Deep Cycle Battery Woes

[solissydney (Ken)]

Hi.
In Feb 2009 I purchased a Century 12V 47 AH Deep Cycle battery.
That battery has now had it.
I worked out that, because of the problems with my old mount, and because of the
bad weather since my purchase, the battery would have been in use for about 150 hours in total. It has been charged on an intelligent charger, one Projecta 4300. It has cost me app. $100.00 a year. I am considering looking into buying a new battery from NRMA with a 3 year warranty.
Any other suggestions?

[Marke (Mark)]

Just get one online , I can get a 150Ah for $350 2yr warranty free shipping . Try here http://www.aussiebatteries.com.au/eS...ndex.cgi?cat=0 45Ah AGM for $159 free delivery , forget NRMA .

Mark

[solissydney (Ken)]

Yes, you are right about where it is best to buy a battery.
Thanks for the tip
Ken

[bmitchell82 (Brendan)]

Thats a bit shot. 150 hrs total out of a battery with a microprocessor charger. They should last a damn long time if your not flattening them completely (be aware that you really shouldn't discharge it much past 50% for maximum life, and if you go deep, don't go past about 80% capacity or you will kill the battery).

Also be aware not all batterys chargers are made equal, some are specifically designed for charging specific types of batteries. Thats why I like my CTEK charger as it is able to do a whole range of them.

here is my setup for remote power and soon I will be adding a solar power aspect.

I purchased a 105 A-H battery from my local store for 240 rods. The thing is rock solid, and my other imaging friend has had the same battery for 2 and a bit years now and its still going strong.

[solissydney (Ken)]

I am about to place an order for one 45AH AGM for $159.00 from Aussie Batteries
This will replace my 50 AH one. I never come near to over-use the battery, usually use it only 2 - 4 hours at any one time.
I looked into chargers for the AGM batt. I was assured by Aussie Batt. that my Projecta 4300 charger was OK to use for the new battery. I am about to get a second opinion on that.
Sounds OK?

[Marke (Mark)]

That 150Ah is to run the Obs including lights its not for portable. It has 15A C-Tek with supply mode connected to it - the 15A does upto 300Ah batteries.

Mark

Originally Posted by bmitchell82

Thats a bit shot. 150 hrs total out of a battery with a microprocessor charger. They should last a damn long time if your not flattening them completely (be aware that you really shouldn't discharge it much past 50% for maximum life, and if you go deep, don't go past about 80% capacity or you will kill the battery).

Also be aware not all batterys chargers are made equal, some are specifically designed for charging specific types of batteries. Thats why I like my CTEK charger as it is able to do a whole range of them.

here is my setup for remote power and soon I will be adding a solar power aspect.

I purchased a 105 A-H battery from my local store for 240 rods. The thing is rock solid, and my other imaging friend has had the same battery for 2 and a bit years now and its still going strong.

[loc46south (Geoffrey)]

Hi - I run my observatory on Solar Power and have found out the hard way that not all batteries are created equal - I suspect you have discharged your battery beyond it's safe point and killed the cell. You shouldn't discharge your battery lower than 11 volts (if you want it to last).

Geof Wingham

[Marke (Mark)]

That should be fine it doesnt take much to charge a small battery and the Projecta will handle it , most chargers do AGMs now .

Originally Posted by solissydney

I am about to place an order for one 45AH AGM for $159.00 from Aussie Batteries
This will replace my 50 AH one. I never come near to over-use the battery, usually use it only 2 - 4 hours at any one time.
I looked into chargers for the AGM batt. I was assured by Aussie Batt. that my Projecta 4300 charger was OK to use for the new battery. I am about to get a second opinion on that.
Sounds OK?

[bmitchell82 (Brendan)]

I think you mis read my reply Mark, i was talking in relation to he only got 150 hours total out of his last battery. not your 150 AH batter.

Originally Posted by Marke

That 150Ah is to run the Obs including lights its not for portable. It has 15A C-Tek with supply mode connected to it - the 15A does upto 300Ah batteries.

