Renogy on sale

[GallenH]

I'm not affiliated with Renogy in any way but noticed that they currently have their 100AH lithium with BMS on sale for $800.

[rowiebowie]

Originally Posted by GallenH

I'm not affiliated with Renogy in any way but noticed that they currently have their 100AH lithium with BMS on sale for $800.

I purchased two back in June on a "Black Friday" sale for $719.00 plus no tax, no shipping. Closest I saw since then was $749, then $779, and now $799.

I guess I got the "steal deal", but now they have introduced a "Smart" lithium battery that is $899 list price. Size of the case has increased so they would not have worked for me and I'm happy with my install (Renogy 3000W inverter, Renogy State of Charge monitor, and Renogy 40A DC-DC charger). But I wonder what I may have missed with their new batteries and assume they may not be compatible with the two I have.

https://www.renogy.com/products/deep-cycle-batteries/

[booster]

There have been few discussions on the drop in batteries and how they will function and hold up over time. I wonder if the new "smart" version is some sort of reaction to systems where they were just dropped in without any other changes to facilitate the switch from wet cells or AGM?


Specs still say to charge and float at 14.4v which is a bit of surprise.

[ikanode]

The "Smart" ones allow connecting multiple batteries in parallel by smart balancing all 4, 8, 12, etc. cells.

For long life of any LiFePO4, the recommended cell voltage ranges are from 3V to 3.45 volts. (12 - 13. Some sources recommend a narrower 3.2-3.4V. (12.8-13.6). Floating can occur at a max of 3.4V The narrower ranges deliver about 80% of the wider range). I looked at the specs and they don't specify what cell voltages they use.

From the specs for the smart version, it looks like they're prioritizing Ah over longevity. 10V to 14.8V (2.5 to 3.7--3.65 is usually the recommended Max but they might not be passing all that on to the cells.)

[Whynot]

Can you simply replace the 12V house battery (under the chassis) of a Simplicity 2018 equipped with UHG, with this or 2 of these batteries?

[rowiebowie]

Originally Posted by Whynot

Can you simply replace the 12V house battery (under the chassis) of a Simplicity 2018 equipped with UHG, with this or 2 of these batteries?

Some lithium batteries have been referred to as "drop-in replacements", but if you speak to a lithium battery vendor tech, they say no. Charge profiles are significantly different for lithiums and your lead-acid engine battery. For that reason you need to charge them differently and isolate them from one-another. You can make sure your lithiums are charged and maintained properly replacing charging components with new ones that are lithium compatible.

In addition, unlike lead-acid batteries, lithium battery's charge status cannot be determined with any certainty by just monitoring voltage. You need a State of Charge (SOC) monitor that tracks energy going in and out to calculate charge status. I installed a 40A DC to DC charger between my engine alternator and lithium coach batteries to properly charge them and prevent possible damage to my engine alternator. My new 3000W inverter/charger lets us use the microwave off the 200ah lithium batteries while boondocking.

As far as the install, if I can do it, you can do it. But there is a cost to replacing a great deal of your components. About $3000 to $4000 worth.

EDIT: The above refers to a typical rv with lead-acid coach batteries. Your Roadtrek is a different system than most with an under-hood generator and the possibility of ecotrek factory lithium batteries.

[Whynot]

thank you , no lithium or ecotrek. I just wanted to somehow find an easy way to increase capacity of single 100Ah battery that came with the coach.

[rowiebowie]

Originally Posted by Whynot

thank you , no lithium or ecotrek. I just wanted to somehow find an easy way to increase capacity of single 100Ah battery that came with the coach.

Your answer is more amp hrs. Bigger or more AGMs (if space is available) will be the simplest and cheapest way to go. Start measuring.

[IdleUp]

Another inexpensive lithium option for an RV is using Tesla battery packs. A lot of my friends are using these packs in their RVs with great success. You can find them on ebay at a super discount from crashed Tesla's with low mileage. This for the most part is not a problem since most lithium packs are good for 15-20 years. Typically a 24 volt 5.2 kw pack goes for only around $1000

Mike

[rowiebowie]

Black Friday Sale at Renogy. Everything 20% off.

I just priced their 100Ah lithium battery (the ones I bought this Summer, not their latest version). It's on sale for $799.00, but when you put in sale code BFSOLAR20 at checkout:

The price is $639.99 with free shipping! Almost $100 less than I paid. Arrrgh!

[IdleUp]

Originally Posted by rowiebowie

Black Friday Sale at Renogy. Everything 20% off.

I just priced their 100Ah lithium battery (the ones I bought this Summer, not their latest version). It's on sale for $799.00, but when you put in sale code BFSOLAR20 at checkout:

The price is $639.99 with free shipping! Almost $100 less than I paid. Arrrgh!

Sounds like you got a pretty good deal. Whats important its a US vendor should you have a problem.

It appears as if the lithium 100 ah field is getting competitive since there are now so many new vendors showing up each month. Presently, there is an actual "Over-Supply" of lithium batteries coming from China. I predict US distributed 100 ah RV packs will reach below $500 by next summer.

Three years ago, when I was working on a military drone lithium project, we were paying $250 kWh. Last time I checked Tesla was around $100 kWh. It's predicted this price will fall to $75.00 in the next year or so. All this competitive US pricing will only plummet China lithium prices further.

Mike

[Bud]

Originally Posted by rowiebowie

Black Friday Sale at Renogy. Everything 20% off.

I just priced their 100Ah lithium battery (the ones I bought this Summer, not their latest version). It's on sale for $799.00, but when you put in sale code BFSOLAR20 at checkout:

The price is $639.99 with free shipping! Almost $100 less than I paid. Arrrgh!

Could have been worse rowiebowie.

