| Author | Message | ||
| Sean Welsh (Sean)
Rating: |
Well, after 20 months on the road full-time, we have used up our battery bank, and I find myself in the market for eight size 8D AGM batteries. Right now I am looking at Lifeline versus Trojan brands, and there is a big delta in pricing (Trojans are about 25% less than Lifelines). I've read all the marketing hype, and even the so-called expert opinions on some of the solar web sites (many of whom have an axe to grind). What I am looking for now is real-world feedback. Do you have AGM batteries (of any brand)? If so, please share any experience or insight you may have with the brand you chose -- availability, service/support, charge rates, discharge rates, actual capacity vs. advertised, etc. Please note: My application requires AGM type batteries, and it also requires the 8D size, so I am not seeking opinions on AGM vs. flooded cells vs. gelled electrolyte. Please keep it to AGM experience only. I'll start the thread off with my own experience to date: To save a little money up front, we bought eight of the discontinued Xantrex XS12-200 batteries about two years ago, when the coach was being completed. These are 8D, AGM batteries rated at 215 amp-hours (20 hour rate -- the 200 in the model number refers to the less common 10-hour rate). Some of you may remember these units because Dick Wright, among others, was selling them at the time. I think we paid somewhere around $120 apiece for them -- a ralative bargain even considering their "issues." To be more specific: Xantrex had purchased these batteries from an Asian company who manufactured them to Xantrex specs under the Xantrex brand, specifically for inclusion in an ill-fated and now discontinued portable power system. (You may remember it: a plastic box with a built-in set of wheels and handle, much like a rolling suitcase, that had a power cord for charging, and a receptacle on it. Inside was one of these batteries and a small 1KW MSW inverter/charger.) When Xantrex discontinued the portable inverter product, they ended up sitting on a truckload of these batteries, which they then liquidated. The batteries were uncoded (well, at least, there was no code that we could decipher) so it is impossible to tell when they were manufactured, but I would guess that they had been "on the shelf" for a minimum of two years, and maybe closer to three, by the time we installed them. So we have batteries that were cheap units to begin with, which are now approaching (or maybe have even exceeded) five years of age. They have been installed for two years, and for the last 20 months they have been cycled hard and continuously. It's hard to estimate the number of cycles, but I would say a good "equivalent" number is around 300-350 cycles to over 50% DOD. The original ratings on these units were for 450 cycles at 50% DOD, or 220 cycles at 100%. The batteries are done. In the last few months, we have seen the usable capacity of the bank drop dramatically. At the start of service, our nominal 860-AH bank delivered something very close to that number -- I know we once drew 720 amp hours out of it, and it remained above LBCO on both our inverter and our fridge (somewhere around 23.2 volts). At the moment, the best we can get out of them is less than 400 amp-hours, and we have lost both the inverter and fridge to LBCO more than once. A couple of consecutive equalizations will bring the capacity up by 10%-20%, but not for long. All-in-all, not bad for $120 batteries -- we got almost two years of service out of them after they had been sitting all that time, and we worked them pretty hard. Alas, that deal is long gone, and I am now looking at a minimum of $300ea for replacements. I am hoping to get nearly five years of service from my next set. If you have specific experiences to share on the subject, please post! Thanks, -Sean http://OurOdyssey.US | ||
| James Smith (Tomcat)
Rating: N/A |
I used four MK 8D AGM batteries in my conversion. At the time, they cost $303 each, shipped. Much more now. Coupled to a Xantrex RS3000 12v inverter charger with tinned 4/0 welding cable, I have to say I'm very happy with my choices so far. I've been fulltiming since October in Colorado. I don't have all my lighting installed yet, but I can boondock for 48 hours without running my genset. I'm running two big flat screen LCD TVs, satellite DTV system, 2 DVD/VCRs, water pump, demand water heater, laptop computer, 12v bath lighting, and the big draw, an 18cf Frigidaire house refrigerator. If I need my micro/conv oven, I pretty much have to be on shore power or genset if I need more than 20-25 minutes use. It takes the RS3000 about 4 hours to completely run through all three stages of charge when I pull the 8Ds down below 11 volts. There are pics in the link below. Jay 87 SaftLiner http://jsbird69.zoto.com/user/lightbox/CAT.0/date_uploaded-desc/0-90 | ||
| Marc Bourget Rating: N/A |
Sean, You're by far my superior regarding electrical issues, but I insert this comment for other BB purveyors. This very point is a topic of discussion in Dave Smead's two 12V books and his primer (and lots more!). I know by your comments that Mr. Smead puts more emphasis on certain parameters. You might find clarification with his resources. I know he touts 13 years (and continuing) service life (with lead acids) on one of his installations, but your use may have been more constant than what I believe the sailboat he referenced was exposed to. I got the impression from Mr. Smead that the AGM's could tolerate usages that would be considered abuse to lead-acid batts and they can be charged at much higher Amperages (than the 20-25% of total AHs, the lead-acid limit)- with a properly sized DC source and with Temp compensation. For anyone besides Sean, it bears repeating FF's comment that short charging lead acid's leads to short lifespans like that witnessed by Sean with his AGMs. | ||
