900Ah Lithium Setup w/700w of Solar

May 31, 2020
28
29
Funster No
71,248
MH
Hymer B668 (2017)
Exp
newbie
Recent install by the legends at RoadPro - I have a smaller setup in my caravan / car which led me down this path for the motorhome.

Why the power? Our use when we travel is full on, we have 2 young kids and I'm often working while travelling and want to avoid any power anxiety whatsoever. Aircon is the real power suck, but with this much solar and charging capacity, I expect to be able to use it off grid a decent amount. I spent a summer off grid with the 600Ah of Lithium in my caravan checking how much power everything uses before putting together a spreadsheet and speccing this out.

Main components:
6x 150Ah NDS LiFePO4
2x Votronic 70A Battery to Battery chargers (with upgraded alternator)
2x Votronic 50A Mains Charger (helpfully these have power switches, so I can switch one or both off when limited by hookup)
2x NDS BlackSolar 180w
3x NDS BlackSolar 115w
Votronic Solar Regulators
Votronic Battery Computer
Dometic FreshJet 3200 Aircon
NDS 3000w Inverter
NDS Priority Switch

The whole lot weighs about 250kg (including aircon), I picked a van with buckets of payload to accommodate this, it's working extremely well so far!

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Jun 24, 2019
962
1,664
Funster No
61,896
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Dethleffs Globebus
Exp
2000
Cool set up but I would think a few speed bumps and the screws will pull out of the floor straps especially as the strap under tension is pulling upwards ?
Do you know a good battery supplier ? eg, 100AH Lithium ?
 
OP
M
May 31, 2020
28
29
Funster No
71,248
MH
Hymer B668 (2017)
Exp
newbie
Cool set up but I would think a few speed bumps and the screws will pull out of the floor straps especially as the strap under tension is pulling upwards ?
Do you know a good battery supplier ? eg, 100AH Lithium ?

Going to keep an eye on it and will figure something else out if needed, feels pretty solid.

I have 2x 100Ah NDS Lithium in the back of my car, again from RoadPro. The NDS ones aren't cheap but they are rock solid.

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Jun 30, 2011
4,782
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Durham
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Concorde Concerto
Exp
Since 2011
Wow what's set up, at Roadpro prices that's £11250 just to buy the batteries and all the other extra stuff on top of that it, must be at least a £15000+ installation.

Can you lend me a fiver.

I'm so jealous of that system, I've just worked an extra overtime shift for £100 lol.
 

Tombola

LIFE MEMBER
Nov 21, 2020
657
2,111
Merseyside
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78,053
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Autotrail Imala 734
Exp
12 years
great set up NIce one.
Im just in the middle of changing mine to lithium, am going 200ah with 400 solar and the polinovel batteries from quality source with bms and temp protection etc are proving to be my route.

what b2b are you using mike and how are you switching over from hookup to invertor is it auto or are you using plugs. I went for this works treat. fit and forget Amazon product
 
OP
M
May 31, 2020
28
29
Funster No
71,248
MH
Hymer B668 (2017)
Exp
newbie
great set up NIce one.
Im just in the middle of changing mine to lithium, am going 200ah with 400 solar and the polinovel batteries from quality source with bms and temp protection etc are proving to be my route.

what b2b are you using mike and how are you switching over from hookup to invertor is it auto or are you using plugs. I went for this works treat. fit and forget Amazon product

Heard good things about those batteries too, with the bluetooth BMS built in.

I use the NDS priority switch, so it's automatic - super simple.

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Jun 24, 2019
962
1,664
Funster No
61,896
MH
Dethleffs Globebus
Exp
2000
I'm saving up for a candle and then a match.
That's the light and heating sorted.

Only joking. Hopefully Lithium battery prices will come down soon.

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Apr 27, 2016
2,856
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Manchester
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Since the 80s
That's an impressive assemblage of useful power, treading a path where many are thinking of venturing.

When you're talking about 900Ah of lithium battery, with a 3kW inverter, I'd imagine the majority of the power is used by the 240V side of the installation. I'd be looking at going to 48V, maybe having four 200Ah batteries in series, plus a single 12V 100Ah battery for the 12V habitation loads.

Most of the loads can be run from the inverter - air conditioning, TV, coffee machine, hairdryer etc. The current from the batteries for a full 3kW load is 250A at 12V, but only 62A at 48V. And for 700W of solar the current is 58A at 12V but only 15A at 48V. A lot less heavy-duty copper required.

Charging the 48V battery bank can be via two 70A 12V-to-48V B2Bs, a 3kW 48V inverter/charger, and some 48V solar regulators.

The small amount of power for the 12V habitation devices can come from a standard split charge relay or a small 12V B2B, and can be topped up if necessary via a standard battery charger running from the inverter.

The advantage of a Victron 3kW inverter/charger is the PowerAssist mode. You can set the maximum amps from the hookup, and it will not go above that. It will take power from the batteries to supply peak loads, and recharge when the loads aren't in use.

What is the function of the NDS Priority Switch? I know its usual use is to avoid connecting loads like aircon to the inverter, but isn't running the aircon one of the reasons you assembled such large battery bank?
 
OP
M
May 31, 2020
28
29
Funster No
71,248
MH
Hymer B668 (2017)
Exp
newbie
That's an impressive assemblage of useful power, treading a path where many are thinking of venturing.

When you're talking about 900Ah of lithium battery, with a 3kW inverter, I'd imagine the majority of the power is used by the 240V side of the installation. I'd be looking at going to 48V, maybe having four 200Ah batteries in series, plus a single 12V 100Ah battery for the 12V habitation loads.

Most of the loads can be run from the inverter - air conditioning, TV, coffee machine, hairdryer etc. The current from the batteries for a full 3kW load is 250A at 12V, but only 62A at 48V. And for 700W of solar the current is 58A at 12V but only 15A at 48V. A lot less heavy-duty copper required.

Charging the 48V battery bank can be via two 70A 12V-to-48V B2Bs, a 3kW 48V inverter/charger, and some 48V solar regulators.

The small amount of power for the 12V habitation devices can come from a standard split charge relay or a small 12V B2B, and can be topped up if necessary via a standard battery charger running from the inverter.

The advantage of a Victron 3kW inverter/charger is the PowerAssist mode. You can set the maximum amps from the hookup, and it will not go above that. It will take power from the batteries to supply peak loads, and recharge when the loads aren't in use.

What is the function of the NDS Priority Switch? I know its usual use is to avoid connecting loads like aircon to the inverter, but isn't running the aircon one of the reasons you assembled such large battery bank?

Good points, I hadn't thought about playing with the voltage side of this too. You're right that all of the higher loads are on the 240v side.

The Victron inverter sounds interesting, i've had to do a similar thing before in the caravan, i.e. where there is only a low current hookup I can run the charger at the lower current and run the higher loads from the inverter.

The NDS priority switch in this setup is to switch all internal 240v power (except the chargers) to the inverter when the external hookup isn't connected.

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