Lithium Batteries

[WestCoastRV'er]

I have been thinking of upgrading to Lithium. I've had my trailer for 5 years and on my second set of 6V Trojan batteries. Some of the benefits I see are I can relocate my batteries to inside the trailer under the bench seats within 5 feet of the charger/inverter located under the fridge. Removing 125lbs of tongue weight and ensuring they can't be stolen. This would also cut the distance from the solar panels to solar charge from 25ft -> 12ft as it is a straight run down the fridge vent. All my electrical (batteries, solar charger, 2000 watt inverter) could be in one place with very short cable runs.

I would upgrade the charger to Progressive Dynamics Lithium Battery Charger. Been planning on removing the stock charger anyway. I believe this is one of the main reasons my batteries failed prematurely.

Plan would be to start out with two 50AH batteries and add to it as needed over time.

12V 50AH Lithium Ion Battery | Chargers and Voltmeters | Smart Battery - Products

PDI Lithium Battery Charger
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[KenHwy61]

It sounds like a great idea to me. I am sure someone on this forum will point out any possible problems. I would love to remove the weight of dual batteries from my tongue. Be sure to let everyone know how it works out.

[rana]

Personally, unless you do a great deal of dry camping, or just have money burning a hole in your pocket, I would hold off on the LFP's. From what I read into your situation, the cost to benefit is just way out of whack.

I understand what you are trying to do, but it might be better suited to just upgrade your charging system to a programmable (So if you eventually make the jump to LFP's a new charger wouldn't be required), and go with AGM's for now. You will spend a fraction compared to LFP's, can relocate your batteries inside your rig, streamline your power systems, and come out way ahead in terms of available ah's.

JMHO...

Two sets of trojan's in 5 years... there is more going on there than just the stock converter/charger. My last set of T105's where in use for 9 years (which is not at all uncommon) before they were forcibly retired a couple of years ago to make room for a set of AGM's in the new rig. They are actually still in use in their new home.

[Herk7769]

I am not 100% sure a standard converter will charge lithium batteries without damaging them.

The lithium batteries in my bike require a special charger (different than the one for the cheaper lead-acid ones).

[WestCoastRV'er]

Originally Posted by Herk7769

I am not 100% sure a standard converter will charge lithium batteries without damaging them.

The lithium batteries in my bike require a special charger (different than the one for the cheaper lead-acid ones).

You are correct. Progessive Dynamics has a new Lithium Battery Charger.

PDI Lithium Battery Charger
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[mud yapster]

WOW those are some expensive batteries!!!!

[techntrek]

I agree with Yarome, the cost/benefit analysis just doesn't work out - even if you dry camp all the time. Weight is critical with something like an electric car, but 100 pounds just isn't a factor for most campers. I also agree that something isn't right with your setup if you are killing batts every 2 1/2 years. If you disconnect them from the camper are you reconnecting them every 30 days, overnight, to take care of self-discharge? If not, they are sulphating quickly and that is the problem.

[WestCoastRV'er]

Originally Posted by Yarome

Personally, unless you do a great deal of dry camping, or just have money burning a hole in your pocket, I would hold off on the LFP's. From what I read into your situation, the cost to benefit is just way out of whack.

I understand what you are trying to do, but it might be better suited to just upgrade your charging system to a programmable (So if you eventually make the jump to LFP's a new charger wouldn't be required), and go with AGM's for now. You will spend a fraction compared to LFP's, can relocate your batteries inside your rig, streamline your power systems, and come out way ahead in terms of available ah's.

JMHO...

Two sets of trojan's in 5 years... there is more going on there than just the stock converter/charger. My last set of T105's where in use for 9 years (which is not at all uncommon) before they were forcibly retired a couple of years ago to make room for a set of AGM's in the new rig. They are actually still in use in their new home.

Yes I agree that going AGM would be cheaper but I'm trying to think where I will be in 5 years and don't want to be replacing batteries again. I know that the WFCO 8955 charger never fully charges a battery and when boondocking I have over discharged my batteries several times. Since installing my solar system I check on my rv on weekends since its in storage for winter. I have a cutoff switch so there is no draw on the batteries. I would think they would always be fully charged. the charge controller monitor shows the batteries under 75% and jumps to 100% in full sun. One of the Trojans is bulging on the side so I assume they are damaged.

