Solar & Battery Bank = most important. Also want upgrade exterior, and refresh the interior

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Hi there forum,

I am looking to thoroughly upgrade exterior, and refresh the interior, of my Sprinter T1N, Class B, motorhome. Once the Corona restrictions lift we want to move on in an effectively new 'home'

WE are working on various upgrades ($$ allowing)
The most important issue is installing the most potent solar & battery system we can.

Any advice you can all offer would be EXCEEDINGLY WELCOME and appreciated:


What is the highest potential solar and battery storage (Lithium) one could fit onto a Sprinter T1N?


I wish to use Lithium batteries instead of AGM.
Unless you all advise strongly against that.

The batteries can weigh a maximum 100kg in total.
They must provide a, total, capacity of 550AH minimum

I already have a solidly crafted metal battery storage box in place just behind the rear axle.
I can store two batteries of 51cm x 27cm x 22cm


Though I am also considering the use of additional foldable & flexible solar panels, I first, need to install the maximum wattage/12v Amperage on the roof.

What would be the best system anyone has experience with and can, confidently, recommend.

Is 45AH produced, in full desert blasting mid-day sun, a realistic aim?

My thanks, in advance, for any advice you all can offer me.🙏


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PS. Roof dimensions, top-down, attached
 

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borabora

Well-known member
Are you planning on running A/C on battery? Because that's the only reason I can see why you would need so much electrical storage in a relatively small footprint Sprinter. Fridge, lights, fans. charging and even things like coffee machine/kettle or microwave can easily be accommodated by 200-300 ah of LIFEPO4 batteries.
But LIFEPO4 batteries are getting pretty cheap and 600 ah will only set you back $4k to $6k nowadays and even less if you build the battery yourself. The question is how do you keep them charged? I am no sure what you mean by 45 ah on the roof -- maybe you mean 450 ah or 45 amps output??? On a very good day multiply the roof solar wattage by 5-6 to get the day's output. 600 watts of solar is doable and those panels yield 3 to 3.6 kwh which is about 250 to 300 ah -- not nearly enough to fully replenish your 550 ah batteries.
There was a thread recently where someone was planning on nearly 1000 Watt of solar on her 170 roof. It can be done but I think you have no space left for a fan or A/C unit. It's also pretty costly. The resulting 5-6 Kwh of power is still not enough to fill a depleted 550 ah battery bank. So, at that point you'd need to resort to alternator charging which has it's own issues.

Battleborn makes good LIFEPO4 batteries and backs them with excellent service and a great warranty for about $950 per 100 ah.
Others sell for less but may be as good even if Battleborn's service cannot be matched. For example Lion Energy 100 ah batteries are currently on special at Costco for 2 x 100 ah for $1400.
I use an off-brand (Expertpower) 200 ah LIFEPO4 battery that cost be less than $1400 and that works just fine.

600 ah of LIFEPO4 will weigh a bit more than 100 kg and you will definitely need more space than you currently have available. LIFEPO4 batteries don't like to be in hot environments so keep them below 120 at all times and best operated below 90 F. Can't charge LIFEPO4 at temps below freezing but you can use them.
I hope that helps...
 

marklg

Well-known member
Links to my installation, but the storage wells for the batteries were already there.


It seems you have to be logged into this forum to see some of the linked pictures. I have to fix that.

I'm seconding that you don't need 550 Ah unless you plan to run AC, and then you probably need twice that and can't possibly fit enough solar panels on the roof of a Sprinter to keep them charged. It is way cheaper to just use a generator for AC.

Regards,

Mark
 

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Had a generator- removed it
Hung too low
Weighed too much
Made too much noise
We tend to park/boondock where quiet & discretion mean we are tolerated as exotic foreigners but no generator for that reason also

if I could find a VERY small portable AC I might use it. Sprinter is a small space after all.

2 things:

1. Rather have a huge battery bank and roof covered in solar when I don’t need them
Than not have them when I do!

2. In a year or two the system will be transferred to a large UnĂ­-Mog or a forest cabin. Thus Inwant the max possible & can swallow the cost as it is a longer term investment than only the future life of the Sprinter.

