Switching to lithium is more complicated than I thought

[Attic_Explorer]

Hello all. Long time reader, first time poster.

I woefully underestimated the capabilities of lead-acid batteries for our want to boondock with our trailer. We got the dual 6V batteries (with 2 solar panels) which does provide some good power if we're stopped for a few hours between powered camp sites but they're not robust enough to handle an electric coffee percolator and shade on the panels for a week.

I did more research and started by buying an extra 100W panel so I can catch the sun where it shines. Then I ordered an MPPT controller so the power can be more efficiently used. And I ordered a Lithium battery after watching some good videos that explained why, in the end, they don't cost more than lead-acid. (And we're working on switching to a stovetop percolator. The hangup with that is the stovetop; the gaps in the grate are too big for a small coffee pot! )

But there are still mysteries I have to solve that I hope someone can help with.

1. I was set to go with replacing the charge controller and battery but only just realized that I can have a problem with current flow back to my tow vehicle. Pin 4 is live all the time AND there's no DC-to-DC controller on that. The new battery does have BMS, though, so would that mitigate any problems while driving? (I unplug the TV when parked.)

2. I have to install a port for the external solar panel because it got dropped from the build sheet without us noticing. I understand that the exposed pin should be the negative lead as that would be the trailer ground. I never saw a definitive answer to this: If the exposed pin of the port is negative and the exposed pin of the plug coming from the solar panel is negative, do you just live with a gender-bender inbetween or do you swap the polarity of the plug from the panel or swap the polarity of the port to the charge controller?

3. The existing charge controller is the remote control for the inverter. I don't like the price of a replacement remote. What have others done about this? (I'm thinking the remote is a momentary contact switch. Documentation is sketchy but I don't think there's actual coded communication going to that port.)

Thanks again for all your help getting us to where we are now.

[Mike G]

I'm no expert by any means, but my initial thought on #1 is maybe to add a diode in the circuit. Diodes let current go one way only. As for the extra portable panel, with mine I use a separate waterproof solar controller and route the power into the 7-pin plug (when unplugged from the vehicle); as an alternative you could clip leads right to the battery. It's not as tidy as installing a port, but it's quick and easy.


Others with more experience are bound to chime in shortly.

[gbaglo]

Your problem is running an appliance with a electric heating element.
I have a tea kettle that fits on a burner, and I have a Melita filter holder ( #4 filters ) and thermos. Boil the water on the propane stove and pour through coffee in filter.
I have one group 27 deep cell battery and have no problems boondocking ( I do have two 40-watt solar panels, if I'm out more than 4 or 5 days.

[Attic_Explorer]

Mike G: Excellent thoughts! I purchased a connector to attach the solar panel through the 7-pin port. I thought that was the easier way to go as I connected the trailer to the truck for extra power at times and I have a cheap PWM that came with the panel. But it turns out to be not as efficient as going through the MPPT. If I'm rewiring then I may as well go that route. I also saw this solenoid in some posts, https://www.etrailer.com/Accessories.../TR118665.html


gbaglo: My thoughts exactly! I should have mentioned, though, my wife will not abide by drip coffee. Hence, the percolator.

[Roadfossil]

Originally Posted by Attic_Explorer

Hello all. Long time reader, first time poster.

I woefully underestimated the capabilities of lead-acid batteries for our want to boondock with our trailer. We got the dual 6V batteries (with 2 solar panels) which does provide some good power if we're stopped for a few hours between powered camp sites but they're not robust enough to handle an electric coffee percolator and shade on the panels for a week.

I did more research and started by buying an extra 100W panel so I can catch the sun where it shines. Then I ordered an MPPT controller so the power can be more efficiently used. And I ordered a Lithium battery after watching some good videos that explained why, in the end, they don't cost more than lead-acid. (And we're working on switching to a stovetop percolator. The hangup with that is the stovetop; the gaps in the grate are too big for a small coffee pot! )

But there are still mysteries I have to solve that I hope someone can help with.

1. I was set to go with replacing the charge controller and battery but only just realized that I can have a problem with current flow back to my tow vehicle. Pin 4 is live all the time AND there's no DC-to-DC controller on that. The new battery does have BMS, though, so would that mitigate any problems while driving? (I unplug the TV when parked.)

2. I have to install a port for the external solar panel because it got dropped from the build sheet without us noticing. I understand that the exposed pin should be the negative lead as that would be the trailer ground. I never saw a definitive answer to this: If the exposed pin of the port is negative and the exposed pin of the plug coming from the solar panel is negative, do you just live with a gender-bender inbetween or do you swap the polarity of the plug from the panel or swap the polarity of the port to the charge controller?

