Power System for Winter Use

[SteevsyWeevsy92]

I'm currently building out a Ford transit, 2020, Heavy Duty Alternator (250a), dual AGM starter batteries and 300ah of Lithium for the house. The the goal is to make it a pretty bomber winter rig. We will be spending lots of time in very snowy places and at high enough latitudes that solar just won't always do it, so I'm looking at adding the alternator to the equation. Ive done extensive research and I've gotten to where I understand there's no exact right answer, so I need to try to clarify my understanding of some things so I know I'm weighing the options properly, and I'm also hoping someone out there has some real world experience with a similar rig to share. Im gonna try to be concise, apologies if it becomes a novel. One note, up until very recently I thought I just about had it figured out but I fell down a rabbit hole once I discovered some options that I hadn't really seen before, (its easy to get bogged down in van blogs but now those feel suspiciously too much like an echo chamber), but the one part of the system I have already purchased is 3 100ahr lithium (ie 300ahr total, planning to wire in parallel) batteries from Renogy on Black Friday. Im still happy with that purchase, but regardless its what I have to work with on this one so the battery part of the equation is already spoken for.

-As mentioned, we can't count on solar at least 6 months out of the year. that being said, we would like the system to default to solar if possible to save wear on the alternator (is that actually a valid concern), and were hoping in the summer that we can pretty much bank on solar alone. Ultimately we will have to see how our energy consumption shakes out in real world use, but from ive estimated we shouldn't have a problem staying well below 100ah a day, and I would think the majority of the time we will be under 70. We are most likely doing propane cooking, an Espar, and the occasional phone/laptop/camera charge, and we like the domestic duel zone electric cooler, probably the 95 variant. but we don't plan to have any super power hungry appliances. we are looking to over-build the system a bit so there's some wiggle room to add more things if we realize we need/want them, or so that when we feel we need to, we can stretch 300amp hours as far as possible, hence the big (for our purposes) battery bank. Were probably looking at 350-400 watts of solar on the roof via two panels.

-We have a 250a alternator, I haven't had the easiest time finding the specs but from what Ive read, according to people who have measured it seems to have a voltage range between 14.4 and 15.5 depending on what's happening when the measurement is taken, according to the BEMM it has a voltage range of 13.1 to 14.1 (output output performance) depending on the temperature. Whats the reason for this discrepancy? My lack of understanding probably...

-We'd like to get the most of alternator charging without running the risk of overdraw. It seems like most DC-DC chargers out there are either in the 30-60a range, which seems like it would leave some power on the floor, or 120+, which seems like it could be pushing the boundaries. We plan to wire the batteries in parallel, which would mean the max they should get (on paper) is 150a according to the documentation. Is it correct, however, that in a proper charge cycle you wouldn't actually be giving the batteries the top end of the charging capability for the majority of the charge time? in other words, at what point if any do we see diminishing returns (in terms of speed to 100% SOC) from a higher amp charging system?

-Do I need a DC-DC in the first place? it seems like the voltage is variable with the alternator which has me thinking DC-DC would be a safe bet. While charge efficiency is a top priority, it doesn't trump reliability/safety, from what ive read DC-DC may be better for the batteries long term than an ACR or some other relay based system, so if we have to lose out on some power for solid reliability were okay going that route, if my understanding of this is correct. just want to make sure im on the right track with that.

- Ive come across REDARK, their technology is appealing to me because of its record for durability/water proofing, We will be spending a lot of time in very wet places, wetness could happen and while we'll obviously do everything in our power to mitigate, I like the idea of equipment that can take something of a beating. Specifically ive been looking at the 50a Dual input BCDC charger with the built in MPPT charger. I know there are trade offs to not putting the system together in piecemeal, especially redundancy if one part fails, but they seen to have a reliable track record and I like the compactness/simplicity. Im also a big fan of the bias towards solar when available. Is 50a going to be adequate/provide a good speed to 100% SOC based on our predicted needs/system?