So, the maximum I can on that roof

lithium batteries have a big problem with high & low temperatures- is that true?

Thanks
 

borabora

Well-known member
Had a generator- removed it
Hung too low
Weighed too much
Made too much noise
We tend to park/boondock where quiet & discretion mean we are tolerated as exotic foreigners but no generator for that reason also

if I could find a VERY small portable AC I might use it. Sprinter is a small space after all.

2 things:

1. Rather have a huge battery bank and roof covered in solar when I don’t need them
Than not have them when I do!

2. In a year or two the system will be transferred to a large UnĂ­-Mog or a forest cabin. Thus Inwant the max possible & can swallow the cost as it is a longer term investment than only the future life of the Sprinter.

So, the maximum I can on that roof

lithium batteries have a big problem with high & low temperatures- is that true?

Thanks
Lithium batteries don't like to operate at high temperatures. It reduces life span. But this should only be a concern if in a confined space that is not ventilated well while the van (or cabin) are not occupied. If you live in it and the battery space does not have a different reason to become very hot then it shouldn't be an issue unless you plan on living in the desert.
LIFEPO4 batteries also must not be charged at temps below freezing. But they may be discharged at those temperatures. The battery may contain electronics that prevent charging at low temps or you can add such blocking electronics or you can add a heating capability that diverts charging current to a heater before charging is enabled. Or, you can store the batteries indoors where freezing will not occur.
Keep in mind that SLA batteries have their own temperature issues as well.
 

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New member
Lithium batteries don't like to operate at high temperatures. It reduces life span

LIFEPO4 batteries also must not be charged at temps below freezing
Hmmm 🤔

That sounds a little worrying & restrictive.

How dit compare with AGM for temperature tolerance?

If they are so particular why do you use them?

Do you/can one use Lithium batteries (mine would be suspended below Van in moderately insulated metal box) in Florida/Arizona in July?
Vail, Colorado or BC Rockies in January?

We cover a wide range of territory & altitudes
 

borabora

Well-known member
Obviously do your own research before sinking thousands into batteries. Here's a summary:

AGM batteries are also heat sensitive. To a lesser degree than LIFEPO4 but sufficiently so that your Sprinter battery is not located in the engine compartment. AGM batteries lose a large amount of their capacity in cold temps but can be safely used and charged at cold temps. AGM batteries should be charged using a temperature adjusted algorithm. Really extreme temps will kill both types of battery.

LIFEPO4 batteries:
- weigh less than 1/2 of SLA
- can be used to full capacity while SLA should only be used to 50% capacity
- don't off-gas explosive hydrogen gas
- charge faster than SLA
- have near zero self-discharge rate
- don't mind being under-charged something that kills SLA batteries
- have higher nominal voltage during discharge cycle
- don't voltage sag as much during high loads
- last up to 10x as many charge/discharge cycles vs AGM when both are well taken care of
- degrade more gracefully than AGM once they start degrading
- cost less than AGM over life time
- usually contain protective electronics (BMS) that manages the battery and acts as a safe guard from unsafe conditions

But:
- initially cost more
- have more temp constraints
- less mature technology than SLA
- embedded electronics creates additional failure mode
- all LIFEPO4 cells are made in China -- QA can be an issue
- used LIFEPO4 cells still work so well that they are sometimes fraudulently used/sold as new
 

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I will read more into for sure :thinking:


Just your personal experience though - is there anywhere you don’t/can’t go in the continental USA (or similar temp range) in the wrong season because your Li batteries won’t tolerate it?
 

marklg

Well-known member
I will read more into for sure :thinking:


Just your personal experience though - is there anywhere you don’t/can’t go in the continental USA (or similar temp range) in the wrong season because your Li batteries won’t tolerate it?
They make Lithium batteries with built in heaters. Choose them if you go cold places or add external heaters. You will need heaters for water tanks too. For hot places, there is not much you can do besides keeping them in the coolest location. AGM batteries don't last as long in hot climates either as the water diffuses right through the plastic case.

Regards,

Mark
 

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