Charger questions

[Mouldy]

<font size="4">I read the article about electricity (for like the fourth time) and decided that i can't afford solar right now. That leaves me to have to buy a charger. Now I have a 105Ah AGM battery or at least i think i do ( it has reserve capacity of 178 min and i found a conversion equation of Ah = (RC/2) + 16. Can anyone verify this? ) Now, i'm looking at chargers and i get the point that i need a multi stage one. The question is, The higher the amperage the quicker the charge eh? Example: 20/10/2 charger vs 12/6/2, would the first one charge almost two times faster? Is there a certain percentage of the battery's charge that it switches to the middle number then again to the 2 amp? Trying to determine roughly how long it would take to charge it at 50% charge. Electricity and I need to get a little more on the same page before I leave here!<br>Thanks, Kris<br></font><br>

 

[blars]

There isn't really a simple formula to convert from reserve capacity (at a rate of 25 Amps) and amp-hours (at a given discharge rate or time -- I think 20 hours is normally used).&nbsp; Most batteries have greater capacity at a slower discharge, until the self-discharge rate winds up being significant.<br>There is also a limit as to how fast a battery can be safely charged, AGM batteries can be charged faster than normal lead-acid batteries of the same capacity.<br><br>

 

[akrvbob]

I have a Trojan battery, and they recommend a 10% charge rate. So I have a 235 ah battery, so I can't charge at more than 23 amps. My smart charger has a 2/10/20/40/Start setting. I set it at 20 amps and if the battery is low, it starts charging at 20 amps. If I sit and stare at the digital dispaly, I can watch it drop by the 10th of an amp. It just keeps dropping until it says "ful". Since i use solar unless I am in he clouds/rain for a long time, I only use my generator a couple times a year. Then to get the most bag for my gas usage, I only run the generator while it is charging at 10 amps or more. I just have to run it maybe every day instead of every other day, but I still use less gas. It burns as much gas when the charger is charging at 20 amps as when it is charging at 3 amps.<br><br>Any battery that lists a reserve capacity is not a deep cycle battery. It is either a starting battery or a marine battery. Marine batteries are a hybrid of starting and deep cycle. Like most compromises, it is not great at either job, but adequate at both. Bob<br>