-Sterling seems to be the reigning king in this realm, is this for good reason? Is it possible to set those up in a way where if the batteries can charge from solar, they will? in other words a diy version of what the REDARK does.

Thanks in advance, we will be very grateful if anyone can shed some light on this stuff.

 

[DiploStrat]

You are opening a can of worms here ...

But I'll play.

-- Winter is a challenge due to cold and lack of sun. A week of clouds can be a killer. While I use an induction cooktop, for extended cold weather use a diesel stove (you can run from a dedicated kerosene tank) may be a better option as it will spare your batteries a bit.
-- Building today, I would go straight to lithium iron for all of the obvious reasons. For winter use, I would simply mount the batteries inside the heated area.
-- Build serious heat, ideally diesel, kerosene, or gasoline. (And learn how to keep your unit from sooting up.)
-- While I LOVE relay based systems, with lithium you probably need a battery to battery charger (DC-DC or B2B). REDARC and Sterling each have their advantages. john61ct extols the virtues of Sterling and I use REDARC.
-- While I do have a solar panel attached to my REDARC, for serious winter use, you will want a separate solar controller - that way the output of your alternator and the sun are additive. Remember, the REDARC never produces more than its rated output, it just takes from the solar first. So most of my panels are on a separate controller. If you use lead acid batteries, make sure that your solar controller does a full absorb stage - 30-60 minutes per 100Ah of battery.
-- Conventional wisdom is that MPPT, especially with the panels in series, is best for cold weather.

EDITED TO ADD: Most of those who claim that solar is not worth it have never installed solar. Most of those with any solar at all want more.

Hope this is hopeful; I believe it all to be accurate.

 

[spressomon]

I have been using the Sterling BB1260 for the past 18 months and like it overall. A couple of little gripes: The menu "system" is cumbersome and I wish they had a BT app to make monitoring and programming simpler (I'm spoiled by Victron's BT app). Just about the time I get familiar, again, with operating/knowing the programming menu...enough time passes and I have to dig out the manual again. The second little nit has to do with the wire connects/clamps. I'd prefer solid ring terminal connections that gives much greater flexibility and utility to wire gauge choices. Whereas their wire compression clamps are limited to 10AWG (I stuffed 8AWG in but less than ideal) and I found they loosen over time and washboard.

Other than the two nits I listed above, it seems to do its job without issue.

Solar: If you are going to rely upon solar, especially shoulder months and lower sun angle, forgetting about PNW type cloud cover for weeks on end, you really need about 2X the amount of solar as you think. I've found, overall and outside of the 3-months of higher sun angle of summer, I need about 2X more panel sq feet than I originally thought (and calculated). And now knowing from real-world experience the output ratings on most/all PV panels is from the "hope and a dream" lab. I don't think anyone complains or regrets having too much...solar.

 

[DiploStrat]

... The second little nit has to do with the wire connects/clamps. I'd prefer solid ring terminal connections that gives much greater flexibility and utility to wire gauge choices. Whereas their wire compression clamps are limited to 10AWG (I stuffed 8AWG in but less than ideal) and I found they loosen over time and washboard.
...

Consider using ferrules. One of the RV solar gurus swears by 'em. Might make it easier to jam in a bigger wire and should make for a more mechanically sound join.

Example: Amazon.com : wire ferrule kit

 

[vtsoundman]

Other great DCDC products are Kisae 1230 or 1250 and the Victron Orion isolated DCDC. (I have both of these running). The Sterling unit's interface is archaic and frankly unnecessary these days. The

Yes, you need a DCDC - it will charge the batteries faster and keep your batteries happier.

Alternator wear is a none issue - and most will run for 'life' (150k or more).

I've found that all I need solar for is to keep the batteries charged while parked in the driveway/base camping for multiple days with the fridge running. I have 640Ah in the van and a 220Ah total in the Jeep (100Ah Aux battery for everything Aux except the comms, which runs off the main 110Ah starter battery).

