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diy solar

Ampere Time 300ah in an RV. Relative newbie to lithium

theroamincatholic

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May 7, 2021
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So I was introduced to this forum by Will's Youtube channel, and was immediately enthralled with the knowledge offered there. First, a little background. I have a 23' travel trailer that I upgraded with two 6V 230ah batteries, and a Progressive Dynamics PD4655V 55 amp converter/charger. I also have a Victron BMV-712 battery monitor installed. I mostly camp in very shady areas, so solar has been a relatively low priority for me. I have a single 100-watt ground-deployed "briefcase" solar panel with a Renogy 20A PWM solar charge controller that has served my needs. I am a part-time RVer at this point, and rarely spend more than 3 nights off the grid at a time.

My dual 6V batteries are just over four years old and still working great, and still hold an excellent charge. I have made sure I have never discharged them below 50%, as measured by the BMV-712, so I am sure that has aided in their long lifespan. That being said, I would like to replace these batteries with lithium, add a pure sine wave power inverter to occasionally run AC devices, and add an automatic transfer switch. Since my solar power is relatively limited, I want to make sure that I have a reliable AC charging method, plus I plan on installing a 40A DC-DC Renogy charger with dedicated charge line from my towing vehicle.

So, I have a few questions that have come up during my research:

First, I plan on using the Ampere Time 300ah battery currently available on Amazon. They seem to be a fairly well-built battery, except for the lack of low temperature charge protection. I rarely camp in below freezing temperatures, and the battery is going to be mounted inside the RV, so it should never be below 32 Fahrenheit while charging. The trailer is placed in storage every winter. Is there a better battery available at a similar $/wH out there that I may not have thought of?

Second, I'm not sure what I should do for charging. Opinions seem to vary as to whether my existing Progressive Dynamics PD4655V can support a lithium battery or not. The maximum output voltage of my PD4655 is 14.4 volts. The float voltage is set at 13.2 volts, and the absorption phase is 13.6V. PD recommends I purchase their lithium compatible 91xxALV series charger to charge LiFePO4 batteries, but I've heard conflicting information. I certainly don't want to damage my shiny new lithium battery with the charger, but if I can use the charger I have, then I will. Eventually, I would like to replace or move the charger anyway, as it is currently located approximately 15 feet away from the batteries, and has a 6AWG wire running to the batteries, and I suspect I could make the charger more efficient by moving it closer to the batteries. The lithium battery will help this slightly, as it will be approximately 5 feet closer to the charger than it is now.

I know this was a lot for my first post, so sorry for all the stupid questions. I am a low-voltage/audio-visual design engineer by trade, but not terribly familiar with the specifics of lithium batteries.
 
I am going to build my own 280 AH LIPO4 battery for my 25 foot trailer (just arrived today) to replace my two SLA batteries. My shunt says I use about 240 Watts a day when I’m camping (I have no inverter).

I have the PD 4655 converter/charger and am going to stick with it. At 14.4 volts it will charge the battery to 90% easily. Even at 90% I am ahead of the two 92 AH SLA batteries I currently have. (250 AH down to 46 AH at 20% = 200 AH of usable power... I’m adding a Victron 100/30 SCC and a 40 amp Renergy B2B DC charger. The newer 4655 PD have a lithium mode (you move a jumper on the main board), but it’s at 14.6 all the time and I’ve read that isn’t particularly good for the longevity of the batteries...https://www.bestconverter.com/PD-4655VL-55-Amp-Converter-Upgrade-Optional-Remote-Pendant-_p_676.html#.YJYzhuRHYlQ

I’ve changed from my original converter/charger that cooked my batteries at a constant 13.6 V to the PD 4655. It was an easy mod and I suspect a dedicated lithium charger wouldd be easy too, but I’m thinking the PD 4655 will work fine.

i like the Ampere Time batteries based on Will’s tests; but if I started over, I think I would go with a 8 100 Ah Fortune cell s in a 2P4s configuration. The fortune cells are more expensive but super easy to put together... and for my use 200 AH (2400 Wh) is plenty.
 
On the charger question, I have the same issue. Some great options depending on what you want to accomplish, keep in mind some of these are going to have reduced efficiencies vs others:

Victron 25amp charger $175 on Amazon
Expert Power 20amp charger $90
Meanwell 25am Charger/Converter $100 shipped
 
Just wanted to chime back in here and let everyone know what I decided. I went with 3 of the metal case 100ah batteries from Aric at ReBel batteries. They seem well-made, and I enjoyed the opportunity to support a veteran-owned US business. Also the metal case gives me some confidence that the battery is serviceable without destruction. I did order through Amazon, as I wanted to use my Amazon store card to get 5% back.

I am going to try using my Progressive Dynamics PD4655 charger for the time being. I do have cables run to add a charger in the compartment where the batteries will be, so if I have to add a charger in the future, it should be simple enough, but I figured I have nothing to lose by trying the charger I have.

I will let everyone know what I think of the batteries once they arrive. I anticipate having them in hand in the next week or two, depending on shipping times. I know Aric has been very busy.
 
Did you ever get your batteries? How do you like them? How is your PD4655 charger working out?
 
My Batteries came pretty quickly — 45 days or so from Blmpow Official Store on AliExpress. After 1000 miles of towing; no loose connections… but I suspect you are asking Mr. Catholic…

PD4655 (in regular mode) seems to do the trick for me I hit the button to elevate the charge and it gives 4 hours at 14.4 v. I keep an eye on the 280 ah battery with the overkill bms or Victron shunt (too much redundancy). Between the converter, the DC-DC charger and the solar panels, I’ve had no problems keeping batteries topped off. I have only done a couple 2-3 days at a time dry camping, but it seems to be working well. I have not broken out the generator yet; even after the sweet wife uses the toaster or hairdryer thru the inverter…I have a week of dry camping set in January; that will be the real test.
 
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