12 volt, 10AH LiFePO4 batteries at good price

[papaof2]

batteryhookup.com/products/relion-rb10-pc-12-8v-10ah-lifepo4-battery?mc_cid=04be9c3b7f&mc_eid=7c6358641e

manfacturer's datacheet:
ceb8596f236225acd007-8e95328c173a04ed694af83ee4e24c15.ssl.cf5.rackcdn.com/docs/product/RELiON-Data-Sheet_RB10-PC.pdf

12 volt 10AH LiFePO4 battery. Relion RB10-PC. Battery is 4s4p of 2.3AH cells so technically 9.2AH but in typical service they would be equivalent or better than a 10AH AGM or gel battery. From the manufacturer's datasheet, it's rated to 3500 charge/discharge cycles at 80% DOD. That's 7 times what a typical AGM battery can deliver but for maybe $10-$15 more than that AGM battery. These were my fist choice for the equipment shed lights until I found a physically smaller equivalent LiFePO4 battery that would fit in the existing enclosure (one less thing to build, wire and test).

I've mentioned these batteries before. BMS for 10 amp charge/discharge via the smaller screws. Up to 50 amp discharge via the larger screws but you need a fuse and some means of checking the voltage so you do NOT over-discharge the battery. They can be charged at temperatures down to -4F (-20C) - (see chart on datasheet).

$35 each plus shipping. New price on these is $300. Shipping to central Georgia is $15 for one via UPS ground or $17 for four - once you get past the extra cost for shipping a lithium battery, the incremental shipping is simply by weight - and they don't weigh much.

I've experimented with several of these batteries and they meet or are very close to the advertised specs. Certainly a bargain if you need some batteries of this capacity. The package is larger than a typical AGM or gel battery of the same capacity but you could open the case, remove the battery pack and repackage it to fit your application - maybe just wrap it in Kapton tape?

Unlike an AGM or gel cell battery, the LiFePO4 battery can deliver its rated AH at any load. AGM and gel can only deliver the rated AH at 0.1C load (10% of rated AH). The LiFePO4 discharge curve is basically flat - holding its voltage until about 90% discharged.

From my experimenting:
rb10-pc

charge 14.2 - 14.6V

balance 14.4V

Solar charging: Use the "balance" voltage as the controller's "float" voltage unless the controller has a "lithium" mode.

Ideally charge at 0.3C (but 0.5 to 5A is acceptable - Max of 10A - see datasheet) A single 100 watt solar panel can deliver about 5A so it would be a good choice for a quick recharge. For one or two batteries in parallel, a PWM controller might be fine - depending on your available sunlight.

[feralferret]

I may have to jump on this one. I have a plastic battery box like for a boat that will hold four of these with some room to spare. I have 500 watts of solar panels waiting for installation after I get moved. I just need a suitable MPPT charge controller, preferably 50 amp to allow for expansion. I have several smaller inverters, but would like to get a larger one at some point. This would be sufficient to have some light, communications, and the ability to charge phones & handheld radios.

Now if only the house there wasn't all electric with no gas line in place. I guess I will have to eventually build a rocket mass heater. The house does have a fireplace, but those are quite inefficient.

[papaof2]

Build a stove that will fit the fireplace or buy an insert (Northern Tool and others or - depending on the size of the firebox, maybe make a stove from a 20lb LP tank from a grill? The firebox here is 48" wide by 31" high so I could use a 20lb tank standing up (using its bottom or 3 welded on legs for support). An angle grinder could cut out the door and open up the top connection for a piece of "chimney pipe" to get it to the damper's input. I have some firebrick (builder's leftovers when they built the two big fireplaces during this house's construction) and I'd have a layer of firebrick at the bottom of the tank so it wouldn't burn through so quickly. A tent stove might be an option for some fireplaces (Cabela's and others) or build your own if you have tools and materials - I have a wire welder and a small stick welder and while I'd never claim to make pretty welds, the extension I did on a shepherd's crook to support two bird feeders in the back yard has lasted out in the weather for more than 10 years so I think "sturdy" or "durable" might be appropriate terms.