The Jeep runs a fridge (50Qt) and all the usual chargers/lights for several days, which is usually the longest I'm in one spot without moving. If I do stay longer, out comes some portable solar panels.

The Van has a lot more creature comforts and is good for 5 days or so on really hot (lots of a Truckfridge 130 running hard) days. I also have a microwave and water, etc...this is without solar. 640Ah in the van is total overkill, but man is it nice to not even think (or be concerned) about power regardless of how it gets used. (Like a vacuum cleaner to get all the dog hair and dirt from the kids!)

Driving for a couple of hours (or more if in the van and it is really discharged) usually handles all the recharging duties.

Couple of more things - my batteries are all LA - AGM in Jeep, Gel in Van. Van batteries are in a Alum box that is not insulated below the floor. In cold temps (0-20F), usable capacity drops by about 30%. Colder temps reduce usable capacity even more. I run a diesel heater(skip gas, too unreliable) in the van...at some point, I may consider heating or insulating the batteries IF it ever becomes an issue. Gel is affected by cold more than AGM...


Sent from my Pixel 4a using Tapatalk

 

[OllieChristopher]

EDITED TO ADD: Most of those who claim that solar is not worth it have never installed solar. Most of those with any solar at all want more.

I am in the camp that is just now starting out to be using solar. I'm so impressed with my little cheesy 35.00 solar battery maintainer I'm doing a dual battery setup with a charge controller and and start off with a 100 watt suitcase. I am blown away at how quickly solar power is advancing in efficiency and cost for the average consumer.

As to system for winter use with less sunlight I recommend a small inverter gas generator and proper charger to keep batteries filled. I think with careful consideration and conservative power usage you can keep the runtime of your generator to a minimum.

 

[Buddha.]

You need a DC-DC charger. Those lithium batteries may kill your alternator otherwise.

 

[vtsoundman]

You are opening a can of worms here ...


EDITED TO ADD: Most of those who claim that solar is not worth it have never installed solar. Most of those with any solar at all want more.

Hope this is hopeful; I believe it all to be accurate.

I can't speak to who/under what context you're referring to...

However, solar has its place...as does the size of the system. I've used solar in my rigs for years - it is all about the type of camping/travel and loads being supplied.

It really sort of curios - folks often brag about how little the batteries are discharged across a given day/night...to me it sounds like a design issue. It is really a statement about the mismatch between actual loads/usage, battery size, and solar size.

Solar allows a vehicle to run smaller batteries or remain in a single place for a long periods.

Rarely do I stay in one place long enough to justify a large solar system (or even one at all)...I would also venture that most overlanders/car campers have a similar profile. (This is likely very market specific...I don't have direct knowledge of say Australia, but would venture that there are quite a few of Starbucks style warriors there too)...

I would venture to say that most will _never_ cycle a battery to death. Most batteries will die from neglect and calendar life.

Large solar is a definitely high on the nice to have, but not quite a must have list for my electrical vehicle build out...nominal solar (enough to run a fridge/diesel heater long term) is a must have...(because I am lazy and don't want to connect a cord or empty a fridge!)

Solar is like big tires - most of the time, 31s will be just fine for 99.5% of mileage and users. Few will ever need 33s, and even fewer will need 35s...now will stop me from indulging, nope...cause it's fun.

Don't mistake fun/indulgence for need!

Sent from my Pixel 4a using Tapatalk

 

[SteevsyWeevsy92]

You are opening a can of worms here ...

But I'll play.

