AGM batteries vs. gel batteries

Topic: AGM batteries vs. gel batteries (Read 1852 times) previous topic - next topic

Re: AGM batteries vs. gel batteries

Reply #25 – August 08, 2013, 09:54:27 am

Ok so here is a big one. How many batteries and how many years would it take to use this type battery Vs Standard AGM or Gel

$3499.00

12V 300AH Lithium Ion Battery
Size: 8D
Nominal Voltage: 12.8V
Amp Hours: 300
3000 Cranking Amps

Length (inches): 20.47"
Width (inches): 10.5"
Height (inches): 9.0"
Weight: 93 lbs.

360 min @ 50A
900 min @ 20A
Max Continuous Discharge 100A

Charge Voltage: 14.6v

Life in Cycles: 3000-5000
12v 300ah lithium ion battery

Re: AGM batteries vs. gel batteries

Reply #26 – August 08, 2013, 11:00:04 am

Quote from: fouroureye – August 08, 2013, 09:54:27 am

Ok so here is a big one. How many batteries and how many years would it take to use this type battery Vs Standard AGM or Gel

$3499.00

12V 300AH Lithium Ion Battery

There have been several threads on LiFePO4 batteries in the past year or so. Here are a couple I came up with doing a quick search for lithium batteries on the forum. Besides the cost of the batteries, one needs to factor in an inverter/charger that is compatible.

Lithium Iron Phosphate batteries

Lithium Iron Phosphate Batteries (was House Battery Replacement)

Re: AGM batteries vs. gel batteries

Reply #27 – August 08, 2013, 11:16:52 am

Michelle,

For Sure.. one day they will be standard equipment and weigh about 40# less.

Re: AGM batteries vs. gel batteries

Reply #28 – August 08, 2013, 11:39:34 am

Not to mention significant fire risk

Re: AGM batteries vs. gel batteries

Reply #29 – August 08, 2013, 01:26:24 pm

I was told the Agm batteries cannot be equalized like the MK gels.

My buddy that does electronics and batteries in big stuff only for 11 years mentioned better life by annually disconnecting the gels and equalizing them individually.

Some last 4-5 years and he has some at ten years.

As a dry camper that I do a lot of the gels were better as was my absorbtion refer in his opinion.

Was not a lifeline fan.

Li ion phospate is what I almost bought instead. Other than the $5k plus price range.

Liberty uses two if memory serves me. Its only money.

Bob

Re: AGM batteries vs. gel batteries

Reply #30 – August 08, 2013, 02:25:50 pm

Yup, Liberty uses Li ion you are right.

Re: AGM batteries vs. gel batteries

Reply #31 – August 08, 2013, 02:52:44 pm

I think you may find Bob that the gels cannot be equalized if I have it right. The AGMs can up to around 15v as I have mine set every 28 days to equalize at 14.7 v (for a short period) just to make sure they are fully charged and this was as told to me by Lifeline themselves, and AMSOLAR set it that way and their business is solar and battery care.
I stand to be corrected.
John H

Re: AGM batteries vs. gel batteries

Reply #32 – August 08, 2013, 03:17:54 pm

Here is my experience with AGM vs Gel.

I have an 11 year old 8D Gel which still has a measured capacity of more than 160 amphours (new was 220 amphours). I connected it at the start battery bank cables of my M11. It cranked fast for 1 sec, bogged for half second, then cranked steady (not real fast) but the M11 started. Rating is 1150 CCA.

I have two Lifeline (made by Concorde) 8D AGM batteries which are three years old.

I connected one AGM at the start battery bank cables of my M11. It cranked fast for 1 sec, then bogged, no more cranking - did not start the M11. Two AGM batteries together cranked faster then one Gel and started the M11. Rating is 1450 CCA.

I do not know why one 1150 CCA Gel starts my M11 but one 1450 CCA AGM does not!

Point 1:
I did discover that the AGM batteries were not fully charged (at 95%) after installing amphour meters on each battery rather than just one for the bank. AGM batteries are now fully charged.

Point 2:
The Gel had a desulfator on it (which I built years ago) for months, but AGM batteries did not (they do now, bought off eBay). I plan to do this testing again and guess that the significant factor is the use of desulfators, rather then not fully charged.

Note:
Desulfators take months to do the same thing as equalization does in a few hours, but is easier on batteries and batteries are always desulfated.