3. The existing charge controller is the remote control for the inverter. I don't like the price of a replacement remote. What have others done about this? (I'm thinking the remote is a momentary contact switch. Documentation is sketchy but I don't think there's actual coded communication going to that port.)

Thanks again for all your help getting us to where we are now.

In response to #2, I have recently added a Renogy portable solar unit to my RV, which had existing standard SAE plugs on outside wall that ran to the battery. After much fiddling with extensions and hookups, I purchased a "SolarEnz" Solar connector to SAE connector adapter from Amazon. Allowed the proper positive and negative leads from the solar set up to be plugged directly into the corresponding plug and socket on the SAE plug on the travel trailer. It was 10 AWG.

[Vermilye]

Originally Posted by Attic_Explorer

Hello all. Long time reader, first time poster.

I woefully underestimated the capabilities of lead-acid batteries for our want to boondock with our trailer. We got the dual 6V batteries (with 2 solar panels) which does provide some good power if we're stopped for a few hours between powered camp sites but they're not robust enough to handle an electric coffee percolator and shade on the panels for a week.

I did more research and started by buying an extra 100W panel so I can catch the sun where it shines. Then I ordered an MPPT controller so the power can be more efficiently used. And I ordered a Lithium battery after watching some good videos that explained why, in the end, they don't cost more than lead-acid. (And we're working on switching to a stovetop percolator. The hangup with that is the stovetop; the gaps in the grate are too big for a small coffee pot! )

But there are still mysteries I have to solve that I hope someone can help with.

1. I was set to go with replacing the charge controller and battery but only just realized that I can have a problem with current flow back to my tow vehicle. Pin 4 is live all the time AND there's no DC-to-DC controller on that. The new battery does have BMS, though, so would that mitigate any problems while driving? (I unplug the TV when parked.)

The battery BMS will not help with "backfeed" to the tow vehicle. Many ignore the problem, however with the more complex charging systems built into newer vehicles, I'd add a DC to DC converter. Either a diode large enough to carry the charge current or a DC to DC converter is the solution, and to save remembering to unplug thee tow vehicle, add a solenoid to the tow vehicle that shuts off the charge line when the tow vehicle ignition is off.

2. I have to install a port for the external solar panel because it got dropped from the build sheet without us noticing. I understand that the exposed pin should be the negative lead as that would be the trailer ground. I never saw a definitive answer to this: If the exposed pin of the port is negative and the exposed pin of the plug coming from the solar panel is negative, do you just live with a gender-bender inbetween or do you swap the polarity of the plug from the panel or swap the polarity of the port to the charge controller?

I'd always check the polarity since different manufacturers use different polarity on SAE connectors. Either use a reversing adapter or rewire the panel or trailer connector. Remember that if you run the portable panel to the MPPT (or the original solar controller), you must bypass the controller (if there is one) on the portable panel.

3. The existing charge controller is the remote control for the inverter. I don't like the price of a replacement remote. What have others done about this? (I'm thinking the remote is a momentary contact switch. Documentation is sketchy but I don't think there's actual coded communication going to that port.)

I added the relatively inexpensive GP-HD-R remote switch at $28.29 from Amazon By the time you make connectors, etc to wire a momentary push button switch, you will be near the cost, plus the "on" indicator is handy..

Thanks again for all your help getting us to where we are now.

I have to add this because the forum doesn't like burying replies in the quote.

[Attic_Explorer]

I added the relatively inexpensive GP-HD-R remote switch at $28.29 from Amazon By the time you make connectors, etc to wire a momentary push button switch, you will be near the cost, plus the "on" indicator is handy..

I need a GP-SWR-A remote to control my inverter. Currently, through an online Walmart vendor the price is $85.46 CAD which is $66.66 USD. Plus tax. No thanks.

[Shon414]

I like using the gopower app as well as the button since are inverter is tucked away.
So is it possible to keep the gopower solar controller just to control the inverter?
Add a Mppt controller for efficiency?

[Attic_Explorer]

Originally Posted by Shon414

I like using the gopower app as well as the button since are inverter is tucked away.
So is it possible to keep the gopower solar controller just to control the inverter?
Add a Mppt controller for efficiency?

