2000 Watt Build completed on Class A RV with 840Ah Prismatic Cells

SolarKimmy

Solar Enthusiast
This project started with the purchase of a nearly new 2019 Fleetwood Bounder. I'm building a total off grid machine. I picked the bounder because of "quality" (they all suck) and 110 gallon water capacity.

I had four 300 watt panels left over from my last build and I purchased four 210 watt very good panels from HITech Solar out of Michigan. They are all hard mounted to the roof and sealed with Dicor.
All electronics are top line Victron except the inverter. It's the stock 2000 Watt Magnum unit that came with the coach. For now, I'm leaving it a 12Volt system. Future plans will call for a Victron 3000 Watt 24Volt conversion. All the systems are all ready for that conversion I will just have to re-wire the batteries and install two DC-DC converters. Victron, of course.
Since I have access to all electronics at wholesale, I made this a top line build. I split the two panels into two parallel charge controllers. I also purchased the new Victron Cerbo which is a high end total solution to system monitoring and control. I can monitor and control from anywhere in the world. I chose to not use much jumper wiring and used BEP Marinco Pro Series buss bars and link bars. Much less wiring and more reliable.

The batteries were purchased direct from China. These are Dongguan 280AH Prismatic cells everyone is discussing. I purchased 20 Cells and I'm using 12 so far on this build for a pack of 840AH. I also used Daly 200 Amp BMS and they are keeping the cells balanced within .002 Volts. . Future plans call for more cellsIMG_7667.jpgIMG_7688.jpg when I can find the space to put them.

I fired up the system two days ago and have been running all sorts of tests and looking for failure points. So far, everything is perfect. I can run a residential refrigerator for days and even heat water with electricity. No AC, that's not possible until I add more battery and switch the inverter. Attached are some pics of the build. IMG_7689.jpgIMG_7690.jpgIMG_7691.jpg
 

bpal

Solar Enthusiast
How are those HighTec 210w panels working out? In one of the other threads wattage output seemed to be under performing in anything other than ideal conditions.
 

SolarKimmy

Solar Enthusiast
How are those HighTec 210w panels working out? In one of the other threads wattage output seemed to be under performing in anything other than ideal conditions.
4 panels in full peak sun, I get about 550-600 watts. Now the panels are flat, so they lose 20-25% from being tilted at the sun. I believe they are ok. Better than a flexible panels and for the price, they are a well build glass panel. I have even walked on them. Time will tell, though.
 

SolarKimmy

Solar Enthusiast
I installed the fourth battery. So now I have 1120 Amp Hours of battery. They fully charge by 10 am, but my loads average 25AH overnight. I have pushed them to my 2000 watt inverter limit, with no sweat. Nothing even gets warm. If you think about it, I'm only pulling 45 Amps out of each pack, so it's a very conservative draw. I under charge to about 90% and my max discharge so far has been to 70% but that was with 840AH. It will be less tonight overnight. I will see in the morning what my battery ends up at.
 

iceledoar

Off Grid, Off Grid. Not even sometimes.
4 panels in full peak sun, I get about 550-600 watts. Now the panels are flat, so they lose 20-25% from being tilted at the sun. I believe they are ok. Better than a flexible panels and for the price, they are a well build glass panel. I have even walked on them. Time will tell, though.
I have two of them and they work very well.
 

Walkdog

New Member
What BMS are you using? I'm totally NEW to all this and actually have a order of 8 batteries atm. I'm totally winging this, but i want lithium for cheap and almost bought a couple golf cart batteries until i come across this.
 

SolarKimmy

Solar Enthusiast
Sorry for the delayed response. I'm using the Daly 200 AMP BMS on each of the four packs. I don't need the fancy app on each battery and plus, the Daly works and keeps things in check. All I really care about is balancing the cells because my pack is so large. My Victron Energy equipment manages everything else including low temp cut off. I'm only using 200 AMP and that is overkill. My max draw from each pack is can only be what the inverter is rated plus some small DC loads. Maybe 60 Amps maximum.
 

