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Re: Batteries

Posted: 03 May 2019, 18:55
by chrisw
peatop wrote:giving me enough information to build my own battery banks
To be honest with Li-Ion it’s probably not worth the effort to try to make a highly reliable series pack for one-off use when you can just buy them, especially considering to do so you want matched cells, and getting cells is the largest cost factor.

If I was going to make a pack for marine use, I’d stick to purely parallel (but separately fused) cells and use a DC-DC converter to get 12v from the 3-4v output. Yes you lose a little power but it has the advantage that the entire pack doesn’t stop working when a single cell does.

In practice, I don’t even do that: I use an 18AH SLA and just deal with the extra weight, ‘cause a PA14 ain’t exactly a feather to start with :evilgrin:

Re: Batteries

Posted: 03 May 2019, 20:48
by peatop
I'm not making them for important stuff, just for charging phone, tablet and light when camping, everything is rechargeable these days and i don't have enough cars to charge them all at once ;) i also use them in my headlamp for fishing at night and use a 8000ma storage to back it up.

I intend on getting old battery packs to make these storage packs from, your idea of using a voltage regulater was something i had thought about, however i was thinking from 2p but single in series wouldn't be a bad idea, would be far easier to look after and easier to charge.

This is still something for down the track, im still investing in fishing gear and saving for my vietnam trip next year, and hoping to go on the next SWR trip if i can arrange it all :shock:

I had forgotten your in werribee or i would have tried to arrange a trip out with you on my last visit down here ;) maybe next time i bring my yak down i will remember :wtf:

Re: Batteries

Posted: 03 May 2019, 21:23
by Jacko
chrisw wrote:
peatop wrote:giving me enough information to build my own battery banks
In practice, : I use an 18AH SLA and just deal with the extra weight, ‘cause a PA14 ain’t exactly a feather to start with :evilgrin:
I use 9Ah SLA. They fit neatly in to the hobie hatch. They also happen to be the same as the batteries in my home computer UPS. They were on special last week for $24 each from a company called LANware in Heidelberg. Two for $48 will give you 18Ah if that is the capacity you need, but I find 9Ah drives my sounder and light for several hours.

Re: Batteries

Posted: 05 May 2019, 17:40
by chrisw
peatop wrote:idea of using a voltage regulater was something i had thought about
One of these would probably suit, provided you aren’t after more than about 5A continuous:

https://core-electronics.com.au/pololu- ... 50f12.html
https://www.robotgear.com.au/Product.as ... r-U3V70F12

Note that both have a minimum input voltage of 2.9v. That should be adequate (though some Li-Ion cells can go down lower and still be ok). For a lower-voltage unit, try https://www.robotgear.com.au/Product.as ... ator-4-25V, which can run off as little as 1.5v (however it’s maximum output is 2A - fine for a sounder I’d expect, but not a lot more).