Why don't folk use external laptop batteries instead of lead acid batteries?

[PapaPlanets]

I'm confused. I'm a noob about to buy his first scope (2nd hand C6 on a CG5-GT) and I'm wondering why (in the UK at least) people don't use lithium ion batteries to power their goto mounts instead of lead acid ones like the celestron powertank?

It seems you can pick up a 7-10AH 12V 2-2.5A external laptop battery for £50-£60. This is the price of a cheap Maplins car battery starter, let alone the £80 7AH powertank. It's smaller, lighter, cheaper, etc. etc.

Universal 10000mAh USB External Battery Pack and: Amazon.co.uk: Electronics

Rechargeable Universal Batteries Laptop/ portable DVD/ TV/ Camcorder

Am I missing something? Is there a catch? A US astronomy shop Starizona, has started branding their own.

Hello everyone btw, first post

[Cath]

You can get Lithium batteries FAR cheaper than that. I have several 12V 4Amp ones (plus a proper charger for them).

Here's some examples ..

Lipo batteries

You just have to be careful never to over discharge them, otherwise they are normally useless after that.

[PapaPlanets]

Thanks for the tip. Didnt think of RC batteries. I think when you get down to cost per AH including the charger, there's prob not too much difference in cost?

Good to know people are successfully using Lithium batteries, cheers

[NickK]

The cold.

Li-ion batteries stop working in cold temps, lead acid continue to work.

[Cath]

A friend of mine who lives in Finland flys his QuadCopter (which uses Lipo batteries) in -40C conditions without any real problems - apart from the odd problem with parts of the electronics not liking it.

[jfox61]

Li Po's are not affected by cold any more than conventional batteries. I have many rc models and take part in airsofting (like paintball but with battery operated realistic imitation firearms). I exclusively use Li Pos.

Couple of caveats with li Po's, and most people will know this anyway, letting them fall below 3.6 volts is usually fatal to the battery. However you can get a voltage cut off for them which will warn you as it approaches the minimum voltage and cut power if it falls to 3.6v.

All batteries are affected by cold weather including lead acid. Li Po's WILL NOt die in cold weather you just have reduced running time, same as any other battery.

You need to keep the cells balanced, so you need a good quality Balance charger. An Imax B6 is excellent.

Cath I think you may be referring to the 11.1v battery when you state 12v. You can't get a 12v Li Po battery, as each cell has a nominal voltage of 3.7v. A 6 cell Nimh would be 7.2v ie 6x1.2v. A similar voltage Li Po would be 7.4v in 2 cells.

If using a Li Po you would need to take into account everything that would be powered from it. You would need to know the ampage that each piece of hardware draws and cater for that in the size of your battery.

The draw rating of a Li po is based on it battery size x it's draw rating, or as it's known, it's C rating. Li pos will have something written on them like 3000Mah 3s 1p 30C. So that's a 3.0ah or alternatively a 3000Mah battery in a series of 3 cells wired together to make one pack. The 30C is a multiplier for it's draw rating. Multiply 3.0ah by 30C and that will give you 90 amps of constant draw power.

However, back to the OP's original question I would suggest that either of those two options you link to would be ok for one or two items, but there just isn't enough outputs on them. Two usb's and a 3.5 jack on the first just wouldn't cut it out in the field. I am pretty sure there's people out there using more than two items requiring power. Goto mount, Laptop, one, possibly two cameras, dewshields, DSLR battery charger etc.

Also some powertanks have other options, USB sockets, two, sometimes three 12v car type sockets, 3 pin plugs, red lamps, jump starter leads, 3.5 jack sockets etc.

Aldi, today, are selling one for £35. now that's almost 50% of the price of one of those power supplies listed by the OP, and much more versatile.

If you are electronically gifted you could of course replace the Lead acid battery inside the power pack with something else, but for that price why bother?

[Cath]

Cath I think you may be referring to the 11.1v battery when you state 12v. You can't get a 12v Li Po battery, as each cell has a nominal voltage of 3.7v. A 6 cell Nimh would be 7.2v ie 6x1.2v. A similar voltage Li Po would be 7.4v in 2 cells.

