 2 hours, four at a time simultaneously.

The charger is mains (US and UK) or 12 volt with a car adaptor supplied. For the truly obsessive, you could fit a Hirose plug and charge from your NP1 adaptor in your mixer while you shoot!

Cost for four + charger is about £80. They are made by i-Power US and I got mine from Richmond Films. Use them about 10 times and they've paid for themselves.

Size wise, I've had no problems with them fitting in the battery tray.

For those who have had them for years in the UK, sorry to break old news! But there must be a few like me who haven't heard of them until now and it really is worthwhile getting them if you use radiomics a lot.

Nick F.

I was suspicious reading about the 9V Li-Ion batteries as they can not be made to deliver 9V. The problem is a fully charged Li-Ion cell is 4.2V, discharged is about 2.75V. So two of them would be 8.4V fully charged. Checking the site http://www.ipowerus.com/specs/9v500mah_spec_060411.htm confirmed that, while they call them 9V, they are in fact 8.4V. So if your equipment expects 9V, it might not work as expected. Also, be aware that if your equipment is not aware of the Li-Ion battery, and does not turn itself off below about 6v (like camcorders), Li-Ion batteries are going to be damaged by overdischarge.

I stand corrected by Alex on the true, measurable under load output of the Li-Ion batteries, which must be more accurate than my multi meter. However.....experience in the field often differs from what theory suggests. I've been using these Li-Ions for three months now and I was recommended to them by people who have been using them a lot longer. We all have had the same experience: a much longer span of useful supply voltage. Duracell PP3s cannot in my radiomic transmitters, and in those of the other recordists I chat with (Audio 2020s being one of the standard professional radio mics here in the UK), supply more than 5 hours before loss of level and distortion sets in. These Li-Ions beat that by about 50%. Ni Cads never were any good for this purpose and neither were NiMHs. So compared with PP3s, we have the Li-Ions offering multi use and longer life. Whatever the meters say, I'm going for the Li-Ions.

If I'm proved wrong and they die in a month or so, I promise to own up and tell you all!

Nick F.

Ipower 9v rule!!!

I stand corrected by Alex on the true, measurable under load output of the Li-Ion batteries, which must be more accurate than my multi meter. However.....experience in the field often differs from what theory suggests. I've been using these Li-Ions for three months now and I was recommended to them by people who have been using them a lot longer. We all have had the same experience: a much longer span of useful supply voltage. Duracell PP3s cannot in my radiomic transmitters, and in those of the other recordists I chat with (Audio 2020s being one of the standard professional radio mics here in the UK), supply more than 5 hours before loss of level and distortion sets in. These Li-Ions beat that by about 50%. Ni Cads never were any good for this purpose and neither were NiMHs. So compared with PP3s, we have the Li-Ions offering multi use and longer life. Whatever the meters say, I'm going for the Li-Ions.

If I'm proved wrong and they die in a month or so, I promise to own up and tell you all!

Nick F.
Hey Nick do not get me wrong, Li-Ion technology is wonderfull, you get roughly 2x more capacity for the same volume as NiMh chemistry, which itself is much better than the Ni-Cad. The reason I am pointing out at the voltage difference, is to understand that the voltage indicator in your equipment (if you have any) if it is calibrated to treat 9V as 100%, would be showing low charge even on the fully charged Li-Ion 2 cell battery.
HTH

It's always good to have as much information as possible, so your warning is very welcome, Alex.

Nick F.

FWIW: Lectrosonics (http://www.lectrosonics.com/catalogs/UniversalCatalogPages/rechargeBatt.htm), Beachtek and some other Audio brands have endorsed the iPower 9V Batteries.

I am into the fifth week of a shoot where a radio mic, a 416 on a radio link and the boom operator having a radio comms link each uses an I-power rechargeable 9 volt battery.

I would have gone through at least six regular 9 volt batteries a day, changing over at lunch time, so in the 20 days of shooting so far I would have got through 120. The I-power rechargeables have lasted all day, each day and I recharge them in the evening, which takes about an hour. Performance has been top notch.

I reckon on this job alone that I would have spent so far well over £200 on normal 9 volt batteries: the i-power batts cost me £90, including charger, and will of course serve me into the future.

It must be the way forward!

Many of us in the US use the iPower 9Vs for our Lectros, ect. Occasionally a battery will slip through that does not function, however iPower replaces them without question... and the president of the company apologizes for your inconvenience. ( he also frequents the production sound forums) Highly recommended IMO. Customer service is top rate like SD and Lectro.