6V AGM Batteries - Prices too good to be true?

[nixsee]

I've been scouring the internet this evening for deals on 6V AGM batteries and have found the following prices. Some of them seem too good to be true, since top brands like Lifeline and Trojan are similar in price to lesser ones.

Lifeline GPL-4CT - 220AH - $285, free shipping.  http://www.invertersrus.com/gpl-4c.html; $300, free shipping http://www.powerstridebattery.com/golf-cart-batteries/lifeline-gpl-4c-6volt-deep-cycle-agm-battery

Trojan T105-AGM - 217AH - $240 + $20 shipping - http://www.atbatt.com/trojan-reliant-t105-agm-deep-cycle-battery.asp

US Battery USAGM2000 - 210AH $250 + $20 shipping - http://www.atbatt.com/us-battery-usagm2000-6v-agm-deep-cycle-battery.asp

Do these prices/retailers seem legit given that FullRiver are apparently similarly priced (though I can't find any comparable ones online)? If so, which would you recommend? I plan to get two of them (minimal power requirements - laptop, monitor, LED lights,  and the odd slow cooker meal), charged by 200W of solar as well as hook up to the alternator.

Lifeline sounds like the best choice, but I know there's concern about requiring a high amp charge from a high depletion state. However,  I presume the alternator would take care of that (though I don't really plan to ever get below 50%).

Thanks!

 

[SternWake]

The alternator, if well wired, can take the batteries quickly to 80% charged, but that last 20%, takes much longer no matter how powerful the charging source, and AGMs are said to be more finicky regarding reaching full charge regularly.  Are you going to have Solar to take them from 80% to 100%?

I do not know if 6v AGM batteries have the same advantage over their 12v AGM counterparts, whereas there is no doubt the 6v golf cart flooded/wet batteries easily outperform and outlast 12v flooded batteries in the same usage.

So if you only need 200 amp hours of Capacity, you can get two group 31 12v AGM's.  You can't just get one 6v battery, you need two. 

Keep in mind that while AGMS are more expensive, it does not make them a better battery.  They are finicky when mistreated and at twice the price, one should make sure they are not badly mistreated and by mistreated I mean chronically undercharged or cycled at partial states of charge.

Charging gasses can be dealt with.  Flooded 6v golf cart batteries give the best bang for the buck, by far.

Scouring the internet for the best prices seems to imply you are seeking the best bang for the buck.

 

[nixsee]

The most important to me is getting the right equipment/technology for the job. I don't mind spending twice as much if AGM is the right choice. Once that decision is made though, I try to find a good deal on something of good quality (I'm not rich enough to buy cheap things).

I wanted to go with AGM as they will be inside the van under my bed and reasonably close to my stove and thought dealing with gasses would be too difficult. How would you deal with the gasses from flooded batteries in a van conversion? I don't really want to make many modifications to the body. I don't necessarily mind refilling them periodically - its just the gas that I worry about and haven't come across anything easy to do yet. I'm open to any suggestions!

 

[SternWake]

Flooded batteries only offgas when being charged, and at higher states of charge. So At night when you are discharging them, no fumes. When charging, fumes.

Lots of people on the Samba forums, who own VW vanagons, completely dismiss the offgassing, as their batteries are inside the passenger compartment, unvented to the exterior directly.

I'm not saying discount the offgassing factor, just realize it is not always an issue. A sealed battery box with a 3/8" diameter tube leading upto the roof vent is one solution. Others put a Small vent in the wall adjacent to the battery box.

I had unvented batteries inside my cabinet for a few years before moving them under the floor, accessible through a sealed hatch. I only ever smelled them at night when I bought a battery charger and actually had access to grid power to charge them overnight.

Most people new to living on batteries, regularly overdischarge their first set of batteries, and do not fully charge them, sending them to an early grave, so less expensive batteries can be considered the learner set of batteries so you know what you can power and for how long.

Regular full recharges is the recipe for a good battery life, and this is not always easy to do in this lifestyle. Lots of copper between alternator and battery, and solar, are a great combination for getting good service from batteries. The other strategy is using very little electricity in the first place.

I live on 25 to 65 amp hours from near sundown to after sunup, and make sure I can return them plus some more. 20 to 30 of those AH are from laptop use.

 

[GotSmart]

Hold your horses.  

I went to a Battery Outfitters and during the conversation I was offered 2 year old DC224-6 for about $60 each.

I had been looking for about 6 months when I found those.  It pays to make phone calls and deal with professional stores. 

 

[akrvbob]

I've had flooded wet cells in my van homes for over 13 years. I have 4 of them in this van behind the front seats right now. None of them have ever been vented. That has never created any issue for me.

However, if you have asthma or other breathing issues you should buy AGM as flooded can exacerbate your problems.
Bob

 

[nixsee]

Yeah, I have asthma (which is yet another reason why I wanted to go with AGM). Again, extra cost isn't an issue - getting the right technology for my situation is most important.

So, back to my initial question: should I get the Lifelines since they seem to be considered the best and are comparably priced? I'm fairly remote right now so calling around for a deal at shops is somewhat difficult.

I plan to have quality a Trimetric charger and monitor, as well as the alternator, so I should be able to maintain the batteries fairly well.

Thanks!

 

[SternWake]

Trimetric makes a charger? Didn't know that.

Lifelines are top Dog AGM Deep cycle battery with thickest positive plates which is the mark of a good deep cycle battery.

Have you read Mainesail's AGM thread?

