โApr-15-2023 04:14 PM
โApr-25-2023 07:06 AM
Sterling1 wrote:StirCrazy wrote:
so, the plot thickens everything I find says 50% or higher and if you're not using them for a long time recharge every 3 to 6 months. I think this is another area where older chemistry myths might be carrying over
Yea, different manufacturers have different recommendations. I just wonder how much difference it makes in the real world.
For someone that really cycles the batteries a lot and is concerned about maximizing the cycle life it may make sense to take extra effort to store them in optimum conditions.
For someone like me who doesn't put a lot of cycles on the batteries storage conditions may not make much of a difference (as long as they aren't stored in a discharged state). They are more likely to die from old age than anything else.
It would just be nice to see how much of an impact storage SoC has on LiFePO4 battery life.
โApr-24-2023 07:03 PM
StirCrazy wrote:
so, the plot thickens everything I find says 50% or higher and if you're not using them for a long time recharge every 3 to 6 months. I think this is another area where older chemistry myths might be carrying over
โApr-24-2023 06:58 AM
Sterling1 wrote:
โฆ.I understand that storing them not fully charged is best;
But I haven't found anywhere on the internet where it quantifies the degradation in life due to starting out storage in a fully charged state.
โApr-24-2023 06:38 AM
Sterling1 wrote:
I understand that storing them not fully charged is best. But I haven't found how much degradation it does to be stored in a fully charged state (but not connected to a charger). If it is a 10% degradation in life I I can live with it, but if it is a 50% degradation in life then I'd probably take the extra effort to discharge them for storage.
I haven't found anywhere on the internet where it quantifies the degradation in life due to starting out storage in a fully charged state.
โApr-23-2023 07:19 PM
โApr-23-2023 06:47 PM
Sterling1 wrote:
I know LiFePO4 batteries should be stored around a 50% SoC for maximum life, but how important is this from a practical standpoint? I dry camp fewer than 10 times a year. If I were to give the batteries a full charge and disconnect them, top them off before going out, fully charge them when I returned (if they were significantly discharged), disconnect them and leave them that way for my next trip, how much am I really degrading their life? I realize I could boil some water in my microwave to get the charge level down but I wonder if it is really worth it.
โApr-23-2023 10:26 AM
โApr-18-2023 06:23 AM
Sterling1 wrote:StirCrazy wrote:
LiFePO4 is a different animal and while it has a few things you can't do like you did with your old fifty buck Walmart special, it isn't really that hard. little things like using a capacitor to preload your inverter circuit before you hook the batteries to it, on a new install, is it necessary probably not, but it does reduce the chance that feedback from a spark will take out any electronics.
even things like making sure you can parallel it, some can't, some have 2 battery restrictions some have 4. same goes for series installation, do the homework.
This is an interesting comment about the inverter. My inverter is currently connected directly to one of my batteries and doesn't go through the switch. I was planning on leaving it this way and see if I have a problem with parasitic draw drawing down the LFE battery when the switch is in the Off position. According to my inverter manual it doesn't draw any current when the inverter is switched off. If it did I was either going to disconnect it for storage or move it to the switch. I would hope the BMS can protect itself from the inverter inrush current. It is pretty common to have inverters connected to batteries and it seems like they would have precautions in the battery manual if it could harm the BMS.
My new LFE batteries are allowed to be connected in parralel but not series.
โApr-17-2023 10:41 AM
3 tons wrote:
Best to just parallel the batteries, and assuming your inverter is less than about 4-5k watt's ( just โtheoretical worriesโโฆ) youโll find that inverter and BMS wonโt much careโฆ:R
3 tons
โApr-17-2023 10:08 AM
โApr-17-2023 08:55 AM
StirCrazy wrote:
LiFePO4 is a different animal and while it has a few things you can't do like you did with your old fifty buck Walmart special, it isn't really that hard. little things like using a capacitor to preload your inverter circuit before you hook the batteries to it, on a new install, is it necessary probably not, but it does reduce the chance that feedback from a spark will take out any electronics.
even things like making sure you can parallel it, some can't, some have 2 battery restrictions some have 4. same goes for series installation, do the homework.
โApr-17-2023 08:26 AM
StirCrazy wrote:mbloof wrote:Sterling1 wrote:
I'm going to replace my 2 lead acid batteries in my Bigfoot truck camper with two 100ah LiFePO4 batteries. I've previously installed a 4 way battery selector switch to allow me to keep one of my batteries at a high enough charge level to start my generator (they are run in parallel). However, this won't be necessary (and probably won't work) with the lithium batteries and I will probably need to have it at the Both position to start my generator.
My question is is can I damage the batteries if I switch to the Both position when one battery is low and the other battery is fully charged?
In a word: No.
A battery is simply a energy storage device.
No matter what "type" or chemistry the batteries are if they have the same nominal voltage (IE: 12V) then the following would be true:
Battery #1 is 12.5V and Battery #2 is 13.5V and you hook them both together in parallel along with a load. What happens?
The load will draw current from BOTH batteries but since Battery #2 is at a higher charge voltage than battery #1 some of Battery #2's energy will flow to Battery #1 until such time BOTH batteries have the same charge voltage.
If you simply hooked a not-so-much charged battery up to a fully charged battery without a actual load the "not-so-much charged battery" would still be a load to the fully charged battery until such time that both batteries have equal voltage.
So can you can see the 'wasted' energy/charge being used for the lesser charged battery?
This is why it is generally recommended that to use two or more batteries in parallel they ought to be the same Brand+type+age+capacity and charge level so stored energy is not wasted charging the other batteries in the bank.
- Mark0.
You're forgetting about the BMS and the electronics in it.
โApr-17-2023 07:21 AM
โApr-17-2023 06:56 AM
Sterling1 wrote:
I'm going to replace my 2 lead acid batteries in my Bigfoot truck camper with two 100ah LiFePO4 batteries. I've previously installed a 4 way battery selector switch to allow me to keep one of my batteries at a high enough charge level to start my generator (they are run in parallel). However, this won't be necessary (and probably won't work) with the lithium batteries and I will probably need to have it at the Both position to start my generator.
My question is is can I damage the batteries if I switch to the Both position when one battery is low and the other battery is fully charged?
โApr-17-2023 06:51 AM
mbloof wrote:Sterling1 wrote:
I'm going to replace my 2 lead acid batteries in my Bigfoot truck camper with two 100ah LiFePO4 batteries. I've previously installed a 4 way battery selector switch to allow me to keep one of my batteries at a high enough charge level to start my generator (they are run in parallel). However, this won't be necessary (and probably won't work) with the lithium batteries and I will probably need to have it at the Both position to start my generator.
My question is is can I damage the batteries if I switch to the Both position when one battery is low and the other battery is fully charged?
In a word: No.
A battery is simply a energy storage device.
No matter what "type" or chemistry the batteries are if they have the same nominal voltage (IE: 12V) then the following would be true:
Battery #1 is 12.5V and Battery #2 is 13.5V and you hook them both together in parallel along with a load. What happens?
The load will draw current from BOTH batteries but since Battery #2 is at a higher charge voltage than battery #1 some of Battery #2's energy will flow to Battery #1 until such time BOTH batteries have the same charge voltage.
If you simply hooked a not-so-much charged battery up to a fully charged battery without a actual load the "not-so-much charged battery" would still be a load to the fully charged battery until such time that both batteries have equal voltage.
So can you can see the 'wasted' energy/charge being used for the lesser charged battery?
This is why it is generally recommended that to use two or more batteries in parallel they ought to be the same Brand+type+age+capacity and charge level so stored energy is not wasted charging the other batteries in the bank.
- Mark0.