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About to buy a LiFePO4 Lithium Iron Phosphate Battery Deep Cycle Rechargeable Battery

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#1 kurtfriedrich

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Posted 22 October 2021 - 06:00 PM

This one is only 20 AH, but I only need my laptop to get polar aligned, ~5 minutes, run the mount, and maybe a dew heater, so this should last me enough hours.

 

https://www.amazon.c..._qh_dp_hza?th=1

 

At $125 it seems reasonable (plus a charger)

 

Curious if anyone has tried this company or has any better ideas?

 

thanks


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#2 WadeH237

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Posted 22 October 2021 - 07:07 PM

I would stay away from this battery.

 

The issue is that it's not clear what the actual capacity is.  Quoting the number of amp hours is meaningless unless you know the voltage at which it's measured.  This battery provides 12v (probably 12.8, actually) at the terminals - but it's not clear that the capacity is quoted at that voltage.  The native voltage of a single LiFePO4 cell is 3.2v.  To get 12.8 volts, you need to connect 4 of them in series.

 

Some vendors quote the amp hour capacity at the native voltage of a single cell.  If that's what has happened here, then the battery actually only has 25% of the capacity that they want you to believe.

 

To clear this up, many vendors quote the capacity in watt hours.  Watt hours is unambiguous.  If they included a rating that the battery is 240 watt hours, then it would, indeed, be 20 amp hours at 12v.  If, on the other hand, it was rated at 64 watt hours, then it would only be a 5 amp hour battery at 12v.  With the information in the marketing material, it is impossible to know which is which.

 

I took a look at the comments, and I saw a number of them that claimed that the capacity was far below what they expected.  That, and my own personal policy of never buying a LiFePO4 battery that does not quote watt hours, would make me steer clear of this one.


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#3 kurtfriedrich

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Posted 22 October 2021 - 07:16 PM

I would stay away from this battery.

 

The issue is that it's not clear what the actual capacity is.  Quoting the number of amp hours is meaningless unless you know the voltage at which it's measured.  This battery provides 12v (probably 12.8, actually) at the terminals - but it's not clear that the capacity is quoted at that voltage.  The native voltage of a single LiFePO4 cell is 3.2v.  To get 12.8 volts, you need to connect 4 of them in series.

 

Some vendors quote the amp hour capacity at the native voltage of a single cell.  If that's what has happened here, then the battery actually only has 25% of the capacity that they want you to believe.

 

To clear this up, many vendors quote the capacity in watt hours.  Watt hours is unambiguous.  If they included a rating that the battery is 240 watt hours, then it would, indeed, be 20 amp hours at 12v.  If, on the other hand, it was rated at 64 watt hours, then it would only be a 5 amp hour battery at 12v.  With the information in the marketing material, it is impossible to know which is which.

 

I took a look at the comments, and I saw a number of them that claimed that the capacity was far below what they expected.  That, and my own personal policy of never buying a LiFePO4 battery that does not quote watt hours, would make me steer clear of this one.

if you scroll down to the table comparing their products, it does say that it is 256Wh, which I assume is 20 amps X 12 volts =  240 Wh.

 

Does it still make you nervous?



#4 ngc7319_20

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Posted 22 October 2021 - 07:26 PM

Agreed you need to check the Watt Hours... and the return policy.



#5 Migwan

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Posted 22 October 2021 - 07:41 PM

Really hard to say, but weight for 20Ah @12VDC LFP and price for 3,000 cycle cells are a little suspect.   I have a 12 Ah Bioenno that is 2000 cycles and weighs as much at the same price.    

 

There are good and not so good LFP cells, just as there has been with all battery types in the past.  In the end, it's hard to say which this one uses.   It may just be great deal and cell prices might be coming down.   If your feeling lucky and it has free returns, go for it.    Myself, I would go with a more established battery producer.    

 

Though specs given in watt hours are more useful where different voltages are involved, I've seen where those have been misstated by some producers, too.   So no guarantees there.

