24V or 48V Server Rack?

[atatistcheff]

Looking at a solar/LiFePO4 solution for my mobile detailing. Right now I'm leaning towards the Growatt 3kV system with a server rack or stand-alone battery storage. I could go with either 24 or 48V. I suppose the advantage of 48V is you can use a smaller gauge wire. That's about the only difference I can come up with. Are there other considerations for using one or the other? This will sit in the back of my F-150 so I'm not too worried about vibrations or rough ride. Battery would probably be in the 5kWh range.

 

[yodamota]

I haven't seen many 24v options to be honest. Or if there is a 24v option, It seems to cost more from what I have seen. Most on here will probably suggest going 48v. However with a small system 48v might be over kill.
I believe there is an eg4 option at 24v.
whereas there seem to be thousands and thousands of 48v server racks.....(exaggeration)

 

[atatistcheff]

Yes, there are definitely more 48V options. Since this would be my first venture past 12V I was a little hesitant to go all the way to 48. But once you go over 12 I guess there's no reason not to go all the way.

 

[yodamota]

are most of your loads going to be 120ac? or will you be wanting 12vdc?

 

[BobH]

One consideration for most solar charge controls is that the input voltage to the SCC/MPPT from the solar has to be ~5V higher than the scc to begin charging. So for a 48v battery, the solar would need to be whatever the battery state is (example 51.2V + ~ 5V = 56.2V from the solar array). That means on a small solar system putting panels in series to reach that voltage threshold. Then shading on the 'series' panels can bring down the output overall & stop the charging.

With a 24V system, the SCC /MPPT requires half the voltage input compared to a 48v one, so more panels can be wired in parrallel to reduce shading impacts. That;s one reasn why i picked a 24v, all my 450W panels are in parallel so I can reduce the impact of shading and also buy cheaper SCC's.

 

[Supervstech]

Looking at a solar/LiFePO4 solution for my mobile detailing. Right now I'm leaning towards the Growatt 3kV system with a server rack or stand-alone battery storage. I could go with either 24 or 48V. I suppose the advantage of 48V is you can use a smaller gauge wire. That's about the only difference I can come up with. Are there other considerations for using one or the other? This will sit in the back of my F-150 so I'm not too worried about vibrations or rough ride. Battery would probably be in the 5kWh range.

In the 3kW range, 24V is fine, and readily available feom many sources.
I wouldnt use a server rack battery in a truck though.
Plenty of options in basic 200Ah stand alone batteries.

 

[Steve_S]

24V @ 250A Max Draw will provide 6000W and is capable of supporting up to 18,000W Surge (using a Low Frequency Inverter).
Victron & others make inverters for 24V that do this very well, you can even choose 120VAC or 240VAC.

I run my home off 24V, even can run my 120V MIG & Big Compressor without an issue BUT I am also using a Samlex EVO 4024 Inverter (tier-1 about $2K USD). This is high efficiency (95%) and only uses 11W in idle (not eco mode) and 8W in eco mode. NOTE that "Value" brand products are usually 88-92% efficient at most and have a considerably higher idle consumption, typically around 30W +/-.

The trick to support 12V properly, is that you need a respectable step-down transformer. I use a Keurl 30V to 12V/30A Transformer to support my 12V devices in the powerhouse and no problem... Now this is not a cheapo potted buck converter (stay away from those they are Nasty Bad Junk).

The Voltage GOTCHA !
When we talk about 24V (legacy from lead acid days) we are talking about 25.6V Nominal up to 30V because you can go up to 29.2V charging if pushing it to 3.650V per cell X 8 cells for "24V pack". The DC to DC Converter therefore has to be able to take 30V as well because of that.

24V/100AH Battery Pack = 2560 Watt Hours or 2.56kWh. Weight : Approx 16Kg / 35.2 Lbs
24V/280AH Battery Pack = 7168Wh or 7.1kWh. Weight : Approx 44.8 Kg / 98.7 Lbs
24V Pack requires 8 Cells, 1 BMS, 1 Fuse/Breaker. Cases are available in different formats as well

 

[atatistcheff]

With a 24V system, the SCC /MPPT requires half the voltage input compared to a 48v one, so more panels can be wired in parrallel to reduce shading impacts. That;s one reasn why i picked a 24v, all my 450W panels are in parallel so I can reduce the impact of shading and also buy cheaper SCC's.

Very good point about the solar voltage requirements. I'm having a hard time fitting enough panels on the truck shell to get a respectable number of watts. I will probably have to put all of them in series anyway and a 48V MPPT might still not have enough voltage. I expect the solar will just supplement the charge and I'll still need to plug this in at night.

