Best power tank

[bomberbaz]

I am looking at purchasing a powertank for my mini imaging rig.

Power draw will be based upon 2 x ZWO uncooled camera's, a SW AZ GTi mount, ZWO ASI Air plus and a peltier cooling mod which draws 2.25amps.

To date I have only looked at the SW powertank 17aH and the Celestron lithium powertank pro 13.2aH.

I don't [removed word] to lug a leisure battery around so I am not going down that route.

Interested what others use as their "in the field" power provision and why.

cheers

steve

[Shimrod]

2 hours ago, bomberbaz said:

I am looking at purchasing a powertank for my mini imaging rig.

Power draw will be based upon 2 x ZWO uncooled camera's, a SW AZ GTi mount, ZWO ASI Air plus and a peltier cooling mod which draws 2.25amps.

To date I have only looked at the SW powertank 17aH and the Celestron lithium powertank pro 13.2aH.

I don't [removed word] to lug a leisure battery around so I am not going down that route.

Interested what others use as their "in the field" power provision and why.

cheers

steve

I have the Celestron Powertank Pro - it's lightweight, I don't have to remember to keep it topped up when I haven't used it for a while and it has both 2.1mm and cigarette lighter as well as USB outputs for a bit of flexibility.

I've used mine with an AVX mount, dew heater and ASI533MC for 3-4 hour sessions and still had enough power for the same again the following night.

I've also used it with an AZ-GTI, and while it should be fine if you are imaging, be aware that the AZ-GTI doesn't draw enough power on its in when tracking to stop the Powertank doing it's auto-shutoff thing - as long as you have another device drawing  power you should be fine.

Cheapest place I found the powertank pro was picstop - mine was £204 but I see they've now gone up to £242. You can get a couple of pounds off if you use topcashback.

[pharscape]

I've been using a Baudens 240Wh (22Ah) tank. Its a LiFePo4 battery pack. That runs an HEQ5, ASIAIR pro, ASI1600mm pro, 2x dew straps, ASI120mm guidescope. With dew straps on max it runs for 5+hrs. If you add the cost of a plastic box to keep moisture off (which I use to store all the cables in anyway) its a bargain at twice the capacity of the smaller astro-units and when I bought it is was also cheaper.  To run all night (8hrs+) I have another 240Wh tank that I built myself for under  £130. (£114 for the LifePo4 battery + charger and the rest of the cost was for switches and a small display:

Edited March 28, 2022 by pharscape

[Elp]

Celestron Lithium LT as it was the most compact option. Last summer doing alt az with an azgti it lasted around 6-8 hours. Full EQ setup with autoguiding, cooled astro cam with asiair pro it lasts around 3 hours in the colder temperatures. Ive usually not run it to empty though so might last a bit longer. Charges up quick within 3-4 hours from empty, 1-2 if topping up but obviously not recommended to top up regularly.

[bomberbaz]

I have found this after doing some looking around, wondered if anyone has unthoughts on it. The specs are quite impressive!

 

350W Portable Power Station, Enginstar 296Wh Solar Generator with Wireless Charger,Backup Lithium Battery Pack Power Supply for Outdoors Camping Travel CPAP Machine Emergency : Amazon.co.uk: Garden & Outdoors

[pharscape]

On 06/04/2022 at 19:43, bomberbaz said:

I have found this after doing some looking around, wondered if anyone has unthoughts on it. The specs are quite impressive!

 

350W Portable Power Station, Enginstar 296Wh Solar Generator with Wireless Charger,Backup Lithium Battery Pack Power Supply for Outdoors Camping Travel CPAP Machine Emergency : Amazon.co.uk: Garden & Outdoors

I think it depends on your equipment and use case. I don't have experience of Li-ion batteries but my web search suggested they are not a good match for equipment that needs a voltage above 12V for a long periods. (Unless you run them with an external regulator to keep the output above 12V. )

An unregulated fully charged 12V Li-ion battery is I believe 3 cells of 4.2V so 12.6V max (nominal voltage is 3.7 so 11.1V on average). Using discharge curves found on the web  the battery voltage will continue falling during discharge dropping as low as 9V in the end. If your setup can handle that then great.   Most of the credible reviews I have read for Li-ion power tanks (that measure these things) report the 12V outputs are unregulated just like this.

Conversely my tests show LiFePo4 12V batteries have a fully charged initial output voltage 13.4+V and voltage falls slowly under load staying above 12V even when it is almost exhausted (less than 10% capacity).

(A new Lead Acid battery fully charged can also be up to 13.7V and most circuits are designed for battery use.)

My HEQ5 likes a voltage over 12V for reliable operation.

Cheers,

Paul