Battery Questions

[rando]

I have posted this before, but it should help guide you in the trade off between depth of discharge vs battery life:

 

[Wallowa]

All this is interesting and valuable information..

But with any battery monitor what is the ultimate purpose?

I can see if you find a severe loss of battery SOC that can't be recovered with your solar or 110/120 you may need to replace your batteries.

The need to monitor outgoing amps from the batteries escapes me; you use what is needed and don't mindlessly waste power. Whatever the essential power usage is seems to be a moot point. The salient issue is if the batteries can support that use. If not you need more battery reserve and/or a different charging system.

I get the need for gadgets, but only if they are needed. I also concur with no wireless [or hard wired for that matter] monitoring of the universe; enough of that in the urban life but for me it seriously detracts from the back country experience.

Neat aspect of our Hawk is that even without any batteries we can boon-dock in it....sleeping bags [no heat], water from gravity spigot [no water pump], lights from stick-on AA lights [no LED lights], vents/windows open without fans and still cooking with propane. Lots of work arounds.

Only battery that I truly need out camping is the one that starts my Tundra; and I have an XP1 to crank it into life if needed.

Just my opinions folks and from a base of primary ignorance so I could be wrong...

Phil

 

[rando]

For me the ultimate purpose of the battery monitor is to allow me to carry less batteries, which is a significant issue in a weight limited set up like mine.

By knowing my batteries state of charge it allows me to modify my behaviors in response, the same way that the gas gauge in my car works. If I know my batteries are fully charged, I may park for best view as opposed to best solar, and won't waste time hauling out my portable panel and will run the fan longer to keep it cooler and drier in the camper. Conversely, if the batteries are a little on the low side, I will park for maximum solar power, and/or deploy the portable panel and dial back the fans a notch or two and not charge the ipad until we are driving the next day.

By knowing my usage and making some minor adaptations I managed to get by just fine with 1 battery, without knowing my usage as well I probably ended up adding a second battery. All though all of this is academic at this point after going to lithium batteries.

Truth be told, like many of us here, both camping and the camper itself are fun hobbies, so I do enjoy futzing with the camper and knowing how it all works. And this is course just my opinion.

 

[PaulT]

I think most of this, as far as #1 thru #4, looks OK (though #3 has me puzzled a little, because when your controller is saying FUL, the charge is below 13V...that's a little low for a float charge), but then your addendum has me thinking that your IOTA is overcharging the batteries once you plug them back in to shore power. Pretty confusing, though, because initially, when you first went to unplug it, it was reading float I believe (steady green light), and you said the voltage on the controller read 13.6V, perfect. Of course, we don't know what happened BEFORE you saw that....maybe the IOTA was over-bulk or -absorption charging for 5+ hours again, like it was when you plugged it in the last time. I think the IOTA is possibly faulty, but like many others have said here, a battery monitor would tell you when and where that voltage is going.

When the Zamp has been inside without solar overnight and on shore power, it appears to go through a power on reset cycle when put into sunshine. This starts out in bulk mode at 14+ volts. It apparently stops charging for some time to determine resting voltage which would account for the 12.7-12.9 reading. On taking it back into the shop on shore power, the IQ4 goes quickly into float voltage. Your readings make sense in my experience.

After the unit has been on shore power for some time with no solar input, you can push the display selector button on the Zamp and watch the unit reset, displaying various configuration factors as it powers up.

Paul

 

[JaSAn]

But with any battery monitor what is the ultimate purpose?
I can see if you find a severe loss of battery SOC that can't be recovered with your solar or 110/120 you may need to replace your batteries.
The need to monitor outgoing amps from the batteries escapes me . . .

As an engineer I am probably not the best person to answer, being that measuring systems to understand their performance is in our DNA.

My battery monitor (Trimetric RV2030) is the tool I use for that understanding of my solar charging system. Once learned I know my system will handle my demands. This might not be important to a weekend warrior but it is tough (and expensive) to find out your system isn't keeping up on day 8 of a 40 day trip up the Alaskan highway.

I am usually traveling for 1 to 2 months in the fall and short trips don't tell me enough about the system to know it will handle extended usage.

jim

 

[doc]

I have posted this before, but it should help guide you in the trade off between depth of discharge vs battery life:

Yes! This! Thanks!

 

[doc]

All this is interesting and valuable information..

But with any battery monitor what is the ultimate purpose?

