View Full Version : Battery type??
September 7th, 2008, 12:48 PDT
I plan on having a small solar setup for emergency lighting adn am not sure how much and what type of batteries I need. I want to keep the batteries inside (and can vent them) because of Winter approaching adn fear of them freezing. I can get reg heavy Duty deep cycle 12v 115amp hour batteries for $69 each but they need venting. The other option is a yellow top Optima for $169 and only 55amp hours. Need help deciding. Will probably run 10-13w cfl bulbs or LED.
September 7th, 2008, 13:03 PDT
what voltage are the lights? 110v or 12 v? IMSMC 13w are 110 v
How many hours a day do you plan on using them?
will you ever run anything else? radio?
you need to plan for 200% in battery capacity relative to use as you do not want to go below 50% Degree of Discharge.
Once you have an estimate of the amount of watts you need come on back and let us know.
Batteries can be selected after your capacity is calculated
September 7th, 2008, 13:10 PDT
I am wanting to go with 12v "solar" CFL or LED lights (see them sold on E-bay) and will run 3 (10w) for 5 hours a night and 1 for 7hrs. I am not sure how to calculate the useage. Sorry, new to this.
September 7th, 2008, 13:39 PDT
Get the cheap, deep cycle battery, and use it in a vented room. Use a charge controller with a BTS (Battery Temperature Sensor) Use LED lights, less power draw then 12V CFL's.
September 7th, 2008, 18:32 PDT
using the 12 v CFLs as an example, per day,
3 x 10 w x 5 hrs = 150w hrs + 1 x 10 w x 7 hrs = 70 w hrs total = 220w hrs
so you need a battery that will be rated for twice that amount of watts
= 440 w hrs @ 12 v = ~37 amps hrs (w = V * A)
so just to round that up a bit, say you need a 40 amp hr battery for one days use.
To be safe and to have a reserve you would want to have 3 days minimum consumption in reserve, in case the power is out for 3 days, so now we need
40 x 3 = ( a minimum of) 120 Ahr battery. adjust this # for your estimate. the cheap one would do...
If you expect the power to be out longer just recalculate.
you did not mention solar or other method of recharging the battery. You will need some method of recharging quickly after use.
If solar you need a panel with 3 - 5% of the ampere rating of the battery larger (~100w) 12 v panels can be in the 6 -7 amp range and would be OK for a battery 200 Ahr or slightly smaller
Yes LEDs are a better way to go as they use far less power (watts) per unit of light generated and would allow you to use a smaller battery, solar panel/charger.
You also need a charge controller so as no to overcharge the battery...
Hope this helps
September 7th, 2008, 22:30 PDT
Thanks alot!! Good to be on a board and get knowledgable answers!
The charge controller I have is the 7amp Northern Tool one. 2 lights, charged and charging.
September 12th, 2008, 6:54 PDT
A word of wisdom:
careful with those LEDs ... most of them I have seen - stink! ... their output does not compare to a CFL, even if they have the same lumen rating - as they are much more directed in their output....
LED ist imho still 1-2 yrs away from being competitive - and thats not even considering $$$$$
(just my experience)
whilst on CFLs, have a very close look to the lumen and consumption ... there are CFLs out there that get 70 lumen/w ... whilst others get 45 L/w.
bring a pocket calculator while shopping :-)
September 19th, 2008, 16:56 PDT
You can find good and cheap deep cycle batteries at Sam's.
I bought some Golf Cart, 6 volts, 200 amp/hour for just around 65 dollars each.
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