| Author |
Message |
FAST FRED (65.58.189.150)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 22, 2002 - 8:59 am: | |
While there has been very little progress in lead acid batterys in terms of KW stored / per pound , since about 1880 , at last there is a better way to test them.
The folks in the marine industry frequently are presented with trouble shooting problems (dead cells , falure to take a charge , no power ect) and at last here is an easy way to measure the batts.
No longer will we have to recharge ,
load bank test and
check with a hydrometer, looking for a poor cell.
To check the batt in a single test of 5 or 6 seconds the meters can be bought from,
www.midtronics.com
www.newmarmarpower.com
www.octtools.com
or even from www.snapon.com
Unfortunatly the cheapest is about $300, and the best with a printed readout is $1400.
But if your dealer has a unit , it will take the guesswork out of measuring batt cap.
The marine folks will replace a bank when its only 60% of orig cap on deep cycles ,
and at the 80% of cap for Start Batts.
AS some folks have wanted to use scrap golf cart batts as a house bank , at last there is a way to tell the great ones from the junk , in only 6 seconds!
FAST FRED |
jmaxwell (66.42.92.20)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 22, 2002 - 1:36 pm: | |
FF: At the prices your talking it would be cheaper to just go buy a new set of batteries if all your talking about is golf cart type. Granted, larger and more expensive types and configurations may warrant the expense of these testers, but I don't think so for the average golf cart bank or other deep cycle bank used in most of our applications. Weak batteries are a pretty obvious problem and all the testers in the world ain't going to correct it; new batteries will. |
FAST FRED (63.208.86.97)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 22, 2002 - 1:49 pm: | |
The problem with a large bank , is not weak batts , its which batts are weak?
At least knowing such a measuring systems exist can allow someone to call the various Bat dealers , and have confidence that its not just R&R for the sake of a sale.
FAST FRED |
Driving Miss Lazy (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 22, 2002 - 8:45 pm: | |
For months I have been telling you about the electronic battery tester that NAPA sells for about $100. It works great. A couple of weeks ago I used it to find one weak battery out of a bank of four D-8's. It would have been almost impossible to find it without the tester.
Richard |
jmaxwell (66.42.92.17)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 22, 2002 - 9:04 pm: | |
From all that I've read and all that I am told, it seems conventional wisdom is to replace a bank if it has a weak batt in it. Reasoning seems to be that the new 1 will be drawn down by all the older ones. I tend to agree w/ that when it comes to a well used bank but am not decided when it involves a fairly new set. Is the conventional wisdom just a sales pitch? Certainly, a tester for $100 might well be worth it, but I have to question the investment when u get into multiples of $100. |
Driving Miss Lazy (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 23, 2002 - 9:00 am: | |
No, you do not really need to replace all batteries when one fails, depending on circumstances, based on the following.
My experience has been primarily in large UPS systems (no, not the delivery service) used to support the large computer complexes. These systems are many times in the hundreds of KW for several minutes, up to possibly an hour to keep the computer system up. These banks of battery jars are many times 2 volt cells connected together to form an overall battery with a total DC voltage of anywhere from 300 Volts DC, up to 600 Volts DC. Some of the 2-volt cells may be as large as a 12 volt 8-D battery. In addition to the 2-volt cells, many jars contain several cells to form a 6 volt and 12 volt battery. It would require about 300 of these 2-volt jars to form a 600-volt bank and there may be three or four banks in parallel for a total of 900-1200 individual jars. (One cell per jar). Complete large rooms full of batteries stacked four high are not uncommon. Hundreds of thousands of dollars go into putting together one of these battery systems. The largest system I personally installed was for a one megawatt (one million watts) for a 15 minute back up time. That was a lot of batteries!
As you can readily tell, it would not be practible to replace all the jars if there is a failure in one cell and it is extremely important to try and determine exactly which cell is defective.
You are correct that one bad cell can pull down the whole string of cells over a period of time. This is the reason that it is important to have a good reliable tester to test the individual jars which can consist of anywhere from one to six cells. The cells will balance out to the level of the lowest cell, so it is not necessary or desirable to replace a whole set of batteries because one fails, unless the whole system is getting old. If my house batteries were five years old and I had a failure in one, then common sense would tell me to replace the whole system as the probability of the others failing in the near future is very high.
