Battery question

I use two batteries, one for mount and one for asiair, but only because i have two batteries. I think my one battery is probably not powerful enough to handle a full night. But i dont think its bad to use only once. In fact i always use only one when im at home. Not sure how it affects the battery, i tend to charge it when at home while using it, but its a nice way for me to connect all my cables without needing any extras.

If your battery has enough capacity for both there is no reason to not do it. For my mobile sessions I use only one powestation, no problems or issues.

In my opinion, it’s better to use separate cables as it’s much less likely to get a cable snag, the mount power cable just drops to the floor instead of running back up to the ASIAir but using the same power supply

I dont think they intended to use the 12V ports on the asiair for powering the mount?

One battery is Ok, but you mustn’t power the mount from the ASIAIR.
I have one battery with two sigarette socket. One cable for ASIAIR, one for mount. Be careful to the battery capacity.

I have a ASIAir mini and have read somewhere on the internet that you should NOT use one battery to power everything ... instead, one battery shud be used to power the mount and a second battery to power ASIair. 
But I see nothing in the ZWO documentation or website that recommends the use of two batteries.
Any thoughts such appreciated. Thanks for reading.

There are no problems with using only one battery.

Curious. Where did you read that ? I've been using a Jackery 500 for everything, without issues whatsoever. Good reflex to cross-check information!

I've been using one battery (12 V 90Ah) to power everything. One lead goes into AM5 and then to focuser/dew heater box, small PC and things like filter wheel, guider. Another lead goes into my camera - FLI8000 which is very power hungry when it opens the shutter. This is the only reason why I use 2 cables and 1 battery. Never had any power issues. The downside of one battery like mine is that is veeery heavy.

I use asiair mini with my lifepo4 battery, but i use differente cables to gear supply. Asiair directly to the battery, as same zwo cameras and dew heaters. In the beginning i used asiair to supply cameras and dew heaters but i had some asiair advices of low voltage that i scared me. This way i have no problem at all

thank you, everyone, for your trouble and advice. much appreciated.

Happy to share my experience here ...

1. It is perfectly OK to use one battery to power everything.

Pros :-
- Simple
- Portable
- Inexpensive

Cons :-
- Power surges on one device can affect other devices - eg slewing the mount can cause ripples on the power supply for your camera.

2. It is perfectly OK to use two batteries to power everything.

Pros :-
- Isolates power surges between devices
- Provides redundancy in case your other battery goes flat
- Easier to carry 2 small batteries.

Cons :-
- More stuff to manage.
- A serious issue - this can create power loops if the batteries run at slightly different voltages - this can be very (very) bad.

Before I sold my ASIAir, I used a single battery to run the ASIAir, which in turn powered everything in my setup, including the mount. It worked perfectly well.

I have two power packs now, each with several separately regulated outputs. I use one output for the controller + cameras, and another output for the mount. But I still run everything from one pack, and use the second as a spare.

Personally, I can't see any benefit at all in running separate pieces of equipment from separate batteries.
Power loops with batteries running at slightly different voltages can make your equipment behave strangely - or worse, can cook your gear.

The most important thing is to make sure your power cables are as short as practicable, and rated at much more current that you expect to use.

I had a situation where my controller shut down every time my mount slewed, but only when the camera cooler was running above 90% power.
The voltage drop through the power cable was enough to make the controller undervolt.
I replaced the cable with a shorter, thicker one and the issue went away.

The same applies to USB cables - use quality USB cables that are appropriate for the task (ie USB 3.x for the camera, USB 2.x for things like focussers), are shielded, have a ferrite at each end, and are as short as practicable.

Summing up - one battery with separate regulated outputs (eg a Bluetti) is the way to go. They can be expensive, but definitely worth it when it comes to providing stable outputs with overload protection.

If using two batteries, connect the negatives together with thicker to prevent your gear or thin cables carrying current ( earth loops)

you don’t need two batteries. Problems suggested here and other places are invariably caused by voltage drop in cables or connectors. Just because someone doesn’t understand electrical stuff and guesses a solution doesn’t make it correct. 

For the most part, only use wire current rating as a guide. It’s more important to keep the voltage drop low for the current you’re handling. Always use the thicker wire and keep them short. Usually the wire sizes is determined by what yo can fit in a connector. Particularly for higher current devices like motors and dew heaters. 

connectors are another potential voltage drop area. I removed any cigarette lighter sockets. Besides their habit of coming loose, they offer a poor connection, particularly with often only one of those wipers on the side wired onto the negative. I use Anderson powerpole connectors

your battery has a low internal resistance and will counter voltage fluctuations with motors. To take advantage of that, try to run mount wires back to a distribution point at your battery. Thin wires are a higher resistance so will develop a larger voltage drop under load. Often your gear will not appreciate that lower voltage (particularly mounts)

if you want to lighten your battery and you’re using lead acid (usually AGM or gel), change to LiFePO4 (ie. lithium iron phosphate - notice I said iron and not ion. USB power banks, cameras, mobiles etc mostly use a different type of lithium ion that don’t easily match the lead acid replacement voltage. They are usually lithium manganese nickel cobalt oxide and are more prone to explode and cobalt gives off poisonous gases). If you do swap batteries to LiFePO4, don’t be tricked into claims of drop in replacement for lead acid using the same charger. 

and lastly 12v battery systems are not 12v. It’s a normal voltage label. If you think you need to regulate the voltage to your gear (I don’t think it’s necessary) then set the voltage to around 13.5v to 13.8v

sorry for the huge reply but it’s only a summary of the things I find people ask after having power issues and some of the issues people have mentioned above are examples of people getting confused over reading some guesswork on the internet