6500EX-48 for RV use advice

[nagz]

Hi all, i'm looking for advice on using this inverter. I have done an energy audit, and I foresee average daily consumption of 4.95kwh per day, with a peak of 8.95kwh per day. I am looking at:

3x 5kwh EG4 batteries
6500EX-48 inverter
~2kw solar

I am hoping to use mostly solar, but also have either a generator or charging from an auxiliary alternator just in case.

My first question is, I see idle power consumption listed at 70w. However, I will never have idle, my base power draw will typically run about 200w from what I've measured (my small fridge, laptop, monitor, and starlink).
Should I anticipate that the idle consumption doesn't matter, but instead be looking at for instance the battery inverter efficiency? I see it lists as peak 90%, so assuming it achieved 80% on my base load, would that mean my 200w load will be using around 250w of battery?

(250w * 80% efficiency = 200w)
If so, that seems very tolerable.

Also, the PV to inverter lists 93% efficiency, so that seems even better.


My second question is, should I be running 24v or 48v batteries? I see both as options for the EG4 batteries. All of the system will be very close, ie the batteries to the inverter will be within a few feet, so that gauge of cable won't be super important. Most of my loads will all be run from 120v AC. (I am building the RV/bus, and using propane stove and water heater, but will have a clothes washer and fridge.)


My final question is, I would like to purchase a second high output alternator, I see many out there listed as 24v and 100-200A and more in the 3-400$ range. Is that all safe to use? Assuming my powering of the alternator is fine and that it does output 120A at 24v (aka, 2880VA), will I be okay using the 6500EX-48? I have been assuming yes because it fits within 500V and 8000W input as specc'd. I do see that the max charging current is 120A though (which would be 120A * 48v = 5760 watts?) Also I see the Solar Input Specifications shows 90VDC - 450VDC... so would that be a problem for alternator charging?

Thanks, I really appreciate any advice given.

 

[nagz]

Also, just in case, please let me know if this should be posted to a different topic/sub-forum ?

 

[James Showalter]

would your alternator just feed batteries? how will it go through the inverter?

 

[Adam De Lay]

My first question is, I see idle power consumption listed at 70w. However, I will never have idle, my base power draw will typically run about 200w from what I've measured (my small fridge, laptop, monitor, and starlink).
Should I anticipate that the idle consumption doesn't matter, but instead be looking at for instance the battery inverter efficiency? I see it lists as peak 90%, so assuming it achieved 80% on my base load, would that mean my 200w load will be using around 250w of battery?

The idle consumption is gonna be the draw the inverter has just to run. So you'll always have the idle draw on top of your loads to consider from a battery capacity standpoint. With the newer inverter revisions, the idle consumption can vary be between 80-130W.

My second question is, should I be running 24v or 48v batteries? I see both as options for the EG4 batteries. All of the system will be very close, ie the batteries to the inverter will be within a few feet, so that gauge of cable won't be super important. Most of my loads will all be run from 120v AC. (I am building the RV/bus, and using propane stove and water heater, but will have a clothes washer and fridge.)

The 6500s are 48v inverters. I would just buy the 48v packs instead of trying to buy multiple 24v packs and put them in series (if that's even supported, I'm not sure).

My final question is, I would like to purchase a second high output alternator, I see many out there listed as 24v and 100-200A and more in the 3-400$ range. Is that all safe to use? Assuming my powering of the alternator is fine and that it does output 120A at 24v (aka, 2880VA), will I be okay using the 6500EX-48? I have been assuming yes because it fits within 500V and 8000W input as specc'd. I do see that the max charging current is 120A though (which would be 120A * 48v = 5760 watts?) Also I see the Solar Input Specifications shows 90VDC - 450VDC... so would that be a problem for alternator charging?

The 24v wouldn't supply enough voltage to use the solar inputs to provide power. I think the minimum MPPT startup voltage 80VDC.

 

[nagz]

Yeah, it feels like I'm barking up the wrong tree here, there doesn't seem to be anyone else using the 6500EX in vehicles from what I can tell. I haven't been able to find much for doing alternator based charging on EG4 48v batteries.

Maybe I should instead start [possibly a new thread] with a more proper question; what is the best (economical) typical path for having about 15kwh of battery in an RV, around 5kw loads possible (ie using the toaster and the blender at the same time as everything else), assuming about 2kw of solar and I will need a secondary power source option. Ideally an alternator, as I'm certainly not concerned with idling the vehicle for a couple hours in low sun (it even has a high idle button! It's actually a bus...) but I could also consider lugging a generator around if required.

I thought the 6500EX seemed like the perfect AIO device to handle those loads, and the 3x EG4 batteries would be enough battery, but the only thing that seems to hang it up is alternate charging methods. It looks like about 6k for the batteries and inverter, I'm hoping I can find an alternator based solution for less than 1k, and the system would meet all the requirements I think, but I'm definitely open to something entirely different.

 

[Adam De Lay]

I thought Victron equipment was designed more for the mobile aspect, so you might want to check there. I know it costs more, but it's quality equipment.

 

[nagz]

Thanks yeah, I emailed Victron asking for what solutions they might offer. I'll post what I find out.

 

[Adam De Lay]

Thanks yeah, I emailed Victron asking for what solutions they might offer. I'll post what I find out.

Good luck!

 

[Samsonite801]

One thing about RVs, is they don't require 240v, and other thing is on RVs, 12v battery voltage is convenient.

