High altitude affects batteries?

Cariboocoot · May 2009

After a week+ of messing about with the satellite, I'm back on-line in he Cariboo!

The system was up and functioning instantly, having survived the winter. Since then I've noticed the same problem as last year: batteries don't perform quite as spec'ed.

Then I got to thinking; high altitude here affects cooking, barometer, and engine efficiency. Does it have any effect on batteries? I couldn't say if I'm adding water more frequently than I would be at sea level, but I do know water boils at a lower temp up here.

So the big question is: does high altitude do anything else to the chemical process of a battery? Anybody know anything about that?

I have to de-rate my generators because of his; maybe I should be de-rating the batteries' capacity as well?

BB. · May 2009

Re: High altitude affects batteries?

I have not heard about altitude affecting batteries (other than cooling -- if your batteries are doing a lot of current).

Temperature of batteries (warmer, higher capacity, colder longer life) and how many cycles (new batteries need to be cycled some 10-20 (?) times to reach their "maximum" storage capacity).

-Bill

dwh · May 2009

Re: High altitude affects batteries?

It's a good question. Thinking about it, it would seem that since the electrolyte is largely water, then altitude *would* have an effect...at least on unsealed batteries.

As you say, water boils at a lower temp at high altitude...so would that change the temp at which batteries should be bulk or float charged?

I dunno, but I think it logical that it would.

mike95490 · May 2009

Re: High altitude affects batteries?

You should never get batteries hot enough to even think about boiling. 110F is PLENTY (dangerously) hot for them. Altitude would be a factor only for vent pressure for sealed styles of batteries.
Generators (engines) and "some" electronics need derate for thiner air caused by altitude. (less O2 for engine, less thermal mass for electronics cooling)

Cariboocoot · May 2009

Re: High altitude affects batteries?

mike90045 wrote: »

You should never get batteries hot enough to even think about boiling. 110F is PLENTY (dangerously) hot for them. Altitude would be a factor only for vent pressure for sealed styles of batteries.
Generators (engines) and "some" electronics need derate for thiner air caused by altitude. (less O2 for engine, less thermal mass for electronics cooling)

Not a question of boiling them: that would be BAD! But batteries 'bubble' when charging - off gassing. Since the altitude does affect chemical processes, I just wondered if it might be reducing the batteries' capacity. I think I need a chemical engineer for this one.

icarus · May 2009

Re: High altitude affects batteries?

Marc,

As an aside, if you are on Xplornet sat servce send me a note. I have some pretty good info about keeping your system in top form/aim. (I've sorta been that, done that with Xplornet sat service).

As for batteries being de-rated for altitude,,, I don't think it is an issue. I also don't think you are high enough even if it were an issue, unless you are in the real high country of the cariboo.

Tony

peterako · May 2009

Re: High altitude affects batteries?

Hi there,
Air pressure ( altitude ) is not affecting battery's.

Temperature is a big deal as stated before and how bigger the battery how bigger the problem. but as well sleeping time i understood that you dint not used the battery this winter .
That is a small problem the chemicals settle down .
Solution slowly bring up the charge and bring them to a gassing sate ( boiling ) after 10 min. stop allow to cool refill the water and recharge.

the same is a problem for backup and not used for a few months the capacity drops. because the battery is a sleep.

greetings from Greece.

Cariboocoot · May 2009

Re: High altitude affects batteries?

Thank you everyone for your input.

I haven't found any info anywhere that says altitude effects the chemical reaction in a lead-acid battery, so I guess that isn't it. Over the winter I just disconnect the inverter and leave the charge controller on, so everything is 'warm' and fully charged when I get here. I think the problem is that these batteries just aren't quite up to spec, or I've got a bit more load going on than I can calculate (hard to do with automatic loads like the water pump and variable draw from comp, 'frige, etc).

So all I need is more amp hours and more panels to charge 'em with! Simple!:p

icarus · May 2009

Re: High altitude affects batteries?

Marc,

Consider a battery monitor,, like the Tri-metric, or at the least a digital ammeter on teh output side so that you can at least monitor the net load. For example,, a 120 vac load might be 30 watts,,, but by the time you include the inverter and wiring loss the net might be closer to say 50 watts. Your mind says "I'm only burning 30 watts why is my battery so low" When in reality you might be burning way more.

I know that I watch the Tri- metric and every once in a while I think most everything is off,, and yet there is an unexplained draw,, and I will search the house, and discover that the satellite modem and router are happily blinking away 1.5 amps doing nothing!

Tony

PS Often times it is just that I caught it when the fridge was in it's ignitor phase that lasts 20 seconds and draws ~1.5 amps.

dwh · May 2009

Re: High altitude affects batteries?

Yea, the only info I can find about altitude and batteries has to do with aircraft, and there doesn't seem to be anything talking about problems at high altitude other than freezing.

So, it looks like altitude (at least altitudes that humans can live at) has little to no effect on batteries.

System2 · May 2011

Re: High altitude affects batteries?

