Community Forums

nothermark · 02-18-2018, 01:27 PM

It's not naysaying. It's rationalization. If I could see a real benefit from going to Li batteries I would. The issue at least to me is that it costs a lot more to put them in than it seems to be worth it for a part timer or someone with a smaller RV or anyone who seldom dry camps. If you have the room for the solar and want to stay off grid then they make sense. How many folks fit that profile? I suspect darn few. OTOH there is a cheering section that wants us to all abandon lead and go lithium when lead does an adequate job for way less cost.

4x4 · 02-18-2018, 01:49 PM

Quote:

Originally Posted by CountryFit

true. there are always naysayers for anything in this world. the funny thing is that those had no exposure to lifepo but trash-talked big about it... i have read a lot of posts over the years on different forums, such as this forum and boondocking, from the same persons.

i have a system similar with yours, it has been performing flawlessly; love it. there are a few differences between ours though -

1) i bought components, assembled, and installed myself. install quality may not be in the same level, but i saved big on the labor part i assume.
2) i installed 2750w panels. remember i asked you to dig into expanding the size?
3) my li pack is 1200ah.
4) i only have one magnum 2800w inverter, while you have 2. that is a big plus.
5) i am using 2 charge controllers.
6) my primary application is charging my plug-in toad. i saved a lot of gas i guess

.

at 10:30 am today in a regular sunny las vegas i took a pair of photos on the charge rates. one showed 67.4a, another 31.5a. at this time of year, and in early morning, i am getting nearly 100a downflow speed!!

in my opinion, it worth every penny of it

.
go enjoy it, have fun!

Now that's some serious solar power! As I said I have as much solar as would fit on my valanced roof. 2750 would be sweet.

Yea dual inverters is really nice especially with so much available battery power.

If you have the ability to do it yourself that is awesome. I'm pretty handy but felt it was beyond what I would want to tackle. Either way I love the way it is operating.

computerguy · 02-19-2018, 12:20 PM

I did mine myself. Really wasn't hard once you understand how things interact with each other.

MisterT · 02-19-2018, 12:32 PM

now... if we could just get manufacturers to design and offer 'All Solar' coaches, we wouldn't have to do all this work ourselves!

cruzbill · 02-19-2018, 12:39 PM

All Solar option would start at $30,000 and go up from there, and remember, at night and on cloudy days, ain't no solar to be had (Ok, NO solar is a bit of an overstatement for cloudy days, but you get my point).

Solar is a battery charger, that's all.

Coral · 02-19-2018, 12:40 PM

Quote:

Originally Posted by 4x4

I started a thread about my large Solar/Lithium install on the Newmar Owners Forum if anyone is interested. http://www.irv2.com/forums/f103/upgr...-a-378619.html

One of my long term goals is to build a system like yours but more likely like CountryFit's system because of pockets, I was looking at the LifeBlue batteries. I appreciate your posting and documenting your installs and also the knowledge you are sharing.

I would like to see your setup someday in person if our paths cross.

4x4 · 02-19-2018, 05:09 PM

I’d be more than glad to give you a tour sometime.

On another note just got some info from Victron. They state there is a 10% headroom designed into their batteries so keeping them charged to 100% is actually not fully charged and recharging to only 70% would not significantly increase their life.

**CountryFit** · 02-19-2018, 05:49 PM

Quote:

Originally Posted by 4x4

just got some info from Victron. They state there is a 10% headroom designed into their batteries so keeping them charged to 100% is actually not fully charged and recharging to only 70% would not significantly increase their life.

the 10% is consistent to cell manufacturers' practice. in today's lfp cell industry, to my knownledge, all of the manufactuers label their cell capacities at about 10% less than the actual capacities. for example my calb cells, the rating is 100ah, but upon fully charged, i have seen consistently above 110ah logged.

4x4 · 02-19-2018, 08:13 PM

Quote:

Originally Posted by CountryFit

the 10% is consistent to cell manufacturers' practice. in today's lfp cell industry, to my knownledge, all of the manufactuers label their cell capacities at about 10% less than the actual capacities. for example my calb cells, the rating is 100ah, but upon fully charged, i have seen consistently above 110ah logged.