 

These often don't come with a charger.  If so, make sure you get the producer's charger with it.  Don't want them blaming the charger if something goes awry.

 

Good luck



#6 Berny

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Posted 22 October 2021 - 08:00 PM

I read somewhere that LiFePO4 batteries will be damaged if you charge them below 32 deg F,  and perform very poorly at low temperatures.  You might want to check into that.



#7 TelescopeGreg

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Posted 22 October 2021 - 09:16 PM

I read somewhere that LiFePO4 batteries will be damaged if you charge them below 32 deg F,  and perform very poorly at low temperatures.  You might want to check into that.

All batteries perform poorer at low temperatures.  So do we :)

 

Correct, lithium batteries should NOT be charged below 32F.  The lead-acid varieties (e.g. SLA/AGM) can be charged at low temperatures, but you only get about 500 charge cycles, and shouldn't discharge them below 50% charge (so take the amp-hour rating in half).  Lithium is good for 90% capacity, at least at room temperature per the above.


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#8 kurtfriedrich

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Posted 22 October 2021 - 10:22 PM

So are there "name brand" lithium batteries?  I don't see any company that stands out on the internet?

thanks



#9 Etrsi_645

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Posted 22 October 2021 - 11:01 PM

Name brands: Bioenno, Battle Born, these two I would consider very high quality batteries, but you do pay for that quality.


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#10 ngatel

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Posted 22 October 2021 - 11:04 PM

Back in April I bought three Miady 12volt 16AH (205 Wh) LiFePo4 batteries on Amazon for $59.99 each. I connected them in parallel for 48AH. I have used them about 150 nights, usually consuming 20-23 amps per night and I recharge them each morning. So far they are still charging and working like brand new. This particular battery isn’t shown on Amazon, but there is a 36AH Miady for $130.
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#11 kurtfriedrich

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Posted 22 October 2021 - 11:35 PM

OK, thanks all, went with a Bioenno. Comes with some strange looking connectors, I'll need to rig up some way to turn that into cigarette lighter socket to connect my gear.



#12 Etrsi_645

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Posted 23 October 2021 - 12:06 AM

red and black Anderson Powerpole connectors?  If so, you can get an Anderson to cigarette lighter cable..

 

https://powerwerx.co...rpole-connector


Edited by Etrsi_645, 23 October 2021 - 12:08 AM.

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#13 Migwan

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Posted 23 October 2021 - 09:23 AM

Actually, LFP batteries work quite well in the cold.    My Bioenno only dropped to 13.4V after 4 hours of use ending at -5F.   It also runs a bit past its rated 12Ah capacity.   I do bring it in to charge during the winter. 



#14 GrandadCast

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Posted 23 October 2021 - 09:45 AM

I would stay away from this battery.

 

The issue is that it's not clear what the actual capacity is.  Quoting the number of amp hours is meaningless unless you know the voltage at which it's measured.  This battery provides 12v (probably 12.8, actually) at the terminals - but it's not clear that the capacity is quoted at that voltage.  The native voltage of a single LiFePO4 cell is 3.2v.  To get 12.8 volts, you need to connect 4 of them in series.

 

Some vendors quote the amp hour capacity at the native voltage of a single cell.  If that's what has happened here, then the battery actually only has 25% of the capacity that they want you to believe.

 

To clear this up, many vendors quote the capacity in watt hours.  Watt hours is unambiguous.  If they included a rating that the battery is 240 watt hours, then it would, indeed, be 20 amp hours at 12v.  If, on the other hand, it was rated at 64 watt hours, then it would only be a 5 amp hour battery at 12v.  With the information in the marketing material, it is impossible to know which is which.

 

I took a look at the comments, and I saw a number of them that claimed that the capacity was far below what they expected.  That, and my own personal policy of never buying a LiFePO4 battery that does not quote watt hours, would make me steer clear of this one.I 

I don’t see how watt hours is any different.  Watt is just E times I, with time added to get watt hours. So in the ‘clear up’, could I, being an ambiguous seller whom didn’t put its the cell in ‘watt hours’ and therefor be no difference than the other ambiguous seller whom sales it at amp hour. 

