Battery Life

Submitted: Monday, Jan 04, 2010 at 21:46
ThreadID: 126281 Views:3387 Replies:5 FollowUps:2
This Thread has been Archived
Our Original batteries are now over 4.5 years old and showing a bit of reduced capacity. Will maintain a voltage down to 12.7 overnight (from a 13.7v float charge) with the TV operating in the evening and fridge etc running, but need sun in the morning to get them back up again - which is quite quick in good solar conditions. I don't like to run them much below 12.7v

How does this compare with other peoples battery performance and what is the typical life we can expect from a set of batteries that are reasonably well looked after. We have a 3 panel and 3 battery combination - currently in mid west WA.

Cheers John
Back Expand Un-Read 0 Moderator

Reply By: NIK `N` OFF - Tuesday, Jan 05, 2010 at 07:02

Tuesday, Jan 05, 2010 at 07:02
John our batteries on solar are at present showing 12.9 in the morning after the usual fridge / TV / Stereo operating and they are floating again at 13.9v by early mid morning. 12.7 is fully charged and i don't see any concern. I have had our batteries down to 12.2v [60%] but i wont allow them to discharge any lower than that, my belief is batteries worked are better than ones not.

4 Batteries / 4 panels.
AnswerID: 579563

Reply By: Boystoy - Tuesday, Jan 05, 2010 at 07:29

Tuesday, Jan 05, 2010 at 07:29
Hi John,

Mine will be 6 years old in April, but will be replaced before then. We are on the road between 4-6 months each year, so maybe do not see as much use as yours.
This last short trip, we used our Honda generator for only the second time to pump up our batteries.
However we tend to use the microwave most days (for 10 - 15 minutes) & this last time it gave us the dreaded RED light for the first time. Also noted that after a 240v session in civilisation with the battery charger on, gives us only about 3 days of normal usage, TV, radio, fan, computer etc. (no microwave) before we need the Honda.
Methinks they have reached their use-by date & will be replaced before the next trip. Can't complain, batteries have a light covering of dust, otherwise still look brand new, & no signs of any leaks.
Maybe I was lucky?

A Bushtracker (or BT) is a "Boys Toy"

My Profile  My Blog  Send Message

AnswerID: 579564

Follow Up By:- Tuesday, Jan 05, 2010 at 08:58

Tuesday, Jan 05, 2010 at 08:58
For the is a myth that batteries last longer if "worked"

Small consumer rechargables usually come with a number of recharges life and this is true of all rechargable batteries whether big or small.

Put simply there are three parameters which govern the life of a battery.

1) Age from manufacture.

2) Number of discharge/charge cycles.

3) Depth of discharge.

If 1 and 2 are zero then 1 determines the life. Increase 1 and 2 and the life is reduced.

Using are 1000w+ microwave oven load is not to be recommended on a small installation as in our BTs.

FollowupID: 852125

Follow Up By: NIK `N` OFF - Tuesday, Jan 05, 2010 at 19:30

Tuesday, Jan 05, 2010 at 19:30
Hi Ern,

Not a myth that i am aware of, not suggesting your wrong for all i know you may be a guru on batteries.

My understanding is all 3 points you state are important but in my opinion the balance between 2 & 3 is the main criteria. Yes Deep Cycle batteries do have a discharge life / number of cycles but if the cycle is kept within it's ideal parameters then it should last indefinitley, unfortunately that doesn't always happen hence a life is taken away and cannot be got back, abused they don't last long, looked after .... years.

We do not have a microwave nor a large invertor.

FollowupID: 852126

Reply By: Roderick - Wednesday, Jan 06, 2010 at 07:44

Wednesday, Jan 06, 2010 at 07:44
Hey John, I would think that you have got good service from your batteries, and that your current specs are fine. You must have good batteries and solar panels. And no doubt there is a bit of skiting going on here! Rod
AnswerID: 579565

Reply By: Uncle Dodgy - Thursday, Jan 07, 2010 at 06:00

Thursday, Jan 07, 2010 at 06:00
G'day John and Happy New Year to you both.

To me I can't see anything wrong in the results you are obtaining.
I wouldn't be too alarmed about an early morning voltage of 12.7. The further above 12 volts though the better. We have been down to 12.3 on rare occasions but the voltage has recovered to high 13's by mid afternoon on a sunny day.
For the benefit of others considering microwave/toaster/jug use through 12V/240V inverters, I offer the following for consideration.
Volts X Amps = Watts, or conversely Watts divided by Volts = Amps or W/V=A.
Consider the case of an appliance that is rated at say 960 Watts, then this in theory would require at 12 Volts a draw on the batteries of 80 Amps, and similarly an appliance of 1200 Watts would result in a 100 Amp draw.
An increase in the current flow through the 12 V wires that supply the inverter to meet that amperage draw results in an increase in the heat generated within those wires.
Provided that the wiring has been designed to meet that demand then no problem other than the demand in the batteries to supply that amperage draw. (Case in point where someone installs a replacement larger inverter without considering the 12V wiring, a hazard could exist.) However if the system as a whole has not been designed to cater for these elevated current draws on the batteries, the end result as I see it is a reduced battery life. If the system was designed to cater to such demands then there should not be a problem.
We prefer to run the high current draw items within our BT on either mains or generator power, rather than inverter supplied power, but that is our choice.

John & Sharyn
Takin' the long way home - Towing a Bushtracker

My Profile  Send Message
Classifieds: Nissan Patrol 6X4 tow vehicle for 19ft Bushtracker., 19 Ft Queen Island Full Off Road Bushtracker.

AnswerID: 579566

Reply By: Grumblebum & Dragon - Thursday, Jan 07, 2010 at 21:16

Thursday, Jan 07, 2010 at 21:16
Good feedback - thanks folks

John and Jean
AnswerID: 579567

Our Sponsors