I was pretty much settled on Universal AGM's until friggin BFL13 bought his new Interstate 6V's. I whipped up a CAD drawing to see if eight of those puppies would fit and they would not. Six, however, DID fit!! I could've sworn I did this already, and could not fit six in there, but they fit with room to spare. Soooo I looked at some Trojan's. Long story short, what do you guys think?
AGM Pros
1. No maintenance.
2. 70% DOD at ~500 cycles.
3. No floating needed.
AGM Cons
1. More expensive.
2. Would have to mount them vertically to fit.
3. Heavy.
LA Pros
1. $200 cheaper.
2. Each battery weighs less than AGM's above. Total is the same.
3. Easier to mount.
4. Six batts = 915Ah
LA Cons
1. Don't know how far I can discharge on regular basis. Trojan says no more than 80% but how many times can you go to say 70%.
2. Maintenance and floating needed.
3. Lower charge rate BUT still over 100A total. Will charge at 60A mostly.
915ah for $1,200 or 800ah for $1,400? Which will let you camp the longest with no gen?
How much farther down in SOC than the Ts will the AGMs have to go to make it a wash?
How much does it hurt the Ts to go below x% SOC compared with the hurt on those particular brand AGMs to do that? Aren't the Ts designed to go low too?
When installed, can you get at the Ts with an hydrometer or do you have to haul them all out? How often will that be necessary for it to matter, if it matters at all?
For that kind of money I would get fewer batteries (but lose some price discount)of either kind and a small gen and recharge while camping as required. Even if you will carry a gen anyway as emergency back-up hoping not to use it, IMO you should still include it's cost in the total picture of costing options for amp hr use by including the option of using the gen.
Wets easier to "recover" to full--not fussy about voltage.
* This post was
edited 02/26/11 07:52am by BFL13 *
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No brainer is right,.....6v interstates LA....7ys old, not 1 bit of noticeable drop in performance yet.
Rich
'01 31 ft Rexall Vision, Generac 5.5k, 9245 conv, 400 watt inv, 2 12v batts, ammeters, KingDome/sat, Two Oly Cat heaters, and towing a '05 Jeep Liberty, or sometimes towing a Lowe bass boat.
First a correction You said AGM and LA (lead Acid) AGM's are LA (lead Acid) The full description is Valve Regulated Lead Acid Absorption Glass Mat. but we use AGM for short.
Second correction: Mouting an AGM on it's side, or even upside down.. Well, the ability to do that is one of the big advantages of AGM.
Finally.. Most folks use 50% DOD as the max.. and Trojan's have been known to last a decade or more.. AGM's not nearly as long.
My recommendations are as follows:
Normally Flooded wet cells are the least expensive, however in some installs access for reasons of maintenance (Cleaning and watering) is a major issue.. If you have problems there, then MAINTENANCE FREE (VRLA but not agm) addresses this issue and is not that much more expensive.. However finding a true deep cycle Maintenance free, though bedoming easier, is still a pain.
If mounting is an issue.. Then AGM is your only choice, it's also the most expensive. at this time
Side note: I suspect new technology in another decade.. but the key words are suspect and decade
Nothin adds excitment like something that is none of your business
Kenwood TS-2000 housed in a 2005 Damon Intruder 377
BFL13 wrote: 915ah for $1,200 or 800ah for $1,400? Which will let you camp the longest with no gen?
How much farther down in SOC than the Ts will the AGMs have to go to make it a wash?
The AGM's have to get down to 60% DOD to just equal 50% on the T's. Both will let me go without a gen for 99% of our camping.
Quote: How much does it hurt the Ts to go below x% SOC compared with the hurt on those particular brand AGMs to do that? Aren't the Ts designed to go low too?
That's the question. Trojan says 80% max but I can't find any graphs on cycles at x% DOD like I can with the Universals. I may have to email them. Getting to the batteries with a hydrometer will not be a problem. I can leave them installed. I don't think I'll need to do that very often so it's probably not as big of a deal as I originally thought.
Going with less batteries in exchange for a generator was considered but Champion genny's are $380. I can get one of those if really needed it without compromising the battery bank. For our camping style which is 3 or 4 days a pop, a genny is not even needed. I can charge at when I get home. I think I could do a week in Yosemite in the summer without one too.
wa8yxm wrote:
Second correction: Mouting an AGM on it's side, or even upside down.. Well, the ability to do that is one of the big advantages of AGM.
Finally.. Most folks use 50% DOD as the max.. and Trojan's have been known to last a decade or more.. AGM's not nearly as long.....
Mounting the AGM's however you want is indeed a benefit but how I want to mount them would require some extra bracing that I don't need to do with the 6V's. Not a big deal but I have to consider that. 50% DOD is my starting point. One thing about AGM's is that you can cycle them pretty deep and still have 100's of cycles of use from them. I am told Trojan's can be done the same way but Universal has a publicly available graph showing you what they're batteries are capable of. Trojan does not. Regardless, both batteries will need to be cycled to lower than 50% on a routine basis and like it. I am expecting 4-5 years of use from either and I think that is quite possible. BTW, the deeper cycles will likely occur in the winter. In the summer, it will typically be around 50%.
Quote: Side note: I suspect new technology in another decade.. but the key words are suspect and decade
It's here but it costs more than AGM's and the supply channel is still kind of iffy IMO. The benefits are there. 1000's of cycles, charging and discharging WELL over the rated capacity with those 1000's of cycles, MUCH lighter and more compact than LA (the TC crowd could actually have a decent amount of storage), maintenance free, and no off gassing period.
I would expect after several days of being below full as they come down with use, that they will sulfate (this point was raised by Mex)so that when finally home for a full recharge, they may not get to full SG. So IMO be prepared to check for that every time and then be able to do something about it, if it happens. Of course doing something requires monitoring progress with that, which means even more hydrometer action.
The same should happen with AGMs? but be trickier to deal with.
smk camps that same way with very deep DOD on his 6s, but has not reported on this sulfation issue, so maybe it is not a problem. ??
* This post was
edited 02/26/11 12:42pm by BFL13 *
I have seen Data sheets on a 100 A/h Universal battery that stated 15 amps was the maximum recharging current, another document that said 40 amps was the max.
Not sure where Trojans are manufactured, or if they are as good as they were in years past, But buying the Universals, you would just be sending more money to China.
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One thing about AGM's is that you can cycle them pretty deep and still have 100's of cycles of use from them. I am told Trojan's can be done the same way but Universal has a publicly available graph showing you what they're batteries are capable of. Trojan does not. Regardless, both batteries will need to be cycled to lower than 50% on a routine basis and like it. I am expecting 4-5 years of use from either and I think that is quite possible. BTW, the deeper cycles will likely occur in the winter. In the summer, it will typically be around 50%.
