trickle charge or not...new volt meter...

[Jack]

thank you to all...again...as we all know it is hard to see old 'faithful' tools that have lived out their life, but...the new meter gives me 12.2 and 12.6...which makes me feel a lot better...and it will fit in my shirt pocket, providing i am wearing a shirt...so sorry to send everyone on a bit of a wild goose chase with bad numbers, however, the answers i received will be very helpful going forward...so back to the original idea...since one battery is down to 50% is a trickle charge the best choice?or do i reinstall and let the alternator charge them after she is back in the water?what is the optimum maintenance schedule for a deep cycle, wet cell battery?Warren, thank you for the numbers and the link, makes things much easier to understand...thanx againJ&R

 

[Don S/V ILLusion]

hope this helps

You'll see references in battery books to the proper charge rate. C/10, C/20, etc. Sometimes it can be confusing. What you need to know is that it means the "time" it takes to fully charge a "dead" battery at a certain amp rate. For example: A 105AH battery will fully recharge (from dead) in about 10 hours at about 10 amps of charge (C/10) or about 20 hours at 5 amps of charge (C/20). Faster charge rates, like C/5 or C/8 shouldn't be used with most batteries because the high amperage required for such a fast charge damages the battery. C/5 on a dead 105AH battery requires pounding in over twenty amps. (This is sufficient reason to stay away from fast-chargers in service stations where a gigantic amount of amps are pummeling your battery when they "charge" (destroy) it in 20 minutes. And when you buy a battery off the shelf, don't let the guy "put it on a charger for just a few minutes" or it will be damaged before you ever use it.In answer to your question, the C/20 rate of 5 amps will charge your partially discharged battery just fine in a lot less than 20 hours. And, since your typical RV converter only puts out a low amp charge anyhow (only 3 or 4 or so), you're about at the safe C/20 rate all the time. If you're in a hurry, plug in your manual charger as well and just keep an eye on things.

 

[Stu Jackson]

Why not learn what batteries need instead of

guessing. Read the West Marine Advisors on that subject and download and read the Ample Power Primer, www.amplepower.com, you'll leanr a lot and be able to make your own decisions.