-- Winter is a challenge due to cold and lack of sun. A week of clouds can be a killer. While I use an induction cooktop, for extended cold weather use a diesel stove (you can run from a dedicated kerosene tank) may be a better option as it will spare your batteries a bit.
-- Building today, I would go straight to lithium iron for all of the obvious reasons. For winter use, I would simply mount the batteries inside the heated area.
-- Build serious heat, ideally diesel, kerosene, or gasoline. (And learn how to keep your unit from sooting up.)
-- While I LOVE relay based systems, with lithium you probably need a battery to battery charger (DC-DC or B2B). REDARC and Sterling each have their advantages. john61ct extols the virtues of Sterling and I use REDARC.
-- While I do have a solar panel attached to my REDARC, for serious winter use, you will want a separate solar controller - that way the output of your alternator and the sun are additive. Remember, the REDARC never produces more than its rated output, it just takes from the solar first. So most of my panels are on a separate controller. If you use lead acid batteries, make sure that your solar controller does a full absorb stage - 30-60 minutes per 100Ah of battery.
-- Conventional wisdom is that MPPT, especially with the panels in series, is best for cold weather.

EDITED TO ADD: Most of those who claim that solar is not worth it have never installed solar. Most of those with any solar at all want more.

Hope this is hopeful; I believe it all to be accurate.

It is extremely helpful, thank you! So to clarify, I could run solar through both the REDARK and a separate controller as two independent solar arrays to charge the same bank? That’s another option I hadn’t thought of but it’s intriguing. Do you need to take special precautions to avoid overloading the battery bank since there are two different controllers taking the batteries through their cycle independently, or does it all self regulate via the BMS? Forgive my ignorance is that’s a dumb question, I’m still wrapping my head around the finer technicalities of these systems.

After digging through the documentation more it seems like the redarc has a relatively low maximum solar voltage (around 32v I believe) which would make running panels in series pretty much a non-starter right? But it makes me wonder, if I had a panel (or two in parallel) on the redarc and a couple in series on a separate controller, would I be able to reap the benefits of both wiring methods? My understanding is that series would work better at higher latitudes during the winter, or at least produce a viable charge for more hours of the day assuming the panels have a clear view of the sky, but a single panel or a couple in parallel would perform better if, say there was some snow or debris, or shadow on the array. Is having both as an option worthwhile or is that getting to the point of overly complex?

 

[SteevsyWeevsy92]

I am in the camp that is just now starting out to be using solar. I'm so impressed with my little cheesy 35.00 solar battery maintainer I'm doing a dual battery setup with a charge controller and and start off with a 100 watt suitcase. I am blown away at how quickly solar power is advancing in efficiency and cost for the average consumer.

As to system for winter use with less sunlight I recommend a small inverter gas generator and proper charger to keep batteries filled. I think with careful consideration and conservative power usage you can keep the runtime of your generator to a minimum.

thanks for the reply, I can see the generator being a good call for certain scenarios, especially if we end up in the FAR north (AK, YT) in the shoulder seasons which is within the realm of possibility, I’ll be looking into that more.

 

[SteevsyWeevsy92]

Other great DCDC products are Kisae 1230 or 1250 and the Victron Orion isolated DCDC. (I have both of these running). The Sterling unit's interface is archaic and frankly unnecessary these days. The

Yes, you need a DCDC - it will charge the batteries faster and keep your batteries happier.

Alternator wear is a none issue - and most will run for 'life' (150k or more).

I've found that all I need solar for is to keep the batteries charged while parked in the driveway/base camping for multiple days with the fridge running. I have 640Ah in the van and a 220Ah total in the Jeep (100Ah Aux battery for everything Aux except the comms, which runs off the main 110Ah starter battery).

The Jeep runs a fridge (50Qt) and all the usual chargers/lights for several days, which is usually the longest I'm in one spot without moving. If I do stay longer, out comes some portable solar panels.

The Van has a lot more creature comforts and is good for 5 days or so on really hot (lots of a Truckfridge 130 running hard) days. I also have a microwave and water, etc...this is without solar. 640Ah in the van is total overkill, but man is it nice to not even think (or be concerned) about power regardless of how it gets used. (Like a vacuum cleaner to get all the dog hair and dirt from the kids!)

Driving for a couple of hours (or more if in the van and it is really discharged) usually handles all the recharging duties.

