I'm attempting to set the amp hour capacity on my recently installed Clipper BM1 battery monitor.
What is the accurate setting?
I have two of these:
(https://s5.postimg.org/dgxzimj5j/20180215_115854.jpg)
??? According to the PDF, this battery monitor is designed for 12V batteries; Trojan T-105s are 6V batteries.
http://www.jgtech.com/pdf/Clipper%20BM1+BM2.pdf
I hope that someone more battery savvy than I will be able to help.
Battery capacity will be 225 ah for the two 6v batteries in series.
Just found this.
Wiring Your Battery Bank in Series, Parallel, and Series Parallel (http://www.batteriesinaflash.com/wiring-your-battery-bank-in-series-parallel-and-series-parallel)
tedeboy-
I looked at an online manual for the BM-1. It wasn't completely clear about that setting. However, the impression I got was to use the 20-hour rate. For your two T-105s connected in series (making 12V), that would be 225 amp-hours.
Mark
Battery capacity will be 225 ah for the two 6v batteries in series.
I was wondering which one to use.
The 20hr or the 5hr.
Use the 20 hr rate - this is the standard one to which battery monitors will calibrate. If properly designed, they will compensate for varying discharge rates to give an accurate reading of battery state-of-charge regardless of how you use them.
Steve
I'm learning that if the batteries don't charge to 100% it means they have degraded some.
The manual does mention that after you are sure they are charged to drop the amp hour base setting to reflect 100% if you like but to keep in mind that they are degraded.
This happens to batteries over time.
This is my first real battery monitor.
If the batteries are new, set the meter's battery capacity at 225-amp/hours.
Batteries do degrade over time, I substrate 8-10%, of capacity, per year, to account for this.
The average deep-cycle battery's life is 5-7 years.
Multiple deep discharges, below 50%, will significantly reduce battery life.
Larry
If the batteries are new, set the meter's battery capacity at 225-amp/hours.
Batteries do degrade over time, I substrate 8-10%, of capacity, per year, to account for this.
The average deep-cycle battery's life is 5-7 years.
Multiple deep discharges, below 50%, will significantly reduce battery life.
Larry
Thank you Larry...as always.
On the bright side, the less you discharge them before recharging, the longer they last. So if you don’t often go as deep as a 50% discharge, and maintain them well, you may see longer life (battery).
On the bright side, the less you discharge them before recharging, the longer they last. So if you don’t often go as deep as a 50% discharge, and maintain them well, you may see longer life (battery).
Mine are 2 years old. They are on stage 2 of the 3 stage charge and showing only 75%.
I should have treated them better I guess. I thought I was pretty good.
I now realize the value of having a real battery monitor.
Mine are 2 years old. They are on stage 2 of the 3 stage charge and showing only 75%.
I should have treated them better I guess. I thought I was pretty good.
I now realize the value of having a real battery monitor.
[/quote
Yes, a battery capacity monitor can pay for itself over the long haul.
Larry
"I thought I was pretty good...I now realize the value of having a real battery monitor."
You're not the only one!
I started out RVing in 2001, in a 1985 Lazy Daze. Thanks to the previous owners (hi, Judie!), I had an advanced electrical system for the time: 204 watts of solar panels and four AGM batteries. Over the next five years I became increasingly frustrated by the fact that despite having a background in electronics, I just could not seem to get a grip on my power situation. Time after time I would get up in the morning to find that my batteries were close to 12 volts. Over time I added more and more solar panels--I ended up with nine, in all shapes and sizes!--until it was almost impossible to walk on the roof. It didn't seem to help much. I had the batteries replaced. That didn't help as much as I thought it should have either.
Finally I got a Xantrex Battery Monitor--an amp counter more or less equivalent to Victron's BMV-7xx series. It was as if a blindfold had been removed from my eyes! At last I had a feeling for the state of charge of my expensive batteries.
That confident knowledge only lasted until the batteries began to age; then the monitor's readings grew increasingly overoptimistic--but I didn't know that. In that rig and my next rig, I beat the batteries to death by trusting a battery monitor that that had been programmed for the rated capacity, and not derated 8%-10% per year as Larry has recommended. As I recall, I went through three or maybe four sets of very expensive AGM batteries in my last rig before I got it all figured out. (One or two of those sets were burned out by an aging solar controller that, it turned out, was feeding them 16-17 volts. Months went by before I caught that. My fault.)