If you have tools and materials or materials and someone to do fabrication, a custom made stove / insert could be very efficient compared to the fireplace. Or look for a cheap/free large LP tank on Craig's List and plumb some gas logs. Small (18" - 24" gas logs are around 30,000 - 35,000BTU. From a spreadsheet I put together, a 1000 gallon LP tank with the typical 80% fill (800 gallons) could run 33,000BTU gas logs for 8872.7 hours. That's 1109 days if the logs are on 8 hours a day. How many hours will depend on how cold it is outside and how much space is being heated inside and how many times the doors are opened and for how long. If you had some alternate power, you could power fans to move the warm air around (at least a little). Getting heat into the next room is a given. Getting a lot of heat down a hall and having it turn 90 degrees to warm a bedroom and a bathroom is another story - although it is possible if the heat is on long enough: we did that for two weeks while waiting for a repair part for an almost new furnace. Heat was 35,000BTU gas logs plus a 22,000BTU kerosene heater. Kero heater in the kitchen and facing the door to the hall. Fan on the counter blowing the very hot air at the top of the kero heater down the hall. Daily highs in the 30s and lows in the teens. Kero heater and gas logs turned off when the rooms got to 75F or so and when we went to bed or left the house. Bedroom about 60F in the morning so it can be done.
A couple of 100 gallon LP tanks at 80% fill would provide 221 days of heat if running the gas logs 8 hours a day. The manual for the 35,000 gas logs we have specifies two 100 gallon tanks as the minimum to have enough vapor pressure in cold weather. If you're OK with having the LP tanks in the house, you could use two 20lb gas grill tanks but they wouldn't last long at 33,000BTU (11 days with the logs on 8 hours/day).

You would have to work out how much space needed to be heated (which room(s) can you close off for the duration, if any?).
How much AC or battery power would be needed for lights & fans (battery-powered fans running on rechargeable batteries are very useful - we have several - with one of the most useful being one I posted here a year or so ago). It's rechargeable fan plus light that gets 50+ hours for light only (on low), 17 hours for fan only (on low) and 15 hours for light + fan (both on low). We've used that a lot in the past year - mostly for having a fan that can go wherever it's needed for a few hours. O2 (and others) sell battery powered fans - usually D cells - and I have two of those with DIY adapters to connect them to a small AGM battery (typical UPS size of 7AH) for about 24 hours on low speed.

If you're interested in the spreadsheet on LP hours of use versus BTU of a heating device, let me know and I'll post it. It includes things like a 4000 or 9000BTU Buddy heater up to a 100,000BTU central furnace and you can add in whatever you might be curious about. All my spreadsheets are in Excel 2003 format so they're readable by almost any spreadsheet program - there are some advantages to keeping old traditions ;-)

[feralferret]

I would much prefer the heat source to be in the basement. The water distribution pipes are there and three of the bedrooms (and a bathroom) are also in the basement. Some of the heat from the basement would rise into the ground floor where the fireplace is located. The one person using an upstairs bedroom could come down to the basement and use a cot or inflatable bed. The other two upstairs bedrooms are vacant (other than full of junk) since the two kids grew up and moved out.

[papaof2]

Try this link: www.jecarter.us/files/propane-use-by-BTU.xls

You could do what a friend did in a rental house (with the approval of the owner). There was a wood burning stove on the main level but the kids' bedrooms were upstairs and very little heat got up there. He cut out a square out of the upper floor and the main floor ceiling over the wood stove and put in some sturdy grates. The warm air easily got to the upper floor and heated it.

They sell non-vented LP stoves and wall-mount heaters (Northern Tool and others). Figure where to place one or two heaters and plumb them to your LP tanks and you could heat the basement and let that air work its way upstairs or add a grate between floors.