During the summer I do boondock camping at Skagit Speedway and State parks in Washington. The reason I was looking at starting small with Lithium was to minimize the start out costs to under $1500. Last year I installed the solar panel/charger and 2000 watt inverter.
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[techntrek]

Is you solar system connected directly to the battery or will your disconnect switch disconnect the solar system too? It should be connected directly and that will prevent sulphation.

It still doesn't make any sense to switch your system to lithium. I'm an active member of a solar forum and all agree it is still far cheaper to stick with lead-acid right now, for stationary and RV use. You need a specialty situation like model aircraft or an electric car for it to make sense - where weight is the driving factor.

[WestCoastRV'er]

Yes the solar is connected directly to the batteries. Thanks for your insight.

[Happy Vibe]

You will need a solar controller to charge the Lithium batteries. According to the spec sheet on the battery you need 14.4 to 14.6V for charging.

[WestCoastRV'er]

You are correct. This is the one I was looking.

12V 60A Lithium Ion Solar Charge Controller - C60 - Xantrex - Lithium Ion Solar Energy Storage Batteries | Smart Battery - Products
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[rana]

The main points there are that you need a special "lithium" charger is a bunch of hooey. A lot of folks will get sucked into forking over hard earned cash to replace a perfectly capable "smart/programmable" charger.

The "standard" charger they are referring to are the lower end RV converter/chargers found in almost ALL RV's. (which are highly inadequate for most battery systems currently in use.. ie., flooded deep cycle wet cells)

The charger you referenced is no different. It's just a plain ol "standard" charger with a higher "factory adjusted" output. It is non programmable. You would be better served to buy a true "smart" charger. Programmable, heat adjusted, and full sensor capability. That would be true with your trojans, AGM's OR LFP's.

They are trying to sell ice to Eskimos.

The "catch" they are trying to scare you with is that all LFP cells charge and discharge at different rates. What they only put in small print is that the cell regulation takes place in the individual cell circuitry.. not within the charger. They DO have different charge requirements to stay happy.. but that's just as true with your wet cells and AGM's.

I understand you are trying to look further down the road, but one other factor you might consider is that you really don't want to be slowly adding cells... mixing old and new cells over a period of years.

It's just my own personal opinion.. but if you have a little extra money right now, you would be better served upgrading the "backbone" (charger, solar controller, battery meter) and sticking with the AGM's. Maybe go with 4-6v'rs and give yourself 220ah's on tap (440ah @ 50% discharge).

In 5 years.. once the LFP's are more reasonable in price... and you've gotten your dollars worth out of your AGM's.. THEN make the jump to LFP.

I know there are folks that are able to take advantage of LFP's now.. but typically those folks are running high voltage 24v or 48v system powerhouses. Probably somewhere in the 1% range of typical RV solar setup's... and there is still not much debate over the fact that the $ to Ah is highly unbalanced. Some of those folks are heavy boondockers that NEED that kind of power storage to run their self levers and hydraulics that might over tax a small 12v low power system.

[rana]

I just remembered a good link that has some really great information is simple to understand language with regard to solar and electrical systems. It might be helpful when re-vamping your electrical setup.

RV Electrical

This guy knows his stuff. More so than 90% of solar installers I have ever run across.

[WestCoastRV'er]

thanks for the detailed feedback.
Do you have a suggestion for a smart charger?

Are AGM batteries safe to store inside the RV?

[rana]

Originally Posted by WestCoastRV'er

thanks for the detailed feedback.
Do you have a suggestion for a smart charger?

Are AGM batteries safe to store inside the RV?

AGM's are perfectly safe inside your RV. They can even be installed on their sides or upside down

Chargers.. that's more difficult to answer. So much depends on your overall setup and needs. Ie, are you happy with a smart charger with preprogrammed charge profiles? Do you require temperature adjustment? Do you want it to have pass through power capabilities from shore power? Is your solar controller "smart" too?

KWIM

[rana]

Caveat: I do not normally pay much attention to stand alone battery chargers.

Just looking around briefly.. there seems to be some good things being said about the IOTA IQ4

and

Zantrex Truecharge2

The Zantrex has the option for a custom setting... which is ideal, but in the owners manual it says:

This setting should only be used
if a custom algorithm has been
programmed by Xantrex or a designated OEM.