 

Jess



#15 ngatel

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Posted 23 October 2021 - 10:49 AM

I don’t see how watt hours is any different.  Watt is just E times I, with time added to get watt hours. So in the ‘clear up’, could I, being an ambiguous seller whom didn’t put its the cell in ‘watt hours’ and therefor be no difference than the other ambiguous seller whom sales it at amp hour. 

 

Jess

Yes, you can use watt hours.

 

The Wh rating for the first battery the OP linked to had that specification buried in the description. I didn't notice that spec.

 

Typically, it is common practice for lead-acid deep cycle batteries to be rated using a 20 hour test. A load is placed on a battery and the amount of amps used until the voltage hit 10.5 volts is the Amp Hour Rating. Manufacturer's like Trojan or Crown also provide a spec for 5 hours, 10 hours, 30 hours and 100 hours. The 20 hour is the rating.

 

With smaller batteries (Lithium types) they often have ports for 12 volt, USB (5 bolt) and even 9 volts. Unfortunately many sellers advertise these as 12 volt batteries, but provide an amp hour rating based on 9 volts or 5 volts, thus inflating the specification and making it look like that is the rating at 12 volts.

 

Most of the larger LiFePo4 batteries I have seen use a rating based on 12 volts, probably because there is no connector or circuitry to run other voltage devices.

But, when buying online, one has to be careful and do some research. So the comments early on were warranted.

Here's a picture of the battery I bought. The specs are clearly marked on the batter itself.gallery_20979_17102_53459.jpg


Edited by ngatel, 23 October 2021 - 10:51 AM.


#16 WadeH237

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Posted 23 October 2021 - 12:05 PM

I don’t see how watt hours is any different.  Watt is just E times I, with time added to get watt hours. So in the ‘clear up’, could I, being an ambiguous seller whom didn’t put its the cell in ‘watt hours’ and therefor be no difference than the other ambiguous seller whom sales it at amp hour. 

 

Jess

I'm not sure that I understand your point, but amps is a unit of current, not power.

 

Without the voltage at which it applies, the number of amp hours tells you nothing about the capacity of the battery.  For an extreme example of this, consider that a rechargeable AA battery is about 2 amp hours at 1.5 volts.  You could truthfully call a rechargeable AA battery a 100 amp hour battery if you rated it at 30 milliamps  (100 amps x .03 volts = 3 watts = 2 amps x 1.5 volts).  The problem is that some LiFePO4 marketing material expresses the number of amp hours at 12.8 volts, and some at 3.2 volts, which has a 4x effect on the capacity.  Both of them are technically true, but not necessarily informative.  I actually did a text search for "watt" on the Amazon link that I visited, but the search turned up empty, so I didn't know that the watt hour spec was listed for that particular battery.

 

If you express the capacity in watt hours, there is no ambiguity.  



#17 CA Curtis 17

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Posted 23 October 2021 - 12:36 PM

I'm not sure that I understand your point, but amps is a unit of current, not power.

Wade that is quite true, but the convention is to quote the Ah capacity at 12V, even though the LiFePO4 batteries voltage actually starts off at 12.8V as you said and a lead acid battery starts at 12.6 to 12.9V.  That is the way the industry does it, like it or not. Also, looking at the add, I don't think there is any funny business on the capacity for this particular battery the op posted.  But that is not a recommendation from me since I have not checked out this vendor in any detail.

 

OK, thanks all, went with a Bioenno. Comes with some strange looking connectors, I'll need to rig up some way to turn that into cigarette lighter socket to connect my gear.

I am just writing a review of Bioenno's 50Ah battery and will post it on my web site soon.  The voltage remained at 12.0V or above for 91% of the rated capacity which I think is reasonable.  The internal BMS (they call it a PCM) shuts down at 10V to protect the internal cells from being overly discharged and to reserve some power for the BMS to function when you want to recharge the battery.  The Bioenno and Battleborn batteries are two of the more expensive brands, but Bioenno is located in Santa Ana, CA and you can get them on the phone quite easily.  Battleborn designs and builds their batteries in Reno, Nv and you can get them on the phone as well.  Many of the cheaper batteries, like Ampertime, are sold out of China and are not as easy to contact.  But from Will Prowse tear down video the Ampertime appears to be well made with the only exception that it does not have a low temp sensor.