I'm getting so frustrated with responses on some of these forums- I too have noticed a shortening of battery life in high altitude areas, since I've been travellng in Tibet, India and Nepal. While I understand that cold temperatures affect batteries, I'm now in Kathmandu where it's bloody hot, an still I have to charge my phone every single day. Usually I just leave itturned off as sometimes it even dies within 24 hours f being charged. The power went off here about an hour ago and my laptop is about to switch to emergency standby dur to lack of power, wheras usually I get a good 2.5 hours out of it. You can't tell me altitude has no effect!!

BB. · May 2011

Re: High altitude affects batteries?

Katherine,

Cell phone batteries are a different chemistry than we are talking about here with Lead Acid batteries.

Your cell phone batteries are probably Nickel Metal Hydride or Lithium Ion.

Altitude can have an effect--but probably from two mechanisms...

One is temperature--Above ~5,000-7,000 feet, many electrical devices need power derating because there is less dense air and less cooling effect.

The other is that many batteries have a pressure vent and less air pressure will let the batteries vent at low pressures.

The above will affect your batteries in two ways... First hot batteries age faster and also have higher self discharge rates.

Aging--a general rule of thumb is for every 10C (18F) increase in temperature, the battery service life will be cut by 1/2... If the battery is rated at 25C and you get the battery upwards of 45C (for example, charging while setting in a sunny window), the life of the battery during charging will be cut by 1/2*1/2=1/4... So the battery will age 4x faster during those high temperature excursions. (keeping batteries cold will lengthen battery service life, but reduce capacity--again varies by battery chemistry).

The second issue is that NiMH batteries are designed to get hot when charging (high end chargers take temperature into account during charging). The batteries may develop higher pressures during charging due to poor cooling. At high altitude, the batteries can vent gases which will cut service life--And they would not have vented at sea level (lower temperatures from better cooling and higher air pressure increasing vent pressure).

Lastly, cell phones are designed to reduce their transmitting power to as low of level as possible. For people traveling in remote (from cell towers) areas--they will find that their cell phones discharge quite rapidly.

Airline pilots who "forget" to turn off their phones, and even myself vacationing in remote areas in the South West US, will find that phones which go normally go for days without recharging--may only get 4-6 hours out of our batteries as the phones go in and out of service areas and as the phone attempts to contact a cell tower by broadcasting at high transmitter power levels (at least at high levels for a cell phone).

Once I am back in a metro area--My phone's battery life goes back to normal.

-Bill

westbranch · May 2011

Re: High altitude affects batteries?

BB. wrote: »

Katherine,

Lastly, cell phones are designed to reduce their transmitting power to as low of level as possible. For people traveling in remote (from cell towers) areas--they will find that their cell phones discharge quite rapidly.

-Bill

Right on the money Bill.

just to add, the extra energy used is from the cell phone 'cranking up' its consumption while searching for a cell signal... and it stays on high until a cell is located.
Here in a more rural area we have several 'no service' zones along the main highway and one that lasts for about 3 hours. kills the battery quite quickly if the phone is left on.

Have no experience with laptops much above 3000 feet, unlike Katmandu ~4500 feet. have had issues with power from a MSW inverter (vs TSW inverter).

cheers
Eric

RCinFLA · August 2011

Re: High altitude affects batteries?

Effect on cellphone battery life may be due to sparcity of towers in Kathmandu.

Cellphones adjust their power output based on strength of received signal and have a feedback control via base station to control output power to only what is necessary to get a good bit error rate.

When you are farther away from a tower the phone's transmitter has to operate at a higher power output which has a very large impact on battery life.

rkymtnoffgrd · August 2011

Re: High altitude affects batteries?

My outback system (seperate than my fathers xantrax being discussed in another post) is off grid at my cabin at 10,125 ft in the rockies. Its comprised of 2 strings of 8 t-105s w/225 cap. These crown batteries are now 6 years old and I couldn't be more happy with how well these batteries have held up with not even a single cell showing a low sg after all this time. I have not had any reason to suspect any altitude issues what so ever. Now I also have an EU 2000i for backup, this has been an ongoing challange trying to charge these batteries through the fx 3648 with any house loads at all. This little generator only outputs 1300 (reliaby) at my elevation, and the FX seems oh so touchy about being able to regulate inconsistent minor house loads while trying to charge the batts. This seems to hammer my little genny with cyclic loads causing a temporary drop in voltage which the FX then kicks off the ACIN. This is despite deregulating the GEN input to 1200watts on the FX. What would really be helpful is to know your genny settings on the fx? What wattage are you getting from your EU. What altitude are you. Have you given up and gone the ITOA route.. (wouldn't all this still pertain High alt charging or is a new thread in order?)

Cariboocoot · August 2011

Re: High altitude affects batteries?

The problem you have there is an over-taxed generator. It's only got 1200 Watts available. Your battery bank is 450 Amp hours @ 48 Volts: a minimum charge rate of 5% would be 1341 Watts.
The FX has a maximum charging setting in AC Amps. If this is set at 8 (roughly 20 Amps on the DC side, not including losses and PF correction) or above there will be no generator power available for loads, and every time anything comes on the gen will kick out.

