Charging Deepy Cycle Battery

[Golfisher]

Is it true that charging your deep cycle battery by anything above 10 amp (say 15 or 20 amp) is bad? I know it's usually charged at higher amp at first and then trickled down later on, but is there any merit to this notion that it should be charged at 10 amp max, or is this is just a myth like not leaving the battery on concrete floor?

[Fisherman]

There's a couple of variables in the equation, one being the battery capacity, the other being the charger max output. Most batteries should not be charged higher than the C/10 rate, or C=Battery capacity/divided by 10. Therefore a 100amp battery/10= max charging rate of 10 Amps. A much larger 200 amp battery can be charged at 20 amps, but for the lifespan of the battery, it is adviseable to do it at a lower rate. Sort of like a 200 lb man can eat 5 hamburgers, but don't try and jam them in all at once.

[Terry]

here is the deal..according to me....

 

you can charge deep cycle batteries up to about 20 / 25 amps..till it is about 85% fully charged

then it needs to drop to 2 to 5 amps till it is fully charged.....

 

when I bought my bass boat it had built in 2 X 15 amp chargers that automatically drops amps at 85% charged...my batteries lasted more then seven years

before that I was lucky to keep batteries 2 years

[Golfisher]

Thanks a bunch guys.

[Rattletrap2]

Trickle charging at a low amp is always best, but if time is of any importance, then as Terry said, go with a 10 amp and then have it trickle down for the last part of the charge.

[ccmtcanada]

I have the Nautilus deep cycle charger from CTC. It starts out at 10amps and then automatically switches to 2amp charge to finish if off.

[Terry]

and that is perfect for deepcycle batteries

[bbog]

My portable fish finder uses a 12v 7.5amp battery. Taking the capacity divided by 10 = 750milliamps. Do I risk frying the battery using a 2amp trickle charger? Would I be wise to use this charger to get to about 85% capacity and then use something smaller (500-750milliamp) to finish?

 

Wisdom of the battery charging experts would be appreciated.

[Terry]

simple answer is yes you can burn them out with a regular charger on those types of batteries

however they are fairly cheap..my fear would be a fire

I do sometimes charge them with a charger when I am there but if I leave or go to bed I put on the small charger that came with it..just to be safe

[Roy]

I have the Nautilus deep cycle charger from CTC. It starts out at 10amps and then automatically switches to 2amp charge to finish if off.

 

Keep an eye on that charger, Cliff. Some folks have been having trouble with that particular one. Apparently it doesn't always drop down to 2 amps.

[Roy]

My portable fish finder uses a 12v 7.5amp battery. Taking the capacity divided by 10 = 750milliamps. Do I risk frying the battery using a 2amp trickle charger? Would I be wise to use this charger to get to about 85% capacity and then use something smaller (500-750milliamp) to finish?

 

Wisdom of the battery charging experts would be appreciated.

 

I used to use those batteries for a portable that I had. If you have a home security system, just keep switching your battery with the security system's battery. The security system keeps the battery fully charged. They use the same batteries in almost all cases.

[bbog]

Thanks Terry and Roy for your responses - seems I have some adjustments to make

[irishfield]

Barnie.. look around the house for a HDuty calculator adapter.. or a 2 million candle power flashlight charger. Anything between 750 to 1000 ma x 12V DC will work perfect.

 

I'm using the charger for my 2 million CP flashlight and added a couple plugs to it's cord... so it can be used for both the flashlight and charging my portable batteries. I could have found a proper female plug for the case... but that's no fun.. not much McGiver work in that! LOL

 

I'm doing like Roy suggests. My emergency lighting uses two sets of 6V-12Ah batteries in series. So I take one set (leaves the house with lighting for about 1/2 hour in an power failure) and go fishing with the other set. After fishing I put the batteries back for charging.... or if I'm not home I use the 1000ma charger for my flashlight.

Edited March 12, 2008 by irishfield

[ccmtcanada]

Keep an eye on that charger, Cliff. Some folks have been having trouble with that particular one. Apparently it doesn't always drop down to 2 amps.

 

Thanks for the heads up Roy. I remember a thread a while ago about the intelligent charger having problems, so I didn't get that one and went with the Nautilus instead. I check mine every month since it's been in storage for the winter....it always starts at 10amps, then switches to 2amps after about 10 seconds then says the battery is charged. The real test will be charging a spent battery and making sure it switches over.

[bbog]

Thanks Wayne, I now have some good ideas to "McGyver" up. I'm sure I have a charger or three that meets your specification.

[dim.]

I'm sure I have a charger or three that meets your specification.

Purchased mine from C. Tire when it was 75% off. Works fine for me. Charger

Edited March 12, 2008 by dim.

[bbog]

Purchased mine from C. Tire when it was 75% off. Works fine for me. Charger

Pretty sure my inventory includes one of those or I will be buying next time it goes on sale.

[dim.]

Pretty sure my inventory includes one of those or I will be buying next time it goes on sale.

Here it goes. Not a lowest price but on sale for 9.99$. Motomaster 1A Manual Battery Charger

[Billy Bob]

or is this is just a myth like not leaving the battery on concrete floor?

 

Not a myth, you should never store a battery on the concrete floor. Just put a piece of wood underneath it and your good to go. Also keep the top of the battery CLEAN. A dirty battery will conduct a discharge as proven my a old professor I had in college. He proved it with a volt meter by using on lead on one battery post and the other lead on the dirty battery top. It showed a volt reading (don't remember how much).

 

Bob

[Fisherman]

Not a myth, you should never store a battery on the concrete floor. Just put a piece of wood underneath it and your good to go. Also keep the top of the battery CLEAN. A dirty battery will conduct a discharge as proven my a old professor I had in college. He proved it with a volt meter by using on lead on one battery post and the other lead on the dirty battery top. It showed a volt reading (don't remember how much).

 

Bob

Maybe your professors first name was Albert, it's a myth myth myth, now say it! It's due to old style porous battery cases that sweated and reacted with the cement. Doesn't happen now. The only other way you get discharge beyond the nornmal self discharge is if the area between the terminals is dirty and damp and will allow continutity. Say it again...myth.

[Maverick]

Here is everything you need to know about deep cycle batteries, their types and charging and maintenance. A great site I found a while back and bookmarked.

 

http://azwindsun.com/Batteries/Battery_FAQ.htm

 

And the concrete floor is a myth for todays batteries as Fisherman said. Enjoy the read, I found it very helpful.

[Dave Frasso]

Here is another link for you... lots of reading..

 

 

http://www.marine-electronics.net/techarti...faq/b_faq.htm#6

 

 

 

 

Dave

 

.

[brickNblock]

Sort of like a 200 lb man can eat 5 hamburgers, but don't try and jam them in all at once.

 

Well,........

I am 6'-3", 160lb of skin an bone..(Strong like bulll tho)

.......and I most likely could eat 5 hamburgers in one sitting

W/Salad on the side.

 

Seriously tho, exellent post about things I needed to know.

ThankYou.