Making your own power station from a battery

[paulgs (Paul)]

Hi All,

I'm interested in having a portable power source instead of plugging in to a long extension cable. Ready to go power stations like Bluetti etc are fairly expensive and I see some people using a battery. Clearly there are other bits and pieces you need to be able to connect. Can anyone point me to a guide or can provide advice on what's needed to DIY? It seems like a fairly big cost saving...

Thanks,

Paul

[Leo.G (Leo)]

Paul the best batteries if you want light weight are the LiFePo4 batteries and when you look into the purchase price of them the Bluetti become good value. Throw in the other hardware and they really are cheap.
I have a good battery box but find lead acid batteries both heavy and not the best if accidentally tipped on their side (even sealed top things can leak) and they need to be charged in reasonably vented space.
Then throw in a proper charger for a LiFePo4 and the readily available units are actually cheap. I did the maths because I have a background in electronics and was going to save a fortune until I realised I wasn't.
Though I haven't yet bought a Bluetti but I intend to when I have the finances.



Anyway, just my $0.02:


https://www.cloudynights.com/topic/7...able-powerbox/


https://stargazerslounge.com/topic/2...12v-power-box/


https://kelly.flanagan.io/astronomy/...rophotography/


Google search will bring up plenty of results.
I dare say there would likely already be some here too but I haven't searched this forum, just Google.

[paulgs (Paul)]

This is good to know.

Thanks Leo.

[Leo.G (Leo)]

Recently Kings auto had an amazing price on a good brand 100A/h LiFePo4 battery, below $200 (maybe 70A/h, I can't remember). There is no such establishment nearby and I know a local friend with a business has an account and I was going to get him to buy one in for me. Unfortunately I couldn't get in touch with him and I missed out and my next check it had jumped back up to over $300.
Very recently Aldi had a LiFePo4 battery on special, the VoltX which is said to be a top brand, I can't remember it's capacity but it was $499.
Some places sell the individual cells and you can mix and match up to your own desired capacity with parallel and serial connections. I've looked into going down that exact path myself until I read so many reviews where many sellers were selling used cells for near new prices and decided to stay clear of the theoretically good deals.


In saying that I've also seen mention of Bluetti and other brands on this forum where they have performed flawlessly and are often on special. Dependant on required capacity a good deal may be possible, higher capacity units have higher prices obviously but it's a warranted complete package. NO, I am not affiliated with Bluetti (the only one I know because I have tabs open everywhere for their equipment), I did the maths and realised the ready to go packages are good value.
Though I would suggest it's worth reading some of the self builds, lead acid are reasonably cheap if you don't have to carry them. I need mine to be portable so I can chuck some gear in a car and go (and carry it up mountains) but if it's just on your own property a small trolley makes the heavier, cheaper battery very viable.

[pmrid (Peter)]

I can certainly vouch for the Bluetti power stations. I've had mine for about 2 years and it has never missed a beat and always has enough grunt to run a full rig for 2 nights. The only negative is that the charger has an internal fan that is noisy but that's a fairly minor issue. Mine has interesting power specs - on the back it says it's power comes from 716Wh from 22 VDC at 32AH.

I recently bought a Lithium battery from Kings at a great price. It is a 720Wh at 12.4 volts at 60AH. It was only $146 I think. So I have put together a small DIY battery box thingy from bits I had lying around. It is based on a little panel of outlets I bought on the net (either Temu or something similar) containing a USB socket with 2 x USB2 2.1 A outlets, a Cigarette Plug, a power meter and an on-off switch. I added a 2.1mm plug-in socket and put it is a box that I connect to the battery. It's small, portable and light plus it provides all I need to run a second rig.

I'll add a photo if I can take one.

All up, it cost about $200 so if you are able to put it together, it's quite a saving.

[Leo.G (Leo)]

I recently bought a Lithium battery from Kings at a great price. It is a 720Wh at 12.4 volts at 60AH. It was only $146 I think

That may be the same deal I saw but it timed out and the price jumped up considerably.
I'm guessing they do the deals on a semi regular basis.
Battery boxes can be had for around $50 and they have Anderson plugs, I think the 12 volt barrel type (I forget their designation (5-21?)), cigarette plug and possibly a Volt meter, I can't remember I have a new one laying around here somewhere.

[pmrid (Peter)]

Originally Posted by Leo.G

That may be the same deal I saw but it timed out and the price jumped up considerably.
I'm guessing they do the deals on a semi regular basis.
Battery boxes can be had for around $50 and they have Anderson plugs, I think the 12 volt barrel type (I forget their designation (5-21?)), cigarette plug and possibly a Volt meter, I can't remember I have a new one laying around here somewhere.