Yes you are right of coarse .. I ort to be more detailed about it when I mention things like this.

I also have one these big yellow car starter thingies, it cost me about £26 off amazon (7AH 12V), but I've found the battery to be of poor quality. I sometimes wonder if the cheap ones use almost factory rejected batteries in them. But it could be more to do with the poor quality charging with them, maybe it's better to replace the supplied little mains charger with a proper sealed lead acid conditioning (etc) charger? .. a charger that tries to take care of the battery.

[PapaPlanets]

However, back to the OP's original question I would suggest that either of those two options you link to would be ok for one or two items, but there just isn't enough outputs on them. Two usb's and a 3.5 jack on the first just wouldn't cut it out in the field. I am pretty sure there's people out there using more than two items requiring power. Goto mount, Laptop, one, possibly two cameras, dewshields, DSLR battery charger etc.

Aldi, today, are selling one for £35. now that's almost 50% of the price of one of those power supplies listed by the OP, and much more versatile.

Good point about the outputs, but I'm not sure that I'd need them personally. I'm getting a non heated dew shield, I'd probably use an iPad over a laptop (especially now I've seen the oh so cool starsafari app & wireless dongle) I'm not into photography yet, but would you really need power for a camera as well?

I guess the Aldi battery is pretty poor quality, so for an extra £15 I'm thinking I might risk it? I just wish someone had done it already.

[hemihaggis]

sorry but lipo batteries are much more effected by cold than large battieries ..simply due to size .

the best option is a lesuire or winch battery

[jfox61]

For a conditioning Battery charger my Imax B6 will do that as it charges all types of battery. You just select the battery type, size and voltage hit enter and away you go. But for Lead batteries I would suggest a dedicated chager and you can't beat an Optimate. My wife uses that for her Motorcycle She's had a battery in her Honda Blackbird for nearly 5 years now and it still holds 90% of full capacity.

One thing you have to remember about batteries is that they need about 6 cycles of charge before reaching full capacity. So if you have a good charger your best bet is a 3 cycle Discharge/charge.

As for powering a camera. Consider someone in the field using their DSLR for AP. I only have one battery for mine. Let's say the temperature outside is about 3 degrees C, a pretty fair estimate of current evening temps. Each exposure would be around 30sec-2 or 3 minutes. You need power for your shutter lock, so all the time your shutter is open you are using battery power, your battery would be dead in an hr or so as you would be taking around 20 or so exposures. Non heated dew shields are ok to a certain extent, but I reckon based on my experiences that you would get about an hr viewing before dew and mist stated forming on the lenses. At least that's how long I am getting.

[jfox61]

sorry but lipo batteries are much more effected by cold than large battieries ..simply due to size .

the best option is a lesuire or winch battery

I have to agree to disagree about the effect cold has on Li po with other batteries, apart from 12v car and 24 truck batteries. I use Li Po's for my airsoft guns and rc models. More so for the guns, I do have some nimhs and nicads and they are used purely for backup. A days gaming ( about 5hrs worth of shooting) will use about 40% of my Li Po battery most of which are 2200 3s1p batteries with a 25C rating. I have never ever drained a li Po in the field. I can guarantee a battery change with my 2200 9.6v Nimh though I will get through most of the day but would need a battery change for the last hr or so.

However I do agree with you on the Leisure winch battery. These are designed for very heavy work loads and the piddly amount of power our hardware would drain from them is minimal.

[hemihaggis]

hi jfox , i also play airtsoft, g+g gr16 , i find in cold weather(scotland) i will use a whole battery by about 2 or 3 in afternoon , i carry a smaller oner as back up ,

if you can get hold of a winch battery or similar you cant go wrong , as you say once you start running dew heaters , cameras , guiders , ect a winch battery owns just abouit everything else !!

[Frank the Troll]

I brought a long time ago, a night spotting lamp, that came with a small lead battery. cost £19.00

[NickK]

sorry but lipo batteries are much more effected by cold than large battieries ..simply due to size .

the best option is a lesuire or winch battery

The laptop battery just gives up in the cold.. the 100Ah Bosch seems to not have a problem

[jfox61]

hi jfox , i also play airtsoft, g+g gr16 , i find in cold weather(scotland) i will use a whole battery by about 2 or 3 in afternoon , i carry a smaller oner as back up ,

if you can get hold of a winch battery or similar you cant go wrong , as you say once you start running dew heaters , cameras , guiders , ect a winch battery owns just abouit everything else !!

I have about 15 guns and 10 pistols. The wife has about 3 guns and 2 pistols. Pride and joy are my Inokatsu M60VN and my DSR 1 sniper rifle. pm me haggis if you want to talk airsoft lol. But back on topic.

My Nicads and Nimh used to last till around lunchtime 2200 8.4 and 9.6. I just find that my Li Po's down here in the south last much longer cell for cell. But yeah all batteries are affected by the cold one way or another.

I tried to buy one of those Battery stations from Lidl, what a nightmare none in stock and the store guys knew nothing about them. Bit the bullet and bought one from Maplin for £50 17ah battery 2x12v sockets 2x USB sockets,lamp, air compressor and booster cables.

There wasn't a 3 pin plug on this one but I already have a 12v 300amp inverter. That will plug in and I can then use a 3 or 4 way extension lead. Anyone thinking of using something like this will also need to remember to keep any power connections dry. I have a wooden lidded box I will modify for the power supplies to keep them dry.

reading the instructions it seems a doddle to change over the battery, so if the battery doesn't prove heavy duty enough and provide the dimensions are fine I may just stick a bigger battery in anyway.

[jfox61]

The laptop battery just gives up in the cold.. the 100Ah Bosch seems to not have a problem

I believe laptop batteries are Lithium Ion are they not. They're a different technology to Li Po's

[Xession]

I believe laptop batteries are Lithium Ion are they not. They're a different technology to Li Po's

As far as I know, Apple is the only manufacturer that is using LiPo batteries in their laptops. Most lithium batteries, especially larger sized versions, are Lithium Ion. LiP batteries have been shown to be more dangerous when scaling them up because the sheets inside can overheat if the battery is overcharcharged, followed by shorting and eventually flame. They can be dangerous if you aren't careful.

-- Sent from my Palm Pre using Forums

[jfox61]

As far as I know, Apple is the only manufacturer that is using LiPo batteries in their laptops. Most lithium batteries, especially larger sized versions, are Lithium Ion. LiP batteries have been shown to be more dangerous when scaling them up because the sheets inside can overheat if the battery is overcharcharged, followed by shorting and eventually flame. They can be dangerous if you aren't careful.

-- Sent from my Palm Pre using Forums

I've been using them for nearly 6 years now and never had one "go up". Nor have any of my Airsofting buddies. It really is an urban myth about Li Po's going off like min nuclear bombs. Mind you, if one does happen to go bang it is spectacular.

Any battery that is overcharged will heat up. Next time you charge a nicad or nimh feel it. Obviously, because of the chemical and materials involved in Li Po's are a lot more dangerous, I don't dispute that.

There are loads of videos on Youtube of exploding li po's. the majority of which are by people deliberately abusing them because of the spectacular results. But, there's also videos of idiots doing exactly the same thing to old Nicads and Nimh's, just with less spectacular results, but nevertheless still dangerous

Charged correctly with a good quality balance charger they are idiot proof. You could go the whole hog and charge them inside a Li Po charging bag, i've never had the need to.

One thing I would say though, just as a safety precaution, if you do decide to use Li Po's, always charge them under supervision and don't leave them alone. Mind you you should do that for any battery charger.

[Auntystatic]

One thing you have to remember about batteries is that they need about 6 cycles of charge before reaching full capacity. So if you have a good charger your best bet is a 3 cycle Discharge/charge.

That's very old information and only really relevant to nicads, lead acid batteries only ever needed one charge after the initial conditioning charge, lithium come semi pre charged just to stop the voltage falling during transit and only need charging prior to use, ni-mh only need the one charge too but have a faster self discharge than the rest so are best charged just before use, except for the new Eneloop type that hold their charge much better.

I use a 115Ah battery from these people, it has a 7 year warranty and is deep cycle, it can run everything all night and still has loadsa spare left over.

Danielle