48V System for an RV

[mkgolfer]

Hi All,
I am a complete newbie to all of this. I am not an electrician but kind of handy. I am looking to build a 48 volt non-intrusive (not re-wiring the entire RV electrical system like folks do with Victron/Battle Born solutions...ewww) system for my RV. At the moment I have no plans for solar charging (that is for add on later) but I do want to use my Honda 2000 gas generator as a means to charge the batteries I have done some research and have found others that have done something similar. Here is what I "THINK" I need to do...please, let me know where I am wrong and could correct/improve.

• I am looking at either the EG4 All in one 3kW inverter or the Growatt 3kW inverter. The only issue I have with the EG4 is the 120v minimum charging for solar.
• I am looking at either the EG4 LifePower4 48v 100AH server rack batteries (2 of them in parallel) but am leaning towards the EG4 WP 48v 100AH batteries (2 of them in parallel). The server rack batteries have breakers and on/off built in where the WP do not. If I use the WP batteries, do I need to install a breaker or some kind of shut off switch between the batteries and the inverter?
• To make thing easier, I would like the AC out on the inverter to be a 120v 30amp RV plug so I can just "plug" my RV into the inverter instead of a power pedestal. I believe to do this I need to disconnect my current RV charger because (for the most part) I will NOT be running the RV AC system from "grid power". Can I wire a standard 120v 30amp RV plug into the AC Out on these inverter units? And if I do plug into a 30 amp pedestal, I would need to shut off my inverter...correct?
• AC input I will just wire a standard 120 volt plug for charging from my Honda 2000 generator (1600 watts continuous output) to charge my system. I suppose this charging is referred to as "grid charging"? Will this work?
• I need to wire a step down converter 48v to 12v and wire that into my RV DC side. What gauge wiring should I use FROM the 48v batteries to this step down converter and what gauge wiring should I use FROM the step down converted to the 12v DC RV system? What amperage should this converter be?
• 7 pin charge from the tow vehicle to the RV. I am not sure what to do here. Do I simply disconnect the 7 pin 12v charging wire on the RV side? I am NOT concerned with charging from the tow vehicle (maybe later a 30 amp DC to DC charger but not for now).

I hope I am clear enough on my plans...any thoughts? What am I missing? Any feedback/corrects/comments would be AWESOME!

Thanks all...love this forum!

 

[SamDeleted]

Honda 2000 gas generator

Is it an inverter generator or a cage?

The most battery charging you'll get out of a 2000w honda is about 30amps@48v
(30amps x 56v = 1680w)


Point to note , when these hybrid inverter you're looking at see AC input lower (eg. generator) they:
A)charge the battery
&
B) bypass loads to the AC in

This can cause issues , if you're charging your batteries at a full 1680w already close to the hondas limit , if you then were to say turn on an appliance that would overload your honda

People solve this by installing a separate charger like the 'chargeverter'

 

[mkgolfer]

Hi Sam,
My Honda is the EU 2000 so Its an inverter generator. 2000 watt surge with 1600 watt continuous.

Ahhh....I was just looking at that. So a chargeverter direct to the battery? That way I can still use the inverter and won't cause an overload on the generator? If I do this direct charging to the battery (bypassing the inverter) will I get a better charging result as well and will this direct charging cause any issues with the inverter?

One more (i am sure silly) question...if I am NOT using the inverter to charge the batteries, is there any reason to have the batteries connected to the inverter? I understand the batteries need to be connected to the inverted if I am doing solar charging...but if I am NOT using solar at the moment?

Are there chargeverters on the market that will use the standard 3 prong 110V plugs. The EG4 uses a 4 prong.

Thanks!

 

[SamDeleted]

Hi Sam,
My Honda is the EU 2000 so Its an inverter generator. 2000 watt surge with 1600 watt continuous.

Ahhh....I was just looking at that. So a chargeverter direct to the battery? That way I can still use the inverter and won't cause an overload on the generator? If I do this direct charging to the battery (bypassing the inverter) will I get a better charging result as well and will this direct charging cause any issues with the inverter?

One more (i am sure silly) question...if I am NOT using the inverter to charge the batteries, is there any reason to have the batteries connected to the inverter? I understand the batteries need to be connected to the inverted if I am doing solar charging...but if I am NOT using solar at the moment?

Thanks!

Hi mate

I have the exact same generator, it's a great little machine. And yes I'm pretty sure that's how it works with the chsrgeverter , they don't actually sell them over here so I'm not 100%

All questions are good questions (well nearly all ?). The inverter needs to be connected to the battery when you want it to draw from or charge the battery. If you don't want to use it , it doesn't have to be connected . But there's no harm in leaving it wired in & just turned off

 

[SamDeleted]

will I get a better charging result as well and will this direct charging cause any issues with the inverter?

Its not that you'll get better charging, it's just safer for your generator and also more convenient to be able to use power as you want whether the Geno is running or not

 

[mkgolfer]

Yea I love my Honda ...we used to have a boat and used that thing a lot...been using it for our RVs for the last several years as well..best $1000 ever spent!

I found on signaturesolar an EG battery charge that plugs straight into 120 AC outlets. Its not a chargeverter just a charger...would that work?

Thanks

 

[SamDeleted]

I found on signaturesolar an EG battery charge that plugs straight into 120 AC outlets. Its not a chargeverter just a charger...would that work?

Have you got a link pls?

If it's rated for 48v lithium then should be perfect

 

[mkgolfer]

yep here it is:

EG4 Battery Charger | 48V 18A

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

just talked with the folks at signature solar and asked them about it

 

[SamDeleted]

yep here it is:

EG4 Battery Charger | 48V 18A

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

just talked with the folks at signature solar and asked them about it

I can't see any reason why that wouldn't work for you , good price too

18amp is maybe a little slow at around 1kwh ,

 

[mkgolfer]

So if all the stuff I have listed out works, from a 12v perspective, I can put together an 800ah systems (minus solar panels) for about $3,000 US. Looking at BattleBorn batteries, to get that many amp hours, you are looking at about $7,000 to $8,000 just in batteries. Technicians in my state for a system like this (including solar panels) are asking about $20k-$30k for a system this large. I am really glad I just happened across Will's youtube channel because I never thought I could afford this let alone do it myself. If you saw anything in my original post besides the charging that looks incorrect, let me know.

And for this price, I am ok with a bit of slower charging having such a large battery bank.

 

[SamDeleted]

So if all the stuff I have listed out works, from a 12v perspective, I can put together an 800ah systems (minus solar panels) for about $3,000 US. Looking at BattleBorn batteries, to get that many amp hours, you are looking at about $7,000 to $8,000 just in batteries. Technicians in my state for a system like this (including solar panels) are asking about $20k-$30k for a system this large. I am really glad I just happened across Will's youtube channel because I never thought I could afford this let alone do it myself. If you saw anything in my original post besides the charging that looks incorrect, let me know.

And for this price, I am ok with a bit of slower charging having such a large battery bank.

Its amazing the difference in price between DIY & pro built systems !

Hopefully someone capable will be along to help answer your few other questions

 

[mkgolfer]

I have been chatting with the folks from signature solar and a couple other folks and it appears I am on the right track. I can hardly wait to start this upgrade. It will totally change how we user our small-ish 5th wheel. And what is great about this build is it is easily portable...so IF we change trailers I can take this with me and once the system is out its a matter of an hour of work to restore the old unit back to "factory".