| niles steckbauer (Niles500)
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Sean - First, to qualify - I am currently using 4D AGM Lifeline's - its seems to be similar enough experience - but you can make that decision When I first bought my bus it had a set of Lifelines that were about 1.5 yrs old - the cases were warped and swollen - can't say what caused it because they were that way when I got them - Having bought in my lifetime numerous batts for vehicles including HOT WHEELS, scooters, motorcycles, all types of Marine craft, on up through HD Trucks - I also, do not believe the battery Hype - When I went to replace them I was seriously considering using the Trojan's - If Lifeline had not made a better offer that's what I would have now - Since I have not actually had to purchase a fresh set of Lifelines I do not know how cheap I could have purchased them - I do know that over a year and a half ago the lowest price I saw (without negotiation and quoting a single batt - not 8) was about $340 each for the Lifelines - To the contrary I did call a half a dozen of the Trojan dealers in the area and got a half a dozen prices - best price quoted was $180 and close enough to pickup (30 miles) - Their quotes varied as to who they thought I was and therefore which column of the price sheet they quoted from (since they're all the same) - The key here is to use a friends business or account w/ a tax# to get the best wholesale price - since we operate a small OD transport Co. and I was buying 8 batts they gave me a fleet price at the dealer w/ the $180 quote - I cannot give you my opinion, long term or heavy use, of my current set - but the cases are a new design and I have not had any experiences similar to the original set or bad experience at all - also relevant is that I use twin Vanner 3600's which have proven to be exceptional inverter/charger's - My next set (barring any warranty claims) will most likely be Trojans - You more than likely can extrapolate the price for 8D's base on the price I was quoted for 4D's - HTH - Niles P.S. - Kudo's for all your hard work with Red Cross - Great Blog - Next time your passing through Tampa please notice me so I can take you all out for dinner if I'm not on the road. | ||
| Jerry Liebler (Jerry_liebler)
Rating: N/A |
Sean, I wonder if they would respond to pulse desulphation. I'm certain that lead sulphate crystal growth is one of the wear out mechanisms but not the only one. The fact that equalizing charges bring back some capacity does point to sulphation. What are you going to do with the replaced batteries? I might like to see if they are restorable. Regards Jerry 4107 1120 | ||
| Sean Welsh (Sean)
Rating: N/A |
Jerry -- One of the thoughts that had occurred to me was to see if you might let me use the rig you made to test your batteries, and possibly the set-up you used for your desulphation. I've got nothing to lose by trying. That being said, if I do just go ahead and replace them, what I do with the take-outs will depend on who sells me the new ones. I'd hope for a credit for the old ones, but, failing that, I will probably sell them on the open market. As far as I'm concerned, you've got first dibs. Marc -- thanks for the pointer. I've read his stuff. As I mentioned, I have no choice but to use AGM's -- the batteries are in the cockpit with us. However, I have been a big fan of AGM's ever since we started using them in the telecom industry, and I would probably have gone that route even if the batteries were in a conventional, vented compartment. The big reason is, as you note, that they can handle deep discharging and high-current bulk charging that would destroy flooded cells. Also, they are much more tolerant of storage. And, if I don't ever have to water another battery for as long as I live, that's fine with me. -Sean http://OurOdyssey.US | ||
| Marc Bourget Rating: N/A |
Niles, Referencing your case distortion, were those batts operated on a charger that did not have temperature compensation as a safety feature? Thanks | ||
| John MC9 Rating: N/A |
Of interest: Battery Manufacturers And Brand Names List Of special interest: Optima SpiralCell Optima for RVs and Marine (Note the 18 month Free Replacement) (Local Interstate dealer quoted just under $200 each for the 31 series) | ||
| Marc Bourget Rating: N/A |
I didn't understand the Optima to be a true deep cycle battery. If so, it lacks the construction characteristics of a true deep-cycle making it more of a hybrid. Sean's typical usage levels, or that of any converted bus in typical "drycamping" use would gobble such up quickly, IMHO. | ||
| John MC9 Rating: N/A |
