Want to go completely on batteries

[SPfeil]

I have a 45' Prevost bus and a bunch of new 425 watt solar panels and 8 x 24v x 200Ah EG4 rack batteries. I also have 2 EG4 6500 watt inverters. Instead of buying a 15-20K generator to run all of the systems of this conversion I would like to go battery only. The bus alternator is 24V. I am wondering if there is a way to charger the battery bank from the alternator. I would also like to be able to plug into 30/ 50 amp to charge batteries as well. I expect there will need to be some kind of transfer switch ( I don't have nor do I know what I would need) and some various other items. First I am curious if this idea is possible. If it is possible, what do I need to make this work? Is there anyone who can provide a stick man schematic that I could follow to get this set-up? I will likely be running 2 mini-split systems, a household refrigerator, camper size washer and dryer, microwave, induction range, multiple TV's, hair dryer, fans. I have not yet identified the water heater. Would prefer to use the onboard diesel to heat but some of those systems also use electricity. A quick estimate is 8-12 solar panels on the roof.

If all of this is a pipedream, I understand. Thanks for your help.

 

[sunshine_eggo]

A few comments/questions:

You have 24V batteries but 48V inverters?

Each panel you install will yield about 1.7kWh/day of collected PV. 8 will yield 13.6kWh/day. 12 will yield about 20.4kWh/day. I'd go for more if you can.

Assuming about 1000W for a mini-split at max output, 20.4kWh/day will allow about 17 hours per day for a single unit. No other loads allows.

A typical full size residential fridge uses 1.5-2kWh/day

Your inverters will consume about 3.6kWh/day, but it could be notably higher.

You will ONLY be able to plug into 50A shore to charge as I do not believe a single unit will charge from 120V when the two are parallel in split phase. You could likely shut off the L2 inverter and operate only off the L1 inverter, but you would not have power to the L2 side of your panel.

You will almost certainly need a generator, or you will have to notably moderate your use when solar is not optimal.

 

[justinm001]

I have a 40ft Prevost XL2. Do you have bus air? If not you likely have a 270a 50dn alternator dedicated to house then another 24v for chassis. I know some house systems have dual alternators.

Since your eg4s are 24v I'd go with a wakespeed ws500 and swap out the Delco external regulator with it then it'll use a lithium profile. Check out camp Prevost on YouTube, Aaron did a ton of videos on his setup and was 24v.

See if your dryer is 240v or anything else is. This is the key to which inverters you need. I know some Prevost that have 240v dryers and others are 120v. Also they make new heatpump 120v combo units which are perfect. If dryer is 240v likely it'll be using close to 10kw alone so will have to only use that and be careful.

You need to estimate your average daily consumption then determine how to make that power. Im just finishing up 5kw solar panel roof on my rig (post is on here with photos). I had 1800w before and wasn't close to enough. I use dc dc converters to pull 3kw from my 50dn alternator which work great but use quite a bunch of space (photos on here).

When running a huge system I feel Victron is really the only way to go. Theyre the most stable, efficient and allow you to build out exactly what you need. I have 3x 5kw Quattro inverters and can run 13a to 100a 120v or 240v into it. 2 are 48v and the 3rd is a separate 12v for redundancy.

When you buy the best rug available it's well worth getting the best stuff to put inside it. The coach is built to last forever, you should get equipment designed to last forever too

 

[SPfeil]

I have a 40ft Prevost XL2. Do you have bus air? If not you likely have a 270a 50dn alternator dedicated to house then another 24v for chassis. I know some house systems have dual alternators.

Since your eg4s are 24v I'd go with a wakespeed ws500 and swap out the Delco external regulator with it then it'll use a lithium profile. Check out camp Prevost on YouTube, Aaron did a ton of videos on his setup and was 24v.

See if your dryer is 240v or anything else is. This is the key to which inverters you need. I know some Prevost that have 240v dryers and others are 120v. Also they make new heatpump 120v combo units which are perfect. If dryer is 240v likely it'll be using close to 10kw alone so will have to only use that and be careful.

You need to estimate your average daily consumption then determine how to make that power. Im just finishing up 5kw solar panel roof on my rig (post is on here with photos). I had 1800w before and wasn't close to enough. I use dc dc converters to pull 3kw from my 50dn alternator which work great but use quite a bunch of space (photos on here).

When running a huge system I feel Victron is really the only way to go. Theyre the most stable, efficient and allow you to build out exactly what you need. I have 3x 5kw Quattro inverters and can run 13a to 100a 120v or 240v into it. 2 are 48v and the 3rd is a separate 12v for redundancy.

When you buy the best rug available it's well worth getting the best stuff to put inside it. The coach is built to last forever, you should get equipment designed to last forever too

How do I get to all of your pictures and specs? Please keep in mind I am a super newbie to forums.

 

[justinm001]

How do I get to all of your pictures and specs? Please keep in mind I am a super newbie to forums.

You should be able to click on my name then go to posts and see my history

Or I think click here.

justinm001

diysolarforum.com

Here's my most recent post of the panels I'm finishing up this week

Whole roof solar replacement

Finally getting around to upgrading my panels. I'm trying not to drill anymore holes in the roof so plan is to utilize the Girard awning brackets and the threaded rods I initially installed. I'll be mounting these Renogy 320w panels horizontal and tilted up a bit to get above all the ACs...

diysolarforum.com

 

[sunshine_eggo]

Since your eg4s are 24v

Has this been established?