The one I bought is still selling for $149. That's 60AH not 100. But because you can run lithium batteries right down, it's still more than adequate for full night imaging.

[Leo.G (Leo)]

Originally Posted by pmrid

The one I bought is still selling for $149. That's 60AH not 100. But because you can run lithium batteries right down, it's still more than adequate for full night imaging.

It may have been a higher capacity I saw, it was reduced to $178 but shot back up to $299 or thereabouts. I don't think it was 100A/h though, maybe 70, I honestly can't remember.

Is that a Lithium or a LiFePo4?
It's OK, I'll search Kings myself.


I couldn't find any 60A/h under $200 except this one which is reduced for 1 day only.


https://www.4wdsupacentre.com.au/kin...g-adapter.html


Could you possibly provide a link?




Another question, will it run mount, camera (plus guide camera) and laptop for 4-6 hours?
I have step transformers here somewhere that would get me to laptop voltages (19 volts), or use an old car adapter I'd have a few of (that saves me stuffing with components I can no longer see, everything is so small these days).

[gregmc (Greg)]

Originally Posted by Leo.G

It may have been a higher capacity I saw, it was reduced to $178 but shot back up to $299 or thereabouts. I don't think it was 100A/h though, maybe 70, I honestly can't remember.

Is that a Lithium or a LiFePo4?
It's OK, I'll search Kings myself.


I couldn't find any 60A/h under $200 except this one which is reduced for 1 day only.


https://www.4wdsupacentre.com.au/kin...g-adapter.html


Could you possibly provide a link?




Another question, will it run mount, camera (plus guide camera) and laptop for 4-6 hours?
I have step transformers here somewhere that would get me to laptop voltages (19 volts), or use an old car adapter I'd have a few of (that saves me stuffing with components I can no longer see, everything is so small these days).

Re the Lithium comment…
If you are referring to batteries in say cameras, mobiles, many USB power packs, many e-bikes, then it’s not correct to say Lithium or LiFePO4.
Both NMC and LPF (or Lithium Nickel Maganese Cobalt Oxide and Lithium Iron Phospate) are both Lithium based chemistries.
The NMC stores more power for its weight but it has a much lower thermal runaway temperature compared to LFP. So NMC is way more likely to combust

BTW, transformers are only for AC although I concede a DC-DC converter would have some form of transformer within as well as many other components.

[gregmc (Greg)]

I would suggest that if you are not knowledgeable re electrical stuff, that you don’t build your own storage. Particularly now a days with the alternatives available.

Most people, even many electrical types, don’t realise the purpose of fuses, where to physically locate them and what type should be used as the first fuse (such as a HRC or other fuse that doesn’t maintain a spark under very heavy loads such as a short circuit)
Wire sizing, distribution etc can get confusing if you don’t allow for voltage drop at your max load.

12v batteries are not 12v. LiFePO4 are more around mid 13v (although about 14.6v charging max) down to around 11v. But from around 12.5 to 11 is a bit useless so thinking you have available the full power of a 12v battery is not a good idea. I have done lots of capacity testing of a couple of 100AH & 125AH batteries and they only meet their spec if you drain to around 11v.
Also, another bit of confusion if substituting LiPo for NMC batteries. LiPo is a construction method that could be NMC or LPF.

So if you measure your voltage drop from your battery, through switches, fuses, (hub devices with power switching) and ever decreasing cable sizes to the back of say your cooled camera, you will see a voltage drop under load (say cooler on full and imaging). I would allow about 0.5v drop on a good system but I’ve seen 1 or 1.5v drop.

So if you measure the capacity of a battery and stop at 12.5v (12v for gear and 0.5v drop), then you will have less power (maybe 10% but it depends).

If you have a very small setup, say an ASAIR, small camera and mount and a small dew heater, then probably 50 or 60AH is fine. Most people quickly add to that so I’d start with at least a 100AH. They are also more popular so you can probably get them cheaper.

Now a box such as Bluetti (I don’t have one but I’ve studied that particular box) usually use a 24v or 48v LiFePO4. This enables them to use a DC to DC converter to drop the full voltage discharge range down to around 13v. This gives you full access to the power in a battery. (This will be my next battery build method if I ever need to build more batteries for my rigs)

The complete units also usually have an indication of voltage/current/power being used and remaining capacity. They also already have built in fusing, charger etc. Something that a beginner doesn’t have to worry about.

While I’d still build my own because I can choose my gear (such as victron 30A charger and Victron Bluetooth shunt, Bussman fuse & powerpole connectors) and I don’t have to include the extra weight of a 240v inverter, I know what I’m doing.

If you are in ASNSW or NSAS, contact on chat and I can supply more info