Back up batteries

[Rearfang]

I have leisure batteries but due to size and weight I'm looking at yausu type not sure weather to go for motor cycle type or large fire alarm style to power my ham radio gear portably

[Yorkshire Andy]

Go bigger fire alarm is intended as a back up and are a long slow discharge .

Motor bike are a high cranking current low capacity usually


Look a a deep cycle leisure battery and never let it drop below half its rated capacity and keep it charged to get max life from it

[Briggs 2.0]

I use the Lucas 22Ahr gel batteries (£30 on eBay, they are green in colour). These are for mobility scooters and have the long cycle Andy mentioned. I run my FT857D radio from one of these and it lasts for days between charges. Not too heavy either and easy to carry one handed.

[dangerman]

I've got a 100 ah leisure battery hooked up to a 4w solar panel to keep it topped up. I use it for camping with a 300w inverter that I got from lidl. Works great for keeping all phones and laptops charged and to power lights. I also have a 27w folding solar panel to take with me in the field (Goal Zero Nomad 27). That will give it a full charge over about a week in the UK.

Problem is, like you, I hate how bulky it all is. So I've bought a small mobility scooter battery and a 100w mini inverter from eBay. This is great for when I go away on the motorcycle.

The only thing is, the battery capacity doesn't give me much laptop and lights time, so I find it best to charge stuff up during the day, that way by the time the sun sets I have a laptop and phone with full charge and a fully topped up battery too.

The solar panel will fully charge up my little battery in about 8-12hrs.

[Briggs 2.0]

@dangerman

Re my post above, I don't think you can beat these for power versus price versus portability.

http://www.ebay.co.uk/itm/Lucas-12V-22A ... 2c620dc871

[dangerman]

Yeah, nice one Briggs, the battery I've been using doesn't hold charge very long so I'm thinking of swapping up. 22ah is 8ah more too so looks like a winner. Might wait till next spring now though.

I believe you can save a few bob by having someone disabled purchase it... Tax free maybe? Not sure if that's the ethical thing to do but I'm always up for a bargain.

[dangerman]

Just in case anyone wants to see exactly how messy my kit is, here's a picture:



The problem with this photo is that it's a bit confusing - I've got both inverters connected to the big battery. It was a while ago (I've even replaced the conservatory now) and I was experimenting.

In the picture is my Goal Zero Nomad 27 solar panel, Goal Zero Guardian 12v charge controller (works with my 7w panel when on the motorbike), 100ah battery, both 300w and 100w inverters. I managed to keep all that kit charged for days and days (battery drained in four days, solar panel would keep it topped up but would need to recoup power after a couple of weeks).

And so in theory, if I were to evacuate and brought all this stuff, I'd be able to keep tweeting and facebooking indefinitely! #priorities!

[Yorkshire Andy]

Having been a bit of a geek and been playing with the dc clamp meter, on the whole dedicated 12v adaptors are much mor efficient than a step up inverter then to step down via a mains transformer even most laptops that run on > 12v DC often have a 12 charger available



Short cable runs help too

Its also never a good idea to drop a lead acid battery under 50% capacity during use

[dangerman]

I read that somewhere else too. But people in campers must be doing it all the time, charging it, using it up while out and about and then charging it back up once home. Thanks for the heads up, but what's the point of a 100ah battery if you can only use 50ah of it? I've not got a gauge either, so how could I monitor it? Also, the Goal Zero Yeti has a lead acid battery - that one seems fine to fully discharge and power back up again. What's that about?

Batteries and electricity confuses me.

I did look at 12v chargers for my mac but they're all crap, Chinese made for eBay stuff. Might just manage with this system for now then will reconsider when I upgrade the computer.

[Yorkshire Andy]

Will give a better reply tonight with links but discharging a battery more than about 50% capacity leads to much greater levels of sulphation of the plates thus reduced capacity and a much shorter life span

Will dig some links out tonight when I get near the PC