What battery pack should I use for AZ EQ6

[lineout]

Hi all,
Me again. I'm looking for suggestions for a battery pack for my SW AZ EQ6. I've seen the one Bintel sells but it looks like something I took from my car. Looking for something a little less utilitarian.

Cheers

Rene

[lineout]

Update:
I purchased the Celstron Power Tank 7. $169. hopefully it gets to me before the weekend.

[raymo]

For some reason you posted a thread looking for advice on a power
source, and then jumped in and bought one without giving anyone a chance to respond. In my opinion, and I suspect many other's too, you have bought the wrong one. 7A.H. will probably just about last for one decent session with little or no reserve, and that allows nothing for any other accessories you might want to run.
raymo

[Eratosthenes]

lineout,

have you worked out what your total power requirements are for your setup is? (your mount power requirements, cameras, dew heaters, laptop, gadgets etc?). Your mount alone may need 20 or 30 Watts.

This will give you an idea of how long your battery will last for your setup. It is possible to assemble your own battery pack but you need to be careful with the type of battery you choose, safety features, connections etc (batteries connected in parallel). Ordinary car batteries are usually designed for high current starts of engines etc and aren't deep cycle. They also have thinner plates. Deep cycle or deep discharge batteries are preferable (and expensive).

cheers
Peter

[Allan]

Rene, I agree with raymo, that battery pack won't be any good for you. If you can, cancel it and ask for a better option.

7 AH is a very small capacity and might not see you through a nights observing. If you want to plug anything else in, like dew heaters, it will only last a few hours. I have a 18 AH for use at home and that gets me through one night only, running the scope, dew heaters and fans. It's good because it is light weight, but I have to charge it after every session. When I go away I have a 65 AH that lasts a few days.

So if you want one of those power tank type setups as a minimum get the 18 AH version.

[LewisM]

Yup as others said, a 7 aH pack is essentially worthless. It doesnt matter what your battery pack looks like :) I use 2 x 18aH starter jump packs I got from Supercheap Auto for $95 each. Have 2 cigarette sockets, powered USB, a light and jumper cables. Been going sold 3 years now.

[raymo]

I've been using well used car batteries for nearly 40 yrs. I get them from the local auto leccy for a few dollars. I get a couple of yrs out of them, and then go and get another one.
raymo

[lineout]

Thansk for all the advice. I'll cancel my order.

Which if these would suit?
http://www.supercheapauto.com.au/online-store/batteries-and-electrical/starting-power/jumpstarters.aspx?id=40701

[Larryp]

Why not buy a good deep cycle battery off Ebay-there are lots of reputable sellers. Then buy a multi-stage charger, which will service your battery properly and get maximum life out of it.
This will cost about the same as or cheaper than a decent jump starter, which usually comes with a rubbish charger anyway.

[bugeater]

I use an ~70 amp hour deep cycle battery. Used to use it to charge my big electric r/c helis in the field. No worries about running out of juice, but it is heavy.

[Eratosthenes]

Golf carts use deep cycle batteries and some marine applications - but they are very expensive batteries. If you know someone that can get some second hand snap them up - way better than car batteries which are designed for crank amperage during start up and then charge via the alternator. (I have 2 GIANT 12V 80Ah deep cycle batteries for a solar power storage application at home, which were expensive but in this application they have already paid themselves off. I have yet to purchase a astrophotographical set up yet - hopefully soon. In the meantime I will use the gear I have - and last night was clear in Melbourne for a change:))

[inertia8]

If you go camping with a fridge then something like the Engel battery box with a decent deep cycle might cover both uses, otherwise get something lighter and put it in a battery box. You should also ensure you have a decent charger to get good life out of the battery.

[JC17]

Don't neglect to consider a 12 V Lithium battery pack. A 100 Ah lithium pack is good for almost 100 Ah of deep cycle use but if you use a lead acid battery then to achieve 100 Ah capacity you need a deep cycle battery rated at least 200 Ah or preferably 300 Ah because they are rated differently and do not like being discharged to below 50% capacity. They are also very heavy! A 100 Ah deep cycle lead acid battery weighs around 30 kg and will set you back around $400, and be good for around 500 cycles to 50 % depth of discharge. An equivalent lithium pack say a 60Ah 12 V battery (actually more useable capacity) weighs 11.5 kg, costs just under $450 and will last for between 5,000 and 7,000 cycles. Do the math and also consider how much weight you want to lug around! I have! Happy to advise and point interested parties in the right direction!

[jenchris]

I use a 110ah deep cycle battery and a four stage charger.
I keep a meter near at hand to check the voltage so don't let it get too low.
It's just so darned heavy.

[Jen]

Yeah I had one of those packs and it only gets you through one night :/ but if you get a cold dewy night I wouldn't even get a night out of it grrrr so I use this set up now :) it's gives me three nights straight with the dew heaters going too and charging the phones and iPods etc :)

182972

[RugbyRene]

Hi all,

Thanks for all the input. I decided to go with an 18ah unit which I bought from Jaycar on special for $75. This will serve my immediate power needs. I may need more power in the future but for now this is all I need.

Cheers

[OffGrid]

Hello Rene,
Some good advice so far in this thread and by far the most important in my opinion is in Peter's first paragraph which essentially advises on working out your power consumption and convert that to accumulated Amp Hours consumed.
This then determines battery and charger size and type, power and fusing distribution, whilst factoring scale ability and other uses such as camping and blackouts etc.

As also mentioned by others, try not to consume more than 50% in accumulated Amp Hours of a battery's rated sized. So if you consume 40 amp hours between charges, then battery needs to be 80 amp hour minimum.

Unless you are confident, very knowledgeable and have lots of $s for lithium, then battery size is often limited to ability to easily carry and store.
Although I have both 18 and 2x 100 amp hour available for Astro ( one fixed in van ) the 18 usually does the trick for non imaging use and easy to carry. I detest though having to move that 100 Ahr battery around, even if left in ute with extension lead for dark sky sites.
Think big scopes, if they are to big to carry/transport and setup then they are not likely to get used much. Same with batteries.

Getting back to determining power consumption.

There are several cheap and easy to use Wattmeters on the market that make this job very simple providing you have basic DC wiring and soldering/crimping skills or know someone that has. These meters must be connected in series between fused battery and load distribution point with a cumulative count limit of 99 Ahrs and 60 amp through current limit. Larger amp models will have an external shunt.
Providing you are starting off each night with a fully charged battery, then 'Total Amps (Amp hours/Ah) since device initialised' is the primary reading you will need to watch from such meters.
Eg, this one with just fly leads:-
http://www.beachloversleds.com.au/shop/voltage-meters/12v-voltage-current-meter/

Or this one with Anderson plugs to make for easy connectivity:-
http://www.aussiebatteries.com.au/solar/portable-panels/solar-watt-meter

And a Jaycar equivalent meter again with fly leads:-
http://www.jaycar.com.au/Power-Products-Electrical/Power-Monitoring/Power-Meters/Digital-DC-Power-Meter-with-Internal-Shunt/p/MS6170

These meters and variations are even cheaper on eBay. They are also great for camping where many people including myself have killed batteries, particularly from portable fridges.

I have built my own multi fused power distribution box which I connect to the battery via the above meter and a fuse link at the battery.

Hope this helps