Battery options

[SolarPoweredRV]

What about hot temps? I hear all kinds of talk about the cold, do these batteries have any limitations say above 90 or 95f? Where I store my rig in the summer it is very typical to get to 110f.

Here are the temperature specifications for the Ampere Time battery available from Amazon that I mentioned above:

Operating Temp: Charge: 0°C~50°C; Discharge: -20°C~60°C
Translation: Charge: 32 F~122 F: Discharge -4 F ~ 140 F

Most LiFePo4 batteries should have similar operating temperatures, check the exact specifications for any battery you are planning to purchase.

[Redapple63]

Here are the temperature specifications for the Ampere Time battery available from Amazon that I mentioned above:

Operating Temp: Charge: 0°C~50°C; Discharge: -20°C~60°C
Translation: Charge: 32 F~122 F: Discharge -4 F ~ 140 F

Most LiFePo4 batteries should have similar operating temperatures, check the exact specifications for any battery you are planning to purchase.

Thanks, exactly what in was looking for!

[SolarPoweredRV]

No need to apologize, everyone is entitled to an opinion. I responded based on your conclusion "In the OP's situation, it would be acceptable to attach the positive lead (from the camper) to one battery and the negative lead (from the camper) to the other battery."

When you configure a battery bank in parallel and daisy-chain all the positive posts and daisy-chain all the negative posts those two daisy-chains are essentially busbars. Any resistance caused by terminal connectors would be minimal and not enough to impact the performance of the battery bank.

BTW ... You never posted the study you mentioned and it would be useful to link it if you are going to reference it and be a basis for your argument.

According to the study I mentioned above, when the load is connected to only one battery there is a disproportionate draw from the first battery in the parallel string. This disproportional draw is lessened if the load is connected to the first and last battery in the string, however, in a longer parallel string (say 4 batteries) even if you attach the load to the middle batteries the load places a disproportional draw from the battery(ies) the load is attached to. The only way to draw evenly from all batteries in a battery bank is to attach all the batteries to buss bars and then attach the load to the buss bars.

Here is the study I mentioned...

http://www.smartgauge.co.uk/batt_con.html

[Soundsailor]

The only way to draw evenly from all batteries in a battery bank is to attach all the batteries to buss bars and then attach the load to the buss bars.

Here is the study I mentioned...

http://www.smartgauge.co.uk/batt_con.html

Yes, that's the approach I took with my 4 battery parallel battery bank (800 Ah in 4 200 AH batteries), what I've dubbed a "star" approach. Each of the 4 batteries is wired directly to a bus bar, the load is then wired into those same bus bars. This approach has worked very well so far.

[Redapple63]

Here are the temperature specifications for the Ampere Time battery available from Amazon that I mentioned above:

Operating Temp: Charge: 0°C~50°C; Discharge: -20°C~60°C
Translation: Charge: 32 F~122 F: Discharge -4 F ~ 140 F

Most LiFePo4 batteries should have similar operating temperatures, check the exact specifications for any battery you are planning to purchase.

How are you handling the low temp cutoff as the Ampretime only had the high temp cutoff?

[Soundsailor]

How are you handling the low temp cutoff as the Ampretime only had the high temp cutoff?

That's a pretty standard issue with the lower-priced Lifepo4 batteries since none of them tend to have the low-temperature cutoff. For me, I added some heat pads that are thermostatically programmed to come on when the temperature in the battery box falls below 40 degrees. I've seen solutions where all charging is turned off when the temps fall below a set point. If you're not camping in cold weather, then you won't need to worry about it.

Some higher-priced batteries have the heaters built-in. Some of the Victron controllers have the ability to use a temperature sensor that stops charging at lower temps. There are many ways to approach the low temperature issue.

[Redapple63]

That's a pretty standard issue with the lower-priced Lifepo4 batteries since none of them tend to have the low-temperature cutoff. For me, I added some heat pads that are thermostatically programmed to come on when the temperature in the battery box falls below 40 degrees. I've seen solutions where all charging is turned off when the temps fall below a set point. If you're not camping in cold weather, then you won't need to worry about it.

Some higher-priced batteries have the heaters built-in. Some of the Victron controllers have the ability to use a temperature sensor that stops charging at lower temps. There are many ways to approach the low temperature issue.

Thanks, and I agree. I have been looking at the Ampretime 300 ah battery it is an awesome value.
Single battery, about 40% more capacity than my current fla gc2’s and at drain to 25% soc doubles my usable capacity. All around a great deal.

[docque]

Yes, that's the approach I took with my 4 battery parallel battery bank (800 Ah in 4 200 AH batteries), what I've dubbed a "star" approach. Each of the 4 batteries is wired directly to a bus bar, the load is then wired into those same bus bars. This approach has worked very well so far.

I read the studies and it is what I remembered. If using cables you have a bunch of wires going every which way to get the most efficient output.

[SolarPoweredRV]

How are you handling the low temp cutoff as the Ampretime only had the high temp cutoff?

If you are in a situation where you won't be charging your batteries in those cold temperatures then you can keep the issue in the back of your mind and manually turn off any charging sources until the temps improve (turn off your Solar and Converter for example).

If you are in a situation where you might face those temps (even I face those temps camping in Florida) then you need to address the issue. If you keep your RV in storage in the cold weather, you can simply disconnect the battery so there is no way the battery can receive a charge.

If there is a chance you will face cold temps then you need to ensure the battery you purchase has a cold temp cut-off or you need to address the issue as SoundSailor suggests above. The easiest thing you can do is to place the LiFePo4 batteries in a heated hold or inside the living area (i.e.: inside a closet, or under the dining table bench seat).

Will Prouse of "DIY Solar Power" on YouTube has broken down several LiFePo4 batteries and has tested them all for cold temp cut-off, if you review his channel he probably has torn down the brand of battery you might be considering purchasing to find out if it has cold temp protection.

[Butcher]

According to the study I mentioned above, when the load is connected to only one battery there is a disproportionate draw from the first battery in the parallel string. This disproportional draw is lessened if the load is connected to the first and last battery in the string, however, in a longer parallel string (say 4 batteries) even if you attach the load to the middle batteries the load places a disproportional draw from the battery(ies) the load is attached to. The only way to draw evenly from all batteries in a battery bank is to attach all the batteries to buss bars and then attach the load to the buss bars.

Here is the study I mentioned...

http://www.smartgauge.co.uk/batt_con.html

This information is true but how often does an RV pull those kind of loads that it would matter? When the loads are much smaller, the battery voltages would all even out.

I'm not saying it does not matter and if you like your A/C on 24/7, then you should be focusing in on the most efficient routing.

I suspect most of us would never get to 100amps long enough that it would effect the capacity of the batteries. The inverter would probably be the biggest draw and how often is that really being pushed? Microwave? Hair dryer? But those are short term draws. I just cannot see a 20-30amp draw screwing up the capacity all that much. I'm not saying it would not, just not enough to be that concerned about.

On the other hand, if you are going to do it right, why not check out all the options and pick one that is right for you.