I've never seen an EG4 6500 at 24V.

Which still begs the question:

You have 24V batteries but 48V inverters?

 

[justinm001]

Has this been established?

I've never seen an EG4 6500 at 24V.

Which still begs the question:

No clue maybe series/parallel 24v batteries? I've always wonder what would happen if you just alternator charged one half of a series/parallel bank since as long as you routinely top oft so bms will balance it should be fine.

 

[OffGridForGood]

"Since your EG4's are 24v" meaning the EG4 200Ah ESS packs I believe.
the 6500 are going to be 48 volt so this is not a match. If the whole point of the 24 volt batteries was to match the alternator, then the OP needs to go with a 24v inverter - but may be a poor choice with the big loads listed. I know very little about RV's coaches etc.

For charging via 30A 120v or 50A 240v a chargeverter would allow either to be used as a option. lower charging rate limit if on 120v.

 

[sunshine_eggo]

No clue maybe series/parallel 24v batteries? I've always wonder what would happen if you just alternator charged one half of a series/parallel bank since as long as you routinely top oft so bms will balance it should be fine.

The same thing that happens as if you draw from a single 12V out of a 2S 12V string... eventually one 12V will be empty, and the other will be full.

You'll also have the fun of the charged battery cutting itself out of the circuit prematurely when series charging.

BMS balance capabilities are rarely enough to correct more than normal self-discharge. Furthermore, when there is NO interaction between series batteries, there's no balancing.

Even with an active balancer like a NEEY 5A, you're still likely to overwhelm the balance current.

 

[justinm001]

The same thing that happens as if you draw from a single 12V out of a 2S 12V string... eventually one 12V will be empty, and the other will be full.

You'll also have the fun of the charged battery cutting itself out of the circuit prematurely when series charging.

BMS balance capabilities are rarely enough to correct more than normal self-discharge. Furthermore, when there is NO interaction between series batteries, there's no balancing.

Even with an active balancer like a NEEY 5A, you're still likely to overwhelm the balance current.

I assumed it would draw power from the higher voltage before the lower one. This is how it works with my dc dc converters as all loads will come from the DC converter and not the battery if say it's set to 13.5v and batteries are 13.3v.

I assumed if batteries were at 50% and only half are charging then one would be 50% and other up to 100% if not actually charge the lower voltage eventually because the voltage is so much higher when at float. Then eventually when they're on shore it'll balance all to 100%. But I have no experience in this just considering batteries like water and filling multiple tanks.

My lead acid starter batteries have a Vanner 100a balancer. I'm surprised there isn't something similar for lfp. Most loads are 24v but can run 12v from either battery bank and it balances.

But if OP is actually running 48v then it makes the most sense to just get dc dc converters like I did. 400w Victron Orion are only like $130 and able to parallel. OP could parallel 10 for $1300 and get 4kw while driving without every worrying about anything. Although it takes a bunch of space and heat can be an issue. I wish they made larger ones and ones with fans like my 24/12

 

[justinm001]

"Since your EG4's are 24v" meaning the EG4 200Ah ESS packs I believe.
the 6500 are going to be 48 volt so this is not a match. If the whole point of the 24 volt batteries was to match the alternator, then the OP needs to go with a 24v inverter - but may be a poor choice with the big loads listed. I know very little about RV's coaches etc.

For charging via 30A 120v or 50A 240v a chargeverter would allow either to be used as a option. lower charging rate limit if on 120v.

So would a pair of Victron inverters or just a 2x120v model

 

[sunshine_eggo]

I assumed it would draw power from the higher voltage before the lower one. This is how it works with my dc dc converters as all loads will come from the DC converter and not the battery if say it's set to 13.5v and batteries are 13.3v.

I don't understand your thinking to the point that I'm no longer certain we're talking about the same subject.

If you have two elements in series, their individual voltages sum to the total. The exact same amount of current must pass though all series elements, so if you pull 10A from it, 10A must come from the entire string, not just the one with higher voltage.

I assumed if batteries were at 50% and only half are charging then one would be 50% and other up to 100% if not actually charge the lower voltage eventually because the voltage is so much higher when at float. Then eventually when they're on shore it'll balance all to 100%. But I have no experience in this just considering batteries like water and filling multiple tanks.

"Eventually" may be days/weeks and even months.

My lead acid starter batteries have a Vanner 100a balancer. I'm surprised there isn't something similar for lfp. Most loads are 24v but can run 12v from either battery bank and it balances.

Few are willing to spend $1000 on a 100A balancer. There are $50 ~2A balancers that are more than enough to maintain balance in a properly designed/healthy system.

After browsing the manual, the Vanner appears to be a purpose built device to supply BOTH 24V and 12V from 2X 12V in series with 24V charging source.

If your 12/24V charging/load experience is associated with the Vanner, please know that it is rare compared to most.

How do I get to all of your pictures and specs? Please keep in mind I am a super newbie to forums.

Why do you have 24V batteries and 48V inverters?

 

[justinm001]

If you have two elements in series, their individual voltages sum to the total. The exact same amount of current must pass though all series elements, so if you pull 10A from it, 10A must come from the entire string, not just the one with higher voltage.

Ahhh I see now, thanks.