Battery Charging Question

If I'm charging a 12V, 32 Ah deep cycle marine battery with a solar panel that has a junction box with reverse blocking diode and a max output of 1.2 Amps, is a charge controller necessary or can I just charge this current straight into the battery?

I'm also shopping for a flexible 20W marine-grade solar panel so if you know of any models other than the Powerfilm model (http://www.vesselprotectionproducts.com ... 9ce1d42b95) going for less than about $350, I'd greately appriciate a link.

Thanks,

-Andy

I checked this out with someone who does know about this kind of stuff, and he says " yes, you do need one
just to make sure you don't overcharge your battery. " happy canoe trips

Thanks - that's about what I expected.

The next question is: What kind of meter do I need to get to tell me how much charge I've got on the battery?

Thanks,

-A

there are special D.C. volt meters available with full deflection between 8v and 16v , one like this would be required if you are to have any luck in determining the state of charge of the battery as there is only really about a volt or so between full charge and empty. This type of meter is often sold in marine stores, also in automotive but the marine store ones would be better.

Ordinary lead acid Batteries (or deep cycle ones either) should not be discharged below 50% or they don't last long. A normal lead acid batter could be destroyed in as little as 10 full discharge cycles but will discharge 50% hundreds of times. a deep cycle will stand a deep discharge more time, but still should not be fully discharged if you want it to last. So you will need a battery big enough to last you through the night without discharging more than 50% for longer time use.
You will need to know what draw your cpap takes and what capacity your solar panel has. you may need to do some tests at home before you take off somewhere! it's quite a complex thing really as there are several types of solar panels, some more efficient than others. It should, I am told, be do-able if engineered properly. Hope this is for next summer.
p.s. If you put an outboard motor with a charging coil on your canoe you can propel your canoe and charge your cpap at the same time!

Your may want to ask the manufactur of that battery. But generaly large car type batterys can be left on
a charge 365 days a year if the charging rate is 1/10 or less than the amp hour capacity. But if your battery
is one of the "never add water" kind this may not be true so it might be best to ask the manufactuer?