Mark

[Marke (Mark)]

Doh! yeah 150 Hr not much

[xstream (John)]

30% DOD is the usual rule of thumb, which relates to about 12.60V in a AGM, go any lower before fully recharging your battery and you are greatly reducing it's life cycle.

The main thing you need to consider is how many Ah are you using and purchase the size of your battery accordingly.

[acropolite (Phil)]

Battery life is, as John has implied, a function of depth of discharge.

Discharge fully and you'll get less cycles before the battery is worn out, lighter discharge will result in a longer service life.

The single most important thing is to fully charge the battery immediately (within a day or so) after any discharge and don't pump high current in to the battery if it's in a low state of charge. Equally important is to maintain the correct electrolyte level, if the level falls below the top of the plates due to overcharging the life of the battery will suffer.


If you leave the battery in a discharged state for any longer than a couple of days the sulphate formed from the discharge process will harden and recovery is difficult if not impossible.

Another factor not usually considered is the care that the battery has had before your purchase, self discharge on deep cycle batteries is around 5% per month, a new battery left on the shelf for months could be in a sulphated state before you even buy it.

Another misconception regarding stat of charge is battery voltage, as a rough guide 12 volts with no load represents 50% discharged, 11 volts is pretty well dead flat.

[naskies (Dave)]

Sorry to hear about your battery woes, Ken.

I placed an online order for a 100 Ah battery and 8A charger from Aussie Batteries yesterday morning... it arrived on my doorstep this morning. The 100 Ah is a heavy beast - in retrospect, I probably would have preferred a 45 Ah battery.

[solissydney (Ken)]

Yes, there is quite a gap between the two. I would have considered going for something in between 45 and the 100 AH. My images last night under a dark sky had elongated stars due to the near dead flat battery. The light on my EQ6 mount was flashing for most of the time I was exposing.

[solissydney (Ken)]

Received my new UP-45 AH deep cycle battery today,.
Where my previous battery was charged to 12 and a fraction Volts. The new one was charger up to 13.25V. One must not deplete the battery below 10V. pity it does not have a carry handle. I did order a carry case at extra cost thinking it had a carry handle, but it just came with 2 grips. Rather useless I think.
Anyone wants the carry case can pick it up in Castle hill.
The battery is (labeled as 40ah 10hr) What does that mean? 4 amps an hour over 10 hours???

[naskies (Dave)]

Internal resistance of the battery... if you drain it at different currents, you'll get different capacities out of it. The 10 hour figure is the capacity if you were to drain it over 10 hours, i.e. you'll probably get less capacity over 5 hours and more capacity over 20 hours.

[GrampianStars (Rob)]

Originally Posted by solissydney

Received my new UP-45 AH deep cycle battery today,......
The battery is (labeled as 40ah 10hr) What does that mean? 4 amps an hour over 10 hours???

A battery rated at 40a hrs. for 10 hours means that if you divide 40 into 10 the battery can be discharged at 4 amperes continuously for 10 hours.
So if you use the battery for 5 hours @ 4amps it will be 50% discharged

Likewise, if the rating was at 5 hours (average night) then divide 5 into 40. This would mean that the battery could discharge 8 amperes continuously for 5 hours.
So if you use the battery for 2. 5 hours @ 8amps it will be 50% discharged

IMO 40ah is very limited and the discharge is too great.
A 100ah /20 hrs should have been your minimum ( So if you use the battery for 10 hours @ 10amps it will be 50% discharged

[xstream (John)]

Batteries are the same as your scope or mount, you get what you pay for.

"A penny wise a pound foolish".

[solissydney (Ken)]

I only use the battery for powering my mount and auto guider

[marki]

Buy a honda or yamaha genset and save yourself from the battery woes. At least half the weight of a deep cycle battery if not more and it only takes a minute to refill and its off again. Mine is running right now, can you hear it? Thought not .

Mark