If I was doing it, I would use a Victron Multiplus 3000/12 inverter, which allow to parallel stack (literal parallel in the case of RV installation), so it stays 120v and just doubles the amperage if you need more beyond 3000w (like 6000w)... Multiplus also have a 12v battery charger built into them as well for shore power charging.

Add in a BMV-712 battery monitor shunt for accurate battery status monitoring.

This way, you can stay at 12v and still expand/scale later, works well with alternator voltages and all accessories voltage, battery isolators, etc..

That's just my take on it.

 

[nagz]

Well, they were fairly unhelpful...

Hello,

I am trying to figure out charging of a 15kwh battery bank (3x EG4 lifepos) from a high output 24v alternator.

Do you have any products that would be good for that? I'm hoping to achieve around 4-5kw of charging (max charging rate of batteries is .5c and should be good for up to 7.5kw)

Also, please recommend anything else I should be looking at if I'm barking up the wrong tree!


Much thanks,

Which got the reply:

No, we don’t offer such products.

With best regards,

Jan Klumpenaar

 

[Adam De Lay]

Hmm, yeah not very helpful.

I saw this “caution” article on their blog. https://www.victronenergy.com/blog/2019/10/07/careful-alternator-charging-lithium/

I think the biggest issue is gonna be going from the 24v alternator up to the 48v battery. I’m not sure how a boost converter would hold up with the alternator. The only time I’ve seen people use alternators to charge we’re on 12/24v batteries.

 

[z_zk_z]

Deleted

 

[z_zk_z]

Deleted

 

[nagz]

Thanks ZK. Valid points on that video. And yeah, w8, I'm thinking of going with the 24v batteries instead of 48v since I see more compatible equipment from Victron going that route.

I'm definitely getting the feeling that I need to re-plan it. My assumptions of 70w max 'idle' consumption seems to be wrong, and also the eg4 6500EX is generally less efficient; so, I might be losing 2.5 kwh+ per day with system inefficiency...
(ie base 70w is often 80+, and then I've seen some people only getting 80% efficiency, so 5kwh/day of usage might incur 1kwh of waste, plus 70wh of idle power consumption making 1.68kwh/day, so 2.68kwh total loss? Possibly more?)

I'm thinking going with 2x multiplus-2 3000w inverters (I just really don't want to have to stop my minisplit because I am going to run the blender, etc, would rather have a surplus of power available) -- they have infamously low idle power consumption AND great efficiency. Plus I can get the cerbo GX view, which is really more for the future buyer when the time comes, because it makes it all look fancy and nice. (i'd be fine with a simple shunt display personally.) The description sounds pretty ideal as far as efficiency: "The Victron Multiplus-2 3000 is 94% efficient with only 13 watts of idle draw thanks to Victron’s revolutionary toroidal transformer design"

The latest EG4 batteries appear to work with the latest Victron setup, from what I've seen, and can communicate with the cerbo gx. They definitely seem to be a great price for 15kwh of battery, and I'm thinking the whole system might be close to this:

1311.55$ Multiplus-II Inverter Charger | 24v Input | 3000
1311.55$ Multiplus-II Inverter Charger | 24v Input | 3000
164.05$ Victron Energy Orion 12/24-Volt 20 amp DC-DC Converter Non-Isolated
164.05$ Victron Energy Orion 12/24-Volt 20 amp DC-DC Converter Non-Isolated
164.05$ Victron Energy Orion 12/24-Volt 20 amp DC-DC Converter Non-Isolated

(assuming 28v 20amp charging current, 560w/ea, 3 units, 1680w total charging current. That is about 1/3 as much power as I'd like, but I can always add units if I find it desirable. I figure 1680w can keep up with demand in the event of no/minimal solar output.)

713.15$ Victron | Cerbo-GX Kit

1449.00$ EG4-LifePower4 Lithium Battery | 24V 200AH
1449.00$ EG4-LifePower4 Lithium Battery | 24V 200AH
1449.00$ EG4-LifePower4 Lithium Battery | 24V 200AH
449.00$ EG4 Enclosed Battery Rack | 3 Slot

So, all of that, looking like around 8,624.40$ in cost on those components ^^. I have yet to find the exact panels, but I see wholesalers on craigslist/FB market place that do panels of 10 or more for around 85$/ea (various size/watts, but I see 250w commonly.) So, 850$ for that I hope. Then cables, crimps, lugs, and everything, I'm hoping to be able to get away with it all for around 11k. Still accepting advice ?

 

[BBMitch]

Did you ever find a victron specific forum or get direct quote or dealer feedback? I posted something similar in concept for my build. You were much more successful in collecting feedback! Good on ya! I have a different scenario. I was thinking of building in a shed initially. My tv has trouble. The shed build puts it with my other add ones (washer, dryer). I want to charge from multiple shore power until I can add solar. The option of charging from an inverter generator or dual shorepower is my goal but I love your idea of the alternator. Plus keeping to 12v /24v can have advantages when you are running a system built for 12v through out already.

Long way of saying please share / point me at what you found in the victron direction? And if you started your build?

Cheers!

 

[nagz]

I never got any good/useful direction from victron or a couple of the retailers I emailed with questions unfortunately. I have been proceeding with the build, but I'm not yet back to OR where I'll be doing it, so it has been slightly on hold. As for the alternator, it sounds like a WS500 is the way to go in terms of controlling one for charging, but I never got deep into it, I decided to find out how effective the solar is, and assuming its generally adequate I think I won't worry about alternator charging.

Also, fwiw, running my bus engine just to provide power eventually sounded like a bad idea (for engine health, what with fickle emission systems), so if I do add fuel based charging it will likely be a portable generator.