I can see if you find a severe loss of battery SOC that can't be recovered with your solar or 110/120 you may need to replace your batteries.

The need to monitor outgoing amps from the batteries escapes me; you use what is needed and don't mindlessly waste power. Whatever the essential power usage is seems to be a moot point. The salient issue is if the batteries can support that use. If not you need more battery reserve and/or a different charging system.

I get the need for gadgets, but only if they are needed. I also concur with no wireless [or hard wired for that matter] monitoring of the universe; enough of that in the urban life but for me it seriously detracts from the back country experience.

Neat aspect of our Hawk is that even without any batteries we can boon-dock in it....sleeping bags [no heat], water from gravity spigot [no water pump], lights from stick-on AA lights [no LED lights], vents/windows open without fans and still cooking with propane. Lots of work arounds.

Only battery that I truly need out camping is the one that starts my Tundra; and I have an XP1 to crank it into life if needed.

Just my opinions folks and from a base of primary ignorance so I could be wrong...

Phil

Phil, I totally see your point. And as illustrated, there is a spectrum. One could be completely satisfied with sleeping in the back of a 1980's subaru with no modern conveniences, but obviously we've all chosen a camper, again with varying degrees of luxury (built in toilet, bucket with wag bags, no toilet, etc.).

In my case, we now have an opportunity to accurately monitor and therefore potentially modify our usage. Perhaps run the heater, fan or lights a little less. Be more conscious of when we charge the kids iPads (often done overnight while ZzZzZz). Maybe choose a campsite that is more exposed for daytime solar, even though we like a nice tree canopy for shade. All in the hope of extending the battery life a bit.

As others have said, you can just be a happy camper and replace the batteries when they're dead too.

 

[scappoosebrad]

Wallowa...thanks for putting our "camper perks" into context--love your comments...but given we have this resource, how--at my limited level of knowledge--can I best use the solar systems we have?

Jim--I envy your engineering expertise...wish I had your level of comfort with all this stuff... I also agree with needing a "longer trip" to give a better performance sample--what can simplify monitoring on a long trip/outing?...so let me simplify with this question and request an "easy to understand" answer if you could: Is your battery monitor different than the reading on my Zamp ZS-30A controller digital reading? (right now it reads 13.4v/float)... How is this reading different than your "battery monitor" reading? How is this a "better" way to monitor? Would you recommend adding this component to assist the Zamp controller reading? would inserting an inexpensive digital voltage display monitor inserted in my 12v power socket work?

Thanks for any help you can offer?

 

[JaSAn]

I'll preface my remarks stating that I am a MECHANICAL engineer. 4 years ago I started from scratch with DC solar charging.

Is your battery monitor different than the reading on my Zamp ZS-30A controller digital reading?
How is this reading different than your "battery monitor" reading?
My understanding from reading Zamp's site is that the readout on the controller gives information on what the controller is doing. My Trimetric tells me what is happening at the batteries. The Trimetric is basically an amp counter: it counts the amps going into the battery, the amps going out of the battery, does some simple arithmetic, and stores the results. The most useful piece of information (for me) is % from full. I did watch the amps in/out a lot the first year to understand my system.

Would you recommend adding this component to assist the Zamp controller reading?
IF you want to have a better understanding of your system, Yes. What the Zamp doesn't tell you is how much you are taking out of your battery, just what you are putting in. Lots of people have gotten long battery life with just the information the Zamp gives you or less. It is just learning what that information is telling you.

would inserting an inexpensive digital voltage display monitor inserted in my 12v power socket work?
The Zamp voltage readout should give the same number. It won't hurt anything. I am not a fan of determining battery state from voltage reading as it will read high just after charging (from surface charge on the plates) to reading too low during and just after discharging. A voltage reading will only be accurate after the battery has rested (no in or out current for up to 8 hours, depending on battery). But one can learn to mentally adjust for your specific battery bank. The Belmar SmartGauge does this for you but they aint cheap (and neither is the Trimetric).

Hope this helps. I'm sure the sparkies on this site will correct any misinformation I've given.

jim

 

[scappoosebrad]

Jim,
Thanks for your responses... it is "good start"...

so the Zamp can only display "incoming and/or gross average levels" but not current "current detailed % charge of the battery" (Trimetic). Our Zamp however does have "an LCD bar" that lights up 100-75-50-25% voltage meter; it also shows 4 battery symbols--green/full, green/above 12.5v, yellow/11.5-12.5 V, red below 11.5v (per the manual).

