I can wet my hands and grab a 12v battery no problem, can't do that with my 48V
Help understanding how long a battery will last.
- Thread starter USMA36
- Start date
- Tagged users None
- Joined
- Jul 16, 2009
- Messages
- 3,271
- Reaction score
- 4,942
Two different concerns. Yes, voltage (and the current behind it) is a danger.I can wet my hands and grab a 12v battery no problem, can't do that with my 48V
However, a high current low voltage stack is far more of a danger with regard to short circuit failures In the stack.
Resistive losses are I^2*R. Doubling the voltage halves the current, and cuts your resistive losses to 25% of what it would have been at the lower voltage.
OP
OP
This is where I get confused. Issue 1. Everything I read says sealed lead acid batteries are only useable to half the rated capacity without damaging them. Am I mistaken? Issue 2. As far of the math goes, that formula says 14 hours but if I do what is recommended in post 6 and convert to watt hours I get less than 2 hours off of a 100ah LifePo4. 100ah X 12.8v=1280wh. 1280wh / 780w = 1.6 hours. Same thing happens using online battery life calculators. There are 2 types I found ah and wh different answers! Which is correct? Thanks for the recommendation on the MPP solar setup. I will look into that . Expensive but looks hassle free. Does the input plug into a wall socket or does it have to be wired to the breaker panel?
How does a 100Ah 24V battery, deliver less amps than a 12v 100Ah battery?
OP
OP
So lower voltage means means more current and more loss over distance of the battery cables?
No idea what stack topology is lol.
Thoughts on this setup posted above?You want something like this plug and play no brainer. Power goes out, backup kicks in no fancy wiring you do not have to be home or rely on some other system to switch the power for you...
pair it up with something like this...
The advantage of higher battery voltage as far as efficiency is minimal, it's there but minimal. The biggest advantage is being able to pair your bats with inverter.
EG4 LifePower4 Lithium Battery | 24V 200AH | Server Rack Battery
EG4 Lithium battery 25.6V (24V) 5.12kWh with 200AH internal BMS. Made of UL Listed Battery Cells. Off Grid Solar Batteries - Off Grid System - Solar Batteries for Home - Lithium Solar Batteries - Deep Cycle Solar Batteries - Power Reserve - Solar Panels Plus Battery - LifePo4 - LifePower4 - Life...signaturesolar.com
One of the issues with the simple amp*hour math is that the capacity of a battery is also a function of how fast you pull out the energy. The Ah rating on batteries are notoriously optimistic, or set at very low discharge rate.
For example:
A 100Ah battery can probably supply 0.5A for 200 hours.
It might be able to supply 1A for 100 hours.
However, it would be a very special battery if it could actually supply 100A for 1 hour.
The recommendation someone made to use the Wh calculation is probably going to end up closer to the truth. Unfortunately, there isn't a way to predict with certainty without having detailed info on all the components involved.
For example:
A 100Ah battery can probably supply 0.5A for 200 hours.
It might be able to supply 1A for 100 hours.
However, it would be a very special battery if it could actually supply 100A for 1 hour.
The recommendation someone made to use the Wh calculation is probably going to end up closer to the truth. Unfortunately, there isn't a way to predict with certainty without having detailed info on all the components involved.
Yep. That is why power lines are running at such high voltages.
The higher current also causes more losses in the inverter.
Ur not wrong... SLABs have their own personalities hehe... you also have to watch how you charge them in addition to making sure the power is cut off at the recommended low voltage... too much nonsense for me
8 Best Deep Cycle Battery in 2024 | Reviews and Buying Guide
Best Deep Cycle Batteries. Lead-Acid (flooded, AGM, Gel), LiFePO4 Deep Cycle Batteries for use in RVs, Boats, Solar, Emergency Power.
www.electronicshub.org
maybe you can do the maths for us 12v 100ah system vs 24v 100ah system?
I still say the difference for what we are talking about here is negligible.
- Joined
- Jul 16, 2009
- Messages
- 3,271
- Reaction score
- 4,942
You can’t do the math without the rest of the variables.
OP
OP
This is the eb832 I’d be using and what is hooked up to it. Not sure if that helps or not. I would program the apex to power off the lights during a power outage.
I can't run the calcs without knowing the resistive losses in the system. However, it is reasonable to say that a 12v inverter will feel 4x hotter than a 24v inverter running at the same power. That heat is all loss.
add in your own variables to make the math work out easier...
NICE! I didn't know the eb could do this. Does it give you a graph over 24 hours or are those amp draws the actual average over time, and what amount of time?
This is the eb832 I’d be using and what is hooked up to it. Not sure if that helps or not. I would program the apex to power off the lights during a power outage.
OP
OP
SteveMM62Reef
Valuable Member
Why do you need your heater? I lost power January 22, for 8 Hours 50 minutes. The 65 Gallon Aquarium temperatures went from 78 F to 71.8 F during that time. I do insulate the Back Glass, Underneath and Back and Sides of the Sump, during the Winter. This is to save on electric bills. I had a quicker temperature drop on my 30 Gallons Quarantine Aquarium, used bottles of hot water and blankets on that Aquarium, this wasn’t difficult. I use a 12 Vdc Battery to Auto run two 12 Vdc Pumps from my Sump to the Aquarium.
OMG that is so sexy!Here you go!
At a minimum if you can, I would steer away from SLAB's I've had 6v 12v Trojan batteries give out on me w/in 2-3 years. You really need special chargers to help extend their life and they don't like sitting around, they like to be used/cycled every now and then... too much to think about
I currently have a bank of Leaf Car batteries 48v configuration just because that was the inverter I found on sale many many many years ago... I'm looking seriously at that mpp this conversation is pressing my finger on the trigger
Similar threads
