That's it. Not the best spot, but empty.Wandering Sagebrush said:I thought that sounded familiar... I was looking through the archives today and found this...
Apologies for the hijack!!!
Gooch_Spring_DSC5599.jpg
Adding a lithium Ion battery to FWC
- Thread starter cdbrow1
- Start date
RC Pilot Jim
Senior Member
I run Lithium Polymer (Li-Po) in my model airplanes.
Upside is double the power and half the weight.
Downside: Explosion/fire danger caused by discharging them below the recommended voltage - 3.3 volts on a 3 cell pack.
i store mine in an outside building in an explosion proof bag.
I wouldn't keep them in the house.
I'm sure the industry has done a good job to mitigate the explosion possibility, though I wouldn't put them in my camper without a
lot of research and watching the experience of others.
Upside is double the power and half the weight.
Downside: Explosion/fire danger caused by discharging them below the recommended voltage - 3.3 volts on a 3 cell pack.
i store mine in an outside building in an explosion proof bag.
I wouldn't keep them in the house.
I'm sure the industry has done a good job to mitigate the explosion possibility, though I wouldn't put them in my camper without a
lot of research and watching the experience of others.
RC Pilot Jim said:
These are not LiPO batteries, which do have that risk. These are LiFePo4 batteries. The Iron makes them much less likely to run away and the built in BMS should isolate any cell that fails. I say should because I have never seen it happen and I hope I never do.
I hate Wikipedia but sometimes it's useful... https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery
Everything continues to work well.
I got some more information this morning when talking to Nations Alternator (great folks).
One of the advantages of Lithium batteries is the lack of internal resistance. This is great when charging from solar because more of the generated power gets stored compared to Lead Acid.
However this has a downside with an alternator - the alternator can overheat if charging a LiFEPo4 battery pack exclusively. This is because the pack will take all the amps generated without resistance, the Alt goes to full output and stays there -something they are not designed to do. When you have some lead acid batteries in the charging circuit this is not a problem because they provide the needed resistance. When I add my second alternator (on order) I will need to add a adjustable regulator with temperature control which will reduce the output when the alternator temperature gets to high. I was not even considering this issue and was just ordering a standard alternator with a normal adjustable regulator when Nations filled me in.
The second alternator is not coming cheap ($1,300) but it includes all the brackets belts, bolts regulator and 270 amp unit. I don't need all that for camper obviously, but I can bridge the systems when I need to use the winch or I could run the whole truck on the camper alternator if the other one failed (unlikely, but redundancy is nice).
I got some more information this morning when talking to Nations Alternator (great folks).
One of the advantages of Lithium batteries is the lack of internal resistance. This is great when charging from solar because more of the generated power gets stored compared to Lead Acid.
However this has a downside with an alternator - the alternator can overheat if charging a LiFEPo4 battery pack exclusively. This is because the pack will take all the amps generated without resistance, the Alt goes to full output and stays there -something they are not designed to do. When you have some lead acid batteries in the charging circuit this is not a problem because they provide the needed resistance. When I add my second alternator (on order) I will need to add a adjustable regulator with temperature control which will reduce the output when the alternator temperature gets to high. I was not even considering this issue and was just ordering a standard alternator with a normal adjustable regulator when Nations filled me in.
The second alternator is not coming cheap ($1,300) but it includes all the brackets belts, bolts regulator and 270 amp unit. I don't need all that for camper obviously, but I can bridge the systems when I need to use the winch or I could run the whole truck on the camper alternator if the other one failed (unlikely, but redundancy is nice).
Additional thing I learned while researching second alternators..... Nearly all 2007 and later vehicles have PCM (car computer) controlled charging systems. These keep the voltages lower than the 14.4 I was taught was "optimal" back in the day (1980s). The PCM reduces the alt load under acceleration and long freeway trips and increases load under braking and after initial starting. Because of this it is very hard to charge a camper battery from a stock alternator anymore - the drop in voltage is even greater at the end of the wires to the camper (unless they are oversized) and even if charging does take place some of the power is lost when the vehicles is on the freeway because the computer reduces the allowable voltage.
Having a second alternator that is not computer controlled is looking like a better decision.
Having a second alternator that is not computer controlled is looking like a better decision.
Time for another update.
I have not been camping too much the last 3 weeks - new Girlfriend keeping me busy.
I have installed the second alternator and programmed the regulator (Balmar 614) for the Lithium Battery. Everything seems to work great, but I really need to run the battery down to see how well the charging works.
