Community Forums

cwk · 02-03-2019, 07:53 PM

Quote:

Originally Posted by Itinerant1

It's all in the planning of the system, what folks didn't know or realize just a couple/ few years ago about heat / cold for lfp batteries can easily be worked around now knowing that these conditions can have adverse effects of the batteries life. If the end user can't build for these possible conditions than lfp might not be the right chemistry.

And, these work-arounds are???

What things must built differently for LFP instead of FLA or AGM batteries?

Itinerant1 · 02-03-2019, 07:59 PM

If you're going to leave it in an outside bay to the elements or put in the rig somewhere or add heating/ cooling to the compartment where batteries will be placed. Add heating pad if it may be needed.

Or you could go blindly in to it and wonder down the road why they prematurely failed. End users $$.

jcussen · 02-03-2019, 09:00 PM

Don't know about all lithiums, But Battle Born batteries can handle temps down to -4 f if disconnected. Unlike Lead Acid, they do not have to be brought to 100% SOC every week or so. They are quite happy to stay at 40 or 50% for long periods. But if you do want to remove them and bring them somewhere else, they only weigh about 30 lbs,. compared to the equivalent lead acid that would weight about 125 lbs

Freqz · 02-03-2019, 09:11 PM

Quote:

Originally Posted by cwk

And, these work-arounds are???

What things must built differently for LFP instead of FLA or AGM batteries?

You just can’t charge them below freezing...so you’d better have a plan on warming them if you’re going to be camped in the cold.

jcussen · 02-03-2019, 09:26 PM

Quote:

Originally Posted by Freqz

You just can’t charge them below freezing...so you’d better have a plan on warming them if you’re going to be camped in the cold.

A 12 volt heated mattress pad with a thermostat works fine, if temps above 24 f, batteries will take charge. They can discharge to a lot lower temp. If you have an open to the elements battery bay, more difficult, but a enclosed bay should not be a problem.
https://www.raneystruckparts.com/ele...lIZd31AJoil7Qt

PbdBlue · 02-04-2019, 07:54 AM

Quote:

Originally Posted by Freqz

You just can’t charge them below freezing...so you’d better have a plan on warming them if you’re going to be camped in the cold.

The simple solution is to locate them inside the RV. They don't vent so no issues on that front.

WileyOne · 02-04-2019, 08:06 AM

Quote:

Originally Posted by Cougarkid

So, my system now is:...
2000 watt Xantrex inverter/charger, and 300 watt pure sine wave inverter.

Why do you have two inverters?
Do you keep the big one turned off until you need it?
How do you prevent them both being activated at the same time accidentally?

jcussen · 02-04-2019, 08:49 AM

Quote:

Originally Posted by WileyOne

Why do you have two inverters?
Do you keep the big one turned off until you need it?
How do you prevent them both being activated at the same time accidentally?

Some people [like me] have a big inverter/charger that they leave off if not using microwave, cooktop,, coffee pot etc. and a smaller inverter only, they leave on all the time to power tv, stereo, sat. and computers and cell phone chargers. Small inverter only feeds circuits that feed the lower load items

C.Martin · 02-04-2019, 09:52 AM

There is a lot of focus on the cold end of the operating envelope. Very warranted.

The other end of the spectrum is worth noting as well...if you intend on traveling to Las Vegas or Bullhead City during the summer.

Technomadia did a three year follow up on their Prismatic cell LiFePO4 install. They ran tests over a period of time, allowing them to measure the amp hours they could use before the BMS shutdown. In a three year period...they had lost a lot of their storage capacity. Much more than the 80% guarantee offered with some batteries for life cycle limits. They attributed the loss to high temperatures...

I don’t know about you...but I wouldn’t be too happy if my $1000/100aH was only putting out 50aH after three years. I believe that most of us are factoring in longer life...not shorter life...by switching to Li.

jcussen · 02-04-2019, 10:16 AM

Hopefully the cylindrical cell design will dissipate heat better than the prismatic design. Only time will tell.

https://www.youtube.com/watch?v=RjKCw1UmBrE

Logan Oregon · 02-04-2019, 10:32 AM

For us, the solar allows us flexibility while minimizing the noise of the generator.

We have 1,440 watts of solar on the roof, with 8 house AGM batteries, and 2 chassis AGM batteries. At this time, we did not add a separate inverter that would allow us to run A/C off of the batteries. We just step outside and enjoy the view in shade. If it's so hot (95+) where it becomes unbearable, then we are simply in the wrong place. We pull up the jacks, and head to cooler climates. Same if it's too cold, too wet, too dry, or we simply don't like my neighbors (we're friendly folks, to a point).

We didn't buy our motorhome, in order to save money. We could buy a lot of hotel rooms for the same money. We could buy lots of diesel to run the generator, for what we paid for solar. We could do lots of things, if we're willing to eat Ramen every day.

We don't buy into the lifestyle of being in one place all winter, then moving to one place for the summer, and then go back and forth to the same places year after year.

Our mobile lifestyle is being used to travel and see as much as we can see. Solar is just one more tool to increase our flexibility at a reasonable price point. Boondocking is an option for us, and since we're not interested in staying long periods in one place, the single limiting factor of water capacity doesn't impact us in our travels. We can stay a full week without needing the generator or shore power, if we're in a livable environment.

It's all about choice, and deciding what fits your lifestyle, your needs, and your budget.

Get out and enjoy.

tundranurse1 · 02-04-2019, 09:23 PM

We are thinking of solar when we retire; but, not everyone drives or hauls expensive RVs. Solar is beyond most people’s budget. Look at the posts that say how many years it takes to recoup the expense of solar.

tundranurse1 · 02-04-2019, 09:26 PM

Again I see many people saying go with Lithium batteries. It’s quite easy to put $4,000 into batteries and solar equipment. I can get Cummins batteries from my son wholesale; since, he works for them.
We are going to probably put some solar; but, buying one panel, inverter and plenty of battery power to start.
We can use our Corning stove top percolator, led lights , and rarely use air when the temp is below 75.
I have a portable battery that powers my CPAP for 3 days without charging. Our fridge is propane/ electric. We cook most of our meals outside with our combo camping stove, griddle, and oven, and our grill.
For us it just doesn’t make sense to spend that much money on solar.

followingsea · 02-04-2019, 11:48 PM

Quote:

Originally Posted by tundranurse1

We are thinking of solar when we retire; but, not everyone drives or hauls expensive RVs. Solar is beyond most people’s budget. Look at the posts that say how many years it takes to recoup the expense of solar.

Bought our first MH with fund in the checking account. Since the generator did not work I got the price lowered. Bought a $88 generator from Harbor Freight to charge the batteries until I got the Onan running.

So compare $88 that works on demand to $1250 that works sometimes.

As far as noise and smell it does not get any worse than a cheap generator. Oh there is the cost of fuel.

Wait a second I am driving a diesel pusher which is a lot better than the first gasser.

I have a sailboat. I have no problem finding a place with no noise. If I need to make electricity, I start an engine to drive a generator.