Portable power for Sky-Watcher Synscan GOTO 8" Dobsonian
Hi everyone,
Apologies for another post about portable power but I didn't seem to find what I was looking for on other threads so thought I would ask here:
I have Sky-Watcher synscan on a Dobsonian that requires 12V but I'm not super electrically minded. Would a 12V car jumpstarter work? Why/why not?/Any additional components or modifications necessary?
I just really don't want to have to spend hundreds just on a powerpack!
Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,494
Jump starter batteries are designed to supply a lot of current for a very short time. You would be better with a deep cycle AGM or lithium ion. If you really want to use a jump starter, someone in this thread describes using a 1200A model. https://www.iceinspace.com.au/forum/.../t-147334.html
As Joe said, jump starters will run the things for a while with the high capacity things being the exception but for the dollars they cost you can get a nice portable power station such as Bluetti and numerous other companies sell (that's the name I know but there are lots of them). You get a dedicated supply which will run so much more than just the mount and not a great deal dearer than a good jump starter and probably lighter too using the LiFePo4 batteries.
Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,494
You pay a lot to have everything packaged in a nice neat box like a Bluetti. Inside something that costs a few hundred dollars, a pretty small $30-$40 battery frequently resides.
I have some very old 12v 7AH SLA batteries that have been recharged more times than I can count. They still run my scope (EM200 - an EQ6 clone) for more than half of a night. If I don't intend to do an all-nighter, I often run my scope off these rather than using my big 120AH Li Ion.
If your power consumption requirements increase later, eg you add a cooled astrocamera, dew heaters, you can either buy extra batteries and put them in parallel or (better) you can buy a different bigger battery and the charger will work with a wide range of battery capacities and types.
I've seen some of the Bluetti units on special (older models) at good prices.
For me the difference is a LiFePo4 battery vs SLA, the SLA is heavy in comparison albeit extremely cheap in comparison. I picked up a dep cycle SLA at Aldi one day, 30KG, thinking it was supposed to be the LiFePo4 but that was the next week. The equivalent LiFePo4 was 12 KG,, a huge difference. To be fair that was a high capacity battery, not a little thing like you've shown Joe.
I've used a 1200Amp jump starter in the past when I've taken my gear up to a local lookout but it was quite heavy when thrown in with the EQ5 Pro mount (inc weights) and 152mm Skywatcher refractor, along with the 80mm Megrez added as a finder, camera, laptop (plus small gas stove and some food and water (for coffee) and pans because my son and I hadn't had dinner and it was going to be a very late night).
All up it was quite a slug up a big hill carrying way too much for someone who had a major heart attack only 2 months prior. I had my son run back down the hill to get my heart medication from the car when I was only half way up (no vehicle access in that spot) and spent half an hour or more just sitting before I was game to continue up the hill.
I must make an electric carry buggy with small off road tyres one day and a cable remote to control it. Then I won't need a power supply, the cart will be the power supply.
I've searched LiFePo4 batteries to make my own rig, I have the battery box with fuses and meters and outlets already built in but the LiFePo4 are far from a cheap battery but extremely light in comparison to SLA.
That is however a much dearer option.
If like me, you worship at the alter of Ryobi 18v power tools and already have numerous batteries, google up Ryobi 18V 120W ONE+ Battery Power Source R18BT12V which is an absolutely awesome add on for a hundred bucks and supplies 12V and usb power with whatever sized batteries you already have.
I run my portable scope off one with a 4Ah battery and its good for a few hours.
I have a 100Ah lithium in a decent battery box for the heavy sessions, but if you just fancy a couple of hours under the stars with an eyepiece ...
These are the Ducks Nuts for the GoTo dobs and the likes, fellas }
12V 20Ah Lithium Battery LiFePO4 Rechargeable Deep Cycle BMS Solar Boat Camping,
They have the hex F2 bolt Terminals aswell
Dimensions - 185-L x 167-H x 82mm-W
Weighing in at 2.05Kg's
They have the options for the smaller 8Ah with the Spade terminals,,, 12Ah, the 20Ah and a 50Ah then onto the larger sizes -- some sizes currently Out-Of-Stock
Thanks Bob that's quite an affordable solution for a light weight LiFePo4 battery. Sorry, Lithium battery.
Any idea what sort of run time with a normal EQ skywatcher mount (EQ5 pro, laptop computer and minimal draw camera?
I have some new 8-AH lithium Aldi 20 volt packs I could run through a buck converter to get the required voltages, not sure how long it would drive my gear but I have a couple of new units and it would be worth me looking into, already having the battery packs, I could wire a couple up in parallel in my dedicated battery box I bought new and have never populated.
Plus I could try them in the yard where I have AC power available as a back up. I'd have to fit a 19 volt outlet for the laptop, a 12 volt regulated output for the mount and 5 volt for the camera but it works straight off USB I believe. It's minimal work to set it all up and try it.
Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,494
Quote:
Originally Posted by Leo.G
I've seen some of the Bluetti units on special (older models) at good prices.
For me the difference is a LiFePo4 battery vs SLA, the SLA is heavy in comparison albeit extremely cheap in comparison. I picked up a dep cycle SLA at Aldi one day, 30KG, thinking it was supposed to be the LiFePo4 but that was the next week. The equivalent LiFePo4 was 12 KG,, a huge difference. To be fair that was a high capacity battery, not a little thing like you've shown Joe.
I've used a 1200Amp jump starter in the past when I've taken my gear up to a local lookout but it was quite heavy when thrown in with the EQ5 Pro mount (inc weights) and 152mm Skywatcher refractor, along with the 80mm Megrez added as a finder, camera, laptop (plus small gas stove and some food and water (for coffee) and pans because my son and I hadn't had dinner and it was going to be a very late night).
All up it was quite a slug up a big hill carrying way too much for someone who had a major heart attack only 2 months prior. I had my son run back down the hill to get my heart medication from the car when I was only half way up (no vehicle access in that spot) and spent half an hour or more just sitting before I was game to continue up the hill.
I must make an electric carry buggy with small off road tyres one day and a cable remote to control it. Then I won't need a power supply, the cart will be the power supply.
I've searched LiFePo4 batteries to make my own rig, I have the battery box with fuses and meters and outlets already built in but the LiFePo4 are far from a cheap battery but extremely light in comparison to SLA.
That is however a much dearer option.
The charger I recommended is both Li ion and SLA compatible. Then Chelle can upgrade to Lithium or stay with lead acid. I have a 120AH Lithium in my 4wd, solar charged that powers my car fridge and provides camping power for charging all my devices. I installed it isolated from the main car battery to avoid accidental discharge. It's easily removed for powering my astro activities. It weighs 15kg, about 1/2 to 1/3 of it's lead acid equivalent. Expensive but cheap compared to the cost of a few visits to the physio to fix the back.
