the great electrical refresh

[zip]

Spoke with Justin today from UJOR Colorado and finalized all details for his ride improvement package install.

When I get my SMB back from him, I will redo the electrical. I love what this guy has done. I think I have a 225 amp alternator and would prefer not to add another. Pretty sure I can fit three 200W solar panels on top. I have the two gaucho couches in back which appears to have enough room underneath, including mounting those two massive 460ah batteries. Renogy, Victron, and Epoch all seem to be good products. Not sure what brand solar panels he has.

I am going to live in my SMB full time, and probably won't stay parked for more that 2-3 days, but who knows? I'm retiring!
I will have a fridge, E Mountain Bike, Lap Top, and Starlink Mini.

Should I add a second alternator?

What do you got and think?

 

[luthj]

What is your typical chassis needs as part of that 225A? Are you using DCDC or direct charging?

There may be 300A aftermarket upgrades to the stock alternator. They typically don't make much more at idle.

You need to work out your electrical energy budget. This means watt-hours for every major device. Do usage cases for summer/winter or any major conditions you expect to operate in. You can use the https://pvwatts.nrel.gov/ calculator to estimate solar production for a given season/region. Just enter flat mounted panels, and divide the monthly kwhr by the days to get daily harvest.

In general if you drive often 100A of alternator output (1.2kw at 12V) is typically fine. That can be a challenge with DCDC efficiency losses, and many factory alternators do not have sufficient surplus to meet that.

 

[zip]

What is your typical chassis needs as part of that 225A? Are you using DCDC or direct charging?

There may be 300A aftermarket upgrades to the stock alternator. They typically don't make much more at idle.

You need to work out your electrical energy budget. This means watt-hours for every major device. Do usage cases for summer/winter or any major conditions you expect to operate in. You can use the https://pvwatts.nrel.gov/ calculator to estimate solar production for a given season/region. Just enter flat mounted panels, and divide the monthly kwhr by the days to get daily harvest.

In general if you drive often 100A of alternator output (1.2kw at 12V) is typically fine. That can be a challenge with DCDC efficiency losses, and many factory alternators do not have sufficient surplus to meet that.

luthj,
Thanks for your input. Just starting my research. Appreciate the calculator.

 

[RVflyfish]

I found Geofff’s thread about a lithium power system over on the SMB forum very helpful. He measured his van’s alternator output and loads, which I hadn’t seen anyone do before.

Something to keep in mind is that most alternators don’t produce a lot of extra power at idle. For that, you want the kind they put in police cars and ambulances. I found these.

I looked at combining one of those with the Victron Orion XS 1400 DC-DC charger. If your alternator has enough headroom, it can give you 50A of charge at 12V.

But even then, you would have to drive/idle for over 18 hours to fully charge 920aH of batteries.

This brings up a point: You’re in the enviable position of having a huge battery bank. But you have to be able to charge it. And like everything else in van life, that comes with trade-offs.

For the record, I’m in a similar position, with 400aH of 24V batteries. To me, that much driving to charge my system isn’t practical.

So that leaves me three other options:

• Shore power
• A big solar array
• A dual alternator system

Shore power is cool because it’s relatively inexpensive and even 15A of output from a 120V circuit equates to 150A of input to your 12V batteries. So your onboard charger becomes the limiting factor. The downside, of course, is that shore power isn’t available when you’re out in the boonies.

Solar is great, but you’ll need a lot of panels to charge your system. That can get heavy and expensive. And full production maxes at about 5.5 hours a day…less in winter.

A dual alternator system with a Wakespeed controller can get you a lot more (100-200) amps of charge than the Orion. But that’s also expensive, in the neighborhood of $2,500.

FWIW, I plan to have all three (eventually…$$$!) because flexibility gives me options…and I want to run rooftop A/C on hot summer days.

 

[luthj]

Yeah, a 10kwhr battery system doesn't make sense for most usage cases where less than 2kw of charging isn't available. There are corner cases where it is a good value, but otherwise its just extra weight and cost.

It is always best to start with an electric consumption budget, and then work backwards to the battery, PV and alternator needs.

 

[zip]

I found Geofff’s thread about a lithium power system over on the SMB forum very helpful. He measured his van’s alternator output and loads, which I hadn’t seen anyone do before.

Something to keep in mind is that most alternators don’t produce a lot of extra power at idle. For that, you want the kind they put in police cars and ambulances. I found these.

I looked at combining one of those with the Victron Orion XS 1400 DC-DC charger. If your alternator has enough headroom, it can give you 50A of charge at 12V.

But even then, you would have to drive/idle for over 18 hours to fully charge 920aH of batteries.

This brings up a point: You’re in the enviable position of having a huge battery bank. But you have to be able to charge it. And like everything else in van life, that comes with trade-offs.

For the record, I’m in a similar position, with 400aH of 24V batteries. To me, that much driving to charge my system isn’t practical.

So that leaves me three other options:

• Shore power
• A big solar array
• A dual alternator system

Shore power is cool because it’s relatively inexpensive and even 15A of output from a 120V circuit equates to 150A of input to your 12V batteries. So your onboard charger becomes the limiting factor. The downside, of course, is that shore power isn’t available when you’re out in the boonies.

Solar is great, but you’ll need a lot of panels to charge your system. That can get heavy and expensive. And full production maxes at about 5.5 hours a day…less in winter.

A dual alternator system with a Wakespeed controller can get you a lot more (100-200) amps of charge than the Orion. But that’s also expensive, in the neighborhood of $2,500.

FWIW, I plan to have all three (eventually…$$$!) because flexibility gives me options…and I want to run rooftop A/C on hot summer days.

I'm inclined to believe the second alternator is the best way for me to go. I just read Geoff's thread. OH MY! Way over my head understanding all this stuff.

 

[zip]

It will probably be best for me to have a professional design a system for me. I would have someone else install the alternator, but I should be able to install the rest. Thanks for this input.

 

[luthj]

If you hand a pro a well defined list of your needs, consumers etc, they should be able to get you a good layout pretty quick. Nothing wrong with going that route, there is lots that can go wrong, and its fairly expensive. This is one of the areas where paying a bit for an experts time is well worth it.

 

[zip]

If you hand a pro a well defined list of your needs, consumers etc, they should be able to get you a good layout pretty quick. Nothing wrong with going that route, there is lots that can go wrong, and its fairly expensive. This is one of the areas where paying a bit for an experts time is well worth it.

Yep, I concur. Thanks.