iPad charging from 12V DC

[ShinyShoe]

It's described as 20000 milliamps which doesn't really make sense - is there such a thing as milli-amp hours? £30.

Yip 1000th of an AmpHour.

i.e. *theoretically* your device can supply 20Amps for 1 hour. As it wouldn't be able to do that you might expect it can produce 2Amps for 10 hours...

**BUT** in addition to the usual caveats with AmpHrs on batteries and not actually being able to use all of that because batteries shouldn't go to 0 charge, you also need to be aware in the LiIon world this is the most conveniently quoted value to make it sound more powerful than the one next to it. In my experience that can mean:

- Out and Out Lies (oops did we but 200,000 mAh on we meant 2,000!)
- Ah rated on a 3.7V LiIon Battery... So even if there was no energy loss in getting to 5V its at least a 25% over estimate
- Ah could be on a 7,2V battery in which case it may be more realistic. But it depends if realism was in the eye of the Chinglish Manual Writer

 

[Mistroma]

Yes this battery bank approach is my solution too. It's much more reliable than plugging an iphone or ipad into a cigar lighter socket. I think in the latest ios updateesapple have introduced software that measures voltage into the ipad or iphone and the slightly jiggly (technical term) connection on a cigar socket may not be steady enough so you get the dreaded 'this accessory may not be supported' on the ipad or iphone. A power bank gives a nice steady output, so it may be useful to have one even if your power source ends up being cigar-lighter-socket-to-power-bank then power-bank-to-ipad. I can navigate with the power bank for 48 hours no problem. It's described as 20000 milliamps which doesn't really make sense - is there such a thing as milli-amp hours? £30.

I try to run laptops, tablets etc. off their own batteries at night and charge next day from solar, engine etc. Helps domestic banks slightly by not dropping SoC quite so low. I guess a bank also makes some sense as Li-ion batteries charging more efficient than flooded lead acid charging. However, transfer efficiency between bank and tablet etc. will reduce the difference and might drop it back to lead acid levels. Big advantage is that you can choose to recharge when surplus power is available.

Yes, there are milliamp hours (nano and pico as well ). No different from putting hours after amps to get Ah, as long as it is being used correctly (i.e. not when it should be just amps).

I assume you meant your bank was 20,000mAh (not 20,000 mA). If so, you could also say 20Ah and that's quite a large battery. I have seen 30,000mAh units advertised and thought that a pair would be close to 1/3 capacity of many car batteries (not comparing CCA ). One of those is getting close to max. you'd be allowed to take on a flight (even with permission from airline).

EDIT: Beaten to it by Shinyshoe. I really mustn't start a reply and then wander off for a beer before completing the reply. I'm talking about not start before a beer part, not skipping or delaying the beer part.

 

[Gunfleet]

Thanks. I meant the manufacturer described the power reserve of the battery as milliamp. I would no more do that than pop down the shops for a foot of milk.

It is quite a large one - about the size of a laptop battery. But I think you’re wrong about the big advantage, which might once have been the choice of when to recharge etc but seems now to be ‘overcomes Apple’s pickiness about supply voltage’. Or milliamperage. ��

 

[BabaYaga]

Beware that as a measurement of stored energy, amp hours (and mAh etc) always assumes a certain voltage. As boat electrics is normally 12V, the voltage is often omitted. But USB charging takes place at 5V, so in that context Ah means something else. Can be a bit confusing.

 

[Mistroma]

Thanks. I meant the manufacturer described the power reserve of the battery as milliamp. I would no more do that than pop down the shops for a foot of milk.

It is quite a large one - about the size of a laptop battery. But I think you’re wrong about the big advantage, which might once have been the choice of when to recharge etc but seems now to be ‘overcomes Apple’s pickiness about supply voltage’. Or milliamperage. ��

Makes sense if you have Apple devices. I'm lucky in that respect as my last Apple devices were Apple II and one of the first Macs to reach UK (tested it, didn't buy it). So time-shifting recharge is plus in my case. I'm considering a power bank at moment.

 

[Gunfleet]

. Topcat’s question was about how to power iPads on board to run Navionic software - hence my answer. I notice you keep your boat in Greece. On a miserable day like this I’d like to be in Greece - Android or IOS!

 

[ashtead]

One solution not to forget with apologies if mentioned is to acquire a portable spare battery . I often run iPad on a 4000mAh pack which also has small suckers on back so it attattaches to pad or phone etc. Model is XP61031 in case of help. Never had any issues charging iPads via USB socket in boat switch panel or by usual Apple plug into boat shore power sockets btw way with an inverter . Keep a supply of these small batteries on board and generally enough back up for when off grid on basis not on long passage

 

[Mistroma]

. Topcat’s question was about how to power iPads on board to run Navionic software - hence my answer. I notice you keep your boat in Greece. On a miserable day like this I’d like to be in Greece - Android or IOS!

I'd like to be in Greece as well but am in Scotland catching up with chores, so weather probably not much better than your area.

Not so much an Android vs. IOS thing, just that I stuck with commercially viable side of things from the start (apart from a few years as a Commodore Amiga Developer). Mainly VAX, PET, Apple II, IBM etc. Much easier and cheaper for me to get hardware and software at low cost from my employer.

e.g. 4 seats for Microsoft Office Enterprise Edition at around £2 each. Pretty certain Microsoft wouldn't have sold me those for Apple as my employer didn't use many of their products. I only ever saw HP servers, laptops and desktops installed for customers. Cant' say that would exactly be a surprise as I worked for HP .

 

[No Regrets]

I use an 'Anker' high performance Cigar lighter USB charger which has two USB outputs and charges my iPad Pro 12.9" beautifully.

No issues, and costs around £12 IIRC.

Anker make decent stuff so very popular and easy to find on Ebay.

 

[prv]

But I think you’re wrong about the big advantage, which might once have been the choice of when to recharge etc but seems now to be ‘overcomes Apple’s pickiness about supply voltage’.

You can also overcome that by installing some half-decent 12v-powered USB sockets instead of a cheapo adapter hanging out of a “jiggly” cigarette lighter. They’re not particularly expensive and you don’t need to think about the charge state of any “intermediate” batteries, or where to stow them. Just plug the phone into power whenever needed.

Pete

 

[No Regrets]

I have fixed USB sockets which are nice, cheap and work fine, but no better than the 'cheapo' Anker (Which costs more by the way)

This thread is far too complex. The plug in ones of known quantity just work fine. Bear in mind I'm using the iPad Pro 12.9" which requires a lot of current to charge properly. Never had an issue with any decent plug in charger. :encouragement: