Battery Bank and Inverter

[cold comfort farm]

Hi all
I am currently trying to get a feel for how big my battery bank needs to be so I bought an electrisave to monitor all my consumption.
During the day I use about 400w/ h = 1.6A on 240V

This is my typical usage during a 24 hour period.
Please assume that high loads such as kettle etc will not be on this circuit. The kitchen is split out separate to the rest of the house.
 
So if we say I draw 3 amps per hour over 4 hours and then 2amps for the remaining 20 hours
= 12amps + 40amps = 52amp hours per day.
 
Assume a 900 amp hour batt bank and assuming we don’t discharge lower than 300 amps = 600 amps usable. At 48V or 24V. I am converting to 240V.

Any one any idea on run times of a Lister, Max amount of charge I can put in the batteries for min run time and how long the batteries will last. And finally is this good or bad usage.

Regards
Stephen
 

[rmchambers]

What kind of inverter do you have? or are planning to get?  I know that on my Trace I can set the charge rate and the battery capacity and depending on how those are set the inverter will slam the battery bank with as much power as they can take and then back off when they start slowing down on the charge.  I do know that on the highest charge setting it will blow the breaker the unit was attached to (I wasn't on a 60 amp breaker, didn't have the wiring for it) so I ramped the charge rate well down to stay in the breaker's capacity.

So, answer 1 - Depending on your inverters charger and your supply of electricity to do the charging will determine how long of a runtime you need to recharge your bank.  Might want to think about putting some solar in the mix too, after the initial installation the sun is free.

Drawing 3 amps at 240v is 30 amps at 24v.  Using your 52 AH/day would be 520AH/day @ 24v so you'd be putting a pretty decent drawdown on your battery bank that you list.  What to do?

Increase the battery bank capacity, reduce the load on it, consider running the Listeroid/gen during your periods of heavier use and let the gen power the loads directly and whatever is left over charge the battery bank, add some solar into the mix to supplement the battery bank during sunny days.

The nice thing about battery banks is that you can always add capacity to them given money/time/space.  Start out with what you're proposing and add to them down the road if you want more runtime.

Robert

[Stan]

Stephen...Robert's advice on adding solar is good.  I run straight solar but I know that the charging cycle on my bank shows a large draw initially, then after that the demand goes way down to a relative trickle which takes the most time for top off.  you could run a gen set initially to cover the large amount of initial draw, then arrange for solar to do the later, smaller, longer term draw.  Running a diesel like a lister with a small load is wastefull and not too good for the diesel.
Stan

[peterako]

Do not under design the battery bank try to setup to run min. 3 days on a battery bank or best 5. yes i know the cost is high specialy if you use 2V batterys. But on this way your gen is not running every day and by using a bigger inverter you can still use your kitchen equipment.

And on this way there is no need to go outside to start the gen by very bad wheather or when you are sick ( i dit it and a easy task is a very difficult one when you are sick )

Also think about wind power if you are on a good location a 1000W or 3000W set will replace a gen set for cheap energie a and the bad wheather part is also wind.

a good setup is expensive but runs for years with minimum cost.
My setup 5000 AH 48V ( 24 * 2V ) a 8KW inverter Piek 16KW plus wind generator and lister is running my complete house ( i am cooking on gas and i am not using aircon.).
It wash costing around 10000 euros but the live time for the battery is above 20 years.

[haganes]

my view of this subject comes from the marine environment where generator run times are minimized for both cost and noise issues.

depending on your battery type, topping up is a long process, and few actually achieve 100%.  also as the batteries age (battery life is effected by depth of the cycle), you again are not able to have a 100% charge.

a good primer on this subject is on the following link: http://www.glacierbay.com/1batcrg.asp

regards,
captain steven

[mobile_bob]

Captain Steve:

thank you for posting that link!

i have supported what is in their recommendation for years.

anyone contemplating the use of batteries would do well to read and understand
what is written there.

good job
great info

bob g

[peterako]

Thanks for the like.
But it is only a part of the story, this is not a battery manufactor

My reference is to 2V batterys in a Glass box used by power switch stations and sub marines.
Special on obard of a submarine replacement is a problem and there use is every day.
All these batterys are tubler and not plates it is even possible to take them out to clean. but that is a extrem normal it only need twice a year filling up water.

Greetings from Greece.

[haganes]

peterako,

could you point me in a direction to find these 2 volt batteries?  in a quick internet search, i found several people looking for them but no one who had them.

regards,
captain steven

[Stan]

Take a look here.  These are the ones I got at their 10 yr age, rotated out of service by our local telephone company as mandated by law, not because of the condition of the batteries (which was mint)
http://www.cdstandbypower.com/product/battery/flooded/xt_12_1001.html

Stan

[peterako]

If you search in Google using " battery opzs 2v" , you will and up with nice reading information.
Every major battery manufactor is producing flooded tubelar batteries. opzs is the reference for flooded tubelar batterys.

