| Author |
Message |
jaredbrandt (Jared) (206.40.45.161)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 02, 2004 - 7:28 pm: | |
Hello all.
In the RTS(II) rigs, does anyone have detailed info on the type and design of the 24V voltage regulator/charger?
In particular, I need to know if the charger is a 2 or 3 stage charger, and what the bulk, float, and acceptance voltages are.
thanks again
-jared 1988 RTSII |
Marc Bourget (209.142.38.81)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 02, 2004 - 9:24 pm: | |
I wasn't aware that ANY bus charger was equipped with a 3 stage regulator.
If anyone else responds, please add your thoughts about ANY bus that was so equipped, esp a MCI-9.
Thanks
Marc Bourget |
jaredbrandt (Jared) (206.40.45.146)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 02, 2004 - 9:59 pm: | |
I am assuming it must have some multi-stage charger. These buses use sealed lead acid batteries and are sensitive to overcharging, as are all sealed batteries. This is due to the fact that batteries will outgas hydrogen and sulfuric acid fumes and water while cycling. In the case of sealed batteries they will contain and reclaim MOST of the gas, but not necessarily all. If the batteries are overcharged enough, this outgassing will rapidly cause the electrolyte levels to fall below the plates and the battery will fail.
Since the RTS was so well designed and built(like a tank), I am assuming that it must have a decent 2 stage charge controller at least.
Also, the electrical schematics for my RTS reference a 12/24V charger.
-j |
James Maxwell (Jmaxwell) (66.81.214.133)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 02, 2004 - 11:36 pm: | |
Jared: True sealed batteries do not have an electrolyte level, as such. They have either a gel electrolyte or in the case of AGM's, contained electrolyte suspended in a special glass matt. Therefore, the electrolyte level cannot fall below the plates. There is a huge diff. between maintenance free flooded cells and these 2 types.
I have to admit that I'm not totally familiar with newer RTS's, but I know the older ones had flooded cells. The VR was a Delco and regulated voltage only, the alternator being self regulating as to amperage. It has one set point only and is not 2 or 3 stage. |
jaredbrandt (Jared) (206.40.45.204)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 5:56 pm: | |
Hello James:
Do you happen to know what this voltage point is?
My guess is a bit lower than 26.6 volts(for a 24v system), which is a standard float voltage for lead acids, and would not cause excessive water/gas losses in sealed batteries.
For the purposes of simplicity I did not go into the gel or glass matt nature of AGM's. You are correct in thier construction. BUT, they most definitely outgas when overcharged, and since you cannot add electrolye or water they will self destruct due to plate exposure.
Check with AGM manufacturers and their specifications. AGM's are very touchy to overcharge and must be used with 3 stage controllers with the bulk, float, and acceptance ranges tightly programmed into the controller.
Here is an excerpt from the BackWoodsSolar Company's webpage. They have been putting PV systems together since the 1970's
-j
SEALED BATTERIES Gel or AGM (absorbed glass mat) types damage easily from overcharge, and so should be used with a 3 stage charge control. Sealed batteries can be excellent deep cycle alternative energy batteries, cleaner and safer, but only if charging is precisely controlled. Since water cannot be replaced and hydrometer testing is not possible, they are considered special purpose batteries. |
James Maxwell (Jmaxwell) (66.81.32.182)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 7:59 pm: | |
I use AGM's and have studied the specs from 3 different manufacturers extensively. They and Trace primarily caution against equalization, and the set points of bulk, absorb, and float are very close to that of flooded cell, within .1-.2 volts. My MK (Deka) have recommendations of 14.2 max bulk never to exceed 14.8 and float at 13.2-13.4. True, they are damaged by excessive voltage for any extended time, but the construction and pressure regulating valve release generally prevents depletion of the electrolyte. The damage seems to come in the form of warped plates due to excessive heat build up with excessive voltage. In fact, one of the key features of AGM, if done at the proper voltage, it is nearly impossible to overcharge them, as they will accept charge at rates unheard of for the other types. |
TIM HOSKINSON (216.96.110.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 9:13 pm: | |
James is correct plate warpage due to heat is the most comon demise of the gel filled bat. I worked for 18 years in the elecronic mantenace shop of a hospital. We used gel cel batteries in everything from emergency lights to hart monitors and I seen first hand this type of failure. |
jaredbrandt (Jared) (206.40.45.140)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 04, 2004 - 10:03 am: | |
Well, that is interesting. It would be nice to know I am wrong because I am considering using some AGM's but have been concerned due to the overcharging issue. This is why I am wanting to know about the voltage points of the RTS regulator/charging system. If they are set too high they can damage the AGM's I am thinking about installing---assuming my information about overcharging is correct.
Apparantly there is a bit of confusion in the industry in this arena.
More research is indicated here.
-j |
James Maxwell (Jmaxwell) (66.81.53.81)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 04, 2004 - 11:36 am: | |
Jared: I'm not trying to imply or saying that u are wrong. I agree that there is a precautionary note with AGM's and that note as I understand it is to avoid excessive voltage--anything approaching 15 volts or greater.
If ure bus is equipped with the Delco (I don't recall the # of it or commonly referred to nomenclature of it) then it has an adjustable set point with the installed potentiometer. 2-3 yrs. ago I had to replace the pot on the Delco in my Grumman (available from DigiKey) and recently installed a new one in the Neoplan, which I adjusted to 28.2 volts for a 24v system. The vr on the Grumman is the standard black box unit that seems to be the most common in most of our buses, however, Delco now produces a replacement that is much more compact (and non-serviceable). However, even it is not 3 stage, but single set point, voltage regulating only w/adjustable set point.
My Neoplan (and the Grumman) basically has 3 different charging systems: the Delco alternator, the Trace SW, and solar(Trace C40 Controller). I have attempted to set the max charging voltage of all at the 28.2v point and in the case of the Trace equipment, 26.7-26.8v float and have eliminated Equalization of both. I also set the max.charge rate on the SW to approx. 40% of batt. bank capacity, up from the 20% I used on the Grumman.
However, admittedly, my expertise on batteries appears to be primarily on the current price, since I probably buy more of them than most (just ask anyone that knows me)! |
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