Charging Inverter Batteries

Crane

New member
Apr 2, 2006
57
0
0
Can anyone tell me if I am having problems with my batteries. I have noticed the last couple of days when the electricy went off for a half hour, it took my batteries over three hours to fully charge back up. I have a 2400 Watt inverter and i have 8 batteries. I always keep an eye on the operation of the inverter, but this just does not seem right. Although, lately my electricity has been real weak. It has also warmed up quite a bit. Do these things have anything to do wiith my situation. Could I have a bad batttery. Any help would be appreciated.

Crane
 
Feb 7, 2007
8,005
625
113
The charge rate may play a role. I had my inverter (newly built) charge rate set so low, that after 6 weeks the 3 + 3 hour blackouts completely discharged the batteries (e.g. discharge 15 A, afterward-charge 10 A, difference -5A etc.) so the charge rate had to be measured and adjusted.

Your batteries may be also a little dry, so try to add battery water. You can buy it in repuestos. You can also get some EDTA and put a tablespoon in each battery cell.
 

Rocky

Honorificabilitudinitatibus
Apr 4, 2002
13,993
208
0
111
www.rockysbar.com
Can anyone tell me if I am having problems with my batteries. I have noticed the last couple of days when the electricy went off for a half hour, it took my batteries over three hours to fully charge back up. I have a 2400 Watt inverter and i have 8 batteries. I always keep an eye on the operation of the inverter, but this just does not seem right. Although, lately my electricity has been real weak. It has also warmed up quite a bit. Do these things have anything to do wiith my situation. Could I have a bad batttery. Any help would be appreciated.

Crane
Hey Crane,
One could not diagnose the problem from afar, but it could be normal that it take 3 hours to charge.
The discharge time and recharge time are not relevant.
For instance, if I had 8 batteries operating only a light, a small fan and a TV and the power were out for 10 hours, it might take only 1 hour to recharge, as the discharge was so minimal, conversely, if you are heavily loaded, you could lower your batteries enough in 30 minutes, that it would require 3 hours charging to get them back up.
Do you have a tester?
If so, does it also have an ampmeter?
How old are your batteries?
Are they all approx. the same age?
Have you ever treated them with EDTA?
Are they all properly filled?
Do they get quite hot, either discharging or recharging?
 
J

John Evans

Guest
are the batteries all of the same type and age? do they need topping up a lot ? do the sides bulge out slightly?-sometimes its more economical to get new -your electricity bill will go down (unfortunately they cost a fortune)


oooops i didn't read the above post
 

rbstoker

New member
Nov 23, 2005
12
0
0
..... i have 8 batteries......
Crane

Wow is that the normal amount of batteries? I have been considering the purchase of an inverter and I am still trying to sort the whole process out before I go into a store and let them "bend me over." However, the prices I have glanced at for a single battery can be as much as $150 US. If 8 is the norm I need to increase my budget considerations.

Reg
 

Rocky

Honorificabilitudinitatibus
Apr 4, 2002
13,993
208
0
111
www.rockysbar.com
Wow is that the normal amount of batteries? I have been considering the purchase of an inverter and I am still trying to sort the whole process out before I go into a store and let them "bend me over." However, the prices I have glanced at for a single battery can be as much as $150 US. If 8 is the norm I need to increase my budget considerations.

Reg
You can get decent batteries here for $110 US/each.
The amount of batteries you need is determined by the load and duration of power outages.
In low consumption situations, 8 batteries could last you 3 days, and in high, 3 hours.
 

rbstoker

New member
Nov 23, 2005
12
0
0
You can get decent batteries here for $110 US/each.
The amount of batteries you need is determined by the load and duration of power outages.
In low consumption situations, 8 batteries could last you 3 days, and in high, 3 hours.

Thanks for info...How does one go about determining the amount of watts and batteries that are needed. I have read several posts in other threads and it all seems so subjective and trial & error sort of driven. A couple of weeks ago when I was in Santiago on at least three days the power was off for more than half the day. Is there a chart or rule of thumb sort of guide that can let me figure out what I will need or do I just go in and say give me the biggest you got and the money left over buy all the batteries they have in stock :bandit:.

Reg
 
Feb 7, 2007
8,005
625
113
Look, I do 12 kW usage of electrical energy per day - 6 low consumption bulbs at night, 1 "high" low consumption bulb, 2 Big TVs on about 5 hours a day, 1 small TV on about 5 hours a day, DVD recorder, 3 cable TV boxes, computer w/LCD screen and/or laptop, printer, 3 cellphone charges, ADSL modem, large 2-door fridge, water pump (average 10 mins per day), washing machine (average 10 mins per day), drier (average 5 minutes per day), A/C on average 3 1/2 hours per day - usually 1 hour late in the afternoon on full, and 2 hours at night.

