Boyntonstu
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How many batteries are in your van and what are their capacities?
What is the highest load that you use?
What is the highest load that you use?
Amp Hour Battery capacity in your van?
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Almost There
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4 Trojan T105REs for a total of 450 ah.
Mine isn't about peak load it's about constant load - a 65 qt Whynter unit set at fridge temp and a second one set at freezer temp!
Mine isn't about peak load it's about constant load - a 65 qt Whynter unit set at fridge temp and a second one set at freezer temp!
Scott7022
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What definition of capacity are you using? How big are your batteries? Or are you asking what is your usable capacity and why? With the beast above 260Ah is the size and it has a maximum "useable" capacity of 130Ah. 50% is the accepted (kind of) maximum drain for not damaging the battery. I have 6 batteries (for the house) 580 useable A/h without voltage drop.
It gets tricky in describing as it is all part of an interconnected system. Bob is all 12 volt and Bill is mixed. Bob drops to 12.1 and it doesn't matter as much as he isn't inverting energy from 12.7 to 110. Bill is and so battery voltage drop interacts with his discharge cycle. He gets to 50 exponentially quicker.
Size/Capacity= Weight, dimensions, Ah, cranking amps, watts, voltage, reserve (expressed in minutes). We get sloppy in English and people get confused because of it. I would love to see consumer protection ignore food labels and legislate more important stuff. Even Ah capacity is hard as different manufacturers use different ways to express this value. It is so bloody confusing and annoying for those that understand it. For those that don't... Doomed!
Not picking on your question in any way. Just using it to help people think about the terms that get tossed around in this industry with reckless abandon. I love reckless abandon, even more so if it is wanton. So good thread to get people thinking about size, what they need, and how they use it, and how to articulate it correctly.
It gets tricky in describing as it is all part of an interconnected system. Bob is all 12 volt and Bill is mixed. Bob drops to 12.1 and it doesn't matter as much as he isn't inverting energy from 12.7 to 110. Bill is and so battery voltage drop interacts with his discharge cycle. He gets to 50 exponentially quicker.
Size/Capacity= Weight, dimensions, Ah, cranking amps, watts, voltage, reserve (expressed in minutes). We get sloppy in English and people get confused because of it. I would love to see consumer protection ignore food labels and legislate more important stuff. Even Ah capacity is hard as different manufacturers use different ways to express this value. It is so bloody confusing and annoying for those that understand it. For those that don't... Doomed!
Not picking on your question in any way. Just using it to help people think about the terms that get tossed around in this industry with reckless abandon. I love reckless abandon, even more so if it is wanton. So good thread to get people thinking about size, what they need, and how they use it, and how to articulate it correctly.
frater secessus
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Ah @ C/20 is the norm for rating deep cycles, isn't it? If one's battery is rated in cranking amps or reserve it's likely not a deep cycle battery.
It seems to me size/dimensions are more of an issue when installing into a a pre-existing environment (commercially built RV).
As far as inverters, I am a member of SternWake's Inverters Are Evil club.
It seems to me size/dimensions are more of an issue when installing into a a pre-existing environment (commercially built RV).
As far as inverters, I am a member of SternWake's Inverters Are Evil club.
Boyntonstu
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Scott7022 said:
You make excellent points. Perhaps questions should be: "How many Amps do you draw and for how long do they last to 50%?" And: "Do you use an inverter?"
sushidog
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True, unless one uses a different battery chemistry like LiFePo4 or NiMh. For instance Lithium batteries can be discharged down to 20% of capacity often without damaging them, but they are easily damaged by overcharging and can go into a thermal runaway (think fire) unless a battery management system is used to prevent this from happening.
BTW, lead acid batteries can be used below a 50% charge occasionally without materially affecting their life as long as they are charged fully as soon as this happens. Letting them sit at 80% charge hurts them more than an occasional dip say to 30% capacity. That said the 50% rule is an excellent tool for planning on the size of the lead acid battery bank you need for maximum life.