Maybe my ID should be "shadetree mechanic"?

[papaof2]

I have four of the Relion RB10-PC batteries, purchased in January 2023. They were last charged in Sept 2023. I got them out today (1-16-2024) to check their status after being untouched for 3 1/2 months. I hooked them up to a solar charge controller fed by a DC supply that's a "15 watt solar panel equivalent" (based on how I would recharge these batteries in a possible future application). Each battery was connected and left to charge until the BMS disconnected it from the charge controller. I allowed 45+ minutes (plenty of time to charge the battery if it is still in the "good" range of self-discharge and to balance the cells if the BMS detects that they need balancing. Every battery finished the charge in under 10 minutes - most in 7 minutes or less. I left them connected to determine whether the BMS did any balancing. Two of the batteries did obvious balancing, with there being multiple small current spikes after the charge current dropped below 0.1amp. The other two batteries didn't spike but continued at a low current (10 - 40mA) for several minutes after the charge completed. I'm guessing they were checking the balance level of the cells but did not find anything that needed immediate or serious balancing.

I beat on these batteries rather hard during testing but they still check as almost new so I'll have plenty of power to continue with one of my projects - I want to have low level lighting ("stumble light") in all the rooms of the house when we have a long power outage. That needs some testing of "How much light in which room?", "How many hours of light?" and "Manual or auto switching?" I'm considering some short strips of LEDs (either just enough for 12 volts or two 12 volt strips) from a long (5 meter / 16.4 feet) strip light. The strip light has an adhesive back and could be attached to the top of a window's inside trim to throw limited light on the ceiling.
1. It's not a large, point source of light and won't be seen from the outside as "They have power!"
2. It's a low power light that can run for a long time off very little power.

Practically, there should be one or two places where the switchover is automatic: the bathrooms without windows should have backup lighting whenever the power is off and the windowed bath after dark. Bedrooms should probably only have manual light control unless there's a child or someone ill needing care in that bedroom. A child being afraid because power is off from a thunderstorm is always calmed by having light - even just a little light.

Most of the wiring to the windows could be hidden by the baseboards on its way around a room and by curtains from baseboard to the bottom of the window trim. No more power than will be needed by the short LED strips, the wiring can be small - 20 or 22 gauge and easily slipped behind a baseboard or window trim. The switching is yet to be determined. All automatic switching could be handled by a power-fail sensor that turns on the selected lighting. Would there be a need to have low level lighting in a bedroom if someone was ill, regardless of the status of commercial power?

If only 1/4 of the strip light is used, the total current drain would be around 0.3amp and one RB10-PC battery would be adequate to power that for at least 24 hours.

So far, just an idea recorded in my computer, but with some tested pieces for use in implementing that idea.

A 20 watt solar panel would be fine for recharging that battery (or batteries) as it would typically have days of sun in which recharge a few hours of use before the next use cycle occurred. If more power is needed, I have two 20 watt panels that could e mounted facing slightly different directions so one might get more sun early in the day and the other more sun later in the day - whatever hours "early" and "later" might actually refer to.

[feralferret]

Unfortunately my wife has an irrational fear of propane. She is fine with natural gas. Go figure.

[papaof2]

Maybe a outdoor "furnace" where the fire is outside the house and a fan brings it inside - but that requires some serious backup power to keep a large blower (several hundred watts) running for 24 hours.

Heating is NOT a good use of battery power. 10,000 watt hours of battery bank can run ONE 1000 watt space heater for less than 10 hours - that's not much heat.

You need an enclosed fire, whether wood, LP, old tires or drawn and quartered NYC phone directories from the 1980's as your source of heat. Limited use of fans to move that heat where needed is almost a given unless the house has some unique bit of construction that provides circulation without power.

[feralferret]

I do have a small catalytic propane heater, so a little better than nothing.

