Hi all, I've been looking at battery pages for quite some time now and thought I'd share what I've found so far. Some it is heavy duty reading, and there are a *lot* of pages. http://evbatterymonitoring.com/ http://www.batteryuniversity.com/index.htm http://www.smartgauge.co.uk/technical1.html http://www.smartgauge.co.uk/technical2.html http://www.powerstream.com/1922-FLA.htm The last item is somewhat dated--but a fascinating read all the same--with lots of good information and some super pictures.
QUOTE(pianotuna @ Nov 5 2009, 01:52 PM) [snapback]19907[/snapback] Hi all, I've been looking at battery pages for quite some time now and thought I'd share what I've found so far. Some it is heavy duty reading, and there are a *lot* of pages. http://evbatterymonitoring.com/ http://www.batteryuniversity.com/index.htm http://www.smartgauge.co.uk/technical1.html http://www.smartgauge.co.uk/technical2.html http://www.powerstream.com/1922-FLA.htm The last item is somewhat dated--but a fascinating read all the same--with lots of good information and some super pictures. Can you recommend if any of these are of the "Batteries for Dummies" level? I need something that is no higher than unskilled layman level.
If you wanted to buy some group 27 size AGM batteries with as much amp hours as you could get, what brand would youuse? As usual price and value are considerations.
Hi abbygolden, I guess it depends on how carefully you wish to read. The battery university is very comprehensive so I might start there. The smartgauge site is a "fun read" (because he has an interesting sense of humor) and has a wealth of information. QUOTE(abbygolden @ Nov 5 2009, 07:23 PM) [snapback]19910[/snapback] Can you recommend if any of these are of the "Batteries for Dummies" level? I need something that is no higher than unskilled layman level.
Hi Lindsay, There are only two major manufacturers of lead acid batteries left. Johnson Controls, and Exide. I'm not really a fan of AGM batteries as they cost a lot more per amp-hour than standard flooded units. If I were going to buy AGM format, I'd look for six two volt cells and wire them in series. AGM batteries have no way to replace lost electrolyte. Therefore they may *not* be equalized. Even the most conservative information suggests that equalization is a necessary feature and must be done at least twice per year. (some sources suggest once a week!) If they *must* be group 27, and *must* be AGM, I'd simply phone/email until I found the best price per amp-hour, so long as total amp-hours are the same. I would favor 12 volt units because of their ability to produce higher amperage for use with an inverter. It is far cheaper to equip regular flooded batteries with a "filler" system than to buy AGM batteries. QUOTE(Lindsay Richards @ Nov 5 2009, 08:54 PM) [snapback]19913[/snapback] If you wanted to buy some group 27 size AGM batteries with as much amp hours as you could get, what brand would youuse? As usual price and value are considerations.
I am going with the AGM batteries for the ease of use. I have 27's now and wanted to use the biggest that would fit. I have 3 gel batteries now that are about 3 1/2 years old and are not holding a charge as well as they should. We are going on a long trip in April and I plan on replacing them before then. Thanks for your help.
Lindsay, If it will fit the AGM GPL-8DL 12 volt will do the job. Weight is 162 lbs each. Discharge rate is 475 minutes at 25 amps. We use two for the house batteries and find they work great plus no water or care needed. Only downside is high cost. We can run everything in motorhome two days before we need to recharge. We had 8D Gel cells before the AGM set. AGM's are hard to damage.
I would love to have them, but I have an Itasca with the battery compartment under the stairs and they would not fit. I already measured before. I could put them in a nearby compartment, but I don't think I could stand to lose the space. (My wife's rock collection you know.).I am going to have to stick to group 27's. My line to my wife is that these will last twice as long, so we can pay twice as much and she seems to have bought into it. They are not in the Wally world online info, but I didn't think they would be. Have to go to the store. Has anybody ever had batteries shipped to your home?
Hi Lindsay, I'll bet one reason for your early failure on the current battery bank is improper balancing of the wiring. For three 12 volt batteries *only* method three works correctly. correctly interconnecting multiple batteries How do I know? I wrote the owner of Smartgauge and he was kind enough to reply! QUOTE(Lindsay Richards @ Nov 6 2009, 07:46 AM) [snapback]19921[/snapback] I am going with the AGM batteries for the ease of use. I have 27's now and wanted to use the biggest that would fit. I have 3 gel batteries now that are about 3 1/2 years old and are not holding a charge as well as they should. We are going on a long trip in April and I plan on replacing them before then. Thanks for your help.
I typed 3 batteries, but I only have 2 gel type house batteries and 1 engine battery. all under the stairs as typical Winny style. The engine battery of course is seperate and hooked up only to the engine. The 2 gel batteries appear to have equal length wires. Sorry for the confusing typo. Do you consider 3 1/2 years, 26,000 miles, and about 300 nights (about half boondocking), as a premature battery failure? This is my first experience with gel type. If you think it is premature failure, please don't tell my wife.