 

[MaikaiLifeDIY]

Looking at a solar/LiFePO4 solution for my mobile detailing. Right now I'm leaning towards the Growatt 3kV system with a server rack or stand-alone battery storage. I could go with either 24 or 48V. I suppose the advantage of 48V is you can use a smaller gauge wire. That's about the only difference I can come up with. Are there other considerations for using one or the other? This will sit in the back of my F-150 so I'm not too worried about vibrations or rough ride. Battery would probably be in the 5kWh range.

Not sure what climate you're in but LifePo4 batteries do not like heat or cold, having them sitting in the back of a truck even if it's not directly exposed to the outside, for example under a bed shell, will most likely expose your batteries to operating temperatures that will not be favorable for long term usage. How will you charge these batteries, will you have solar panels on your truck so it's charging during the day?

 

[MaikaiLifeDIY]

Honestly, it's a lot of complexity for something that could probably be easier done with a nice Honda Generator. I know it's not as "Green" but you're running a business and this system will most likely be troublesome to get out of it what you intend to do with it.

 

[atatistcheff]

Honestly, it's a lot of complexity for something that could probably be easier done with a nice Honda Generator. I know it's not as "Green" but you're running a business and this system will most likely be troublesome to get out of it what you intend to do with it.

No offense but you sound like my wife! ;-) Ya I have a generator now but I like to tinker and I don't like the noise. To me, using a generator is like a cop out - anybody can do that. Why use a $600 generator when I can spend over $2k for a solar solution?

Looking at 300W of solar on the truck shell. It gets hot here but nothing that these batteries can't take, especially in the shade. If you've seen one of Will's latest videos on his gate controller battery, turns out these lithium batteries might not be as heat sensitive as we think.

 

[zanydroid]

Truck bed battery systems are pretty common and I don’t think there’s a good non LFP option. You would need heaters or garage parking with heat to consistently charge. I think getting rid of the generator is a fine goal. From a noise and pollution angle.

Please do yourself a favor and do a feasibility check of the solar panel wrt failing fast and moving on from that. It’s basically performance/sculpture art and not functional, with the amount of footprint you have and inability to use deployable panels in a workday workflow.

 

[Partimewages]

Run a watt load calculation to make sure you have enough inverter. Anything that has a motor can be a very large start up current on the system.

 

[atatistcheff]

Run a watt load calculation to make sure you have enough inverter. Anything that has a motor can be a very large start up current on the system.

Yes, I've already emailed Signature Solar with questions about their 3kW all-in-one. That is one of my biggest concerns, will it run my pressure washer which is rated at 20A/120V? Now it just has a regular NEMA plug (not the 20A plug) and runs fine on a 15A circuit but the last thing I want to do is get this and find out it won't run my tools. I'm not sure how to measure that startup current since it's such a short pulse. Any advice would be appreciated.

 

[SeaGal]

... This will sit in the back of my F-150...

Why use a $600 generator when I can spend over $2k for a solar solution?

So, why not go the whole hog and trade it in for a F-150 Lightning with 9.6kW V2L output? ??

 

[atatistcheff]

So, why not go the whole hog and trade it in for a F-150 Lightning with 9.6kW V2L output? ??

You obviously haven't seen Will's F-150 Lightning video... ;-)

 

[Supervstech]

So, why not go the whole hog and trade it in for a F-150 Lightning with 9.6kW V2L output? ??

He probanly wants a long bed...

 

[Supervstech]

Yes, I've already emailed Signature Solar with questions about their 3kW all-in-one. That is one of my biggest concerns, will it run my pressure washer which is rated at 20A/120V? Now it just has a regular NEMA plug (not the 20A plug) and runs fine on a 15A circuit but the last thing I want to do is get this and find out it won't run my tools. I'm not sure how to measure that startup current since it's such a short pulse. Any advice would be appreciated.

I have a basic 2400W 24v inverter, i can test some loads.
It hasnt struggled with anything i have thrown at it so far.
What pressure washer do you have?

 

[Partimewages]

Pressure washer is a hog!

 

[zanydroid]

I'm not sure how to measure that startup current since it's such a short pulse.

You can buy a clamp meter with surge measurement. Maybe search on the forum to see which of the value ones on Amazon are favored by people here.

You do need to shop specifically for it because it's not a guaranteed feature. I bought my clamp meter before knowing to look for it, and it doesn't have it.