Electrical advice please

[Nick555]

We are buying an RP Rebel with Off-grid upgrade. This is an all Victron system replacing the stanard hab system with
2x 160A Lithium batteries
2 x 30A DC/DC charger
3,000W Inverter
115W Solar panel
Control system

I have a drone photography business & will need to charge my 8 drone batteries when off-grid. The battery port specs are 26.1V max & 6.75A max per port, so that is x8. (It takes about an hour to charge 8 batteries.) I "think" that gives a draw of 1,409.4W. I know that people have run this with success on a 2,000W generator (albeit with no batteries to go flat).

Can a 3,000W inverter system cope with this? (The fridge is electric, lights are LED) Also, how should I manage the usage? Can I charge 2 complete sets in a day?

Further options include an additional 115W Solar panel & Lithium battery upgrade to 2x 200A with 50A DC/DC charger.

 

[Carpmart]

Your batteries and inverter will cope okay with this, I would suggest more solar unless you’re driving around a lot or on hook up?

Is your fridge a compressor 12v fridge or are you running off the inverter at 230v?

Give it a go, if needed you could revert to running a generator for two one hour periods. The issue with that is, depending on the quality of the drone cells, you could end up with longish balancing at the end of the charge, so little current draw but long charge times (Longer Gennie running) unless you don’t balance the LiPo’s every time and only do that when on a hook up power supply.

Would also be worth charging whilst driving if you can time it between jobs?

 

[Two on Tour]

A 115 watt solar panel will struggle to recharge your 320aH of lithium and going to 400aH and 230 watts of solar will put you in the same boat on anything but a good sunny day if your a heavy electric user and static for any time.

 

[Carpmart]

One other thought, you could charge, if your LiPo charger is smart enough, at lower current… 1/2C rather than 1C rate?

 

[Nick555]

Your batteries and inverter will cope okay with this, I would suggest more solar unless you’re driving around a lot or on hook up?

Is your fridge a compressor 12v fridge or are you running off the inverter at 230v?

Give it a go, if needed you could revert to running a generator for two one hour periods. The issue with that is, depending on the quality of the drone cells, you could end up with longish balancing at the end of the charge, so little current draw but long charge times (Longer Gennie running) unless you don’t balance the LiPo’s every time and only do that when on a hook up power supply.

Would also be worth charging whilst driving if you can time it between jobs?

Thank you

Good question about the fridge, I know it's electric & suspect it runs off 12V, but I will check.

I don't have a generator & won't really have the room for one. (The drone kit is significant as it is). Charging as I'm driving sounds a good idea. The Drone batteries & Battery Station are all high end Pro kit. Batteries are paired & the Battery Station aims for all batteries to finish charging at the same time. This usually takes 45-50mins as I never completely flatten the drone batteries.

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[Nick555]

One other thought, you could charge, if your LiPo charger is smart enough, at lower current… 1/2C rather than 1C rate?

I can charge to 90%, I can fully charge & I can discharge batteries. I don't think I can change the current.

Edit: I can put less batteries in - 4, instead of 8?

 

[Nick555]

A 115 watt solar panel will struggle to recharge your 320aH of lithium and going to 400aH and 230 watts of solar will put you in the same boat on anything but a good sunny day if your a heavy electric user and static for any time.

Thank you.

 

[Carpmart]

I can charge to 90%, I can fully charge & I can discharge batteries. I don't think I can change the current.

Then this is the end where you should invest. Look up iChargers.

Do you make your own cell packs up?

What size batteries Ah do you use(?) they are obviously 6s packs based on the voltage, what connectors do the batteries use, XT60/90, Deans, Bullets? I’m assuming they have standard LiPo balance charge plugs on them?

You can then do all this straight off your Lithium batteries, no inverter needed… I have an iCharger 8 and can charger on each channel six 6s packs concurrently, 12 in total, all individually balanced and depending on the capacity of the packs, can do it a up to 4c.

 

[Nick555]

Then this is the end where you should invest. Look up iChargers.

Do you make your own cell packs up?

What size batteries Ah do you use(?) they are obviously 6s packs based on the voltage, what connectors do the batteries use, XT60/90, Deans, Bullets? I’m assuming they have standard LiPo balance charge plugs on them?

You can then do all this straight off your Lithium batteries, no inverter needed… I have an iCharger 8 and can charger on each channel six 6s packs concurrently, 12 in total, all individually balanced and depending on the capacity of the packs, can do it a up to 4c.