There were a lot of things about RV battery/solar systems that I didn't know in my first fifteen years of RVing, and it took me far too long to learn them. Off the top of my head, here are a few of the things I didn't know.
• As we’ve discussed here, voltage alone wasn’t a reliable way to judge my batteries’ state of charge. I was incredibly frustrated for years until I understood this.
• Amp counting battery monitors are great as long as you remember to lower their "bank capacity" setting every year. For a long time I didn't, and they led me astray.
• Adding all those solar panels was pretty much a waste, since my wiring was inadequate. My first LD ended up with 589 watts of panels (on a 22-footer!)… but the wiring had been sized for 204 W, and I didn't have the brains to realize that the voltage drops were throwing away gobs of power. That's probably the only reason I didn't burn out my 400 W (max) solar controller: it never saw all the power that the panels were putting out! It's also why my batteries weren't getting recharged. I should have spent money on heavier wiring instead of more panels. And I should have learned to use a voltage drop calculator (http://www.nooutage.com/vdrop.htm).
• Idling the engine doesn't do a good job of charging batteries. It doesn't put out that much juice at idle speed (it's optimized for driving, not sitting still), and its output voltages aren't regulated for best charging. I did a lot of this in my first couple of winters, when my solar panels weren't doing the job and I was desperate to get power into the batteries. Not only was it annoying and a waste of gas, but I ended up paying for new exhaust manifolds and other repairs that were probably needed, or needed sooner, because of all that idling.
• Pulling 70 to 150 amps from my batteries (via inverter) in order to run a microwave oven or Shop-Vac—even briefly—drained them a lot more than I thought, due to the Peukert effect.
• Not bringing AGM batteries back up to 100% every day shortens their lifespan considerably. So does overcharging them, but for the first five or six years I didn’t have either my AC charger or my solar charge controller set to the optimum voltages for AGMs.
I could go on, but you get the idea. I made a lot of mistakes, and paid thousands of dollars dealing with the consequences. Now I have lithium batteries, so I have a chance to make a whole new set of mistakes! ;-) I guess the moral is: read up and educate yourself as much as you can, or you'll end up paying for what you didn't know.
Andy
"I thought I was pretty good...I now realize the value of having a real battery monitor."
You're not the only one!
I started out RVing in 2001, in a 1985 Lazy Daze. Thanks to the previous owners (hi, Judie!), I had an advanced electrical system for the time: 160 watts of solar panels and four AGM batteries. Over the next five years I became increasingly frustrated by the fact that despite having a background in electronics, I just could not seem to get a grip on my power situation. Time after time I would get up in the morning to find that my batteries were close to 12 volts. Over time I added more and more solar panels--I ended up with nine, in all shapes and sizes!--until it was almost impossible to walk on the roof. It didn't seem to help much. I had the batteries replaced. That didn't help as much as I thought it should have either.
Finally I got a Xantrex Battery Monitor--an amp counter more or less equivalent to Victron's BMV-7xx series. It was as if a blindfold had been removed from my eyes! At last I had a feeling for the state of charge of my expensive batteries.
That confident knowledge only lasted until the batteries began to age; then the monitor's readings grew increasingly overoptimistic--but I didn't know that. In that rig and my next rig, I beat the batteries to death by trusting a battery monitor that that had been programmed for the rated capacity, and not derated 8%-10% per year as Larry has recommended. As I recall, I went through three or maybe four sets of very expensive AGM batteries in my last rig before I got it all figured out. (One or two of those sets were burned out by an aging solar controller that, it turned out, was feeding them 16-17 volts. Months went by before I caught that. My fault.)
There were a lot of things about RV battery/solar systems that I didn't know in my first fifteen years of RVing, and it took me far too long to learn them. Off the top of my head, here are a few of the things I didn't know.
• As we’ve discussed here, voltage alone wasn’t a reliable way to judge my batteries’ state of charge. I was incredibly frustrated for years until I understood this.
• Amp counting battery monitors are great as long as you remember to lower their "bank capacity" setting every year.