I asked the Interstate dealer/distributor, what batteries would be best for the "house" battery bank, since I would be draining the living hell out of them. He said the Optima were designed for deep cycling, and rapid charging. The 18 month free replacement is the kicker. If the manufacturer is that sure of their product, it's enough for me. However.... I did buy their standard 950 cca 31 series for the engine. The $200 each for the Optimas was a lil' overkill, just to start the rig. The standard 31s are 1/2 the price, so even without the 18 mo free replacement, they're still cheaper. If I still lived in Massachusetts, I'd have gone with the Optima, since you can freeze 'em and not loose much. He had a spiral wound that had a broken case (accident), and the thing still tested perfect! But yes, according to the manufacturer, they are designed for deep cycling. | ||
| Arnold J Molloy (Ayjay)
Rating: N/A |
Marc: I don't know where you get your information on Optima batteries, probably from the Lifeline web page. I've been using Optima TRUE Deep cycle (yellow top)batteries for over six years Check here: http://www.1st-optima-batteries.com/deep_cycle_battery.asp AyJay | ||
| truthhunter@shaw.ca Rating: N/A |
No experience to share on flat plate AGM or AGM spiral, but I don't understand the justification for the Optima spiral battery. Unless I am reading the data wrong, they are averaging only 350 deep cycles were as I read the claim of Lifeline AGMS at 1,000 deep cycles- have I misinterpreted the manufactures data claims??? Further in my comparisons on the price guesstimates, the spiral plated Optima (group 31=A$300ish for 85 amp hour) seem to be more than twice the price of flat plate AGMs like Lifeline by Concord (8D=$300ish for 225 amp hour). Which translates to well over twice the "amp hour price" for the Optima , justifiable in extreme vibration service like a speed boat or off road vehicle but not in my air ride MC 8. There is little doubt of the extra value of a shorter charge time/higher charge & discharge rates of AGM over flooded lead cell. Have I flubed my interpration of the two manufactures data claims, or am I right on the money with my preliminary cost analysis of amp/hour=/x life cycle cost of approximately 7.246 : 1 ,with Lifelines being the best buy over optima ?$?$?$? in NON extreme-bumpy (average RV) use. Does my bottom line need more data in it's calculation ?$?$?$ I am only hunting for the truth from those that have real experience as I have no experience to promote one style or brand of AGM over the other, so I could very well be totally wrong here in my data claim interpretations an ddo not wish to slander the newer technology of spiral wound or dissmissed the developement cost on a fresher patent! | ||
| John MC9 Rating: N/A |
No AGM experience, but it sounded like too much moolah, to me. The fact they give a 18 month free replacement, regardless of it's use, attracted me to the idea of using one initially, but hell..... Walmart and Sams give a two year replacement guarantee on all their batteries.... I understand some Sams have the 31 series and deep cycle ones.. | ||
| Sean Welsh (Sean)
Rating: N/A |
I don't think very highly of Optima's for this application. The so-called "deep cycle" version is really a marine dual-purpose battery. Like most such batteries, they excel at neither purpose. I will say that, if that's the type of application you have, then Optima's can be a good choice. However, I will spare you all the lengthy mechanical and chemical discourse on why Optima's are the way they are, because it is completely moot in my case: They simply don't make them in 8D, and I can't achieve the storage density I need with the sizes they offer. (Even if I could fit 850 amp-hours, which would require 22 of the largest size they make -- group 31 -- it would be ridiculously expensive, at $4,400. Compare that to $3,200 for the same capacity in Lifeline, or $2,400 in Trojans, and you'd have to get stellar cycle performance from them to justify it. Their specs don't indicate that such stellar performance would be forthcoming.) So, again, I am looking for real experience with AGM batteries (in contrast to sales claims) that are available in size 8D. Whenever I complete my research and make a decision, I will post it here and in my blog. -Sean http://OurOdyssey.us | ||
| John MC9 Rating: N/A |
I felt it would be "storage density", vs "depletion amount", that would be of most concern, since the ability to recover from an over depleted state, that would decide the cost effectiveness... But hell... what do I know? | ||
| niles steckbauer (Niles500)
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Sean - I think you can have the Trojans for $1600 (bank of 8) - let me know - Niles | ||
| Stephen Fessenden (Sffess)
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There are different types of flat plate AGMs too. Some are put together with compression of the mats and plates and are made to last 20 years. But didn't the above testimonials show a failulre of AGMs to live up to their reputation for long life. I got 5 years out of my last set of 8D wet cells. I think I would prefer a forklift battery but I can't fit one in my compartment. They are frequentlly 31" high by 31" wide by 15" deep. Another size was 31" wide by 31" deep by 24" high. Sizes posted for those early in construction so they won't be surprised and unable to use them if they choose. | ||
| truthhunter@shaw.ca Rating: N/A |
With a fork lift battery , my concerns were spreading the excessive weight out across the bay as weight distribution is a very real concern for vehicle handling dynamics as well as frame fatigue and collision safety considerations. 1,000 lbs or so might be better spread out over the width of the bay, but I would fell uneasy loading it on a area of only 961"sq. |