These are the primary visual gauges we have been monitoring to adjust our drain or filling of batteries... but to get a more exacting read on the "state of your batteries", we would need to add the Trimetic component... So nothing short of that install can be used to measure "state of the battery" in your opinion?

 

[rando]

The LCD bar on the Zamp is just a graphical representation of the voltage (base on a table like posted earlier in the thread), the Zamp doesn't have any knowledge about the loads pulling power out of the battery so it can only guess by looking at the voltage. If you really in tune to what is going on in your electrical system, the voltage alone can give you a reasonable estimate of the state of charge while discharging, but it is not as easy as just glancing at the number.

You are correct - in order to really know the state of the batteries you need another device (a battery monitor) that knows about both the energy going in and coming out of the battery. This would be a Victron BMV-700 or BMV-712 or a Trimetric.

 

[Vic Harder]

Wallowa...thanks for putting our "camper perks" into context--love your comments...but given we have this resource, how--at my limited level of knowledge--can I best use the solar systems we have?

Jim--I envy your engineering expertise...wish I had your level of comfort with all this stuff... I also agree with needing a "longer trip" to give a better performance sample--what can simplify monitoring on a long trip/outing?...so let me simplify with this question and request an "easy to understand" answer if you could: Is your battery monitor different than the reading on my Zamp ZS-30A controller digital reading? (right now it reads 13.4v/float)... How is this reading different than your "battery monitor" reading? How is this a "better" way to monitor? Would you recommend adding this component to assist the Zamp controller reading? would inserting an inexpensive digital voltage display monitor inserted in my 12v power socket work?

Thanks for any help you can offer?

The inexpensive digital voltage display would not tell you much more than the ZAMP. Both are telling you what voltage the battery has, not what the SOC (State of Charge) is. The "battery monitor" gives a much better SOC reading, based on measuring amps in/out using a shunt. Recommended models on this forum tend to be the Trimetric TM2030 and the Victron BMV712

 

[craig333]

And how hard is it know when you're seeing resting voltage? Pretty hard. Sometimes I look at my volt meter and see 13.1 volts and I wonder why its not 13.6 when I realize the fridge is running. Its pretty darn quiet. If I look at the trimetric and see its at 100% soc then I really don't care what the volt meter says.

Plus, how happy are you making your batteries with most controllers that only give you three charge options. I have some twenty or more (manual isn't in front of me) parameters I can choose from to optimize my charging. How close I am since the batteries I went with gave limited info compared to some manufacturers. Admittedly I don't mind reading the manual and playing with the settings since, while I'm not an engineer I lean that way

I'm in the 50% camp. Mostly because its seems 7 out of 10 people who claim to be smarter than I lean that way. Plus I tend to be conservative with my batteries. Having two large batteries in the camper and a truck that doesn't care about weight I afford to be conservative. Never even come close to 50% so far. I can see bad weather changing that.

 

[JaSAn]

. . . but to get a more exacting read on the "state of your batteries", we would need to add the Trimetic component... So nothing short of that install can be used to measure "state of the battery" in your opinion?

It depends on what you want. There are a number of people on this forum and others that just use battery voltage as their figure of merit and try to hit a voltage target at the end of the day. They're happy with their battery life. One can buy another set of batteries for the cost of a battery monitor (~$300).

But if you want to understand how your system is functioning then you need to also monitor loads on the battery, not just charging. A battery monitor is just a convenient package for this. There are cheaper shunt based amp counters but I don't know much about them.

jim

 

[Vic Harder]

It depends on what you want. There are a number of people on this forum and others that just use battery voltage as their figure of merit and try to hit a voltage target at the end of the day. They're happy with their battery life. One can buy another set of batteries for the cost of a battery monitor (~$300).

But if you want to understand how your system is functioning then you need to also monitor loads on the battery, not just charging. A battery monitor is just a convenient package for this. There are cheaper shunt based amp counters but I don't know much about them.

jim

+1

I guess I wonder how many of us would be content to drive our cars/trucks without a gas gauge. I mean, once you have run out of gas a few times, I guess you could use the trip odometer (which I do too) as a rough way to figure out when you are going to need to tank up. Or you could use a dipstick in the tank, but you can only use that when you are parked and not using the vehicle.