[papaof2]

Have you considered the diesel RV/parking heaters? Somewhere between $120 - $250 depending on the date, time, phase of the moon and the brand of underwear the vendor is wearing. 10 liters (2.6 gallons) will run the heater at full output for about 19 hours (5KW, about 17,000BTU - so a little less than the typical round kerosene heaters - which are another option). The diesel heater will need a minimum of a 12 volt 100AH battery to run 24 hours, allowing for the higher drain when starting & stopping and for running at higher output during colder hours - and you'll need to be able to recharge that battery during the next day of heating so the solar panels must be big enough to run the heater and charge the battery at the same time. The heater is inside and heats and circulates inside air. The burner uses outside air for combustion and exhausts to the outside. Not as quiet as a kero heater - the fuel pump goes tick-tick-tick continuously, with the speed determined by how much heat you've requested: more heat needs more fuel so the fuel pump puts a shot of diesel in more frequently plus the sound of the fan. A kero heater has the advantage of needing only fuel and a match or grill lighter or batteries in the kero heater's electric lighter.
Kero heat does not smell especially bad IF you always take it outside to light it and get the flame stable for a couple of minutes and you watch the fuel level closely enough that the heater is taken outside to be extinguished, allowed to cool and then refilled - and relit if still needed. We used the gas logs and a kero heater for two weeks while waiting on repair parts for the gas-fired furnace about 10 years ago. There was a faint scent of kero but not enough for either of us to complain about and we're both sensitive to unneeded aromas - whether "air freshener" or kero. Depending on the outside temperature, the size of the space to be heated and how warm you want that space to be, expect a 22,000BTU kero heater to burn a gallon+ per day. If you're buying 1-K at Lowes for $9/gallon that's expensive. If the heater has a fiberglass wick or it's listed as OK for red kero, it's usually much cheaper than 1-K. You may or may not be able to find a gas station with a kero pump. For me, that's just into the next county and up a little two-lane road. YMMV.
If there are small children, you need to find the "cage" of fiberglas rods that can keep kids (pets, if needed) far enough away that they can't touch the heater - it's top can easily be 600F. Some of the heat powered fans can work on top of a kero heater. lehmans.com has a very nice oscillating stove top fan which should be able to move warm air to a lot of a room.

Don't know how much of this you might be able to implement but I'm watching the temperature drop and the number of power outages wander up and down, seemingly without any reason or correlation to the weather and it seems useful to pass along all the ideas on the off chance that one or more might work for you or inspire you to do something else.

I use the remote to turn the gas logs on long enough to raise the room's temperature a couple of degrees, then turn them off and wait for the temp to drop. Doesn't take long when the outside temp is 15F. Even good insulated doors would be better with some quilts over them...

[papaof2]

They also have some 40AH 12 volt LiFePO4 batteries with BMS that can be wired in series for 24, 36, or 48 volts:
batteryhookup.com/products/valence-u1-12rt-lifepo4-12-24-36-48v-40ah-512wh-used?mc_cid=be0d4c2916&mc_eid=7c6358641e
$85 each + ship

Same battery but with the cables cut so no connector for putting them in series (and maybe access to BMS - I haven't read the datasheet).
batteryhookup.com/products/fully-tested-valence-u-charge-rt-series-u1-12rt-lifepo4-battery-12v-40ah-512wh?mc_cid=be0d4c2916&mc_eid=7c6358641e
$69 each + ship.

HQSTsolar has 12 volt 100AH LiFePO4 batteries for $199.99 with free ship and 10 year warranty:
hqsolarpower.com/hqst-12v-100ah-lifepo4-lithium-iron-phosphate-battery-10-year-warranty/?mc_cid=e574e3b8e7&mc_eid=ab8480f6be
HQST sale ends 1/26/24

[papaof2]

DIY fireplace insert that burns waste oil: www.youtube.com/watch?v=hwcNrDWOE4Y

The fuel is cheap ;-)