For those using Duracell Alkaline batteries in your Nexstar scopes - beware!

[Cjg]

If like me, you power your Nexstar scope from mains / power pack and use alkaline batteries as a back up and to retain alignment settings if the power cable comes unplugged - Go check their condition!

I've discovered two nights ago that one of the 8 Duracell Alkaline batteries had leaked and caused damage to one of the battery contacts. The pack has only been in 6-8 weeks and I use the mains / Powertank to run the scope and mount.

[Hugechris]

ouch - not nice - hope it has not leaked onto the circuitry inside. A good rub down with a bit of emery board can recover a contact if it hasnt gone all the way through.

I have been using a power tank, underneath the tripod to get around the cord snagging issue. I am not too fussed about realigning the scope each time as I tend to use either a 1-star or solar system align.

[Capricorn]

Just a question but should the batteries be in when running from mains?

Just wondering if the damage was caused by that as you could to an extent be trying to feed current into a non-rechargeable battery, this could have caused the battery to fail (overheat) and so leak.

I hve no idea if Celestron recommend this but I would have thought that it was a suspect situation.

[squeaky]

Me too.

Maybe a blocking diode could be fitted into the circuit? I.e. to only allow current OUT of the batteries but not in?

[knobby]

Oops ! I leave mine in too ... skulks off to inspect mount hurredly !

[ggreene1]

When I bought my scope (used) a battery had leaked. Fortunately the contact was not badly damaged and was easily fixed. I now use a power tank and don't even put batteries in the scope. In case it ever becomes necessary to run the scope without the power tank, I took a small project case with the correct amount of AA batteries in it and attached a cord with the correct connector on it to be able to plug it directly into the scope. I also found that the AA batteries didn't seem to fit well into the scope's battery compartment.

[glowjet]

I am not sure about this, but I do not think that batteries and an external power pack should be connected and used at the same time, quite often manufactures of battery operated goods tell you to remove all batteries before connecting an external power supply to their device. There is something that Sqeaky commented on with regard to a blocking diode, if the circuit does not have these it may cause the internal batteries to receive current from the power source and cause them to heat up with a resulting possible acid discharge, under normal use Alkaline batteries are not supposed to leak which is why they are preferred to the standard types. Possibly the best way to deal with this in the future is to put spare batteries in your pocket, or carry them in your equipment case, or make up a battery pack with a lead and plug as already mentioned

John.

[pete_l]

I've discovered two nights ago that one of the 8 Duracell Alkaline batteries had leaked and caused damage to one of the battery contacts. The pack has only been in 6-8 weeks and I use the mains / Powertank to run the scope and mount.

That's worrying, I had the impression that Duracell's famously didn't leak.

Are you sure they are genuine as there are some fakes around, apparently. Fake batteries! Good grief

[knobby]

I am not sure about this, but I do not think that batteries and an external power pack should be connected and used at the same time, quite often manufactures of battery operated goods tell you to remove all batteries before connecting an external power supply to their device. There is something that Sqeaky commented on with regard to a blocking diode, if the circuit does not have these it may cause the internal batteries to receive current from the power source and cause them to heat up with a resulting possible acid discharge, under normal use Alkaline batteries are not supposed to leak which is why they are preferred to the standard types. Possibly the best way to deal with this in the future is to put spare batteries in your pocket, or carry them in your equipment case, or make up a battery pack with a lead and plug as already mentioned

John.

Try http://stargazerslounge.com/index.php?/topic/158114-Charging-10-1.2v-nimh-in-series?#entry1599241

[Cjg]

Thanks all for the replies and advice. From the downloaded manual, there is no mention of removing the batteries when using external power sources. My understanding is that an external source does not charge the batteries, and they can safely be left inside to maintain alignment if the external power fails.

Duracell in the UK are "owned" by Proctor and Gamble, who have so far been great; they are arranging for the mount to be collected and will be dealing with the damage.

i'd wondered about fake batteries, have seen a few dodgy looking packs, but can usually get them from a decent retailer, without paying silly money...this pack came from toysrus and was buy 4 get 4 free?

The mount and scope still work, and was put to good use last night at Seething (wasn't it great).

Chris

[8kids]

I have been told deeply discharged batteries build up gases inside and rupture. Even unused they continue to discharge.

[Carbon]

How about Sanyo or EverReady batteries?

[jonathan]

...this pack came from toysrus and was buy 4 get 4 free?

Duracell often have that type of pack on sale - 4 + 4 free. It is the only time that I buy Alkaline Duracell batteries.

[Cjg]

How about Sanyo or EverReady batteries?

Hi Carbon,

In what regard?

Sanyo batteries are not so readily available as Duracell in the UK I don't think; Duracell have the "leak proof guarantee" so I tend to use them where cannot use NiCads or NiHM batteries, with EveryReady, I see more of them as the cheaper Zinc Carbon batteries and do not use them at all.

Chris

[Distorted Vision]

Best batteries are Energizer Ultimate Lithium or Sanyo Eneloop for rechargeables.

[Cjg]

Just to update this thread.

After numerous emails and photographs sent to Proctor and Gamble in the UK, the defective batteries have been collected by UPS today to go to Proctor and Gamble in Galashiels and from there to the tech department of Duracell in the USA (at P&G's expense).

Because of the time taken from my initial contact to get to this stage, P&G called today and have arranged a bank transfer to cover the cost of the repair by David Hinds (thanks FLO) and all carriage fees.

Am delighted with the response from P&G, who I think once they had seen the pic of the battery in question decided that it was really faulty, and the assistance from FLO in getting the quote from David Hind.

Chris

[andrew63]

Glad it's all sorted out for you Chris - they appear to be a first class outfit.

andrew

[JamesF]

FWIW I've never known a piece of equipment that could be powered by batteries or from the mains that didn't break the battery circuit when the mains power plug was inserted. "Standard" two-pin power connectors are designed with a built-in breaker that does this. That doesn't mean that it's always the case, obviously, but it's uncommon for a piece of electrical equipment to die without afterwards being disassembled to satisfy my curiosity and I've not seen one yet that didn't.

James

[LukeSkywatcher]

I dont trust batteries in my 8SE.............

I only ever run it off of a power pack