• Adding all those solar panels was pretty much a waste, since my wiring was inadequate. My first LD ended up with 589 watts of panels (on a 22-footer!)… but the wiring had been sized for 160 W, and I didn't have the brains to realize that the voltage drops were throwing away gobs of power. That's probably why I didn't burn out my 400 W (max) solar controller. It's also why my batteries weren't getting recharged. I should have spent money on heavier wiring instead of more panels. And I should have learned to use a voltage drop calculator (http://www.nooutage.com/vdrop.htm).
• Idling the engine doesn't do a good job of charging batteries. It doesn't put out that much juice at idle speed (it's optimized for driving, not sitting still), and its output voltages aren't regulated for best charging. I did a lot of this in my first couple of winters, when my solar panels weren't doing the job and I was desperate to get power into the batteries. Not only was it annoying and a waste of gas, but I ended up paying for new exhaust manifolds and other repairs that were probably needed, or needed sooner, because of all that idling.
• Pulling 70 to 150 amps from my batteries (via inverter) in order to run a microwave oven or Shop-Vac—even briefly—drained them a lot more than I thought, due to the Peukert effect.
• Not bringing AGM batteries back up to 100% every day shortens their lifespan considerably. So does overcharging them, but for the first five or six years I didn’t have either my charger or my solar charge controller set to the optimum voltages for AGMs.
I could go on, but you get the idea. I made a lot of mistakes, and paid thousands of dollars dealing with the consequences. Now I have lithium batteries, so I have a chance to make a whole new set of mistakes! ;-) I guess the moral is: read up and educate yourself as much as you can, or you'll end up paying for what you didn't know.
Andy
Wow Andy that's a lot of learning!
When my batteries finish charging I'll see what their capacity actually is and set the default capacity accordingly.
Thanks for your detailed response!
Andy, thanks for your gotchas. You probably know that a big one for lithium is don't let them get hot - off the top of my head I remember not even to 92 degrees F. (And the balancing of course).
You have them in a nice cool spot and where the cat doesn't think they are great to lie on, right? :)
Sent from Yahoo Mail for iPhone (https://overview.mail.yahoo.com/?.src=iOS)
"I started out RVing in 2001, in a 1985 Lazy Daze. Thanks to the previous owners (hi, Judie!), I had an advanced electrical system for the time: 160 watts of solar panels and four AGM batteries."
It was a screaming 204 watts - four 51-watt panels - yee haw ! But with no microwave or much else electrical, it was several years before we hauled out the electric cord. Yes - 204 screaming watts! This was tall cotton in 1991!
We are about to replace our current four AGM's (system installed by AM Solar) that are now eight years old, working with 400 watts of solar. The per year loss has brought these batteries down considerably, but we seldom boondock any more and are more frequently in a campground with a power pedestal.
Virtual hugs,
Judie <-- Sierra Vista, Arizona
Adventures of Dorrie Anne | Photographing the West (http://dorrieanne.wordpress.com)
Today: Mama's Little Helpers
*****************************
Solar Power and battery capacity and Lions and Tigers and Bears...oh my.
Just put my 2cents in the LDO Amazon kitty by ordering “Mobile Solar Power Made Easy”. 2017 edition should be pretty up to date. I’ll see how Solar Savy I am by the end of 2018. Thanks Andy...now I have something good to read. Ran out of Zane Greys a long time ago.
Kent
Now I have lithium batteries, so I have a chance to make a whole new set of mistakes! ;-) I guess the moral is: read up and educate yourself as much as you can, or you'll end up paying for what you didn't know.
Andy
It's been an education for a lot of us, no matter what our professional background are.
Hopefully, we have added to the LD and RV knowledge base, with information based on our successes and failures.
You should have better luck with your new TT, assuming you bought the Victron lithium battery system and it's matching accessories . It's marine grade equipment and should hold up to the RV environment.
Better to let someone else go through the expensive engineering development .
Larry
With this monitor I am seeing just how slow my PD4600 converter charges these batteries on shore power.
It seems generator charging is quicker...no?
With this monitor I am seeing just how slow my PD4600 converter charges these batteries on shore power.
It seems generator charging is quicker...no?