Wait, that sounds a lot like having to let the batteries rest before you can use a voltage gauge (dipstick).

I prefer to have some idea of what's going on in my car/truck's fuel tank, and also in my camper's batteries.

 

[Wandering Sagebrush]

+1

I guess I wonder how many of us would be content to drive our cars/trucks without a gas gauge. I mean, once you have run out of gas a few times, I guess you could use the trip odometer (which I do too) as a rough way to figure out when you are going to need to tank up. Or you could use a dipstick in the tank, but you can only use that when you are parked and not using the vehicle.

Wait, that sounds a lot like having to let the batteries rest before you can use a voltage gauge (dipstick).

I prefer to have some idea of what's going on in my car/truck's fuel tank, and also in my camper's batteries.

I did that for years with my first Volkswagens. No gauge, just a lever to flip and put you on auxiliary. First sputter, flip it ove and you had about 40 miles.

Maybe that’s why I don’t get too worried about the batteries. I’m happy with a simple voltmeter.

 

[dharte]

I have a Victron battery monitor for the same reason I have EGT, boost and fuel pressure gauges in my diesel truck. I want to know if there is a problem before things get damaged or start to go south. Having the monitor was the main reason I knew my Zamp was overcharging my batteries.

 

[Chrish]

In non grid tied home power systems, the biggest killer of batteries is not getting a full charge at least once a week.

It's common that during the winter months or areas of the country with less solar gain, people will run their generators because there's not enough solar gain to achieve a consistent full battery charge.

They'll run the batteries up to about 80% charge and because it takes a long generator run time to bring the batteries up that last 20% to 100% SoC, they'll just run the batteries from 80%. Doing that day after day causes areas of the plates to become clogged with the stuff that needs to get back into the electrolyte solution, but can't because a full state of charge hasn't been achieved.

As more and more of the plate area gets clogged the batteries become less efficient and are on the way to failure without an equalization charge, which is a charge rate at a higher voltage that is now necessary to drive that Gunk back into solution.

Using a amp counter meter, like the trimetric,really helps giving understanding of the charge cycles and your personal power demands and how power usage is affecting your batteries.

Once you get a good understanding of what's going on with the batteries, reading voltages is very effective.

In wet lead/acid systems, a hydrometer gives you a good understanding of what's going on at an individual cell level.

In large battery banks, using a hydrometer can catch shorts before they become a problem and let you know when an equalization charge is needed.

 

[Wallowa]

I did that for years with my first Volkswagens. No gauge, just a lever to flip and put you on auxiliary. First sputter, flip it ove and you had about 40 miles.

Maybe that’s why I don’t get too worried about the batteries. I’m happy with a simple voltmeter.

Love it! Do remember the VWs; and, Model A Fords with no gas gauges; somehow we survived and we never were stranded.

Otherwise "you live by the gauge and die by the gauge"; trust the gauges only with verification...like those wonderful "idiot" lights.

All posts and discussions obviously and correctly point out that each of us adopts the systems that we are comfortable with...personal choice, which is a good thing.

It is my opinion, and I could be wrong, that today too many are hyper-connected [my new word for the day] to too many information streams in a quest for total and absolute situational awareness. But with this sophisticated monitoring of everything comes vulnerability from inaccurate data and inaccurate assumptions; plus the addition of yet another system to monitor. Knowing when enough is enough is critical to peace of mind.

Or as my Bride says: "Many know what they know and don't know what they don't know". Ignorance as in my case may be bliss.

So just for a few of us "KISS" in the end keeps the cranial stress dialed down and enjoyment of moments dialed up.

Again, the question: How many FWC users have had charging systems and/or electrical system failures? Perhaps the sky is not falling after all.

Notwithstanding that if adding system monitors eases apprehensions; then by all means go for it.

Again, just my views and thoughts and not meant to denigrate anyone else's views.

Phil

 

[cwdtmmrs]

It is my opinion, and I could be wrong, that today too many are hyper-connected [my new word for the day] to too many information streams in a quest for total and absolute situational awareness. But with this sophisticated monitoring of everything comes vulnerability from inaccurate data and inaccurate assumptions; plus the addition of yet another system to monitor. Knowing when enough is enough is critical to peace of mind.

Boy, ain't that the truth! I only have so much RAM in my head and have to choose what information to save!

cwd