Can I use both of these batteries together?

[ShelbyWatson]

I have followed the instructions for installing the all in one MPP 24v 2.4kW PIP Model . Love it and it works great. I have 600w of solar panels hooked to it. I currently have two 12v vmaxslr200 vmax tanks agm 200ah hooked in series to get the 24volt- per instructions. Was wanting to add another battery to this system like the 50Ah 24v LifePO4 Deep Cycle Battery.
Can I use these two together or do I need to get the same type I already have installed?

 

[gnubie]

Lfepo4 and AGM batteries have fairly compatible charging voltages so, IMO, you could hook the the lifepo4 in parallel with your AGM string. At 600 watts I'm concerned that your panels won't be able to produce enough power to lift the battery to fully charged each day unless you are only drawing low amounts of power from it, which defeats having more battery capacity in the first place.

Lead acid batteries need to be kept fully charged as much as possible.

 

[ShelbyWatson]

Lfepo4 and AGM batteries have fairly compatible charging voltages so, IMO, you could hook the the lifepo4 in parallel with your AGM string. At 600 watts I'm concerned that your panels won't be able to produce enough power to lift the battery to fully charged each day unless you are only drawing low amounts of power from it, which defeats having more battery capacity in the first place.

Lead acid batteries need to be kept fully charged as much as possible.

Ok, thanks. ( I am a complete nube to this)

I have 6 100 watt panels hooked to it since I believe any more added to the system would be above the voltage allowed for the Mpp 24v 2.4kW PIP model?
Specifications

• Maximum Power: 100W
• Maximum System Voltage: 1000V DC (UL)
• Optimum Operating Voltage (Vmp): 17.8V
• Open-Circuit Voltage (Voc): 21.2V
• Optimum Operating Current (Imp): 5.62A
• Short-Circuit Current (Isc): 6.02A
• Weight: 16.5 lbs
• Dimensions: 39.6 x 26.6x 1.4 inches

 

[gnubie]

How much power do you draw out of the battery over a day? If you don't know you can use a meter to measure it. The Drok range of meters are fairly popular on the forum. You could also do an approximation using the ratings of the various devices, DC and AC, that you have your system powering. If all your loads are AC, ie all connect to the inverter rather than to the battery, you could use a kill-a-watt style meter instead.

Once you know how much you are using over a day you'll be in a better position to work out how much solar you need.

Your 6 panels in series are at the limit of the MPP's DC input but you have plenty of current space to play with so if you do need more power from solar (and can fit it!) you could change the panels from series connected to some arrangement of series/parallel to lower the voltage, but increase the amps.

 

[ShelbyWatson]

How much power do you draw out of the battery over a day? If you don't know you can use a meter to measure it. The Drok range of meters are fairly popular on the forum. You could also do an approximation using the ratings of the various devices, DC and AC, that you have your system powering. If all your loads are AC, ie all connect to the inverter rather than to the battery, you could use a kill-a-watt style meter instead.

Once you know how much you are using over a day you'll be in a better position to work out how much solar you need.

Your 6 panels in series are at the limit of the MPP's DC input but you have plenty of current space to play with so if you do need more power from solar (and can fit it!) you could change the panels from series connected to some arrangement of series/parallel to lower the voltage, but increase the amps.

Thanks for the help. Feel like I'm slowing keeping my head afloat on this.
Ok, so to add more watts, I just change their hookup.
I am not using a lot of power. I maybe hit 11% of available load.
My mini fridge, fan, router extender, tv and ps4. That's pretty much it.
My heat and cook stove is gas with all my lights being battery.

 

[gnubie]

If you are only drawing 11% of the existing battery capacity is there really any need to add another into the mix?

 

[ShelbyWatson]

If you are only drawing 11% of the existing battery capacity is there really any need to add another into the mix?

Probably not. I think part of it is my being a nube to this. I was looking at the battery usage and it goes down to 2 bars at night so I thought I was emptying my battery halfway. But now that I look at the instructions for the NPP, I'm not so sure. It states it shows differently depending on the percentage of load??
I am using solar only for my system.

 

[Supervstech]

I agree. I would save the money for another battery in a few years when your current battery degrades.
Put the money you would spend on the lithium and buy stock or a money market fund...

 

[gnubie]

OK, important thing to check first is that your existing AGM batteries are being bought up to full charge. Keep an eye on the charger information the MPP provides today to see if your AGM battery is making it to float charging.

 

[ShelbyWatson]

OK, important thing to check first is that your existing AGM batteries are being bought up to full charge. Keep an eye on the charger information the MPP provides today to see if your AGM battery is making it to float charging.

It seems to be going into float ok. During the day it will show fully charged, with the 4 bars staying on (ie not charging anymore)

 

[gnubie]

It seems to be going into float ok. During the day it will show fully charged, with the 4 bars staying on (ie not charging anymore)

Save your money, let the AGMs run their normal life span and then towards their end look at buying a lifepo4. The prices on lifepo4 will likely have dropped by the time to purchase comes along, and you never know lifepo4 may have been knocked off its perch by a superior battery by then too.