No.
On shore or generator power, the battery is charged by the converter. The charge times will be the same on either.
The Onan Microquiet 4000 generators do not have a built in battery charger.
Many smaller, portable generators will have a low amperage, 12-volt charger, used to keep their starting battery charged.
LD's Onans use the coach battery for starting.
Larger converters are available. Upgrades to the wiring and fusing may be needed to utilize larger converters.
Larry
I just reset my baseline capacity from 225 amp hrs to 171 amp hrs.
These batteries have degraded 24% in 2 years.
We're leaving soon for a 5-6 month trip.
Should I replace them? We will be at sites with no electricity a lot.
I just reset my baseline capacity from 225 amp hrs to 171 amp hrs.
These batteries have degraded 24% in 2 years.
We're leaving soon for a 5-6 month trip.
Should I replace them? We will be at sites with no electricity a lot.
Two year old batteries should be good for your trip.
A 24% reduction may be too high an estimate of reduced capacity unless they have abused by multiple deep discharged.
The somewhat good news is that batteries are widely available, just in case they do go bad, while traveling.
Larry
Two year old batteries should be good for your trip.
A 24% reduction may be too high an estimate of reduced capacity unless they have abused by multiple deep discharged.
The somewhat good news is that batteries are widely available, just in case they do go bad, while traveling.
Larry
Good idea.
On review: I've reset the capacity to reflect the actual amp hr capacity. At what resting percentage should I recharge them? 50%?
"At what resting percentage should I recharge them? 50%?"
There's no specific answer; it depends upon how long you want them to last. The chart below will give you the idea. It's based on LifeLine AGM battery data, so the specific numbers may differ for your batteries, but the trend is going to be pretty similar for any common lead-acid battery. If you never drain your batteries below 80%, you can expect thousands of charge/discharge cycles. If you routinely drain them to 40% or less, the lifespan drops into the hundreds. You get the idea.
When I had lead-acid batteries (and finally knew what I was doing), I tried never to let them get below 70%. But I had four or five batteries, so I could afford to not run them down too far. (Also, they were expensive batteries, and replacing the whole bank was a matter of $1,400 or so, so I wanted to make them last.)
But if it suits you, you could take the opposite tack: with a couple of relatively inexpensive flooded-cell batteries, you could use them hard, knowing that you'd have to replace them in two or three years instead of six or seven. That's a perfectly legitimate strategy; it just depends on how you want to do things.
That makes sense Andy.
Thanks.
"You probably know that a big [gotcha] for lithium is don't let them get hot”
Yes, I’ve read that. The datasheet for my Victron Smart Lithium batteries says the operating temperature range is -20° C (-4° F) to +50° C (122° F), but I don’t intend to let them ever get that hot. For one thing, they’re located in a ventilated space under my bed, and I’d never let my bedroom get that hot! For another, they have enough thermal mass that their temperature stays fairly stable, hovering around 60° F. in the month or so I’ve been using them, even as inside temperatures ranged from the upper forties to low eighties. In any case, my charging system will automatically cut off all loads if the temperature gets too high.
Low temperatures are another gotcha, but it’s a special case: you can draw power from them down to -4° F, but you basically must not charge them at temperatures below freezing. (Victron says, “maximum charge current when battery temperature < 0° C: 0.05C, i.e. 10 A in case of a 200 Ah battery.”) I don’t have automatic protection against this scenario, but again, my bedroom never gets that cold.
(Bear in mind, though, that I live here. If I were storing the rig for part of the year, I’d probably disconnect the batteries to protect them from temperature extremes.)
The third gotcha is the need to keep the cells balanced with each other. In my case, Victron has built balancing circuitry into each battery, so it’s taken care of automatically. My batteries’ cells stay with ten millivolts of each other.
“It was a screaming 204 watts - four 51-watt panels”
Thanks for the correction, Judie. Yes, the odd number had slipped my mind. 200+ watts was almost unheard of in a small class C back them, and I was very lucky to get such a technology-loaded rig for my very first RV.
“Just put my 2cents in the LDO Amazon kitty by ordering ‘Mobile Solar Power Made Easy’ ”
Let us know how you like it, Kent!