 

 

Actually, LFP batteries work quite well in the cold.    My Bioenno only dropped to 13.4V after 4 hours of use ending at -5F.   It also runs a bit past its rated 12Ah capacity.   I do bring it in to charge during the winter. 

This is a point of confusion for many.  LiFePO4 can supply power at low temps, I believe more so than a lead acid battery, although all batteries lose capacity at low temps.  But, LiFePO4 batteries should not be re-charged below freezing (some manufacturers spec 28F instead of 32F) to prevent permanent cell damage. The BMS inside should protect for this, but, as an example, the Ampertime battery does not have a low temp sensor for low temp charging protection.  Also, LiFePO4 batteries should not be re-charged or dis-charged above ~104F (check the manufacturer's spec) for the same reason.

 

Best Regards,

Curtis


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#18 TelescopeGreg

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Posted 23 October 2021 - 01:15 PM

Where the Wh vs Ah thing comes into play is when there's a power inverter built into the unit.  Some product might have, for example, a 3.6v internal battery and an inverter to generate 12v from it.  The unscrupulous supplier might quote the 12v output, and, say, 10 amp-hours for the capacity, but "neglect" to mention that the 10 amp-hours is at 3.6v not 12v.  So the actual capacity is only 36 watt-hours, not the implied 120.  That's a really big difference. 

 

They often also say Amps, not amp-hours.  Amps is not a capacity, it's an instantaneous current.  Same with Watts instead of Watt-hours.  The product may have a 500 watt inverter, but a tiny battery driving it.  To be fair, I think some of this is just sloppy advertising or stuff getting "lost in translation".  Just be careful. 

 

I'm always wary of products advertising with smiling families enjoying an outing in the woods, powering everything from cell phones to laptops to ice cream makers, all from a tiny box and a pair of briefcase-sized solar panels.  Technology is amazing these days, but too good to be true is still too good to be true.



#19 Etrsi_645

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Posted 23 October 2021 - 01:16 PM

d##m it! whatever happened to the truth in advertising law?


Edited by Etrsi_645, 23 October 2021 - 01:16 PM.

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#20 WadeH237

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Posted 23 October 2021 - 02:26 PM

Wade that is quite true, but the convention is to quote the Ah capacity at 12V, even though the LiFePO4 batteries voltage actually starts off at 12.8V as you said and a lead acid battery starts at 12.6 to 12.9V.  That is the way the industry does it, like it or not. 

I don't have an issue with 12.0v versus 12.8v.

 

The issue is that, regardless of convention, some vendors quote the amp hours base on the voltage of a single cell.  So it's not 12 vs. 12.8.  It's 12 vs 3.2.

 

Where the Wh vs Ah thing comes into play is when there's a power inverter built into the unit.  Some product might have, for example, a 3.6v internal battery and an inverter to generate 12v from it.

Not at all.

 

All native LiFePO4 cells are 3.2 volts nominal, regardless of the voltage output of the assembled battery (which contains many cells).  To get 12.8 volts, there is no inverter or anything like that.  You get 12.8 volts by connecting four 3.2 volt cells in series.  You increase the capacity of the assembled battery by connecting many of these 4-packs in parallel with each other.

 

Also, note that there are two different batteries mentioned in this thread.

 

The battery in the first post is the one that I looked at on Amazon.  I still cannot find any watt hour rating for it.  I did find this customer review where he measured the capacity of the 10ah unit.  According to the reviewer, it looks very much like its amp hour rating is at 3.2 volts.  This is exactly what I was talking about in my response to the first thing I quoted above.