The good news is the camper battery and truck batteries are now fully isolated from each other - no more draining for the camper batteries from the lead acids in front and no chance of draining the truck batteries by leaving the isolator connected. Still working on the wiring to allow me to "bridge" the systems if needed - main problem is finding room underhood for all the switches.
I have not been camping too much the last 3 weeks - new Girlfriend keeping me busy.
I have installed the second alternator and programmed the regulator (Balmar 614) for the Lithium Battery. Everything seems to work great, but I really need to run the battery down to see how well the charging works.
The good news is the camper battery and truck batteries are now fully isolated from each other - no more draining for the camper batteries from the lead acids in front and no chance of draining the truck batteries by leaving the isolator connected. Still working on the wiring to allow me to "bridge" the systems if needed - main problem is finding room underhood for all the switches.
Time for another update.
I finally finished replacing all the wiring from the second alternator to the camper battery. Everything is 2 gauge all the though (using an Anderson connector) Charging rate is downright scary - 48 amps at idle. In fact this is so high it might be a problem - the battery has a max charge rate of 50 amps (Max discharge is 100amps). I am not sure what happens if the max charge rate is exceeded so until I talk to the vendor I will be leaving it disconnected. I can control the charge rate indirectly via the regulator by changing a number of settings if need be. Hopefully the max charge rate is something the battery regulates on it's own without triggering the battery management system.
With this setup I should be able to fully recharge the battery n just over 2 hours of driving - although it is likely that 48 amp rate would drop over time.
Also I have noticed an increase in the charge rate for the IOTA charger with the upgraded wiring inside the camper. I used to top out at 26-29 amps, now I am getting 31 amps out of the IOTA charger (which is rated for 30).
Yes this system is complete overkill, but my beer will always be cold.
I finally finished replacing all the wiring from the second alternator to the camper battery. Everything is 2 gauge all the though (using an Anderson connector) Charging rate is downright scary - 48 amps at idle. In fact this is so high it might be a problem - the battery has a max charge rate of 50 amps (Max discharge is 100amps). I am not sure what happens if the max charge rate is exceeded so until I talk to the vendor I will be leaving it disconnected. I can control the charge rate indirectly via the regulator by changing a number of settings if need be. Hopefully the max charge rate is something the battery regulates on it's own without triggering the battery management system.
With this setup I should be able to fully recharge the battery n just over 2 hours of driving - although it is likely that 48 amp rate would drop over time.
Also I have noticed an increase in the charge rate for the IOTA charger with the upgraded wiring inside the camper. I used to top out at 26-29 amps, now I am getting 31 amps out of the IOTA charger (which is rated for 30).
Yes this system is complete overkill, but my beer will always be cold.
Spoke with the battery vendor today. They have no concerns with the charging rate. The rate is advisory only for fixed rate chargers. They have no concerns about an alternator since the charging rate will vary as the voltages get closer together. They have seen 100 amp rates for short periods without a problem.
I will be dropping the regulator voltage a few tenths and increasing the belt protection (with drops the alt output) a few steps tonight and then all the fine tuning should be complete.
I will be dropping the regulator voltage a few tenths and increasing the belt protection (with drops the alt output) a few steps tonight and then all the fine tuning should be complete.
DrJ
Senior Member
48 amps at a time. That is very impressive and effective.
Nice work.
I have a magnum inverter/charger on my toy hauler that can do up to 50 amps and it makes charging much easier.
With lithium batteries that would make charging crazy fast.
Nice work.
I have a magnum inverter/charger on my toy hauler that can do up to 50 amps and it makes charging much easier.
With lithium batteries that would make charging crazy fast.
billharr
Senior Member
If you add them to your gallery it is much easier. Make different folder for topics.cdbrow1 said:
The system is rock solid. My solar panels got recalled so I just had to scrape them off the roof (not fun), but the LiFePo4 hardware is working great. I have put on 30k miles since I got the camper in January 2015. Probably 15 nights camping, but just about every other weekend I am out hiking and cooking in it.
I wanted to post another update. I have had zero problems with the system and continue to use it on a regular basis. I did adjust the solar voltage down slightly to keep the batteries from getting overcharged. I was at 14.2 volts, but looking closely at the logs on the Morningstar I saw some spikes as the BMS kicked in. I dropped the solar to 13.8 and have not seen any issues. I will probably adjust the regulator voltage down to 14.0 or 13.8 in the near future. I am not seeing spikes from the BMS while on the regulator, but I would rather be overcautious.