Completely discharging any battery will greatly shorten their life, regardless of battery chemistry.
One other thing, the rate of discharge is important to getting the full amount of energy stored in the battery. The higher the battery's internal resistance the lower rate it can be discharged at without reducing its capacity (see Peukert). This means that batteries like Lithium and NiHh who have a lower internal resistance have a have a higher potential rate of discharge. This is important for high amp loads like a microwave or air conditioner.
Chip
BTW, lead acid batteries can be used below a 50% charge occasionally without materially affecting their life as long as they are charged fully as soon as this happens. Letting them sit at 80% charge hurts them more than an occasional dip say to 30% capacity. That said the 50% rule is an excellent tool for planning on the size of the lead acid battery bank you need for maximum life.
Completely discharging any battery will greatly shorten their life, regardless of battery chemistry.
One other thing, the rate of discharge is important to getting the full amount of energy stored in the battery. The higher the battery's internal resistance the lower rate it can be discharged at without reducing its capacity (see Peukert). This means that batteries like Lithium and NiHh who have a lower internal resistance have a have a higher potential rate of discharge. This is important for high amp loads like a microwave or air conditioner.
Chip
VanKitten
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16 lithium. Total. 12v, 400ah
Boyntonstu
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VanKitten said:
Please describe your 16 lithium. Total. 12v, 400ah setup.
IOW Did you buy or build, etc.?
Do you have 16 25 Ahr 12V batteries in parallel?
How do you charge them and to what voltage average per cell?
VanKitten
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Each of the lithium batteries is 3.2v (nominal) 100 ah
First .. 4 in series...that adds up to 12 v (ok 12.8v nominal)
Then each set of 4 series in parallel... that adds up to 400 ah
I am building the entire thing.
The charge is 700w from solar panels and/or inverter/charger (when I have shore power available)
First .. 4 in series...that adds up to 12 v (ok 12.8v nominal)
Then each set of 4 series in parallel... that adds up to 400 ah
I am building the entire thing.
The charge is 700w from solar panels and/or inverter/charger (when I have shore power available)
Bank capacity does have a standard, C/20 AH at 12V.
Understood that LFP yield more usable than lead.
Other voltages need to be noted, get down to portable power packs (I hate the use of "generator" for those) is where watt-hours is needed.
Understood that LFP yield more usable than lead.
Other voltages need to be noted, get down to portable power packs (I hate the use of "generator" for those) is where watt-hours is needed.
Boyntonstu
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VanKitten said:
Each of the lithium batteries is 3.2v (nominal) 100 ah
Did you assemble or purchase the 100 Ah battery?
VanKitten
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I purchased the individual batteries...pre assembled cells.
CampingOdyssey
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Does anyone have any experience with the REDARC LFP1225 or LFP1240?
It says you can charge a Lifepo4 by wiring it to your cars battery as well as utilizing it as a charge controller with solar. Seems like a pretty good set up geared towards the adventurer/rver Would this be an ideal plug and play charger to maximize life expectancy of the Lifepo4? Does anyone know if it could be used with any alternator/car battery set up to charge the Lifepo4? Wondering if it would be a good system with my Honda odyssey (also a system I could take out and put in a different vehicle if I decide to upgrade from my Odyssey). On a side note: I recently took my van in to get the breaks done and do a check up and the mechanic mentioned that my starting battery wasn't at a full charge which seems to suggest my alternator isn't functioning properly. I also think I remember a different mechanic mentioning the same thing 5 years ago when I had him check it out before I bought the van used. Haven't had any problems with it since I've owned the van, though. If I installed the REDARC should I get a new alternator installed or would the REDARC and internal bms still do fine with a alternator / starting battery that may not be fully charging?
