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Christopher A avatar image
Christopher A asked

Need Help in expanding this system

I have the first phase of my RV solar up and working.

It's a 12V/120V(via 1000W inverter) Coach and it came with two 6V 220AH AGM house batteries in series. Everything so far is new, so i'm not trying to trash new stuff If I can incorporate it into an expanded system in a practical method.

I have installed four 300 Watt panels and a 150/70 Smart Solar MPPT controller and a 712 Battery Monitor.

Questions I have:

1. Does it make sense to now expand the AGM batteries although in the future I want to go to Lifepo4?

2. If I junk the 12V AGM batteries should I size the new system for 24V?

3. I have yet to install a higher power inverter. This will play into my decision on 12V or 24V. How does this play into with the alternator charging 12V dc to the House Bank?

4. Right now, the solar generates more than the batteries can take, since I'm not using many loads at this time. I will in the near future move the refridgerator to the inverter and other items as well. How does this play into expanding the system to more capacity (battery capacity).

Thank you for your opinions on this in advance.


battery capacity
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1 Answer
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wkirby answered ·

1. You need to make that decision for yourself soon. Whilst your current AGM batteries are new you can add more. If you leave them to age (or cycle) for more than 6-12 months than it will not be a good idea to add more. If you decide to spend money on AGM batteries then you are in it for at least 5 years.

2. If they are new you should be able to sell them on rather than dump them. A higher Voltage is almost always better. Consider 48V too if you plan to run air conditioners, cooking appliances or other high draw gadgets. This ties in to Question 3.

3. If you want to have a higher power inverter then that is even more reason to go with a higher Voltage. Engine charging can still be done either by upgrading the alternator, running a separate alternator just for the house battery systems or a battery-to-battery charger.

4. Continuous (24H) loads will demand more battery capacity. If you have more solar than battery capacity already, then you have another reason to invest in a bigger battery bank.

The decision is yours to make as to whether you want to invest in Lithium today (lots of money) or spend less on upgrading you current AGM bank with more AGM and then think about what to do in five years time. You have got a lot to think about and some decisions are dependent on others either immediately or further down the line.

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