Every solar or wind power company is also aware about manufactors or selling there own brand. this is not a off the self battery but produced on demand

Greetings from Greece

[haganes]

peterako and Stan

thanks for the info.  but i have googled until my fingers were sore to find a technical comparison between this 'tubular' or lead calcium batteries to other types of lead acid, gels, and agm's.

about 15 years ago, i was part of the rush to purchase trojan (golf cart) batteries for 'house' batteries- as the word was that these things out performed all other lead acid batteries.  the problem was that they were slow to charge in comparison to other batteries.  for me, on a sailboat, this was a deadly shortcoming.  I had 4 large solar panels (only good in the middle of the day if the sun was shining), and two wind generators (air marine).  i had a fixed amount of space for batteries 1300ah @ 12v.  10% of the time there as enough wind and solar...........but most of the time the generator had to be run.  instead of the usual 2 hours per day, with trojans i was now up to 5 hours per day.  i had 350 amp hours of battery chargers, but the batteries would not accept a high rate of charge.

needless to say the trojans were tossed after six months - and i turned to maintenance free deep cycle batteries.

on my current ship, generators run 24 hours per day, but i still have house batteries (normal flooded batteries) for various reasons including ups.  i am always interested in something better - but i have learned it must be better for my application.

can you please give me a link to compare these batteries to other types of lead acid, gels, and agm's?

regards from Malaysia,
captain steven

[peterako]

Hi captian steven.

Sorry but i wash not aware that you are on a boat

The problem is the next one the opzs battery are stationary batterys

 my battery has the following dimensions 214*576*830 MM weight 227 KG for every 2v cell
I have 24 battery cells = 5448 KG and filling a big room .

I first placed the batterys on there frame by crane from the delivery truck and then i build the room around it.

I am aware that the batterys are used on board of submarines but also here the batterys are placed before final clossing the rings. adding spare based on failure rate ( military over seized ) but real removal is not possible after clossing.
I worked on the wirring as a student.

Placing this on board of a boat is not easy. if your boat is the size for this weight.
To solve your problem for realy big batterys you must also use a special charger.
In my case it is a computer controled system asking the first 6 to 10 hours the full 3 KW from my generator and later when the charge current drops it is switching on a secondary power line to my house . on this my wash machine is running to keep a load on my lister. i am running my lister ones a week on this way
I have also a wind generator directly putting 48V dc in my battery.

Greetings from Greece

[captfred]

Captain Steven.

More than a few years ago I drove, dove, flew a LG48-250 class Laivateollisuus tourist/survey submersible here on island that operated with four 120 volt banks and three 24 volt banks made up of 2 volt wet cell batteries.  These submersibles demand extreme service from these batteries - high amperage draw for longitudinal, lateral and vertical  thrusters, as well as, HVAC, CO2 scrubbers etc. with rapid, overnight recharge for the next day's operations.  These be some bad arse batteries.

I'm going down on Monday to the sub-base to check into some batteries that have been cycled out of the sub for my own home system, no guarantees but I'll see if they will provide me with supplier information.  (If you were in Phuket  prior to the Tsunami, this is the same company that had the sub there).

Cheers, Fred

[solarphil]

Hi All

If you want to accurately determine the energy used each day you will need to:

1.  Determine the watt.hrs used by each appliance.
2. Divide the watt.hrs of each appliance (If AC) by the power factor
3. total up each appliance watt.hr
4. Divide this figure by the efficiency of the inverter (if producing AC)

    This will give you the total DC energy provided by the battery each day.

5.  To provide this amount through charging, you will then have to divide this figure by the battery efficiency - say 90% (0.9)

So, in summary, there are many areas where energy is lost , (reactance, inverter, battery) and this needs to be made up

Generator charging as already as been mentioned is inefficient for complete battery charging.  Solar and wind are preferable for float and equalisation charging, which is extremely important for extended battery life.

Phil

[haganes]

captfred.......

remember the sub.  i was in patong on tsunami day.  yes, i would like the literature if you can get it.

the idea i am trying to get across here it that the rate of acceptance of charge varies based on the battery type.  it is one thing to discharge a battery (and this is what all the spec are showing), but it is a whole different kettle of fish to recharge the battery.  when you are using a diesel generator for recharge, and you would just as soon turn it off as soon as possible.  a diesel does not like to be lightly loaded.....and this is the primary issue for me.  there are too many cloudy days and too many windless days for solar panels or wind generators.

regards,
captain steven