SolarKimmy

Solar Enthusiast
After nearly 2500 miles of traveling and daily testing, I can't find anything wrong with the system. I recently upgraded to a Victron 3000 watt multiplus inverter ($1061.40 plus 9 bucks shipping) and it handles all my loads easily. I sold the stock Magnum 2000 watt for about the same price on Ebay, so it was a wash to upgrade to all Victron. So I have a 100% Victron system now, except for the batteries. I still do not run air conditioning because it will drain my battery pack and there is not enough sun, even with 2000 watts on the roof, to replenish the battery bank. I recently rewired the whole system and I'm contemplating on adding more battery.... But that is a different project.
 

Bud Martin

Solar Addict
Are you running 12V system with four 12V batteries packs connected in series?
Never mind, I see how the batteries are connected now, so it is 12V system.
 

SolarKimmy

Solar Enthusiast
Yep, 12V. I toyed with the idea of 24v, but with the conversions and two way 24V step up and down, I tossed that out. Easier this way, although a little bulkier.
 

texskeet

Solar Enthusiast
Yep, 12V. I toyed with the idea of 24v, but with the conversions and two way 24V step up and down, I tossed that out. Easier this way, although a little bulkier.
Be sure to use a lithium battery combiner thing so your alternator does not get burned up.
 

SolarKimmy

Solar Enthusiast
Be sure to use a lithium battery combiner thing so your alternator does not get burned up.
I may be wrong, but with this much Lithium, I'm not concerned about burning out my alternator. I have nearly 3000 miles and it appears that the total internal resistance is ok for the stock alternator, although it only charges to about 13 volts. The solar tops it off to 14.2 on good days. All in all, the system is healthy. Yeah Yeah, I saw that video. But I'm dealing with 1120 AH of lithium. It seems like it can take a lot of charge with no hic-ups.
 

texskeet

Solar Enthusiast
This is not every day it is when your house batteries are down and you start to drive once your starter bats get charged the alt will start in house bats. the lithium will take all the amp the alt will put out and that is when the problems start. The ir of lithium is much lower than LA.
 

SolarKimmy

Solar Enthusiast
I do not want to start an argument, I have installed tons of systems and there has never been a problem with the alternator charging the lithium pack. It appears that the total resistance of the pack is enough for the system to not fail. But I will keep you posted if something does come up with all my installs. so far, no problems. I have done around 70 installs with no issues. If you have a small lithium pack with low IR, I would be suspect, but all the installs I have done are over 600ah of Lithium, either Prismatic cells or Battle Born Crap. Curious ,outside of videos, have you ever seen an alternator failure and can you document it for us to get some real numbers?
 
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snoobler

Solar Honey Badger
Moderator
I do not want to start an argument, I have installed tons of systems and there has never been a problem with the alternator charging the lithium pack. It appears that the total resistance of the pack is enough for the system to not fail. But I will keep you posted if something does come up with all my installs. so far, no problems. I have done around 70 installs with no issues. If you have a small lithium pack with low IR, I would be suspect, but all the installs I have done are over 600ah of Lithium, either Prismatic cells or Battle Born Crap. Curious ,outside of videos, have you ever seen an alternator failure and can you document it for us to get some real numbers?

Not sure about your logic on the small vs. large. Alternator failure risk results from the LFP battery being able to accept the full output of the alternator for long periods of time thus running it at a higher duty cycle. The large battery represents the greater danger because it has the potential to push the alternator to its max current for a longer period of time. A small bank will fill and taper current faster.

Something that's not factored in most alternator discussions is the voltage drop from the alternator to the bank. Using a hypothetical 20' run with 2awg, 90A current and 14V, voltage drop will be 0.6V. The alternator may be running at peak voltage and already limiting current while the battery is 0.6V lower. If the alternator isn't running at 100% current, the risk of failure is lowered. Also, starting a drive with batteries mostly full or having solar charging along with the alternator both work to lessen the load on the alternator.
 

SolarKimmy

Solar Enthusiast
Then, why has my alternator not failed and all the other systems I have installed failed? I see it push 120 amps into the battery pack everytime I drive. It's just a stock ford F53 alternator. Please lets take this to real life experience and not theory. I would assume that a battery bank that is down to 20%, then driving for 8 hours, under your "theory" would destroy the alternator. It has not. Maybe it will, eventually. I have access to any equipment at MFG cost, and I do not find a need for it, at this time. If it's not broken, should I fix it?
 
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