 

The second battery is the one pictured in post 15 of this thread.  That is a different battery from the one in the first post.  The pictured one clearly shows the capacity in watt hours.


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#21 ngatel

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Posted 23 October 2021 - 04:24 PM

A fully charged 12 volt LiFePo4 battery actually starts out at over 14 volts. Last night after 5 hours of imaging, I shut things down due to clouds. I just measured the voltage and it is 13.3 volts without charging it.

I mention this because my BeeLink GK55 mini PC shuts down if the voltage is > 13 volts. I have to use a buck converter to keep it happy. I can hook everything up to my trailer’s 12 volt lead-acid battery bank and not use the buck converter.

#22 CA Curtis 17

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Posted 23 October 2021 - 04:50 PM

I don't have an issue with 12.0v versus 12.8v.

 

The issue is that, regardless of convention, some vendors quote the amp hours base on the voltage of a single cell.  So it's not 12 vs. 12.8.  It's 12 vs 3.2.

Wade, I don't doubt you but I have never seen that myself.  We agree to be careful of those types of vendors.

 

A fully charged 12 volt LiFePo4 battery actually starts out at over 14 volts. Last night after 5 hours of imaging, I shut things down due to clouds. I just measured the voltage and it is 13.3 volts without charging it.
 

I have seen seen a LiFePO4 battery that remained at 14 or more volts with a load.  The correct charging voltage for LiFePO4 is 14.2 to 14.6 volts and that is what you are seeing initially.  I expect you would not measure 13.3 volts with a load present.  Both my Battleborn and Bioenno batteries stay at 12.9V with a 60W or 90W load through the first 20% of their capacity.  This is very repeatable.  Just like lead acid, actual cell voltages for lithium cells do vary with 3.2V being the nominal, as had already been stated, but some slightly above that to give the higher voltage at start that you and I both see.  The voltage drops slowly dropping below 12.0V at around 95% of the battery's capacity.

 

Regards,

Curtis



#23 ngatel

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Posted 23 October 2021 - 05:18 PM

A battery’s voltage reading with a load applied is not an accurate measure of a battery’s state of charge. The higher the load, the lower the voltage reading. Disconnect the load and the voltage will go up.

An extreme example is my camper. Let’s say the battery bank is at 12.6 volts. If I turn on the inverter and the 1200 watt microwave, the voltage will drop below 12 volts. The longer I leave the microwave on, the lower the voltage gets. The inverter will shut down at 10.5 volts, which turns off the microwave. After a few minutes the voltage will be much higher than 10.5 volts, but nowhere near 12.6.

This link

https://www.renogy.c...ge-percentages/

shows state of charge charts for AGM, lead-acid, and LiFePo4. Note that at 12.9 volts a liFePo4 battery is at 20% state of charge. This is with nothing connect. In my camper I use a battery monitor that measures amps in and amps out. It knows 225 AH is full and calculates percent full based on how many amps have been used. It ignores voltage in this calculation.
Edited because I forgot to paste the link

Edited by ngatel, 23 October 2021 - 05:20 PM.


#24 CA Curtis 17

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Posted 23 October 2021 - 06:04 PM

A battery’s voltage reading with a load applied is not an accurate measure of a battery’s state of charge. 

I respectfully disagree with this statement.  You are correct that you can get an accurate measure of the SOC by taking a no-load voltage reading.  And you are correct that the no-load voltage at a particular SOC will be higher than under a load.  And we should note that to get the most accurate reading, one needs to wait a couple of hours or more after charging or discharging the battery to allow the chemistry to come to equilibrium,  However, you are overlooking or discounting the fact that the SOC can be accurately measured while under load.  This is important to us because when we are in the field we often want to check the SOC without shutting everything down.  With a solar generator there is a capacity meter integrated in the generator which will keep us up to date on the SOC.  I have found those to be very accurate, within a % or 2.  With a stand alone battery, as in this discussion, we have to insert our own in line meter to keep tabs on the SOC.  Power hubs like the Pegasus Power Box have an A, W, Ah, Wh and run time meter conveniently integrated to make this easy.  Otherwise one can add one of the many inexpensive power meters available on line.  As you have stated, the loaded voltage will be lower than the no-load voltage at he same SOC but this will also follow a well-defined curve providing a much more convenient way to check the SOC without interrupting the power to our setups.  The voltage curve will be different with a different load applied, but within the range of loads we typically use, 20W to ~120W, this will not vary noticeably.  How do I know this for certain?  I recently measured the V, Wh, and Ah from 100% SOC to 0% SOC for both a 60W and a 90W load on a Battleborn 100Ah battery and the voltage vs capacity curves are identical.  I will publish this on my web site once I am done with the remainder of my tests of the Battleborn battery.