He stresses the importance of being able to fully recharge them regularly:

A well wired alternator meets their minimum recharge current, but will not meet their full charge requirement unless driving hundreds of miles.

http://forums.sbo.sailboatowners.com/showthread.php?t=124973

Battery monitors are great tools, but they need to be set up properly, and when wired in a vehicle, requires reworking of the vehicles grounds so that no wires go to the starting battery that do not go through the shunt. If this is not done, the alternator's contribution is not measured accurately, and some loads will not be measured accurately either.

Do some browsing here too:

http://www.pbase.com/mainecruising/boat_projects

There are two good articles about battery monitors, and Mainesail is the ultimate authority online.

 

[akrvbob]

If Lifelines are that picky about how they are charged--and I think they are, I wouldn't even consider them.

I would be inclined to get the Trojan.
Bob

 

[SternWake]

If Lifelines are that picky about how they are charged--and I think they are, I wouldn't even consider them.

I would be inclined to get the Trojan.
Bob

All Agms are picky, they all recommend a minimum current when deeply cycled, 0.2C for full river, lifeline and Trojan. 20 amps per 100 Ah of capacity when deeply cycled.

Odyssey wants 40 amps.

Of course they can be mistreated to some degree, and the shallower the discharge the less necessary the the high amp recharge and the 100% recharge is . 

 Lifeline make the best AGM, and make them in the USA.  What make Lifeline a good value best value is they actually recommend and prescribe a 'conditioning' cycle when capacity loss becomes evident, where none of the others will. This conditioning cycle requires special equipment and the skills to monitor it though.

You want any AGM to last, you treat it as best you can, within reason.

This means high amp recharges when deeply depleted, and 100% recharges as often as possible.

Remember, works 'just fine', simply means it has not failed yet.

Only those with an amp hour counter who take note of morning voltage and see a drop off of voltage in the same AH consumption, know that capacity is decreasing, and can plan accordingly to either recharge better or know to plan for imminent replacement

For everybody else, it is just fine, till the day it is Not.

Knowing what the battery wants, puts that day well off in the distance, instead of a surprise wake up by a low voltage alarm on the inverter, or a warm fridge, and a panic attack when trying to recharge  and the batteries want no part of it.

Flooded batteries do not require the high amp recharges and can handle partial state of charge cycling better, and can do so for half the price.

But even the trusted flooded battery makers recommend 10%, or 10 amps per 100 AH of capacity.  Trojan recommends 10 to 13%, and this is 2 solar watts minimum for every 1Ah of capacity.

Other higher amp sources employed regularly can drop that ratio.  But a Solar only recharge  with a 1 to 1 ratio on AGM's that recommend 20% rate, is asking for premature failure.

So 2 years and perhaps less instead of 4 or 5.  Is that acceptable?

That is upto the user.

I aim to inform people how to get maximum cycle life from their batteries.  They can choose how far to implement 'ideal', but knowing what 'Ideal' is  is the starting point  for those who are researching this, and planning a system.

I wish I had another 75 t0 100 solar watts and could fit a flooded true deep cycle battery, not these hlafass group 24/27/29/31's with deep cycle stickers on them, and I speak of the Trojan, Usbattery and Deka true 12v  flooded deep cycles. The Marine versions are sorry imposters of the hlafass 12vs.  Good luck getting 300 cycles to 50% from those.  You might not even get 300 cycles to 75% State of charge if you can't close in on their recharge parameters.

They do make for good learner batteries though, as premature killing of a pair of 100$ wally world group 29's is not going to hurt as much as killing a pair of 6v lifeline AGMs at ~650$ from improper charging.

While batteries can certainly be manufactured badly, 99% of the time, Batteries are murdered by improper recharging, and too often the murderer points fingers everywhere else.

 

[MikeRuth]

Just a comment on ATBAT.COM. They are a good company in Valencia Ca.

They treated me right and I bought two T-105's FLA and picked them up at there warehouse.

 

[MikeRuth]

Just another observation, T-105's in FLA are $125.00 and the same battery in AGM is $239.00, all I gotta say is WOW! more than double and you do need as mentioned above to take DANG GOOD CARE of them.

 

[nixsee]

Thanks for all of the info!

I read a lot from the links you guys provided and some others and learned quite a lot. I've decided on the Lifelines.

However, I'm now looking more into LiFePO4 batteries... there are some great resources out there and it seems like it is a superior technology in every way, and should be far more cost effective in the long run. I'll provide details of my research and decisions in the build thread that I'll start sometime in the next week or so.

 

[akrvbob]

One of our members has switched to lithium, find him here: http://techno-viking.com/

And the Technomadia blog is a treasure trove of info.
Bob

 

[nixsee]

Thanks. I came across that post and technomadia, which has lead me to a truly daunting volume of information at our water dwelling friends over at Cruisers.

http://www.cruisersforum.com/forums...or-those-using-them-as-house-banks-65069.html

Fortunately I love researching and learning new things. I'm in the early stages of my reading, but almost certain I'll be going with Lithium now. They are much smaller, lighter, have much better usable capacity (80% vs 30-50%), charge much faster, longer life, safer, capacity not affected by the discharge rate (which could rob another 30-50% from lead battery capacity), etc... It seems like a no brainer and it's more just learning the specifics at this point and trying to figure out which equipment I need and how to maintain it.

 

[IGBT]

Lithium is more for experimenters right now.  I am an electrical engineer and even I went for Lifelines over lithium.   Swollen cells for no good reason, warranty that requires shipping back to China (costing more than the bad cell), need for extra electronics to closely monitor the cells during charge/discharge, unproven lifespan (claims of many thousands of cycles but no hard real world data and ignore the fact that lithium batteries lose capacity with age and elevated temperature)

 

[ccbreder]

No, lithiums are not drop-ins like lead acid. But if you have reading comprehension and the mechanical ability to assemble a battery of CALB type cells, that is prismatic LiFePo4, they are great.