Imagine that someone like you was deciding on a major electrical upgrade at about the same time. But unlike you, they decided the Renogy 100 watt lithiums were just a little to much money and went with agm's!

Bud

[rowiebowie]

Originally Posted by Bud

Could have been worse rowiebowie.

Imagine that someone like you was deciding on a major electrical upgrade at about the same time. But unlike you, they decided the Renogy 100 watt lithiums were just a little to much money and went with agm's!

Bud

Good one, Bud!

At least the AGM versus Lithium wars are not nearly so contentious as "Gas vs Diesel" or "Chevy vs Ford vs Dodge" on some truck forums.

[Davydd]

Seems most lithium batteries are coming from China. Are they affected by the trade war tariffs?

[rowiebowie]

I've been watching the Renogy Black Friday sale since last week. Put a few things in my cart just to see the final price calculation.

Then today I get an e-mail that they have a additional 8-12% off for Cyber Monday, code: CMSOLAR20.

Even though the 20% Black Friday promo code: BFSOLAR20 was supposed to end yesterday at midnight, it looks like I was able to apply both codes to their $799 100Ah batteries in my cart.

It may be a fluke that I already had the Black Friday code in my cart, but the result is 30% off their $799 sale price:

4 Lithium 100Ah batteries for $563/ea. (free shipping, no tax)

[rowiebowie]

I did not pull the trigger on the Renogy batteries as I just couldn't justify adding more lithiums at this time. The only reason to do so would be to go with a huge (and expensive) bank of batteries to run the roof a/c. And then, I'd have no adequate way to recharge such a large bank of batteries.

Once I came to my senses (in the late hours last night), I deleted my cart.

Just as a test, I then added them back to my cart and this time sales tax was now added to the charges. I agree with sales tax on internet sales, but I've never paid tax or shipping from their site before. Don't know why.

[markopolo]

Likely a smart move deleting the cart. The pricing is getting interesting. I know that was double coupon sale price but maybe we'll start see $5 per Ah for ready made batteries next year.

[markopolo]

Just adding that price alone shouldn't be a primary factor when considering switching to LFP batteries. Caring for the batteries should be a a primary factor and it should be easier to care for smaller LFP banks or divided LFP banks.

It appears that a full or near full discharge followed by a full recharge is optimal care. It's easier to fully discharge and then fully charge a 100Ah battery compared to a 600Ah battery for example.

Look for "Memory Effects" on this page: Marine lithium batteries in operation | Nordkyn Design - it's just below halfway down the page.

A few quotes from that page:

For a memory effect to appear, an incomplete charge cycle followed by a rest period and a discharge must have taken place earlier (memory-writing cycle).

The memory effect was found to strengthen with the number of incomplete charge cycles performed before the erase cycle. It was also strengthened when a partial charge was followed by a shallow discharge, rather than a deep discharge.

In order to erase the cell memory of the previous interrupted cycle(s), a full charge must be performed (memory-releasing cycle) and this requires overcoming the bump caused by past partial cycles.

[booster]

Originally Posted by markopolo

Just adding that price alone shouldn't be a primary factor when considering switching to LFP batteries. Caring for the batteries should be a a primary factor and it should be easier to care for smaller LFP banks or divided LFP banks.

It appears that a full or near full discharge followed by a full recharge is optimal care. It's easier to fully discharge and then fully charge a 100Ah battery compared to a 600Ah battery for example.

Look for "Memory Effects" on this page: Marine lithium batteries in operation | Nordkyn Design - it's just below halfway down the page.

A few quotes from that page:

That article seems to blow holes in a lot of what he have heard about LFP batteries, although I need to read it more thoroughly a couple more times, I think.

What they seem to say differently:

We have always heard the big advantage of LFP was no memory or damage from partial discharges and/or recharges and they say otherwise.

Charging threshold for cold temps is probably higher than the 0*C we hear all the time.

Even at as low as 3.4v, you can overcharge LFP and damage them.

High charge and discharge rates shorten LFP life per the article and both are best at about .3C which is about the same as AGM.

They say the only accurate way to terminate charging is by voltage and current together.

The article appears to be very well written and documented, so looks quite believable. Written in 2015, so I am surprised we have heard of or seen it before.

Following all the charge, discharge, memory elimination, rates, temps, and control suggestions they make certainly makes all the control circuits much more complex.

The big question still remains as it always has been when we discuss the various batteries, though, I think.

Will the shortening of life from very basic BMS and charging controls really be big enough to tilt the cost/benefit scale? I think this is particularly of concern for the drop in, leave standard controls in place, systems.

[RossWilliams]

From that same article:

The memory effect was found to strengthen with the number of incomplete charge cycles performed before the erase cycle. It was also strengthened when a partial charge was followed by a shallow discharge, rather than a deep discharge.

These latter aspects have proved to be of key significance when considering the longer term performance of LiFePO4 batteries in house bank applications, because incomplete charge cycles are common when relying on renewable energy sources and shallow discharge cycles are also frequently experienced. These have the potential to render battery banks near unusable after as little as 2-3 years in regular service in the absence of memory-releasing cycles.

I don't see how to avoid that situation for most RV use when charging with solar or with an alternator. You are essentially limited to shore power or a generator where you control so that charging only occurs when there is the ability to fully recharge the battery between uses.

That is a bit a deal killer for lithium in rv's.

edit: after reading more carefully, deal killer is a bit of an exaggeration. It does mean that you need to regularly bring the batteries to full charge using sufficient voltage and amperage to eliminate the memory effect. The author says this:

My experience so far has been that any termination voltage below at least 3.5V/cell should be considered as inadequate if the installation experiences incomplete charge cycles. Any charging system that is unable to provide an adequate absorption down to at least C/20 or less when required should also be considered as unfit for purpose, because it will fail to deliver charge cycles capable of erasing the cell memory.