Yea, their reply had me scratching my head. So if that is true then the batteries are actually being charged to 100% anyway although they do have 10% extra potential energy but it still results in the problem with always charging to 100%.

On another note, having the Victron hybrid system is a great upgrade from a simple EMS (Energy Management System) or for that matter even some other hybrid systems.

I am currently on 50amp service with weak breakers. I had to dial down my system to only take 35amps (actually 35x2) otherwise it would trip the breakers. FYI I've had my system on different 50amp service without any problems so it is the breakers at this pedestal which are weak. It's cold here right now but above 32º so I can run all 3 roof heat pumps, the electric engine block heater (for tomorrow AM), the inverter battery chargers (240amps) plus whatever else I want. The system will continuously adjust between using battery power and charging the batteries as current is available because of the heat pumps cycling. As an example all 3 heat pumps are currently on so it is using 67 amps from the batteries. When one goes into defrost mode I'd be about even and when one cycles off I get 140amps charging into the batteries.

The previous hybrid system I had had 2 separate inputs for the charging current and the house current so you have to split (whatever ratio you desire) the current between the two systems. The disadvantage is the charging current doesn't dynamically change as the usage changes so there could be a lot of current not being used even when available.

Finally the non hybrid system relies upon the EMS to shed devices that are lower on the energy pecking order and it can't use any battery power to assist running any of the devices. On a lower power pedestal you'll be limited to which couple of units you want to use and if you wanted to use the microwave, hair dryer or whatever you would need to manually turn off one of the other devices. With the hybrid systems (especially with lithium) you mostly just do what you want instead of always worrying about overloading the system.

Just showing the advantages of a hybrid system that even a part timer could use. I do understand that the cost of such a system may not be of that much value to someone but I am not discussing that as that would be an opinion and I am not addressing opinions here, just the advantages.

Itinerant1 · 02-20-2018, 08:14 AM

4x4 are you leave the inverters on all the time? If so what is your parasitic amp draw?

Remember that SoC "100%" can be different from "100%" SoC

depending on where you hold the voltage constant after you reach the desired SoC. Not sure if this would apply towards the dropin batteries but might be something for new comers thinking about LiFePo4 or trying to understand them to think about.

BatteryPro was explaining in CountryFits thread from a couple years ago.

http://www.irv2.com/forums/f56/what-...es-247416.html

**CountryFit** · 02-20-2018, 09:16 AM

Quote:

Originally Posted by Itinerant1

BatteryPro was explaining in CountryFits thread from a couple years ago.

http://www.irv2.com/forums/f56/what-...es-247416.html

thanks for freshing up the old memory... yeah that was the time i was building my system just shy of 3 years ago. there was a lot of info in the thread...

4x4 · 02-20-2018, 11:04 AM

From my reading in the spec sheet each inverter uses 20 Watts while idle so about 3 amps dc per hour. Since it’s such a tiny amount I never bother turning off them off. I also never turn them off because I never shut the refrigerator off.

On another note I spoke with Victron again and the reiterated that there is no reason not to charge their batteries to 100%. They further stated that since their batteries can theoretically be charged to 16.5v that charging them to only 14.2v will safely preserve the batteries.

4x4 · 02-20-2018, 03:17 PM

To further ease my worries about the state of charge at 100% charge the voltage is 3.49 to 3.5 per cell so a total of "only" 14 volts so certainly within the safe range of battery voltage for longevity. After rereading others older posts I'm certain keeping my batteries at this level is fine even for long term storage.

**CountryFit** · 02-20-2018, 07:53 PM

14v is perfectly fine. i once talked with a calb engineer. he recommended charging at 14.6v as his lab did all kind of tests without problems. i am pretty sure 14.6v is in safe range as calb is the largest lifepo4 cell manufacturer in china and export to all countries besides supplying cells to massive domestic production of ev and e-bus in the country. but, i feel that would still be an overkill for me. i like to play at the safe side so i set the voltages on the controllers at 14.4v on bulk and absorb, and float at 14v. about 3 years have passed, i have not seen the pack capacity drop.