The average usage is about 0.5 kW per hour, but it varies by the time of day. The most usage I have, everything on + A/C and it's about 2 kW. I don't run A/C off the inverter, and I have 2 kW inverter with 4 batteries.

Now, as the summer nears, the AC would use up more power/kilowatthours, but again, it does not effect inverter and battery settings.
 

Rocky

Honorificabilitudinitatibus
Apr 4, 2002
13,993
208
0
111
www.rockysbar.com
Thanks for info...How does one go about determining the amount of watts and batteries that are needed. I have read several posts in other threads and it all seems so subjective and trial & error sort of driven. A couple of weeks ago when I was in Santiago on at least three days the power was off for more than half the day. Is there a chart or rule of thumb sort of guide that can let me figure out what I will need or do I just go in and say give me the biggest you got and the money left over buy all the batteries they have in stock :bandit:.

Reg
For the inverter, it should be approx. double your nominal consumption and a good 20% above your max.
So, for instance, if you measure the total amps with the maximum you might ever have on at one time and you get a reading of 15 amps, then something like a Trace/Xantrex 2.4k would be perfect for the job.
As for how many batteries, you can start with 4 and see if it does the job.
If you're running out of power, then buy more.
As long as all the batteries are within a few months of each other in newness, you'll be OK.
 

karlheinz

New member
Oct 2, 2006
451
4
0
determining power use

Batteries are rated for amphre hours, i.e., the number of hours of cold cranking time. A car battery for example would be about 60 amp hrs, a scrubber battery or golf cart battery (deep cycle) is normally in the 105 amp range.

Lots of people on long range sailboats use deep cycle batteries to power their entire electrical system via inverters, most use large industrial equipment batteries like those for golf carts, floor scrubbers, etc. They withstand the constant charge and discharge cycles better than a standard car battery. in the US they costs about 75-100$ each but put four in series you get some 400 amp hours of use, 8 = 800 amp hours.

A car type battery will not withstand the deep discharges and will eventually stop taking or holding a charge. Meaning you can power up a battery charger to max amps and zap a "bad" battery for hours and find the battery wont accept or hold the charge.

SO, what does all this mean in regarding to power use on the inverter?
Read below:


Now, each electrical device plate usually shows watts/ hr used, i.e. the 100 watt light bulb or the 600 watt (color tv).

Battery power is stored in units of current = AMPS

Current (amps) = watts / volts

a 100 watt light bulb on 110v power is 100 W / 110 V = 0.90 amp/hr used
a 100 watt light bulb on 12v power is 100 W / 12 V = 8.33 amp/hr used

So, from this you can see two things. It takes a lot more current / ampherage to power 100 watts via a 12 volt circuit (your inverter system) than it does a 110 volt circuit (wall power).

So, when your devices are powered by the inverter at 12volts you are using at least 8 times more power (amps) than when your using the same device via 110volts. And subsequently it will take longer to recharge those lost amps when the power comes back on.

So, using the above formula you can check each device plugged into your inverter to determine the minimun amps draw on the inverter.

A TV, two - three 100 watt bulbs, a fan going - would probably range somewhere in the 1000-1200 watt / hour range i would guess.
Therefore, 1000 watts / 12 volts = 83 amp hours.

Your battery bank is probably in the range of 400 amp hours if your lucky. So it would take only 4.8 hours to totally drain your batteries to a less than readable voltage.

The moral of the story - if your on your inverter and you have essentialls like lights and fans, etc...turn off the high wattage stuff like TV's, DVD's, Refrigerators especially, A/C's.

Good luck, things I learned while living on a sailboat and using everything on 12volt system. Of course I could recharge my system with wind and solar power every day.

Karlheinz
 

megabiteme

[ - Mute Button -] Click!
Jan 9, 2008
123
0
0
me too

Can anyone tell me if I am having problems with my batteries. I have noticed the last couple of days when the electricy went off for a half hour, it took my batteries over three hours to fully charge back up. I have a 2400 Watt inverter and i have 8 batteries. I always keep an eye on the operation of the inverter, but this just does not seem right. Although, lately my electricity has been real weak. It has also warmed up quite a bit. Do these things have anything to do wiith my situation. Could I have a bad batttery. Any help would be appreciated.

Crane

I found out the hard way after we lost our eletric and our inversol did not kick in. It was low on water, so make sure to check it from time to time if you have this kind of batteries. Also make sure that you buy distilled water or the so called battery water that cost more, but is really distilled water. I hope this helps. good luck! Anthony