[Elecraft] Re: What battery to use?

[Mike B]

Something to keep in mind when you desire your battery to have a 
relatively long life.  Taking out 50% of the capacity will, in general, 
seriously shorten a battery's life as compared to only drawing it down 
to 80%.  Most renewable energy systems shoot for the 70 - 80% mark.

Since we're talking emergency battery operation here, it can be assumed 
that you'll likely be drawing the batteries down quite a bit before a 
recharge.  Higher capacity batteries are always better - other than in 
size & weight.

My suggestion is to do this right.  Don't use any kind of flooded 
battery (with removable caps to add water), or "maintenance-free" 
flooded batteries - same internally but you can't add water.  True 
maintenance-free batteries are either gel or AGM.  Gel batteries can 
supposedly handle really deep discharges better, but I wouldn't worry 
about that.  Good AGM batteries beat gel in every other respect.  Some 
manufacturer's charts show more discharge-charge cycles for their gel 
than competitor's AGMs, but from what I've heard in real-world 
scenarios, AGMs are more robust and actually hold up longer.

Concorde AGM batteries came out clearly as the best AGM in the months of 
on-line research I did when recommending new batteries for work, and 
their price was comparable to anything else out there.  No relation, but 
http://thesolar.biz/Concorde_Battery.htm has one of the best prices out 
there for the 100 and 105 Ah Concorde batteries.

Hope this helps a little.

-- 
73,
Mike Boice, KW1ND
Karns, TN
Behold the power of the penguin
Reclaim Your Inbox!  http://www.mozilla.org/products/thunderbird/