For those of you who boondock at lot and depend on batteries I came across this on another board and found it to be very interesting...
(reposted with permission)
Cheers
Ted in Seattle
Some of you sat in on the seminar at Lazydays during our recent
> gathering/rally where the fellow talked about using lithium
> ion batteries in RVs. Well, I almost didn't attend this but decided to
> go at the last minute and was glad I did. What the fellow said about
> those batteries was fascinating to say the least.
>
> It was a coincidence that I needed batteries—again. I had now gone
> through a second set of Lifeline AGMs in our 2007 Dynasty and by the
> time of that presentation at Lazydays, I was only getting about 1.5
> hours of inverting time from my four, Lifeline GPL-8D coach batteries
> before my Auto Generator Start would kick on at 12.1V. Our best guess
> was this was due to the fact that they were simply wearing out due to
> the number of recharge cycles. That is, we boondock an average of 12
> nights per month (40% of the time)—it's our normal lifestyle. I was
> told by Lifeline that my AGM batteries have a recharge cycle of 1,000
> times. The recharging is, we believe, what wore out our AGM batteries.
> If our generator ran (recharged the batteries) an average of only 3
> times in 24 hours, for us that would be 684 recharge cycles during the
> 19 months our second set of AGMs lasted. I truly believe we wore them
> out and know we didn't get close to 1,000 recharge cycles.
>
> So, we made arrangements to park at the company headquarters where the
> lithium ion batteries were being made. We met and talked at length
> with the owner/inventor, we decided to try them, and they built and
> installed the first two production lithium batteries in our coach—one
> new chassis battery and one new coach battery replaced the eight AGMs
> I had. The new batteries have the Serial #s "001" and "002."
>
> If you rarely boondock and functioning on battery power is not
> important to you, then some of this may not apply to you. Lithium ion
> batteries are expensive up front but the belief is that long-term
> usage will prove them to be much more cost effective than AGMs and
> they will simply blow lead-acid out of the competition. From decreased
> generator-run time to a low estimate of 3,000 recharge cycles to
> significant weight loss in the coach to much more efficient operation
> of all those electrical appliances and motors in your coach, these
> batteries are impressive.
>
> The reasons we decided to do this, the differences between lead-acid,
> AGMs, and lithium ion batteries, how it was done, decisions we made,
> and the data we learned is fascinating. I am posting my experiences,
> what I learned, battery comparison, verifiable data, and gut reactions
> here... RVing Tips- RV LifeStyle - RV Travel Full Time RVing - RV Maintenance - RV (http://www.aboutrving.com/rr_one.php) That should be equally
> fascinating.
>
> Note that About RVing - RV LifeStyle - RV Travel Full Time RVing - RV Maintenance - RV (http://www.aboutrving.com) is my RV website but I don't sell
> batteries. What I am doing is field testing these.
>
> The first information has been posted. We are on a field test now and
> will be for months. The goal is to see how they function with our real
> RVing lifestyle. I will continue to post everything I find but this
> will take some time. Nothing much happens battery-wise while we are in
> a campground and plugged in. So check the website every couple of
> weeks or so. There may be some new info.
>
> If you belong to other RV e-mail groups or forums, tell them about the
> website, too.
>
I am pleased to read that lithium-ion batteries may be available for RVs. With appropriate charging and monitoring systems, they could be an improvement over current technology.
We seldom boondock. When we park overnight, I try to be conservative with power consumption.
I read most of the article and associated blog. I finally found what I was looking for. He chose to run his generator 2.5 hours to charge four 8D AGM batteries from a voltage of 12.1V. Based on my limited experience with three 8D batteries, and what I have read regarding battery care, it sounds like he is running the batteries too far down and not fully charging them. It seems to me that he has chosen operating parameters that lead to premature failure.
I monitor the amp-hour measurement, charging current, voltage, and the status lights (charge|accept|float). I charge until charging current is low, voltage is high, and the monitor indicates "float" status.
I would be interested to read a response from a person with significant experience and knowledge regarding care and treatment of house battery systems. This looks like a case of abuse of AGM batteries to me.
JD I am thinking the same thing.. taking too many Amps out and not putting them back... It will be very interesting to see how the Lithium's last under the same conditions.
Cheers
Ted in Seattle
Key would be is this 12.1V loaded or resting? If loaded the 'rebound'
when the load is removed could pop up as high as 12.5V.
Lets say four 230AH batteries - ~ 900AH. 50% discharge (acceptable) =
450AH.
My old Heart Freedom 25 has one of the most powerful 3 stage chargers at
130A in bulk - I couldn't do 450AH recharge in 3 hours much less 2.5.
That means he is probably only dropping to 60-70% capacity.
Or perhaps never reaching 100% full with a 2.5 hour charge time.
Thanks for pointing out that 12.1V may be a conservative setting for a coach that is inhabited.
Another interesting article that investigates heavt-duty battery use and new types of batteries is
Ocean Navigator | The magazine for long-distance offshore sailing and power (http://www.oceannavigator.com/content/battery-revolution)
The author, Nigel Calder, has been a boat maintainence guru for years.
Great techie stuff !!!
HTH
Thisis a great article. I knew most of it from my boating days but came across a coach with a forklift battery sized battery. The coach builder is Bruce and the ar. Boat builder. This battery is very interesting and can go a couple days between recharges.