I just spent a few days boondocking out in Black Rock Desert with the setup in 95-100 degree heat. No issues at all. I ran a "swampy" mini swamp cooler+fridge+CPAP+Microwave+plus lights all night 2 nights without any issues. Battery dropped to 70% first night. The second night I had to move off the Playa because of a large thunderstorm at 1:00am (lighting and flash flood worries). Once again no issues at all even though I threw everything at the system I could.
Not having to worry about power while Boondocking is a great experience - as is having frozen solid ice cream after a long day in the hot sun.
Not having to worry about power while Boondocking is a great experience - as is having frozen solid ice cream after a long day in the hot sun.
I have a 100Ah CALB based DIY LiFePO4 pack that I will be installing in my soon to arrive Fleet Flatbed. I wanted to get some feedback on the low temperature charging issue.
I had originally planed on installing the battery under the hood to move some of the weight forward (albeit not that much weight with Li). However given the temperature issue, I will install the battery in the camper. My thought is that the temperature issue won't be so great when we are using the camper, as we will heat it to maintain temps above freezing. However, it will be an issue when it is parked outside over the winter in sunny but cold Colorado, either in the driveway at home, or wen we are out on ski trips. My plan is to install one of these between my 160W solar panel and the charge controller:
Single Pole Double Throw Thermostat
The solar panel will be the input and the normally closed output (ie closed when T > set point) will go to the charge controller, and the normally open output will go to a 120W adhesive heater attached to the battery pack. I will set the thermostat to 5C or so, with temperature probe attached to the battery. This way on a chilly morning (say T = -10C), when the sun comes up, all the power from the solar panels is dumped directly into the battery heater. Once the battery reaches a safe temperature to charge (say 5C) the thermostat closes, the solar panels are connected to the charge controller, and the batteries charge as normal.
Am I missing something here, or do you think this will address the low temperature charging issue?
I had originally planed on installing the battery under the hood to move some of the weight forward (albeit not that much weight with Li). However given the temperature issue, I will install the battery in the camper. My thought is that the temperature issue won't be so great when we are using the camper, as we will heat it to maintain temps above freezing. However, it will be an issue when it is parked outside over the winter in sunny but cold Colorado, either in the driveway at home, or wen we are out on ski trips. My plan is to install one of these between my 160W solar panel and the charge controller:
Single Pole Double Throw Thermostat
The solar panel will be the input and the normally closed output (ie closed when T > set point) will go to the charge controller, and the normally open output will go to a 120W adhesive heater attached to the battery pack. I will set the thermostat to 5C or so, with temperature probe attached to the battery. This way on a chilly morning (say T = -10C), when the sun comes up, all the power from the solar panels is dumped directly into the battery heater. Once the battery reaches a safe temperature to charge (say 5C) the thermostat closes, the solar panels are connected to the charge controller, and the batteries charge as normal.
Am I missing something here, or do you think this will address the low temperature charging issue?
Just to add:
I do some reading and it looks like the heat capacity of LiFePO4 packs is about 1000 J/(K Kg) = ie it takes 1000J to raise 1 Kg of battery 1 degree C. Based on a hypothetical situation where my morning temp is -10C, and my solar panel is working at 50% of max (80W) and my battery weighs 15Kg, it will take ~45 minutes to raise the battery temperature from -10C to 5C, at which point charging can begin.
I do some reading and it looks like the heat capacity of LiFePO4 packs is about 1000 J/(K Kg) = ie it takes 1000J to raise 1 Kg of battery 1 degree C. Based on a hypothetical situation where my morning temp is -10C, and my solar panel is working at 50% of max (80W) and my battery weighs 15Kg, it will take ~45 minutes to raise the battery temperature from -10C to 5C, at which point charging can begin.
rando said:
I am in California Central Valley so extreme cold is not a problem when stored. I do head into the Seirras and Great Basin at any time of year and I used the system into the single digits last year without trouble. My batteries are inside in the stock location (below the furnace) so I assume they are warmer than the exterior (there are no battery vents). My supplier does not recomend charging when the battery (not ambient) is below freezing, but discharge is allowed down to -30C. There is no issue of fire, but there is an issue of "dendrite growth" and failure of the cell.
The Battery Management System (BMS) is the most important component - make sure you know how yours works.
https://starkpower.com/safety-of-lithium-ion-batteries/
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