The Derelicte Bus

[Rusty]

Great progress !!! Sure makes it easier without the white stuff covering everything, but you go !!!

Thanks for the updates and videos- You do good work.

[Velocipedic]

What do you mean about it being easier without the white stuff covering everything?

[Rusty]

Originally Posted by velocipedic

what do you mean about it being easier without the white stuff covering everything?

(that is snow, for our Southern friends)
.

[Velocipedic]

Originally Posted by Rusty

Attachment 18915






(that is snow, for our Southern friends)
.

Ahhhhh, yes. One of the few benefits of being here. I can work on the bus every day, but it's a mad dash to get my roof rack installed so that everything is covered before it starts getting stupid hot.

[Velocipedic]

I drew this up at work. Any input or assistance is appreciated!



https://imgur.com/a/1y7WP

[Velocipedic]

[david.dgeorge07]

Two questions: do you plan to charge your batteries ever off of your alternator while you are driving? Also how do you plan to switch between shore power and inverter power? And do you want the inverter to ever charge your battery bank? I don’t have a system that uses solar but I’ve tried to build one that could have solar added later easily. The above questions were ones that I asked myself and eventually did solve.


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[Velocipedic]

I do not plan on ever charging from the alternator. I also plan on having a switch from shore power if/when I'm ever hooked up to it. The Inverter won't be able to charge the battery bank because it'll be on AC, while the batteries are DC.

[david.dgeorge07]

Originally Posted by Velocipedic

I do not plan on ever charging from the alternator. I also plan on having a switch from shore power if/when I'm ever hooked up to it. The Inverter won't be able to charge the battery bank because it'll be on AC, while the batteries are DC.

I bought an inverter that is also an automatic transfer switch and charger. I really recommend that style of setup.


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[Twigg]

Originally Posted by david.dgeorge07

I bought an inverter that is also an automatic transfer switch and charger. I really recommend that style of setup.


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Agreed ... and of the bunch, the AIMS units seem very good.

[Velocipedic]

My biggest question currently is regarding the "rated output" of an MPPT controller. I'll have about 45A going in at 38V. If I step it down to 12V for charging, will I pass the 96A output limit? What would happen if I were to do that?

[david.dgeorge07]

Originally Posted by Velocipedic

My biggest question currently is regarding the "rated output" of an MPPT controller. I'll have about 45A going in at 38V. If I step it down to 12V for charging, will I pass the 96A output limit? What would happen if I were to do that?

What’s is limited at 96A?


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[Velocipedic]

96A @ 12V is the best I can find. http://https://www.wholesalesolar.com/3900141/midnite-solar/charge-controllers/midnite-solar-classic-150-mppt-charge-controller

[PNW_Steve]

Keep in mind the max charge rate for your batteries. My best understanding is that you want to shoot for 10-13% of your battery banks 20 hour rate.

If you want to charge at 96 amps you best be charging a 900A/H battery bank.

If you have a more modest battery bank then look at 10% of your bank capacity as a guideline for max charge rate.

All of the above assumes FLA batteries. If you run AGM check with the manufacturer. I think that you can charge most AGM at 20% of the 20 hour rate.

Bottom line: there is a limit to how fast you can charge your batteries without killing them. If in doubt check with the battery manufacturer.

[Velocipedic]

Originally Posted by PNW_Steve

Keep in mind the max charge rate for your batteries. My best understanding is that you want to shoot for 10-13% of your battery banks 20 hour rate.

If you want to charge at 96 amps you best be charging a 900A/H battery bank.

If you have a more modest battery bank then look at 10% of your bank capacity as a guideline for max charge rate.

All of the above assumes FLA batteries. If you run AGM check with the manufacturer. I think that you can charge most AGM at 20% of the 20 hour rate.

Bottom line: there is a limit to how fast you can charge your batteries without killing them. If in doubt check with the battery manufacturer.

The plan right now is 6 2XXAh batteries so I should be in good shape.

[PNW_Steve]

Originally Posted by Velocipedic

The plan right now is 6 2XXAh batteries so I should be in good shape.

If you are planning to run 6 GC2s to create a 12 volt bank you will wind up with about 645 A/H bank. If you follow the 10% recommendation you will want to limit charge current to 65amps. The more agressive 13% would be closer to 84 amps.

[john61ct]

Go straight to 120+A, long-term investment, should last linger than the vehicle.

Next bank - they are a consumable - may be higher CAR.

Make sure to get adjustable setpoints, only equalize manually.

[Velocipedic]

Originally Posted by john61ct

Go straight to 120+A, long-term investment, should last linger than the vehicle.

Next bank - they are a consumable - may be higher CAR.

Make sure to get adjustable setpoints, only equalize manually.

Crown makes 200+AH batteries at 6V. I was planning on using 6 wired at 12V? Does this not work?

[PNW_Steve]

Originally Posted by Velocipedic

Crown makes 200+AH batteries at 6V. I was planning on using 6 wired at 12V? Does this not work?

I don't understand what John is trying to say but I can tell you that 6 x 6 volt batteries can be configured for a 12 volt bank.

Connect pairs of batteries in series. That will give you 3 pairs (@12v) that you can connect in parallel.

That would yield a 12 volt 600 A/H bank.

[Velocipedic]

Maybe he’s saying that the amp output would be too high?

Honestly though, I have NO idea what the volt -> amp conversion is as the MPPT controller steps down from 38v->12v... if I’ve got 45A at 38V, then ?A at 12V?