Brucey
Solar Wizard
Would have to be in an insulated box versus just sitting outside in the elements I think. Or all the charge power will just go to the heaters and it will never get to above freezing.
What do you experts think of this solar+battery+inverter system for my small RV?
- Thread starter MegaMosquito
- Start date
MegaMosquito
New Member
Lol. I hope you don't. That sounds rather unpleasant.
I just copied/pasted the product documentation about the -25C (https://www.epochbatteries.com/products/48v-100ah-lithium-server-rack-battery-size-3u-ul9540-pending)
The SOK 48V/100Ah batteries are certainly sweet hardware, but they are significantly larger (7 inches tall versus 5.2) than the EPOCH ones and space is very tight for me. Also, the EPOCH batteries have built in heaters. If the SOK were smaller I could add external heaters (they are very thin).
-13F seems cold but I think this is doable with self heating. Especially inside a compartment.
MegaMosquito
New Member
Can get rack mount 24Vs
EG4 LifePower4 Lithium Battery | 24V 200AH | Server Rack Battery
EG4 Lithium battery 25.6V (24V) 5.12kWh with 200AH internal BMS. Made of UL Listed Battery Cells. Off Grid Solar Batteries - Off Grid System - Solar Batteries for Home - Lithium Solar Batteries - Deep Cycle Solar Batteries - Power Reserve - Solar Panels Plus Battery - LifePo4 - LifePower4 - Life...signaturesolar.com
Yes. I see. Two of those are just slightly larger than the 48V pair and provide the same kWh total. Then I could switch to a Multiplus II 24/300/xx. That would make Vbat+5 charging easier (anything over 30.6V to start). Thanks!
MegaMosquito
New Member
The battery bank will be in an interior cupboard area and my plan includes forced air ventilation from/to the living space. I think it will normally be well above freezing in there (or we will be frozen too!) I originally felt I needed heated batteries because I was thinking of a different location next to an outside metal wall. But that location was too small for 10kWh so I moved to this closet location. Rethinking this now, in this closet location I probably don't need heated batteries.
MegaMosquito
New Member
In a compartment, that I think will be "near room temperature" (or warmer).
MegaMosquito
New Member
24V is looking pretty good to me now, but I remember reading somewhere that the rule of thumb is to use only up to 1kW of A/C loads with a 12V system, up to 2kW loads on a 24V system, and then to use 48V systems if you will ever have loads greater than 2kW.
What do you all think of this rule of thumb? It seems easy to buy a 24V 3kW inverter, so maybe it's fine to exceed 2kW?
What do you all think of this rule of thumb? It seems easy to buy a 24V 3kW inverter, so maybe it's fine to exceed 2kW?
SoggyShoes
New Member
@sunshine_eggo why are you not a fan of the Lynx shunt?
Do you like the Lynx distributor and power in?
If so, how do you connect them?
I have seen a system where they used the Lynx distributor with to the left of that, a bmv-712 and bus bars instead of the shunt and power-in.
What would your preference be?
SoggyShoes
New Member
@MegaMosquito the other nice thing about a 24v system is that you can easily use the Victron 12v to 24v charger from your alternator. This way when you are driving the engine can aid in charging your system. I don't think Victron makes a 12v to 48v charger.
I am doing this in the system I am installing. I will then be using another 24v to 12v charger to go from my 24v system to my 12v house battery (which I am switching from 2 6v lead acid to one 12v 304Ah LFP battery). This allows me to be able to leave all my existing 12v stuff alone. I think that was what @sunshine_eggo was suggesting.
I am ordering my batteries from Amy at Luyuan (https://szluyuan.en.alibaba.com). They were significantly less expensive (but literally are on the slow boat from China). I have never ordered anything direct from China before, but she seems to have a better reputation that most of the US companies for several years. So far, she has been awesome to work with. She can make custom cases for your batteries. Or you could make your own case that might better fit your closet.
I am doing this in the system I am installing. I will then be using another 24v to 12v charger to go from my 24v system to my 12v house battery (which I am switching from 2 6v lead acid to one 12v 304Ah LFP battery). This allows me to be able to leave all my existing 12v stuff alone. I think that was what @sunshine_eggo was suggesting.
I am ordering my batteries from Amy at Luyuan (https://szluyuan.en.alibaba.com). They were significantly less expensive (but literally are on the slow boat from China). I have never ordered anything direct from China before, but she seems to have a better reputation that most of the US companies for several years. So far, she has been awesome to work with. She can make custom cases for your batteries. Or you could make your own case that might better fit your closet.
sunshine_eggo
Happy Breffast!
Expensive. No BT, VE.CAN only. Must be used with GX device.
No. Expensive. No or limited class T fuse options.
Bus bars and wires.
No Lynx products.
SoggyShoes
New Member
Wow! It must be true for you to say not to use blue!
So do you recommend a similar layout as the Lynx with a positive and negative bus bar for the batteries on one side. The BMV-712 in the middle with the chassis ground. Then on the other side a positive and negative bus bar that has feeds from the inverters, MPPT solar controllers, and DC-DC chargers in and out?
Brucey
Solar Wizard
SoggyShoes
New Member
So @Brucey that looks like you are just not using the Lynx shunt, and instead using a SmartShunt and a breaker instead. And they are connected by 4/0 on the power-in side and solid copper bus bar material on the other.
Is that correct?
Edit: @Brucey what size (rating) shunt and breaker are you using?
Brucey
Solar Wizard
Correct, as eggo mention the lynx shunt is expensive for what it consists of, the value option is the smartshunt for $111, I'm using a cerbo-s so the limited Bluetooth range versus the 712 wasn't an issue as I'm connected using ve.direct. that's a midnite mnedc 250A DC breaker.
I'm using 1/0 cable there, I only have about 2kW of load right now.
Brucey
Solar Wizard
It's the 500A one.
The other option you can do is 3d print an enclosure that holds a smartshunt plus a victron shutoff switch to keep it all seamless:
www.printables.com
The other option you can do is 3d print an enclosure that holds a smartshunt plus a victron shutoff switch to keep it all seamless:
Printables
www.printables.com
