New to me Lithium battery upgrade

[admin-rich]

Lithium Iron Phosphate (LiFePo4) (also known as LFP) prices have come down from a couple of years ago.
So I bought two 12volt 100amp hour batteries from an outfit name AmpereTime.
I'm currently in Arizona and they warehouse ship from locations in California and Texas.
Delivery was within 5 days.

I'm very pleased with AmpereTime from their shipping, packaging, documentation and the physical product.
AmpereTime sells on Amazon but I purchased direct from the company website to save an additional 5-percent.
Total cost for the two batteries delivered was $739.00

My camper already had 400 watts solar on the roof and a 30 amp solar controller.
So this was pretty much "plug-&-play".
The solar controller has a LiFePo4 setting - it was easy to switch charging parameters from AGM to LFP.

I decided to change out the Progressive Dynamics converter to a PD Lithium converter.
It wasn't really necessary but I found that prices were going up for the PD9145ALV and I found one on Amazon Warehouse at a better price.

One thing I didn't like was that the AmpereTime battery does not have battery posts.  
Instead it comes bolts that one must insert through the battery cable eyelet and thread into the battery.
It's a hassle.

The install is complete and I've only gotten two camping days off grid so far.
I somehow managed to get the fridge switched over to battery battery power for an afternoon when washing the rig.
That little caper brought the battery voltage down to 13.1
So there's that. . .

Anyway, so far so good.

[3 tons]

Smart move Rich!!…In nominal terms two 100 a/hr LFP’s are roughly equivalent to having four Lead-Acid types…I made the switch to a single 200 a/hr LFP about 20 months ago and couldn’t be happier…I mounted it beneath the dinette seat and simply repurposed the smallish EC 995 battery box for storage…

[3 tons]

Hey Rich you inspired me!! We recently returned from Qzite and I’m now in the process of upgrading my 440w of solar by another 120w for a total of 560w, and considering adding a second 200a/h LFP…During warm weather we occasional run our 11kbtu air cond from the single 200a/h LFP battery for an hour or two (concurrent with solar) and hate having to eventually drag out the Honda….Hoping that the added solar capacity will help the two 200a/h LFP batteries recover upon the next peak solar harvest period…LFP’s tend to recharge much faster than lead acid types…

[admin-rich]

Hey Rich you inspired me!! We recently returned from Qzite and I’m now in the process of upgrading my 440w of solar by another 120w for a total of 560w, and considering adding a second 200a/h LFP…During warm weather we occasional run our 11kbtu air cond from the single 200a/h LFP battery for an hour or two (concurrent with solar) and hate having to eventually drag out the Honda….Hoping that the added solar capacity will help the two 200a/h LFP batteries recover upon the next peak solar harvest period…LFP’s tend to recharge much faster than lead acid types…

Would you buy a name brand battery such as BattleBorn or go with one of the low cost competitor batteries such as AmpereTime or Chins?
I see AmpereTime is now offering a heated battery (not available when I purchased mine) and they lowered their "purchase direct" from a 5% discount to a 3% discount.

[3 tons]

Good Question Rich, Since I already have one 200a/h Aims LFP (theinverterstore.com), I feel that for a parallel second battery install it’s likely prudent to use the same make and capacity to ensure the BMS’s will properly coordinate…In my case, to make for the necessary space, after a bit of surveying it’s obvious that the easiest and most available second battery mounting location would be indoors, under the forward dinette seat, but where the nylon battery box resides…If you think about it, the exterior vented battery box exist for Flooded Lead Acid type batteries anyway - Lithium doesn’t need venting!

But due to the larger size of the 200a/h LFP (too big to fit inside the battery box), and the otherwise (under the dinette seat) wasted space that surrounds the parameter of the battery box, I’d simply unscrew, and remove the battery box and seal and insulate it’s hinged door opening…This approach also resolves the heating issue and opens up even a bit more usable space that what’s actually needed…

FWIW, Where unheated (e.g. exterior mounted), LFP’s will continue to discharge to as low as - 4f, and due to LFP’s far deeper depth of discharge, charging can often be deferred and resumed till the beginning of peak harvesting hours, or even skipped say till the next day or so… Another alternative would be to install an insulated battery heating blanket available on Amazon - a fair tradeoff for the extra usable capacity Lithium makes available…

With the added solar (at 540w), I believe that assuming ideal conditions 35 MPPT amps per hour might be achieved, but given the vagaries of solar 25 amps per hour (say, 75 a/h recovery over 3 hrs…) is a more conservative number to shoot for, which for the most part (including off-grid desert camping and RZR riding) negates having to use the Honda 2200…

In fact, I’m even thinking about running the refer off solar - this as kinda a ‘diversion load’ to use once the batteries have sufficiently recovered..Note that with Lithium (unlike Lead-Acid) there’s really no real need to do a full 100% SOC recharge, except for occasional cell-rebalancing and (if applicable) SOC Shunt Meter resynchronizations…

[admin-rich]

There's probably some degradation after two years of use of the original battery - depending on it's use, storage, charging, etc.
Have you arrived at a conclusion regarding that possibility?

