Yesterday I upgraded the 12 volt electrical system in my Wolf Creek truck camper from two Interstate Group-24 RV/Marine wet cell batteries to two 6 volt Golf Cart Lifeline AGM batteries. I’m really thrilled with the upgrade. The golf cart batteries increase my capacity from 160 amp hours to 220 amp hours. Yes, Lifeline AGM batteries are expensive– each set me back $296–but for me they are worth it. Why? Keep reading.
Absorbed Glass Mat (AGM) batteries offer numerous benefits over traditional wet-cell batteries. First and foremost they require no maintenance or watering as they are sealed. Like wet-cell batteries, AGM batteries are still technically lead-acid batteries, but the electrolyte in them is encased in a fibrous glass mat that can’t be spilled. AGMs use the same battery charger as wet-cell batteries and since there is no liquid in them they are practically impervious to freeze damage. Most AGMs, like those made by Lifeline, have very thick positive plates that can suffer more discharge cycles than hybrid batteries commonly found in many RVs. More importantly, AGMs charge up to 20 percent faster and also have a slower self-discharge rate, about 1 to 3 percent a month. Since AGM batteries contain no liquid they can also be mounted on their side, an important benefit for some battery and storage compartments.
The fact that AGM batteries can be mounted on their side was a HUGE benefit for me. The small size of my battery compartment, which measures 12 inches tall, 16 inches wide and 14.5 inches deep, basically left me with two, very limited choices: two miniscule Group-24 batteries or two beefy, power-packing 6 volt AGMs. Let’s see. Should I stay with two hybrid 12 volt wet cell batteries that together provide only 160 amp hours or buy two deep-cycle 6 volt, 220 amp hour batteries that require no maintenance? For one who likes to boondock and dry camp it was a no brainer. Especially when you consider all the benefits that AGM batteries provide over wet cell batteries.
Wiring a pair of 6 volt batteries so that they’re compatible with your 12 volt electrical system is actually pretty easy. Simply wire your positive leads to the positive post on one 6 volt battery, then wire the negative leads to the negative post on the other 6 volt battery. Lastly, wire the empty positive and negative leads between the two batteries, as illustrated below. That’s it! See, I told you it was easy. This is called wiring them in series.
It’s often claimed that AGM batteries require no venting because they are sealed. The Lifeline owner’s manual, however, states that their batteries produce minimal gas during charging, so proper ventilation for AGM batteries is required. I quote: “WARNING: All batteries must be adequately vented during charging to avoid accumulation of explosive hydrogen gasses. Never install or charge in a sealed container or room.” Yes, it’s true AGM batteries produce very little gas during normal charging, but the real issue arises if they are ever overcharged. Excessive amounts of hydrogen gas would be produced if that scenario ever occurs. The bottom line is that it’s best to be safe than sorry to ensure that your AGM batteries are properly vented, period!
I’ve been meaning to follow your lead on the battery upgrade for some time and I fianlly just purchased 2 X 6V lifeline batteries for my Lance 825. I’m really looking forward to the extra capacity! Plus, having AGMs will allow me to remove all the ventilation and frame that was set up for the old flooded group 27 and just taking up room under my dinette. I do have a couple questions on how I can best take care of my investment. First, I have a 100W solar panel. I am going to see how that performs but will likely add a second panel in short order. My controller can handle up to 30 amps.
My larger concern is overcharging. Is it possible to damage the battery when plugged into shore power or running off my truck alternator for extended road trips? Any other tips for caring for these batteries?
You’re going in the right direction with the Lifeline AGMs. They’re great batteries. To answer your question about overcharging. Not from your alternator, but when plugged into shore power it is possible to overcharge if your converter/charger goes bad. Likely? No. Possible? Yes. That’s why I disconnect the batteries at the battery disconnect switch after a day or two. I rely primarily on my solar power system to keep my batteries charged and maintained, but it is good to give them a good equalization charge on shore power every once in a while.
Thanks for the reply. Good to know that the alternator is safe. I store my camper in a storage yard and always disconnect, only the solar is active. It sounds like how you do it. I only use shore power to recharge after a trip and before I bring the camper back to storage.
Thanks for the great website. I bought my camper one year ago and have learned a lot from the information you have provided. Learned a few things the hard way too!
Yep, that’s how I do it. I appreciate your kind words.
I have another follow up on my new Lifeline AGMs. What is the ideal resting voltage for fully charged AGM 6Vs? I measured 14.8V after being in storage for a week with one 100W solar panel. Seemed a little high based on the literature from Lifeline.
That’s the charging voltage and that does seem a tad too high. Did you set your charge controller to AGM?
Yes, AGM was selected as charging profile. I have a goPower PWM 30amp.
Then you should be fine.
Sam's Club – Duracell AGM DeepCell (105 AmpHr) Group 31 – $179 in Richmond, VA
1997 Chinook Concourse
That's great. AGMs certainly seem to be coming down in price.
Just looked at a MK battery … 245 amp/hr agm 12v for $629. Cha Ching It measured 11/11/21 inches and weighed 158 lbs. It wouldn't have fit in your battery compartment but I was wondering how heavy your batteries were. I mean 158 lbs for this MK sounds like a lot to me.
That sounds about right, actually. According to the Lifeline website, my 6v AGMs weigh 90 lbs a piece.
where do you buy the lifeline agm batteries?
I bought mine at a local battery store. You can buy them everywhere. If you go to their website, I'm sure it lists dealers by zip code.
PowerSonic offers a groups 27 12volt 93Ah battery with a 10 year life. Expensive but I never have to worry about the battery. Hap@the-powersource.com
Those will be my next batteries. I have two 6V batteries, but didn't know when I bought them that they were taller and barely fit in my battery compartment that USED to roll out. The guy took out the tray, unbeknownst to me, so now I can't reach the top of the batteries. My solar guy installed a gizmo that I can use to add the distilled water.
I like the sound of your batteries.
Reviews of these batteries are universally positive. Solar power and AGM batteries are made for each other. I'm sure I will love them.
have used them for years, and they are great batteries.