 

I have an RV and like you I also notice the voltage drop when I turn on my inverter to run my microwave.  Just last week I had to abort microwaving water for a cup of tea because it was draining the last bit of useable energy out of my AGM batteries and I had one more day to go in the field.  I ended up running the generator later in the day to top off a little.  I do not yet have solar panels on my RV, which be a next spring project.

 

Regards,

Curtis


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#25 ngatel

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Posted 23 October 2021 - 07:59 PM

Curtis,

 

Good feedback. Of course we aren't running large loads at our scopes. I don't need dew heaters and where I live if temps go much below freezing we call the National Guard.

 

As I mentioned earlier, I use around 20 amp hours if my equipment runs for 12 hours. I measured it before buying a battery. This is why I opted for a 48AH battery bank so I don't have to worry about the battery going dead, nor do I have to monitor or measure anything. This is so important to me. I can leave my slide rule at home (yes I still have one) when camping. The battery bank will easily last for two nights without charging, although I charge it daily.

 

But I do have a meter and can measure how may Wh I have used. I never look at it because I have plenty of capacity. Below is a "power center" I built. It can connect to my 48AH LiFePo4 battery bank, my trailer battery bank, some TalentCell batteries using their included cables, or an AC powered regulated power supply. I used the meter to size the battery bank. Nowadays I just look at the voltmeter when I power on my system to verify there is power.

 

Power-Center.jpg

 

 

Since you are interested in solar for your trailer — a trailer is a different story vs. a scope, as we are talking much different amperage demands and operating strategies, as you know. The trailer has solar. My battery bank is 225AH and the state of charge rarely goes below 80% on purpose. I sized it so I can maximize the number of charging cycles. I have 280 watts of solar. Monocyrstalline panels made by Kyocera that are permanently mounted on the roof. I also have a 2000 watt pure sine inverter for sensitive electronics. But we rarely use electronic goodies camping, unless I bring my telescopes.

 

I do have a couple Honda generators that we use to run the A/C at night when we are camping in the desert during summer . . . when daytime highs are 110F - 125F. Other than these summer trips, the generators stay home. I use them maybe two or three times a year. Mostly because I hate generators, but have become too old to sleep comfortably when nighttime temps are in triple digits. 

 

All the other times we depend on solar and we often camp in remote places for weeks at a time. We can have several days in a row with rain and no solar generation, so I need to know exactly where my battery bank is as regards state of charge when this happens. I use a well-regarded battery monitor called the Trimetric, made by Bogart Engineering. This meter can tell me the percent of battery capacity left, battery voltage/charging voltage, amps (charging or discharging), and a bunch of other stuff.

 

Here is the Trimetric (left), remote display for the solar charger (right)), and the panel for my inverter when I turn it on (bottom). Don't really need the solar charger display or the inverter panel.

 

Milan-2013-10-05-01401.jpg

 

I have been using solar and Trimetric Battery Monitors since 2003 and have never had a dead battery on a camping trip, nor have I ever had to charge my battery bank with a generator or the electrical grid.

 

The other important thing is I rarely look at these monitors if we have several days in a row with little or no solar generation. I have sized my solar array and battery bank to work without me worrying about the battery state of charge or how many amps my solar array is generating, which ties into my earlier comment about sizing my LiFePo4 battery bank.

 

Good conversations in this thread! 


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CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


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