You could still parallel the new and old batteries using an marine switch capable of  "1 - 2 - Both" connections.

[3 tons]

You’re correct, but when asked I was told Lithium is a bit more tolerant in this way - maybe up to even 6 mos…My older generation LFP had a capacity defect (failed a load test) and they replaced it outright in early December with a new 2nd Gen battery (with bluetooth) with no pro-rating and no questions asked  (10yr warranty), so I feel I’m still within the ballpark…To be sure, they load tested the new 200a/hr battery using a 500w halogen lamp and it tested out at a full 215a/hrs - in fact just to verify, I charged it up then purposefully ran it down to 10% SOC (via accurate Victron shunt meter) and it still ran the microwave at 136a…So for some more fun I continued to draw it down to even zero% SOC and it still brewed coffee via the Keurig pod brewer at 125 amps without a hitch, and without even sounding the inverter’s low voltage alarm!….A truly quite astonishing performance!

As far as the aforementioned refer diversion load idea goes, my thinking has evolved a bit and now I’m entertaining the idea of switching out the 13 yr old 6 cu/ft Norcold refer entirely with a new uber efficient 9 cu/ft Danfoss-compressor type refer that fits into the same cabinet space…Amperage is rated at about 5.3, but at say a 50% duty cycle (for approx thumbnail calc’s) this drops by about one half…

[3 tons]

To add to my previous, the main concern of battery degradation is more related to flooded wet cell type batteries due to a process of plate sulfation, especially when the battery is being deep-cycled say below 50% SOC, or by improper or infrequent charging which prevents the sulfate (sulfate forms during each discharge event - the result is ‘power’!!) from being driven back into the electro-chemical soup…This process in not 100% efficient, and to a small degree the sulfating process begins even from the moment the battery is manufactured - this is why multiple batteries should be of the same approx build date, else charging could be somewhat unbalanced…

Lithium (LiFePO4) is not affected in this same chemical way (thus, their extreme longevity), but can be damaged primarily by an *overly-extended charging interval, charging at too low temperature (32d/f >), or by an inadvertent complete discharge…

*can lead to the formation of cell damaging dendrites

[admin-rich]

First week long trip, six nights, some at or below freezing, mostly sunny but several cloudy days and the Lithium reached "Full charge" by noonish using only the solar panels and whatever charge provided by the truck alternator.

I unplugged the converter before we departed Arizona and use only 400 watts solar for charging the batteries.
So no other charging systems involved - no generator or shore power charging.
Basic usage was propane heater, lights, DVD / TV player and whatever "gas valves" needed for fridge and water heater operation.

The solar/lithium system has no shunt meter to show how much energy is left "in the tank".
I'm "winging" it to learn what the Lithiums can do and how far they can go.

The lithium battery compartment has not gotten to below 32 degrees yet.  Solar charging begins slightly after dawn.
The batteries are not heated.

[3 tons]

First week long trip, six nights, some at or below freezing, mostly sunny but several cloudy days and the Lithium reached "Full charge" by noonish using only the solar panels and whatever charge provided by the truck alternator.

I unplugged the converter before we departed Arizona and use only 400 watts solar for charging the batteries.
So no other charging systems involved - no generator or shore power charging.
Basic usage was propane heater, lights, DVD / TV player and whatever "gas valves" needed for fridge and water heater operation.

The solar/lithium system has no shunt meter to show how much energy is left "in the tank".
I'm "winging" it to learn what the Lithiums can do and how far they can go.

The lithium battery compartment has not gotten to below 32 degrees yet.  Solar charging begins slightly after dawn.
The batteries are not heated.

Glad to hear it’s working out well for you Rich!!…My LFP’s are working out even better than I’d ever hoped!  To update, I added a second 200a/hr LFP (in parallel) for a total now of 400 a/hrs, and added yet another 100w PV panel, for a new total of 660w, and truly couldn’t be any happier… Our normal daily usage might run just under 30 a/hrs, say when using Keurig, microwave, furnace, lighting and computer charging, and with the new panels in decent spring weather (some occasional clouds) have been able to harvest about 30amps in approx just 1 hour or so - so at this juncture (not counting air cond) basically energy self-sufficient…When considering the 11k air conditioner (say during mostly clear sky concurrent harvest…), I would estimate typically 5 hours of run time or more (with compressor cycling), with plenty of battery reserve to carry over until sunrise and till the start of prime harvest hours in preparation for the next days use of the air conditioner….Much of this is due to LFP’s far deeper depth of discharge ability… The nice thing about LFP’s (per hands-on testing) is their far deeper ‘depth of discharge’ ability without incurring a significant drop in voltage, 90% DOD (and beyond, via testing!) has proved to be routinely possible…

                   

Sorry about the Victron Bluetooth pic upside down, but it shows the harvest amps (minus parasitical loads) and SOC (state of charge)…
The two added panels to the rear are a 100w in the foreground, and a 120w (a new total of 660w)…I fashioned some raised brackets to avoid shadowing from the baggage rail and air cond…The digital meter (from Amazon) readings are the 120v inverter with the air conditioner running…