K-7 replacement battery D-LI90

Hi All,

I have a few photo trips coming up this autumn and been thinking about reserve power for my K-7 as I'll be camping. Usually I manage fine with 2 x original D-LI90 batteries but figure a spare or two wouldn't go a miss...

Anyone have any experience of the cheap replacements that can be found on fleabay for £8.99?

And does anyone have any recommendations for units to use for recharging via my car cigarette lighter?

Thanks in advance!

Will

Having no experience with K-7, I will refrain from commenting.

As for car chargers, there are some nice 12VDC -> 240VAC converters around. These should do the job.

I had previously linked to:

http://www.amazon.co.uk/Replacement-Digital-Battery-Charger-Minolta/dp/B002GKBUZ...=sr_1_2?ie=UTF8&s=electronics&qid=1268128362&sr=8-2

for the K20D

There is likely to be an Innov8 equivalent for the K7 battery.
http://www.inov8-memory.co.uk/battery_chargers.html Call them and find out.

If you go the way of the inverter, you should use a Pure Sine Wave Inverter, it will be more expensive than a square wave, but you will pay for it in the long-run by reducing the life of the battery.

If you can get a 12v to 7.2v charger to suit the camera battery it is the safer way to go, 240v in the car is not a nice combination it is lethal voltage, if any thing goes wrong.

Utter rubbish ...

Given that the charger is an SMPS which initially rectifies the incoming supply and then chops it at high frequency followed by smoothing to get a clean DC output then the type of inverter will have no effect on the output.

The charger's gonna convert the ac from the inverter to dc so it shouldn't affect the batteries. There are a few things which require a pure sine wave converter but most gadgets are fine. I lived with a cheap inverter as my only source of ac electricity for nearly five years and the only thing which wouldn't work was my friends hair straighteners, and an electric fan heater.

But unless you are going to need to power other devices, a 12v car charger seems the best bet.

Indeed !!! Switch Mode Power Supply..spent 30 years selling them

It does indeed rectify the mains directly , with no transformer , hence the reason they are smaller than conventional PSUs, usually the regulation is not as good as with a linear regulator though but more than adequate for most purposes.

End of lesson

Howard

Here's one:
link from 7dayshop. It is the full capacity one unlike the INOV8 which is only 1300mAh or so (and the one available from SRS). I have both and both work fine
Andy

I dont want to contradict the comments above but we had power tool-battries running of inverters, and found when we went to pure sine wave the battries lasted longer, mabe it was a bad batch.

Here is a quote from Free Sun Power, on solar power with inverters.

Square Wave power inverters :
This is the least expensive and least desirable type. The square wave it produces is inefficient and is hard on many types of equipment. These inverters are usually fairly inexpensive, 500 watts or less, and use an automotive cigarette lighter plug-in. Don't even consider one of these types of power inverters for a home system.

Some general observations.

I have 3 Pentax and 1 Innov8 battery for my K20D, although the Innov8 ones is of lower capacity I can see no difference in normal use.

I bought a cheap battery from China for use with my Canon camcorder, and it works well. HOWEVER, there was no mention in the advert that it came with its own charger, both mains and 12V car, because it can't be charged in a Canon one or in the camera. Neither can the Canon battery be charged in this new charger. The battery can't communicate with the camera so you dont get a display of remaining battery life.

At an eighth of the price of the genuine article I'm not complaining but you do tend to get what you pay for.

Thanks for the link , I was also after an extra battery for my K7 , just ordered one .

Howard

Glad to be of help Howard!
Andy

The battery can communicate with the camera. Have a look at the battery in a K20 - there are only two terminals and the battery yet the camera can show the battery level (or a reasonable estimation of it). The usual method is to try to draw a very high current for a very short period of time. The lower the internal resistance of the cell, the higher current this impulse will be, and this will indicate the cell is more charged.

As to the power supplies, switch mode are more efficient, that's why they are more prevalent. By the nature of a linear power supply the power semiconductor(s) will act as a variable resistor, and passing a current through a resistor generates heat (waste energy). With the very low resistance of modern FET/IGBTs when forward biased and extremely high impedance when switched off, the heat generation in either condition, and therefore the inefficiency is very low. The ability to drive a load is not as good though.

It's too much current that's lethal not voltage. 240V won't hurt you if the current flow is low enough.

Asda have a universal battery charger that I have used successfully with ebay batteries for the GX20 and K-7 batteries. Also for phone mobile batteries.

Its a Vivtar branded charger and I think it was about £20.
You adjust the contacts for the different batteries and there's a little LCD display.

BTW ebay batteries are fine. Don't buy the cheapest nor the most expensive. They all seem to come from the same factory no matter who you buy from. Probably lower capacity and not as decent quality as genuine ones but cheeeeeeeeep.

I usually buy a couple to help with the genuine one and have never had an issue.

-

Too late I see you've bought.