As far as the Lifepo4 battery goes... trying to decide between the Battle Born 12v 100ah, the GreenLiFE 12v 100ah or the Smart Battery 12v 100ah. Does any of those stand out as the obvious winner, or are they all pretty much the same?
It says you can charge a Lifepo4 by wiring it to your cars battery as well as utilizing it as a charge controller with solar. Seems like a pretty good set up geared towards the adventurer/rver Would this be an ideal plug and play charger to maximize life expectancy of the Lifepo4? Does anyone know if it could be used with any alternator/car battery set up to charge the Lifepo4? Wondering if it would be a good system with my Honda odyssey (also a system I could take out and put in a different vehicle if I decide to upgrade from my Odyssey). On a side note: I recently took my van in to get the breaks done and do a check up and the mechanic mentioned that my starting battery wasn't at a full charge which seems to suggest my alternator isn't functioning properly. I also think I remember a different mechanic mentioning the same thing 5 years ago when I had him check it out before I bought the van used. Haven't had any problems with it since I've owned the van, though. If I installed the REDARC should I get a new alternator installed or would the REDARC and internal bms still do fine with a alternator / starting battery that may not be fully charging?
As far as the Lifepo4 battery goes... trying to decide between the Battle Born 12v 100ah, the GreenLiFE 12v 100ah or the Smart Battery 12v 100ah. Does any of those stand out as the obvious winner, or are they all pretty much the same?
Unless the charger's voltage setpoints can be user customized (possible)
or is
( ( already AbsorbV set at 13.8V maximum and FloatV around 13.2V)
or **stops charging completely** at 13.9V )
(very unlikely)
then not recommended.
Haven't seen a charger yet with vendor settings optimized for bank longevity. I think they're afraid the bank will last 20+ years.
Sterling ProCharge Ultra or ProMariner Pronautic P would be my recommendation.
or is
( ( already AbsorbV set at 13.8V maximum and FloatV around 13.2V)
or **stops charging completely** at 13.9V )
(very unlikely)
then not recommended.
Haven't seen a charger yet with vendor settings optimized for bank longevity. I think they're afraid the bank will last 20+ years.
Sterling ProCharge Ultra or ProMariner Pronautic P would be my recommendation.
CampingOdyssey
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I checked out the manual for the LFP1225 / LFP1240.. Under specifications it says:
LFP1225(LV*) / LFP1240(LV) *LV stands for low voltage:
Continuous current rating (LFP1225- 25A, LFP1240- 40A)
Input / Output Fuse Rating (LFP1225- 40A, LFP1240- 60A)
Output Power (LFP1225- 375W, LFP1240- 600w)
DC Input Voltage Range (9-32... 9-16 for LV models)
Solar Panel Open Circuit Voltage (17.5V-28.0V)
Battery type (LifePo4)
Constant current stage voltage level (14.6V)
Constant voltage stage voltage level (14.5V
No load current (<100mA)
Standbut current (<8mA)
Ambient Temperature (-20 C to + 80 C)
Minimum O/P battery volts (4.2V)
Standards (CE, C-Tick, AS/NZS CISPR11:2004)
In section 1.2 titled "charging Algorithm" it says...
"When the LPF1225(LV) / LPF1240(LV) is turned on, it will move into the Constant Current stage. This stage maintains a constant current until the battery voltage reaches its set point. The current may vary during operation in order to maintain safe operating temperature, or to limit the difference between input and output voltage.
The charger will then move to Constant Voltage stage. This stage maintains 14.5V on the output battery, keeping the battery topped up. This stage also counteracts the batter's self discharging. When a load applied to the battery causes it to lose charge, the charger will move back into the Constand Current stage."
In section 1.3 it has the on/off thresholds for the LFP1225 / LFP1240 as well as the LFP1225(LV) / LFP1240(LV)...