Thank you. But I must use the proper kit. It's in my operations manual, plus I cant risk the batteries. They're very expensive.

 

[autorouter]

I have a drone photography business & will need to charge my 8 drone batteries when off-grid. The battery port specs are 26.1V max & 6.75A max per port, so that is x8. (It takes about an hour to charge 8 batteries.) I "think" that gives a draw of 1,409.4W. I know that people have run this with success on a 2,000W generator (albeit with no batteries to go flat).

You can calculate the energy capacity of the leisure batteries. The charge capacity is 320 Ah, and the voltage is 12V, so the energy capacity is 320 x 12 = 3840 watt-hours (Wh)

Drawing 1409W for 1 hour will take out 1409 x 1 = 1409 Wh. This is about 37% of your 3840Wh battery capacity. So you could do this twice and still have 26% energy remaining. But realistically these figures are theoretical, and there will be some inefficiency losses, so you could probably get two charges out of the batteries, but have very little left.

A 115W solar panel won't make much of a dent in this requirement. It will give you about 40Ah on a good day, which is 40 x 12 = 480Wh. You'd need three times that to refill the drone even once.

A 50A B2B will give you 50 x 12 = 600Wh for each hour of driving, so it would take 2.5 hours to refill the drone once.

I don't know which brand of inverter you are using, I'd say get a pure sine wave type. For example I have a Victron Multiplus 3000 inverter/charger, which would not have the slightest problem with a 1409W power draw, especially if powered by 320Ah of lithium batteries.

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[Lenny HB]

As said the batteries will cope but no point in fitting Lithium if you don't have means to charge them quickly
You really need 300-400 watts of solar.

 

[Nick555]

You can calculate the energy capacity of the leisure batteries. The charge capacity is 320 Ah, and the voltage is 12V, so the energy capacity is 320 x 12 = 3840 watt-hours (Wh)

Drawing 1409W for 1 hour will take out 1409 x 1 = 1409 Wh. This is about 37% of your 3840Wh battery capacity. So you could do this twice and still have 26% energy remaining. But realistically these figures are theoretical, and there will be some inefficiency losses, so you could probably get two charges out of the batteries, but have very little left.

A 115W solar panel won't make much of a dent in this requirement. It will give you about 40Ah on a good day, which is 40 x 12 = 480Wh. You'd need three times that to refill the drone even once.

A 50A B2B will give you 50 x 12 = 600Wh for each hour of driving, so it would take 2.5 hours to refill the drone once.

I don't know which brand of inverter you are using, I'd say get a pure sine wave type. For example I have a Victron Multiplus 3000 inverter/charger, which would not have the slightest problem with a 1409W power draw, especially if powered by 320Ah of lithium batteries.

Excellent info & I actually understand it! Thanks!!

 

[Carpmart]

Thank you. But I must use the proper kit. It's in my operations manual, plus I cant risk the batteries. They're very expensive.

Exactly, which is why you should use a high quality charger.

One thing I do know something about is LiPo batteries. I know very little about anything else in the world….

 

[Bessy765]

We have a Victron 12/2000/80 inverter charger with 700 watts of solar and 2 x 100 amp Transporter Lithium Batteries. This what we get around midday on cool but bright weather. But when driving 2.3 150 comformatic alternator puts in 70+ amps if batteries are down. First picture solar parked up, second picture cruising at 55 mph 1500 rpm whilst running the roof air-con. The negative shown on d.c power is the charge rate from the alternator. When the d.c. is discharging no - sign is displayed.
just done 85 days in France no EHU needed.

 

[CazPaul]

For the price of the off grid upgrade can RP fit more solar included in the price?

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[Just smiffy]

Definitely need at least 300-400w of solar otherwise you’ll be driving around for 4-5hrs a day to recharge the batteries and that will cost a lot more in diesel then solar at the moment…

 

[Nick555]

For the price of the off grid upgrade can RP fit more solar included in the price?

Everything is an extra with RP. 2x 115W solar panels are the most I can fit on the van.

 

[Nick555]

Definitely need at least 300-400w of solar otherwise you’ll be driving around for 4-5hrs a day to recharge the batteries and that will cost a lot more in diesel then solar at the moment…

Would 2x 200A batteries be "better" than 2x 160A? (Both Victron lithium)

 

[Just smiffy]

Would 2x 200A batteries be "better" than 2x 160A? (Both Victron lithium)

Of course they will give more but they will still need feeding (charging) more..

 

[Nick555]

Of course they will give more but they will still need feeding (charging) more..

Understood, thanks.

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