When I bought the Lifeline AGM 8D batteries in May 2010, I was unable to find a source for Gel 8D batteries that was not 50% more expensive than Lifeline AGM 8D batteries. My first choice was Gel but money talks.

I believe that the suppliers of sealed batteries are reluctant to sell Gel batteries because they are much more vulnerable to misuse than AGM batteries are. I believe that statistics from a battery supplier would reveal much higher % of warrantee claims with Gel batteries than with AGM. If I were a dealer, I would promote and sell AGM batteries.

I also believe that the Gel is the cycle king if managed properly but that the lifetime cost per cycle is about the same (unless the Gel can be purchased at the same price as an AGM).

I have noticed that when solar charging my batteries, the Gel battery is still being trickle charged for almost two hours after the AGM batteries are fully charged. I have reset the charge point to 14.6 volts on the solar controller which is recommended for AGM but too high for Gel. I believe 14.6 is fine for Gel from a solar system because the amperage is limited by the solar supply (not the battery) and therefore not harmful to the Gel. From an alternator (mine is set at 14.4v) or high capacity battery charger, 14.6v would damage the Gel because of the high current.

Based on my experience with faster solar recharge, when my Gel battery is no longer serviceable, I will replace with AGM.

Another interesting observation is that when checking in the morning, the Gel has provided 50-100% more amphours than either AGM battery and when solar charging, the amps into the Gel is 50-100% higher than amps into either AGM battery. I believe that this is due to the lower internal resistance of the Gel, in spite of what manufacturers claim.

Re: AGM batteries vs. gel batteries

Reply #33 – August 08, 2013, 08:01:58 pm

I have a question regarding use of a desulfator on the house batteries. My bank of 3 gel batteries is now 10 years old. It has been a couple of years since I determined they were still holding a good charge, and use tells me they are still in good shape.

Now to the question....I attached a single desulfator to the outermost battery a couple of years ago. Are the other two batteries getting sufficient benefit or should I consider moving it to the center, moving it periodically, or adding two more? Also, would the starting batteries get any of the goodness with the boost switch on, or is the cable length too long?

Re: AGM batteries vs. gel batteries

Reply #34 – August 08, 2013, 08:31:21 pm

I will put my 2 cents out here about what I was told by the manufacturers of a desulfator. They recommend 1 for each battery but you can use one across all 3. As they connect to the + - of each battery posts it seemed to me to be more prudent and make the unit work better if I got 3 so I did. They are the same as Wyatt now uses (wizbang) and mine have been on about 3 months so hopefully are now doing their job. There is a lot of talk from different sides as to whether they do anything, but I am willing to give it a try. The principle is obviously correct and I hope to get the benefit of them and make my batteries give good service and life. Hope it works.
John H

Re: AGM batteries vs. gel batteries

Reply #35 – August 08, 2013, 10:06:52 pm

Quote from: John Haygarth – August 08, 2013, 02:52:44 pm

I think you may find Bob that the gels cannot be equalized if I have it right. The AGMs can up to around 15v as I have mine set every 28 days to equalize at 14.7 v (for a short period) just to make sure they are fully charged and this was as told to me by Lifeline themselves, and AMSOLAR set it that way and their business is solar and battery care.
I stand to be corrected.
John H

When my guy mentioned equalizing the MK gels I did not question him as he was on a roll.
Was delivering a fifth wheel with three MK gels in plastic boxes and a large magnum inverter to run ducted roof air without a gen over a weekend. Evening use dry camp noise compliant use.

Will write down his explanation but he designed the electrical systems for vogue motorhomes in 1985 and only does 45's and busses for the last twenty years.

Maybe the mk's can take things differently. Never thought about it. Will ask.

My installation is currently one new MK and two used ones.

He said the two used ones tested 1100 cca's with a new rating of 1150. But he said new mk's consistently tested at 1300-1400 cca's. my used came out of a 24 volt bus. Two of the four typically die he said and as he would only replace all four for a prevost I thought I would see how the combo holds up. I know it wrong but and easy fix later. He redid the cabling to have the positive from one end battery in the system and the negative from the other end of the string. And added my desulfinator to the same ends so its slowly working on all three batteries.

He mentioned 16 volts to the mk's annually individually to equalize them. And he has ten year old sets equalized annually. not sure how long but bill does this stuff all day.

