Im lucky with batteries

[bobanne]

Hi all

ive just been offered a couple of near new forklift truck batteries, one of which i am fairly certain of grabbing. The first battery is a 24 volt model and weighs about half a ton and he wants $500 au for it, the other is a 72 volt battery but im not sure i can use it on my the 24 volt system i am building up. I will be seeing them on thursday, the bloke that has them owns a forklift breaker yard and said the new batteries were too much for the old forklifts to handle any more. I sure would like to be able to use that 72 volter!!!!

[richhagen]

Hopefully they are 2V cells strung together that you can rewire.  I'll keep my fingers crossed for you.  Rich

[wpowokal]

new batteries were too much for the old forklifts to handle any more.?

That statement would worry me, how so is it too much, I wonder?

Bob it seems you are building up quite a bank of batteries, in ways this is good in ways not.

One thing to remember, that for longivity, it is not good to discharge lead acid batteries too much. Also it is not good to not discharge them enough, or I prefer the term exercise.

Bit of a double edged sword but there is realy such a thing as the correct size battery bank. Oh which usually means a compromise on sometimes running a back up supply.

After 3 years of using a 5200A/h bank I have been there done that.

regards Allan down under (or over west for you ppl)

[antw]

Have you had problems with your large battery bank not getting enough exercise?  If so, what problems?

I ask this because I have a 1300AH bank which we are only using on the weekends until we finish building the house and can move in (six months and counting).  The bank is lucky to discharge five percent over the weekend.

Regards

Antony

[wpowokal]

Anthony,

        What I have noticed is an improvement in capacity when they are given a good work out occasionally.

I first noticed this when I decided to do a capacity test on One of my 8 banks. After the test and recharge I noticed all of these batteries had somewhat better specific gravity readings.

For the whole bank generally I have had time when relos have stayed with a young baby and run a oil  colum heater o/n so total days consumption was around 20Kw.

Obviously this has to be replaced but overall battery voltage o/n (without this load) is higher.

Also I now run a coolroom off Re in summer with similar consumption and the batteries love it.

Battery chemistry is complex, and full of compromises, with a few hard and fast rules.

Lead acid batteries can sulfate up if left static for months. That said I have some batteries that were "spares" that is charged and placed to one side with no further action and they are just fine.

In my opinion provided you use yours every so often, say monthly they should be OK. Oh and there is no substitute for a high quality hydrometer, specific gravity comparison between like batteries is a good indicator.

Its a big subject with a lot of miss-understanding, with much personal preferences, but enough for now.

allan down under

[steak2k1]

Well a hello to Allan down under from steak2k1 on up near the top..Alberta - mate.

Some real good info.  I have 2 Trojan T105 6V in series for my Tent Trailer.  Many times I have not really used the batts too much and am thinking that from your suggestion, they need a good run...well we shall see.  Gonna go on long camping 2 week trip.  (only have a 40w panel - home built to charge with), and am running one of those extra "CoolMate 12V powered fridge/coolers".  I am hoping that will be enough of a load to exercise these batts...as well as a couple of 12v lights that likely don't take much wattage. Cooler takes (assuming that it's 120-12V converter which tells me output is 12V @ 5 amp) about 3-4.5 amp 12-13V.  Will run the batts only at night obviously and will check charge in Am to see usage.

thanx...ya got some good exp and nice to see it expressed in lay terms that a electrical newb can figure.

Long term plan is to add solar hot water to home and maybe an off-grid system to supplement grid supply. Energy is goona start to climb outa sight once the world reaches "peak Oil" (demand exceeds supply), 2007-2008 me thinks.  And then all hell is gonna break loose...even here in Alberta with all of our Oil Sands...by then "locally" owned by the Chinese.! Learning and gettin ready.

rgds,

stk