Basically that generator simply does not have enough output to charge that battery bank at a decent rate and still have any power left over for loads.

rkymtnoffgrd · August 2011

Re: High altitude affects batteries?

I've learned to survive quite well by turning off the well pump and the fridge during charging. (both are on switches) With Eco-Throttle off and the AC input limited, I deal with it...I just have to power nazi patrol to make sure no one turns stuff on and off during charging...annoys the crap out of my wife who enjoys cooking. I suppose the best, cheapest solution is an ITOA, which would allow me charge unaffected by house loads? The thing is, these little honda 2000 are so hard to beat when it comes to realibilty, and freakin quiet!!! Plus, there are so many on the market that barely used ones can be found in the $700-800 range.

Cariboocoot · August 2011

Re: High altitude affects batteries?

Using a stand-alone battery charger would eliminate the drop-out problem, but could give you a new one; over-loaded battery charger. The lack of gen power is there no matter what.

If you really want to eliminate the trouble, buy a second EU2000i and gang them together. You'll have 2400 Watts to work with. You could get the charge rate up to 5% minimum and still have 800 Watts leftover to run things. They have a "companion" model now with a 30A outlet on it for when it's used in parallel with another unit.

rkymtnoffgrd · August 2011

Re: High altitude affects batteries?

You've made a very good suggestion, one I've considered before myself but thought it might be better to eliminate the FX altogether from charging. Truthfully, spending my money on another eu is really where I'd rather go. I love these little HONDAS!!

mike95490 · August 2011

Re: High altitude affects batteries?

Or a power factor corrected charger. Iota is not, I dont know about the outback you have

Cariboocoot · August 2011

Re: High altitude affects batteries?

mike90045 wrote: »

Or a power factor corrected charger. Iota is not, I dont know about the outback you have

Outback's built-in charger are not, alas, PF corrected. Something like 0.85.

SCharles · August 2011

Re: High altitude affects batteries?

I just came across this topic and back to the OP's elevation/battery pondering: we live at 8500 ft. MSL and have been using lead acid banks in our home [PV charged] since 1985. Since this is the only place I've lived since going PV, I cannot compare our experience with any other. However, we have never noticed or suspected any elevation-related battery performance differences from what they, the batteries, are rated to do. We do use Hydrocaps and add almost no water to the batteries, maybe a gallon a year to our 1875 amp hour set. Which is very little for such large cells. [By the way, I mean a gallon a year to the entire bank, not each cell.]

I'd be quite interested to hear that there are, indeed, some problems or derating for batteries at altitude, but we've never seen any evidence of it.

BB. · August 2011

Re: High altitude affects batteries?

Check your specific gravity / State of Charge... Using too little water can be an issue too (under charging).

Some batteries due tend to use more water than others.

For example, the new Trojan L16RE-B have been reported to use ~1/2 the water of the older types. Fork Lift batteries seem to use more.

-Bill

Cariboocoot · August 2011

Re: High altitude affects batteries?

I have found that hydrometers read inaccurately at higher elevations. Mine seems to be off by 0.050 at around 3200' elevation. Higher up should be worse, as the electrolyte would expand against the lower density air thus making the electrolyte less dense as well.

rkymtnoffgrd · August 2011

Re: High altitude affects batteries?

Really? Anyone else notice this?

waynefromnscanada · August 2011

Re: High altitude affects batteries?

rkymtnoffgrd wrote: »

Really? Anyone else notice this?

Could happen if there were micro-bubbles of H2 or O2 suspended in the liquid. These micro bubbles would expand, displacing a bit more of the liquid, thus making each unit of electrolyte volume less dense. The actual liquid itself only changes volume (density) with temperature changes. The micro bubbles of gas within it however, will and do expand and contract with c

RCinFLA · August 2011

Re: High altitude affects batteries?

rkymtnoffgrd wrote: »

Really? Anyone else notice this?

Never heard of this. I would caulk it up to generally lower temp at higher altitudes.

In searching for any reference I did find a good paper on battery maintanance.

http://www.usbr.gov/power/data/fist/fist3_6/3-6.PDF

Cariboocoot · August 2011

Re: High altitude affects batteries?

Fluid density is effected by both temperature and pressure.

techntrek · August 2011

Re: High altitude affects batteries?

Lower temp would mean denser liquid, so that wouldn't explain it.

BB. · August 2011

Re: High altitude affects batteries?

From what little I have seen, I would expect, maybe, a 0.1% change in density of water in high elevations...

Lack of heat transfer should be a much bigger deal (and possibly gas bubbles as mention earlier.

-Bill

mike95490 · August 2011

Re: High altitude affects batteries?

Cariboocoot wrote: »

Fluid density is effected by both temperature and pressure.

Does air pressure affect incompressable fluids ?

I'd think gravity (or the reduced gravity at altitude) woud have an effect too. But is any of it detectable with gear we can afford ?

Maybe lower air pressure allows faster evaporation ...

High altitude affects batteries?

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