Power in the Field

[Hailfire101]

Hi guys. 

I'm almost ready to take my equipment on a road trip and spend the night taking photos. Buy alas, last thing I need is power. 

I need to power an NEQ6 pro and a laptop. I'll use 12v cigar plugs to charge both. 

I've seen the Celestron Power tanks on FLO's. 

What I need to know is, is 7ah enough? Or is the 17ah ideal due to the laptop?

Thanks in advance, Mike

[JonC]

17ah is £40 from Halfords, but if your looking at long term use a deep cycle battery and good charger are a better bet. I use Halfords one to run my mount, works fine.

http://www.halfords.com/workshop-tools/garage-equipment/battery-chargers-jump-starters/phaze-4-in-1-jump-starter

 

[vlaiv]

It really depends, but here some math that might help you figure it out. I'm myself as well in the process of sizing battery pack and finding a solution for this (my power requirements are a bit different, because I image, so more power needed).

EQ6, from what I've seen uses less then 1A for tracking and less than 2A for slewing. You can easily assume that you will be tracking 90% of the time (lower bound). This means that the mount will use 1.1A (probably less) on average.

You can calculate laptop power use by looking at your laptop battery. It is probably in the range of 4000-5000 mAh - that being 4Ah - 5Ah - and if it lasts on normal operation up to 2h this means that it is drawing around 2A of current.

So let say that you need 4h of power in the field - laptop battery will last you 2h so you need another 2h at 2A for laptop - that is 4Ah. Mount will be powered by battery the whole time that will get you in the area of 4.4Ah - total being 8.4Ah.

So if you plan your sessions 3-4h then 7ah might be enough but just about. For longer independence (or if your laptop is more power hungry) - I would opt for 17Ah.

[RayD]

Rather than the expense of the proprietary power banks, have you considered something as simple as an AGM golf cart type battery like to one linked below?  Light, leak free and more power for less bucks.  They are deep cycle so fine to discharge to 80% DoD without damage.

I use a 33Ah one in my battery box and it works a treat.

22Ah AGM Battery

[Cornelius Varley]

For the price of the SW 17Ah powerpack you can get a 110Ah deep cycle leisure battery and charger.

[JonC]

Does depend how portable you want to be, just looked at 110ah deep cycle battery one and it weighs 25Kg.

[Hailfire101]

1 hour ago, RayD said:

Rather than the expense of the proprietary power banks, have you considered something as simple as an AGM golf cart type battery like to one linked below?  Light, leak free and more power for less bucks.  They are deep cycle so fine to discharge to 80% DoD without damage.

I use a 33Ah one in my battery box and it works a treat.

22Ah AGM Battery

This sounds like a good option. Lots of amp hours for your money. 

What battery box do you have? I need at least 2 cigar 12v car ports. 

Also, will any charger do? 

Thanks

[RayD]

3 hours ago, Hailfire101 said:

This sounds like a good option. Lots of amp hours for your money. 

What battery box do you have? I need at least 2 cigar 12v car ports. 

Also, will any charger do? 

Thanks

They are just that, simple and basic but ideal for what they're needed for.

Many of us have made little boxes if you're a handy type of person.  Below is a picture of mine when I built it, which then had the cigarette type plugs, and I added a USB port and voltage meter.  In all including the battery I think it was about £120, which as I said is for the 33AH, and it has a fuse board inside the lid.

In reality your cigarette plugs are probably already fused, as most are, so you can just put a twin/triple port adaptor on to the battery, and then plug both leads in to that.  Some, like the one below, also have a USB port for charging your phone, which can be handy.  You just chop the plug off, put ring crimps on and connect it to your battery with a 10A inline fuse.

3 port adaptor

With regards to chargers I use an optimate, which keeps the battery in float mode, and it has an AGM setting.  Any low powered (5A or so) charger should do the job though as you won't be fast charging, but if it isn't an optimiser, or 3/4 stage charger as they are sometimes called, then you will need to unplug it when the battery is charged as it will keep outputting full power.

All of this, and the battery link are just ideas of course, and many have good success using other methods, but I think you do pay a lot for the proprietary battery banks considering the power they offer, so it's worth investigating the separate battery route and having a shop around, and getting exactly the power that suits your needs.

 

[RayD]

31 minutes ago, JonC said:

Does depend how portable you want to be, just looked at 110ah deep cycle battery one and it weighs 25Kg.

Could be worse.  My off grid system in Spain uses 1150Ah batteries that weigh 86.6Kg each, and there are 24 of them 

[RayD]

You can also buy the battery boxes pre-made like below, and then just add your chosen size of battery, which with a 22Ah coming in about the £35 mark works out pretty reasonable.

Battery box