I have used the tester available from NAPA and other sources for years (no FF, it is not a new development) for testing thousands of individual 12-volt batteries and I have found it to be 100% reliable. If it says a battery is bad, it is bad and you had better replace it. I think it is the best $100 a person can invest in testing equipment, and I do not know of a single person that has never had battery problems and been unsure as to whether it was a bad battery or some other reason causing the problem. I always know if I have a bad battery in a matter of seconds!
Richard |
Bus Jock (198.81.17.184)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 23, 2002 - 10:09 am: | |
Richard,
Can you tell us how this tester works? Seems I would want to measure the impedance of the cell. Perhaps under load?
Jock Fugitt |
FAST FRED (65.59.75.149)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 23, 2002 - 1:56 pm: | |
A complete explanation is on most of the web sites.
Or for a simple explanation Professional Boatbuilder magazine was the source of my info.
Perhaps they have the article on line.
FAST FRED |
Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 23, 2002 - 2:40 pm: | |
Oh heck; years ago when we wanted to capacity check our small (very small) string of ni-cads, all we did was charge them up really really good for a long time.
Then we would let them set for about 3 days to get rid of the surface charge while we sat around drinking beer waiting for this to happen.
Then we took a hunk of 18 gage wire about 26 feet long or soooss (I forget the exact length) and direct shorted the cell from post to post.
While taking voltage readings with our beat up but unkillable Fluke mulitmeter every 30 minutes and then kept on doing this for about 8 hours or.
Until the cells got below 1.00 volts each. Then we figured out the amp hour capacity per cell in this fashion and did all the other cells the same way.
Which took all day and a bunch of 16 gage wire and a whole lot more beer, but it was fun and cheap (except the beer) and accurate. Sometimes.
A weak cell would come back kinda by recharging and discharging several times but not always. Now I hear there is a quicker way to do it? I am sold! Thank you. |
Driving Miss Lazy (66.190.119.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 23, 2002 - 3:43 pm: | |
Jock, I have never found out a detailed explaination of how it works but I suspect it measures the impedance. Many years ago, battery testers actually loaded the cells, but they got very hot after just a few checks. On this electronic device, you can check a hundred batteries and it never gets hot.
Richard |
Jack In KC (24.94.180.233)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 23, 2002 - 6:47 pm: | |
Does anyone have a good source / brand / model for a 24v charger? Thanks |
Stephen Fessenden (Sffess) (65.130.19.16)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 23, 2002 - 9:12 pm: | |
I have looked under the marine adds and under marine chargers on Ebay. I have decided against buying a portable 24 volt charger in favor of putting a permanent 3 stage charger on each system. One is the inverter. I still need to put one on the engine batteries and the generator battery. I found them available for around $100. Some would charge each battery in a 24 volt system separately. The marine chargers are waterproof also.
I guess I am lazy, but I don't find I keep a schedule of puttng the batteries on charge very well so I need a permanent automatic system. |
Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 24, 2002 - 3:12 pm: | |
I also am looking to spec out one or two 24 VDC chargers in the 50 to 60 amp range. Yea, a big bank. Any ideas out there as to how much I will be paying? Thanks in advance. |
FAST FRED (63.208.87.236)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 25, 2002 - 5:59 am: | |
Take a look in the West Marine catalog CA or Defender Industries CT, (free with an 800#)
They will cover most of the good stuff.
You will need a 3 stage if you don't boondock on your batt bank , and a 4 stage (includes an equalization stage) if you do.
If you have big $$$ batts the high end chargers can be adjusted to charge AGM or Flooded , what ever you have.
IF your gona be recharging a BIG bank from a gen set , the very slow going of even a big charger might have you consider a big (150A )alternator and 4 stage regulator.WITH temp sensing!
ON a BIG batt set this can reduce the charge time by 3/4.
You need about 20% of the total battery sets deep cycle rating to charge as fast as possable.
FAST FRED |
Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 30, 2002 - 8:17 pm: | |
Thank you Fred. I sent off for the West Marine catalog, but never got it, ssooooo I requested it again and should be getting it in a couple weeks or so.
Reason for the twin chargers may be that right now it looks like the batt bank will be a split system. Engineering constraints. Weights and balances.
Still have to figure if long runs of 0000 cable will work also instead of two chargers and if that would be cheaper if not better. Thus right now the 24 VDC scheme. Thanks again. |