[The Bus Crew]

I know some of you have switched from lead acid to lithium and I am now at the do it point.   Before I make some expensive learning mistakes I was hoping you could recommend what may have worked for you. 

What I am planning on doing:  I will keep 2 lead acid 8D batteries in the back for the Detroit start batteries.  I will put 2 lithium 300ah batteries with built in battery management in the house/generator battery location. 

Future plan includes adding 8-10 300 watt solar panels.  

If you see a problem or opportunity for improvement with my plan please share.   
My needs include being able to boondock (with or without generator).

Questions :
1. I have the original converter and a newer inverter.  I understand I have to replace the converter to charge the lithium.  Do I get a converter/inverter combo or separate units?   Why?

2. I plan to install a battery trickle charger from the lithium to the lead acid.  Will this be enough to maintain the lead acid if I remove the original converter (I know the converter is for the house without merge) but if the engine start batteries die how do I charge them as I do not think I can merge if I go lead acid and lithium?

3. How do I determine the correct ratio of battery ah to solar watt capacity?

4. What am I missing?

[Tf175]

You might look up Bus Grease Monkey You Tube videos where he installed solar system on his old bus. Also " Beginning from this Morning ". They have You Tube videos,  Facebook , website . Roof of his bus is covered with solar panels , looks to be a good system he set up. 
I think BGM used Battle Born batteries .

[folivier]

How do you plan to use your coach? Do you do much extended dry camping or just an occasional overnight?
The first step would be to determine your daily Amp Hour usage when dry camping. Victron BMV-712 battery monitor is great, and bluetooth. Their Smart Shunt is the same monitor without the display just bluetooth app on your phone or tablet. Once you determine how many amp hours you use then you'll know if 600 amp hours of LiFePO4 will be enough. Then comes the solar charging, ideally you'd like to have enough solar panels to fully recharge each day. There are various solar calculators online.
There are various ways to charge using the inverter/charger and your battery manufacturer will have the specs.
Also consider that if you plan to charge using your alternator while driving that the acceptance rate of the LiFePO4s could overheat your alternator. Victron Orion and Sterling both make a battery to battery charger that replaces your isolator and works well for different battery types.
Sounds like a nice project.

[Richard]

Yes, take out the converter and inverter, replace with a full sine wave combo unit.

Yes, you need a Battery 2 Battery charger to trickle charge the starts from the house. This will keep the chassis batteries up. One watch out here, as documented in another guru thread, is the commonly recommended charge setup for a Magnum inverter on BB’s website doesn’t play well with trickle charging the chassis batteries. http://newellgurus.com/showthread.php?tid=1124&page=9

Leave your merge switch and solenoid in place, just in case. You can merge for an emergency start, just not like you currently would. Merge the batteries and let the LiPo’s charge the house for about 30 minutes, then crank. If you try it right away with dead chassis batteries you can blow the big 400 amp fuse. You can also use the alternator to charge the house batts in am emergency situation using the merge switch. I am not a fan of using the alternator to routinely charge the lithiums.

[The Bus Crew]

Update (although this may change again) on plan. I was encouraged to spend the extra money on more battery amp hours and to reduce or eliminate the solar panels. It is more of a bang for the buck, I will get more amp hours per dollar on batteries than solar. What I was told and have been reading simply put was I can not fit enough solar panels to power everything without energy conservation to a large degree. But with batteries I can power everything night and day (within reason) and when the batteries get low charge them back up on the generator (which I already have).

Maybe keep just one or two solar panels to keep a charge option (not sure if that is worth it or not).

I will be replacing and adding a full sine wave inverter/charger kit that is supposed to regulate the current to the lithium batteries without damage. Victron does seem to be the best for what I am wanting but it is twice the cost of some others so I am still looking into if i am paying for a name or if it is that much better. I understand quality cost more but price does not mean quality.

Leaving merge switch as a last resort if ever needed, good idea Richard.

Still need to figure in my needed amp hours per day (sounds like we need a trip).

[valento]

"What I was told and have been reading simply put was I can not fit enough solar panels to power everything without energy conservation to a large degree. But with batteries I can power everything night and day (within reason) and when the batteries get low charge them back up on the generator (which I already have). "

I can disprove this with my coach. I have 3320 watts of solar on my roof and over 2400Ah of lithium batteries and my solar charges my batteries without a problem. I have a residential fridge, dishwasher, washer/dryer combo, GE Advantium speed cook microwave/oven and induction cooktop and the solar panels keep up fine. In the winter I do have to use my diesel for the aquahot. In the summer if I am using the AC I will also have to use the diesel for the aquahot. I have spent winters at Jojoba Hills RV Resort near Temecula, CA and also Venice, FL and never had to plug in or use the genset for recharging the batteries. I keep my starting batteries charged using a Victron IP65 for I never turn off my Victron Quattro 24/5000/220-100/100 120V Inverter/Charger so it continually charges my starting batteries.

But yes, much cheaper without all the solar. Keep in mind it will take a long time to charge with your generator for your batteries will only be charged at the rate of your charger.

Take care, safe travels and have fun with your new system.
Oscar

[Richard]

Mark,

I have seen Oscar’s setup, and I know the detail that he applies when doing anything. I would pick his brain for all the details IF boondocking is your primary motivator for reworking the 12V electrical system.

[The Bus Crew]

This is why I post on here. Thank you Oscar for disproving. I do like the idea of solar. Looks like I need to spend a little more time figuring this out. It is hard to make a decision when there is so much information going different direction on the internet.

[Tf175]

I will attempt to post link to video of solar installation , not a Newell , but the concept might apply . Might be worth a look , other videos detailing the project from the start are also on You Tube .
Chris
https://youtu.be/wQRnECDIQ8E

[360]

Oscar, that is amazing you can run purely from solar with just a bit of diesel for the aquahot.