| Author |
Message |
Michael Lewis (Puffbus)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 23, 2004 - 9:10 pm: | |
I have local access to several Leibert computer room backup units. Each holds several batteries which I think are 6v deep cycle. Is there any value to these for house batteries? Are any of the other components of value? These units obviously convert DC to AC and I would guess that it must be prety clean power. Do we have any experts?
Michael |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 23, 2004 - 9:59 pm: | |
Hi I have worked with ups systems for some years and in fact have a 75kva unit sitting here in front of me. As far as the ups units them selves being of use as a iverter this would be more trouble than it would be worth. Today inverters can be bought so cheaply that it just is not worth the time and effort to modify a ups. the older units were a six step modified sine wave not to unlike the cheap inverters available on the market. The batteries used are usally a gel filled deep cycle of good quaity. If the batteries are less than three years old and have not been out of service for more than one year you will end up with some good house batteries. Depending on the current capacity rating of each battery you may want to parrallel several together but remember when parallel wiring batteries they should be isolated using diodes from each other for longest life. hope I have been of some help Tim |
Gary McFarland (Gearheadgary)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 23, 2004 - 10:46 pm: | |
Yeah.
What Tim said.
Gary |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 24, 2004 - 9:44 am: | |
How do you use diodes when parallelling batteries, or strings of batteries? How are they wired? Seems like you would have trouble with either the charging circuit or the discharging circuit, depending on where and how the diodes are installed.
BTW, I manufactured and sold UPS systems for many years in sizes ranging from 5 Kva up to 1000 Kva and with literally hundreds of batteries on the larger systems and I never heard of using diode isolaters to isolate strings of batteries.
The batteries are not manufactured by Liebert. Liebert is the UPS manufacturer, and to my knowledge never manufactured batteries. Also, to my knowledge, deep cycle batteries were/are NEVER used to support UPS systems. The batteries are generally float rated and only rated for limited deep cycles.
Richard |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 24, 2004 - 10:46 am: | |
Hi Richard the battery strings on a ups system are normally in series requiring no isolation from each other. Even when strings are paralleled on a ups system the need to isolate is of no concern do to the fact the batteries are constantly under charge from the utility power charcing system. How ever in use for power supply in a rv the batteries will at times sit wired to each other and not under a charge potential and their for will tend to try to share charge. Since this process allows currents to flow even when nothing is being run in the coach the battery life will be shortened. As far as the battery name brand I didn't see where anyone made mention to liebert making the batteries if I somehow implied that I did not mean to . Power battery co. was the name brand used in the units I have worked with. I have used these batteries for dc power for camping many times with very satisfactory results. Wile they are not constructed the same as a typical deep cycle battery they will preform nealy as well for this use and if a person has a sorce for them at a reduced price from the off the shelf deep cycle battery their is nothing wrong with using them. As far as a diode isolation and still be in circut for charging this can be done with diodes and if you wish I can send you a schematic of the circut. Tim |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 24, 2004 - 12:47 pm: | |
Tim, I absolutely agreee with you. I also used Power brand batteries and they are generally limited to a relatively low number of deep discharges (100 or so IIRC). However if you can get them relatively inexpensively, they would be be great.
If you have several batteries in parallel, they will balance out to the lowest voltage of any one battery, but I do not think that will really cause much, if any, harm or detriment to the battery life unless you have a bad cell in one of the batteries. Would the diode isolators prevent this from happening?
Richard |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 24, 2004 - 3:06 pm: | |
Richard the diode isolation would allow one or more batteries to mantain a charge level of their own in the case of one battery having a weak cell it then would not allow that battery to cause the others to seek the weak batteries level. I would assume that in most cases if a person was pursuing ups batteries for this use it is because they have access to them at little or no cost and typically the batteries will be used condition. The isolation is importanted in part due to the piont you have brought up. Used batteries will normally have a range of different cell condition especially if they were removed from different strings or even different machines. Tim |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 24, 2004 - 4:48 pm: | |
I think you may be right. The typical warrenty on Power batteries was five years, but I had a lot of customers that changed them out every three years, to make sure they worked. They actually had to pay to have the batteries returned to an enviromental disposal site. I feel certain they would have been glad to have given these to anybody that wanted them. They should still be good for a couple or more years in house battery service.
Richard |
C Fred
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 24, 2004 - 6:05 pm: | |
I use 4 ups 140 Amp hour batterys that I got from a hospital 5 years ago and they work great. they cost new $340 each. I believe the best type are AGMs cost about the same. But you can't beat free. Fred |