For the 12 LFP1225 and LFP1240:
Input Open Circuit Low voltage conditions (Turn ON above 13.2V) (Turn OFF below 12.7V)
Input Loaded Low voltage conditions (Turn OFF instantly below 8V) (Turn OFF after 20 secs below 9V)
Input Over voltage shutdown (Turn ON below 15.5V) (Turn OFF instantly above 16V) (Turn OFF after 20 secs above 15.6V)
Output Under voltage shutdown (Shutdown if Output Battery < 4V)
For the 12 LFP1225(LV) and LFP1240(LV):
Input Open Circuit Low voltage conditions (Turn ON above 12V) (Turn OFF below 11.9V)
Input Loaded Low voltage conditions (Turn OFF instantly below 8V) (Turn OFF after 20 secs below 9V)
Input Over voltage shutdown (Turn ON below 15.5V) (Turn OFF instantly above 16V) (Turn OFF after 20 secs above 15.6V)
Output Under voltage shutdown (Shutdown if Output Battery < 4V)
I couldn't find anywhere in the manual where it said you could change the settings. Do the above specs look like they'll shorten the life span of a LifePo4 battery (even with a bms installed)? If so, do you know of any battery charger that offers the ability to tweak the settings to optimally charge a LifePo4? Thanks.
LFP1225(LV*) / LFP1240(LV) *LV stands for low voltage:
Continuous current rating (LFP1225- 25A, LFP1240- 40A)
Input / Output Fuse Rating (LFP1225- 40A, LFP1240- 60A)
Output Power (LFP1225- 375W, LFP1240- 600w)
DC Input Voltage Range (9-32... 9-16 for LV models)
Solar Panel Open Circuit Voltage (17.5V-28.0V)
Battery type (LifePo4)
Constant current stage voltage level (14.6V)
Constant voltage stage voltage level (14.5V
No load current (<100mA)
Standbut current (<8mA)
Ambient Temperature (-20 C to + 80 C)
Minimum O/P battery volts (4.2V)
Standards (CE, C-Tick, AS/NZS CISPR11:2004)
In section 1.2 titled "charging Algorithm" it says...
"When the LPF1225(LV) / LPF1240(LV) is turned on, it will move into the Constant Current stage. This stage maintains a constant current until the battery voltage reaches its set point. The current may vary during operation in order to maintain safe operating temperature, or to limit the difference between input and output voltage.
The charger will then move to Constant Voltage stage. This stage maintains 14.5V on the output battery, keeping the battery topped up. This stage also counteracts the batter's self discharging. When a load applied to the battery causes it to lose charge, the charger will move back into the Constand Current stage."
In section 1.3 it has the on/off thresholds for the LFP1225 / LFP1240 as well as the LFP1225(LV) / LFP1240(LV)...
For the 12 LFP1225 and LFP1240:
Input Open Circuit Low voltage conditions (Turn ON above 13.2V) (Turn OFF below 12.7V)
Input Loaded Low voltage conditions (Turn OFF instantly below 8V) (Turn OFF after 20 secs below 9V)
Input Over voltage shutdown (Turn ON below 15.5V) (Turn OFF instantly above 16V) (Turn OFF after 20 secs above 15.6V)
Output Under voltage shutdown (Shutdown if Output Battery < 4V)
For the 12 LFP1225(LV) and LFP1240(LV):
Input Open Circuit Low voltage conditions (Turn ON above 12V) (Turn OFF below 11.9V)
Input Loaded Low voltage conditions (Turn OFF instantly below 8V) (Turn OFF after 20 secs below 9V)
Input Over voltage shutdown (Turn ON below 15.5V) (Turn OFF instantly above 16V) (Turn OFF after 20 secs above 15.6V)
Output Under voltage shutdown (Shutdown if Output Battery < 4V)
I couldn't find anywhere in the manual where it said you could change the settings. Do the above specs look like they'll shorten the life span of a LifePo4 battery (even with a bms installed)? If so, do you know of any battery charger that offers the ability to tweak the settings to optimally charge a LifePo4? Thanks.