“the Victron lithium battery system and its matching accessories [are] marine grade equipment and should hold up to the RV environment.”
Yes, I bought Victron’s lithium batteries, battery management system, load and charging cutoff relays, solar controller, and of course battery monitor. I chose not to get their charger or inverter because everything they made was too tall to fit under my bed. Instead, I installed a ProNautic marine charger (top of the line equipment) and a 1,500 W Xantrex inverter (nothing fancy, not even pure sinewave).
Victron’s equipment is very well made and their tech support is quite responsive. I was a bit disappointed in their documentation—while slick-looking, it doesn’t have the level of technical detail that can be found in the Lifeline Technical Manual (http://lifelinebatteries.com/wp-content/uploads/2015/12/6-0101-Rev-E-Lifeline-Technical-Manual.pdf).
What I really love about the Victron equipment, as I’ve probably said elsewhere, is that everything is Bluetooth-enabled and can be monitored and controlled from their well-designed iPhone/iPad app. That meant I didn’t have to find space for a collection of wall-mounted monitor panels, nor run wires to them. Everything I need to know is in one place on my phone, with more useful detail and historical data than any wall panel can show at once... all available at the swipe of a finger. Even the batteries have built-in Bluetooth—I was able to check their condition while they were still in their unopened crates on the loading dock!
All this convenience came at a cost. I have friends who put together lithium battery systems for less than half what I spent. They bought cells from China, assembled them into battery banks, added support systems, and so on. They have display panels that let them monitor what’s going on. When cells need “rebalancing,” they do it manually. With Victron components, I took the easy, but expensive way out. It was the right way for me, but not for everybody.
Note to those with sharp eyes: the attached screenshots of the VictronConnect app were taken at varying dates and times under varying conditions, so don't expect them to be consistent with each other.)
All this convenience came at a cost. I have friends who put together lithium battery systems for less than half what I spent. They bought cells from China, assembled them into battery banks, added support systems, and so on. They have display panels that let them monitor what’s going on. When cells need “rebalancing,” they do it manually. With Victron components, I took the easy, but expensive way out. It was the right way for me, but not for everybody.
Considering how easily it is to kill a set batteries with improper charging, no matter what type they are, it's a smart move to buy a well engineered and proven system.
You are in good company, AM Solar is now installing Victron lithium kits, instead of their building their own.
It might be interesting to check back with your friends, in a couple years, and see how their home-brew systems are holding up.
On the other hand, ten years ago you might have been willing to build your own kit too, if the parts had been available.
I guessing that after 15 years of messing with batteries and chargers, you are ready for a power system with less drama.
Larry
"guessing that after 15 years of messing with batteries and chargers, you are ready for a power system with less drama."
Yup! True, most of the "drama" back then was due to my ignorance. But when I made the jump to lithium*, which is still a relatively new technology in the RVing world, I wanted a system that "just worked"--not one that I'd have to constantly monitor and tweak.
* technically, lithium iron phosphate (LiFePO4)
Back in 2013 I installed a 1000 AH LiFePO4 system in my Newell. I bought 4 large cells from Balqon (who unfortunately is now defunct) along with their BMS system. I used a 12 volt spotlight to bring each cell down to equal each other. They ranged from 3.446 to 3.481 when I received them, which is not bad but 3 years ago I sold this system to an engineer buddy who is still using them in his coach. He recently told me they are still within 0.002 volts. So the BMS is doing a great job of internally balancing the cells. And after 5 years they are still holding their original capacity.
I would expect your Victron cells to last even longer since Victron has a greater R&D and quality control.
It was amazing to watch the system voltage when running the large microwave. It would only drop 0.2-0.4 volts! compared to 1 volt or more with the 6 8D wet batteries.
LiFePO4 is an amazing battery technology.
Here is a link to my install: Lithium battery install (http://newellgurus.com/showthread.php?tid=1149&highlight=LiFePO4)
"Here is a link to my install"
My hat is off to you, sir. That was a massive (by LD standards, anyway) 1,000 Ah installation, and your detailed descriptions were very enlightening. Tackling that project back in 2013 on a DIY basis, using parts from a company with little to no customer support, took courage. (My friends also used Balqon cells and had the same complaints.) Well done!