Hi Lindsay, Gel or AGM? If Gel I think they have done quite well. If AGM I think it is a little premature. My previous 12 volt walmart wonders have lasted seven years, 360 cycles (as low as 10.5 on more than one occasion) and are still serving the new owner of the RV. They were flooded cells maintained by a 30 watt solar system--and watered once per year. They were wired in method #2, not by knowledge but by accident. Method #2 would be correct for a 12 volt pair, or Method #3. QUOTE(Lindsay Richards @ Nov 7 2009, 06:03 PM) [snapback]19942[/snapback] I typed 3 batteries, but I only have 2 gel type house batteries and 1 engine battery. all under the stairs as typical Winny style. The engine battery of course is seperate and hooked up only to the engine. The 2 gel batteries appear to have equal length wires. Sorry for the confusing typo. Do you consider 3 1/2 years, 26,000 miles, and about 300 nights (about half boondocking), as a premature battery failure? This is my first experience with gel type. If you think it is premature failure, please don't tell my wife.
My existing two coach batteries are gel. When we bought our first coach (97 Rexhall). It came with one dead 12 volt. I replaced with the two gel batteries and then put them into my current coach (2004 Itasca). I have read so many good things about AGM and we tend to boondock so much, they seemed like a good choice. If you figure how much usage you get, it works out to only a dollar or two per night on the gel and I think I can get a lots more on the AGM. Save a lot of campground money also. The gels are not doing as well as before and we have a 3 month trip coming up in April, so I plan on replacing them before then. Only shorter trips between now and then.
Lindsay, I spent 40 plus years working with big batteries in telephone offices around the USA. Our 48 volt systems had batteries that each one had a weight of 2200 lbs and put out 2.20 volts at 2000 amps and we used 23 batteries to get 50.6 volts. Over the years we change flood cells over to Gel that had a weight of 350 lbs each with number of banks to make up the number of amps we needed. You may have killed your Gel battery by now due to wrong voltage level. You need a three stage charger that can keep voltage at 14.0 to 14.2 and no less. Most charges only are single stage set at 13.1 to 13.9 tops. Also charger needs a setting for warm or cold weather. The AGM battery will use the same charge level as a flood cell 13.1 to 13.9. You will never dry one out, it will die from sulfate damage first. No need to equalize an AGM battery. Life on Gel batteries we have use in MH is around five years. Only problem is high cost and high current that will pull the acid off the plates and this will damage the cells. AGM's do not have this problem and will take more damage to kill it. The AGM's in MH now are couple years old and you do not know they are in place, no problems. I was called on by GTE in AL to come up and see what was wrong with telephone office power plant. Found maintenance people had reset the voltage level to wrong levels. We had the correct level at time of service. It was off by .2 of a volt per cell and this killed 46 batteries (two racks) in two years. The cost to replace was in the $100,000 range, GTE was sick. All the cells went to the junk yard. It pays to get it right.
Pianotuna: I went to our Super Wal-Mart and could find nothing about AGM batteries. The staff was no help. It did no have an automotive center. What should I be looking for?
Hi Lindsay, Maintenance Free Batteries. (i.e. no filler caps) QUOTE(Lindsay Richards @ Nov 11 2009, 12:53 PM) [snapback]19984[/snapback] Pianotuna: I went to our Super Wal-Mart and could find nothing about AGM batteries. The staff was no help. It did no have an automotive center. What should I be looking for?
So if they have no battery fillers, they are AGM? I am down at my daughters and they have a automotive center at their Wal-Mart. Thanks a lot.
Hi Lindsay, Probably. I'd definitely ask that question. QUOTE(Lindsay Richards @ Nov 11 2009, 08:26 PM) [snapback]19991[/snapback] So if they have no battery fillers, they are AGM? I am down at my daughters and they have a automotive center at their Wal-Mart. Thanks a lot.
Don and Lindsay, Some mix up here on AGM and filler caps. If battery has a filler cap it is a flood cell. You will not have a filler cap on AGM or Gel battey, no need for it. Only a valve vent. You will not find an AGM or Gel at Wal-Mart. Only place to find them is a battery supply house or on line. Due to the weight shipping is not a good plan.
Hi John, Eight years ago I did purchase maintenance free starter batteries at Walmart Miles City Montana. I do not know the battery technology for sure--and my old RV is a bit of a hike from here so I'll not be able to check that out for some time. Walmart keeps changing things too! So it may be that they do not sell deep cycle maintenance free batteries. Or AGM either. QUOTE(John Blue @ Nov 17 2009, 08:39 AM) [snapback]20027[/snapback] Don and Lindsay, Some mix up here on AGM and filler caps. If battery has a filler cap it is a flood cell. You will not have a filler cap on AGM or Gel battey, no need for it. Only a valve vent. You will not find an AGM or Gel at Wal-Mart. Only place to find them is a battery supply house or on line. Due to the weight shipping is not a good plan.
I went to Wal-Mart and looked. They sell deepcycle maintance free, but they are wide plate and not AGM. They are made by Johnson Controls and are about $85 for a group 29. They say for marine and RV use. They have sealed tops. I talked to the folks there, but they knew much less than I did and I suspect that will be just about everywhere. I did a search on Johnson' Control, but could not trace any AGM to Wal-Mart. I did see where several online ompanies will ship them Fed-X ground for about $10. I will be doing something before my 3 month trip starting in April.
