Caravan upgrade to 24v or 48v

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Dan007a
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Caravan upgrade to 24v or 48v

Post by Dan007a »

Question
Lifepo4 better on 24 or 48v (blancing etc) ?
Upgrading van power from 12v lithium (20s) to 48v
With 6 300w 48v panels
The thinking is less loss with my pvm tristar 60 controller.
Pip inverter looks good to power but worried about fan noise. As bed is forward and inverter can only be place in front storage.

But seen the victron 3000 48v at 2x the price. Looks like a good kit . And was impressed with my battery charger.

Should I worry about going 48v?
Dalkin 3.5 max draw
Dalkin 3.5 max draw
20201108_184628.jpg (2.62 MiB) Viewed 379 times
Use the mppt built into the inverters?
Give up on my goal to go free camping with only solar.
Last edited by Dan007a on Wed, 18 Nov 2020, 16:11, edited 1 time in total.
Dan007a
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Re: Caravan upgrade to 24v or 48v

Post by Dan007a »

Testing lifepo4
Testing lifepo4
20201024_131100.jpg (3.96 MiB) Viewed 378 times
dRdoS7
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Re: Caravan upgrade to 24v or 48v

Post by dRdoS7 »

Hi,

I have no experience with 24V or 48V in a caravan (have 2 x 100Ah Solarking drop-ins), but I don't see any advantages, as you already have a working 12V system.

12V gear is easier to find, especially when away from home.

Another advantage of your current 12V, is if one or more cells fail (pretty unlikely), you'll still have 3 x 12v groups. May need a slight rejig of wiring.

Maybe get an MPPT SCC?

Unless you're having balancing problems, I can't see the point. Is there a balance problem?

You could go to 24V, that's probably a better option, if you want to change.

dRdoS7.
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Adverse Effects
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Re: Caravan upgrade to 24v or 48v

Post by Adverse Effects »

it depends on if you use mostly 12VDC or 24VDC or 48VDC or 240VAC

if its 12VDC then maby just beef up what you have
if its 24VDC then ... upgrade if you feel like it
if its 48VDC then ... upgrade if you feel like it
if its 240VAC then no two ways about it upgrade because there are many many advantages to 48VDC to get 240VAC
If you don't have time to do it right,
When will you have time to do it over

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jonescg
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Re: Caravan upgrade to 24v or 48v

Post by jonescg »

Dan - I still have the two 40 Ah CALB cells set aside for you. You still need them?
Chris
AEVA National Secretary, WA branch chair.
paulvk
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Re: Caravan upgrade to 24v or 48v

Post by paulvk »

48v is a good way to go now that converters are cheaply available , getting 12v from 48v or less is simple most would give 12v with 36v input.
12v to 48v chargers are also available to charge from the car while traveling. Note it seems caravan manufactures are going the 48v way.
Victron are good units but expensive , the fan noise would not be a problem as you would not need the inverter on when sleeping and the fans only rev up under load but any inverter put in an enclosed space is going to need a lot of forced ventilation.
dRdoS7
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Re: Caravan upgrade to 24v or 48v

Post by dRdoS7 »

Hi,
paulvk wrote: Tue, 24 Nov 2020, 16:06 48v is a good way to go now that converters are cheaply available

Victron are good units but expensive
I thought so too, until I saw this while looking for a PIP5048MG replacement:

https://askwise.com.au/product/inverter ... art-solar/

https://www.victronenergy.com/inverters ... mart-solar

Going to try building an "08 Error Buster" instead, see how that goes first.

dRdoS7
paulvk
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Re: Caravan upgrade to 24v or 48v

Post by paulvk »

When you read the victron specs its a high frequency inverter like the MPP Solar and this note about output "Increases linearly from 4800 W at 46 VDC
to 5300 W at 52 VDC" so it is not 6000 watts . I would also like to know if the solar is isolated from the battery.
dRdoS7
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Re: Caravan upgrade to 24v or 48v

Post by dRdoS7 »

Hi,
paulvk wrote: Wed, 25 Nov 2020, 12:56 When you read the victron specs its a high frequency inverter like the MPP Solar and this note about output "Increases linearly from 4800 W at 46 VDC
to 5300 W at 52 VDC" so it is not 6000 watts . I would also like to know if the solar is isolated from the battery.
Yeah, like all Victron stuff, the naming is not watts, so it's 6000VA, variable. The non-PF1 MPP solar is also not watts.

APC UPS were the same, made them sound bigger. The first one I had was a 3000, but 2250W (or 2500W).

Still a reasonable price.

I did wonder about this from the manual:
Isolation, and earth fault protection
The AC output is isolated from the battery DC input. The DC PV solar inputs are not isolated from the AC output. The neutral is
connected to the chassis with an internal ground relay when the inverter is on. An internal earth leakage circuit breaker protects the
solar input. If an earth leakage is detected from solar panels to earth, the inverter shuts down. Please note that a true neutral and
grounding of the chassis is needed to ensure correct operation of the internal and external earth leakage circuit breaker.
Whether it would be like the MPP MG I have if the panels get wet when running from grid (though this doesn't have any grid input).

dRdoS7
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Re: Caravan upgrade to 24v or 48v

Post by TyTower »

Old thread but . The point of going to 48 volts ,actually around 54 volts usually, is the higher voltage needs smaller diameter wiring because only a quarter of the amps flow. This also gives less voltage drop over distance runs.

DC up to about 90 volts is fairly safe and stick welders commonly run on 72 volts DC out . If you sit on wet concrete and weld you will feel a buzz but its not so bad if you are not on a pacemaker or something. Even on 48 v you will feel it if you put your finger across it .

48v is becoming a very common choice for vans ,boats and houses and there is plenty of stuff for 24 volts now for trucks. There will be more and more for 48v . BMS's etc are cheaply available and inverters are plentiful in 48v.
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