Yes, but...
Keeping the old controller where it is is fine. Not in the way. I imagine that to continue to use it as a switch would require it to be powered from the battery since it's a soft button. So I'd have to leave those cables in place. Of course, I don't know that for sure. And I don't know the parasitic drain.

That was Plan A, though. Thanks.

[DGLP]

Originally Posted by Attic_Explorer

I added the relatively inexpensive GP-HD-R remote switch at $28.29 from Amazon By the time you make connectors, etc to wire a momentary push button switch, you will be near the cost, plus the "on" indicator is handy..

I need a GP-SWR-A remote to control my inverter. Currently, through an online Walmart vendor the price is $85.46 CAD which is $66.66 USD. Plus tax. No thanks.

Check this out on Amazon - $38.43 US
https://www.amazon.com/gp/product/B0...ie=UTF8&psc=1#

[Attic_Explorer]

Originally Posted by Vermilye

I have to add this because the forum doesn't like burying replies in the quote.

Originally Posted by DGLP

Check this out on Amazon - $38.43 US
https://www.amazon.com/gp/product/B0...ie=UTF8&psc=1#

Thanks. $52.99 after shipping and duties.

[Allan Bornestig]

Glenn Baglo
Hi Glenn, we are always using the simple Melitta system it is so easy it is laughable.
For two people it is perfect.On huntingtrips with my sons we use the Coleman coffee machine that you put on top of the burner
For the morning brew we have two of those going at the time.
BTW That Coleman oven you donated was used in the bush last year to make Bran muffins.Instant success.Using a custom made welding blanket cover helps keeping the heat in
and it does not take long to bake a load.
Take care.
Allan.

[gbaglo]

Excellent. The beer you gave me in exchange tasted wonderful.
Thanks.

[Perry Butler]

Melitta system for the past couple of decades camping.

Because of the complications with lithium, I decided against it. We added 300 watts to the 170 watts we got with the camper, took our cheap GoPower and replaced with Victron 100/30 for our rooftop solar and a Victron 100/20 for our Renogy 100 watt portable, that we haven’t needed since the additional 300 watts were installed. We use gas appliances, but have a 1500 watt inverter to make toast.

Previously I would advise to get the biggest batteries possible, but now after having 465 watts on the roof (-5 watts for the slight VMP mismatch) we usually fill by 10am standard time every day and don’t need massive amp hours.. If/when our batteries fail we’ll either get two 6v flooded, or AGM’s. We have friends with an Airstream with two 6v Lifeline batteries that are still running strong (and 300 watts on the roof), who use their microwave and other 120v items all the time. Too many changes/additional equipment needed for lithium, which I believe is oversold. YMMV.

Enjoy,

Perry

[Attic_Explorer]

One problem solved. 6 cup percolator!

[Civilguy]

Originally Posted by Attic_Explorer

My thoughts exactly! I should have mentioned, though, my wife will not abide by drip coffee. Hence, the percolator.

Thank you!

I have been reading about these lithium-battery, MPPT controller, DC-DC charger implementations, followed at times by appliance control-board replacements and modifications to limit over-voltage, and now I finally understand the driving force behind these conversions...

It's the coffee!

[Attic_Explorer]

Originally Posted by Civilguy

Thank you!

I have been reading about these lithium-battery, MPPT controller, DC-DC charger implementations, followed at times by appliance control-board replacements and modifications to limit over-voltage, and now I finally understand the driving force behind these conversions...

It's the coffee!

HA! Yeah, alot of time and effort to sit outside and have a hot coffee in the morning and a cold beer in the evening.

[alanmalk]

Originally Posted by Attic_Explorer

HA! Yeah, alot of time and effort to sit outside and have a hot coffee in the morning and a cold beer in the evening.

No, you are missing the point entirely.

Its the ice cream.

[Mike G]

Originally Posted by alanmalk

No, you are missing the point entirely.

Its the ice cream.

Yep. I'll be right over.

[Scambo1]

Ive built several solar setups both lead acid and lithium.

My take on what you are trying to do…

Our 5.0 ta has escapes solar package. When we got the camper, I was certain I was going to upgrade to a lot more battery (storage). However after boondocking mostly with the camper, we have found the setup to be completely sufficient for coffee pot and microwave needs. Adding batteries, however, is simple.

When we get back from camping, as part of my storage checklist, I turn off the inverter using the on off switch on the inverter. It is accessible through the dinette seat and from the outside access door.

Im in the process of compiling another solar setup for a cabin we are building on a river property we own. Im using lead acid. Its the economical solution.