Found every electrical issue in my 16 year old coach and fixed them for minimum hours.

Old bud. We used to be the bluebird guys for the so cal dealer in 1990. Roof air ran of of batteries in a bird in those days. Need one of their dual plug in cord setup. 30 and twenty amp box then fifty to the coach.

Re: AGM batteries vs. gel batteries

Reply #36 – August 08, 2013, 10:32:33 pm

Bob, if you read all the different articles out there you may find that a lot of the things you mention are the exact opposite of what you mention he said was ok!!!!
I am not an electrical expert in any way, but did judt read an article on MKs that said do not charge over 14.1 volts

I would not mix new and older ones- but sometimes we have to do it.
read some of the Battery articles on Beamalarm to see what I am saying.
John H

Re: AGM batteries vs. gel batteries

Reply #37 – August 08, 2013, 11:18:36 pm

14.1 volts is rated max charge voltage at about 65 degrees with higher voltage at colder battery and lower voltage with warmer battery. So a temp compensated charger is very important to use.

Re: AGM batteries vs. gel batteries

Reply #38 – August 09, 2013, 01:27:10 pm

Desulfators:
The desulfators I use are considered passive because they draw about 60 milliamps from the battery and send a 50 volt, 6amp spike back into the battery. Because they are passive they are not very powerful by design, to limit the draw from the battery, such that a lead wire of even 12 inches will considerably reduce the amount of spike energy that reaches the plates in the battery. The desulfation process with a passive desulfator requires a day per amphour with short leads. Our 8D batteries take at least 6 months to be desulfated with short leads. With long leads desulfation will take much longer. Definitely use a desulfator for each battery with leads as short as possible. I attached mine with 3M tape to the battery case.

In my case there is 6 feet of battery cable plus two amp shunts between the negative posts of the two AGM batteries behind the rear tires. I installed the amp shunts inside under the foot of the bed rather than outside behind the rear tires.

After I built a desulfator (circa 2005), I attached it to a start battery which would not start my car and would not take a charge. I checked the voltage of the battery many times during the next week and was surprised that the voltage was getting higher each day for the first 5 days, even though the desulfator was drawing 65 milliamps and there was no battery charger being used. I attached a trickle charger at that point and left it for a couple months. Battery would then start the car and take a charge.

The stabilized voltage (disconnected for 10 or more hours) of a fully charged battery will vary with the type of battery and the state of health of the battery. A healthy fully charged flooded battery will have a stabilized voltage of 12.75v, an AGM battery will be 12.80v, a Gel 12.85v. Desulfation will raise that stabilized voltage. My 11 year old Gel which has been desulfated for years has a stabilized voltage of over 13 volts.

If you are curious, check the stabilized voltage of each house battery before desulfating and check it again after a year of desulfating. I would be most interested in what each of you discovers.

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Re: AGM batteries vs. gel batteries

Reply #25 – August 08, 2013, 09:54:27 am

Re: AGM batteries vs. gel batteries

Reply #26 – August 08, 2013, 11:00:04 am

Re: AGM batteries vs. gel batteries

Reply #27 – August 08, 2013, 11:16:52 am

Re: AGM batteries vs. gel batteries

Reply #28 – August 08, 2013, 11:39:34 am

Re: AGM batteries vs. gel batteries

Reply #29 – August 08, 2013, 01:26:24 pm

Re: AGM batteries vs. gel batteries

Reply #30 – August 08, 2013, 02:25:50 pm

Re: AGM batteries vs. gel batteries

Reply #31 – August 08, 2013, 02:52:44 pm

Re: AGM batteries vs. gel batteries

Reply #32 – August 08, 2013, 03:17:54 pm

Re: AGM batteries vs. gel batteries

Reply #33 – August 08, 2013, 08:01:58 pm

Re: AGM batteries vs. gel batteries

Reply #34 – August 08, 2013, 08:31:21 pm

Re: AGM batteries vs. gel batteries

Reply #35 – August 08, 2013, 10:06:52 pm

Re: AGM batteries vs. gel batteries

Reply #36 – August 08, 2013, 10:32:33 pm

Re: AGM batteries vs. gel batteries

Reply #37 – August 08, 2013, 11:18:36 pm

Re: AGM batteries vs. gel batteries

Reply #38 – August 09, 2013, 01:27:10 pm

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