Couple of more things - my batteries are all LA - AGM in Jeep, Gel in Van. Van batteries are in a Alum box that is not insulated below the floor. In cold temps (0-20F), usable capacity drops by about 30%. Colder temps reduce usable capacity even more. I run a diesel heater(skip gas, too unreliable) in the van...at some point, I may consider heating or insulating the batteries IF it ever becomes an issue. Gel is affected by cold more than AGM...


Sent from my Pixel 4a using Tapatalk

thanks for the response! So it sounds like 50a from the alternator is probably enough to keep our battery topped off for typical day to day use if we are able to go for a drive fairly regularly, even more so if there is some solar input.

 

[SteevsyWeevsy92]

I have been using the Sterling BB1260 for the past 18 months and like it overall. A couple of little gripes: The menu "system" is cumbersome and I wish they had a BT app to make monitoring and programming simpler (I'm spoiled by Victron's BT app). Just about the time I get familiar, again, with operating/knowing the programming menu...enough time passes and I have to dig out the manual again. The second little nit has to do with the wire connects/clamps. I'd prefer solid ring terminal connections that gives much greater flexibility and utility to wire gauge choices. Whereas their wire compression clamps are limited to 10AWG (I stuffed 8AWG in but less than ideal) and I found they loosen over time and washboard.

Other than the two nits I listed above, it seems to do its job without issue.

Solar: If you are going to rely upon solar, especially shoulder months and lower sun angle, forgetting about PNW type cloud cover for weeks on end, you really need about 2X the amount of solar as you think. I've found, overall and outside of the 3-months of higher sun angle of summer, I need about 2X more panel sq feet than I originally thought (and calculated). And now knowing from real-world experience the output ratings on most/all PV panels is from the "hope and a dream" lab. I don't think anyone complains or regrets having too much...solar.

this is good feedback. I’m thinking it may not hurt to throw more panel up there than I had originally planned. Do you have a take on series vs parallel panel wiring for real world, winter time use? Both, through separate controllers? It seems like there’s no hard right or wrong with this because they both have very specific traits but I’m wondering what others have experienced.

 

[shirk]

How long will you be stationary in the winter? I am working on planning a similar winter primary system. Solar is near useless for a PNW/BC ski weekender rig.

Does the 2020 Transit have a smart alternator circuit? I am looking at doing a 48v - 12v hybrid solution in order to be able to maximize the alternator charge and to future proof my electrical system. It looks like more new vehicles are adding a 48v secondary system into them (Ram e-torque).

Charge the 48v battery via a bidirectional boost buck converter. Try and set up as many of the items to run off 48v or do point of load conversion to 12v as needed.

https://www.safiery.com/3kw-12-48v-canbus-integrated-buck-boost-power-chard

From my current research I think this is about the fastest way to recharge your lithium based house bank off the alternator.

I found this a good read.

https://www.t6forum.com/threads/guide-dc-dc-charger-for-leisure-battery-how-i-done-it.15066/

 

[DiploStrat]

It is extremely helpful, thank you! So to clarify, I could run solar through both the REDARK and a separate controller as two independent solar arrays to charge the same bank? That’s another option I hadn’t thought of but it’s intriguing. Do you need to take special precautions to avoid overloading the battery bank since there are two different controllers taking the batteries through their cycle independently, or does it all self regulate via the BMS? Forgive my ignorance is that’s a dumb question, I’m still wrapping my head around the finer technicalities of these systems.

After digging through the documentation more it seems like the redarc has a relatively low maximum solar voltage (around 32v I believe) which would make running panels in series pretty much a non-starter right? But it makes me wonder, if I had a panel (or two in parallel) on the redarc and a couple in series on a separate controller, would I be able to reap the benefits of both wiring methods? My understanding is that series would work better at higher latitudes during the winter, or at least produce a viable charge for more hours of the day assuming the panels have a clear view of the sky, but a single panel or a couple in parallel would perform better if, say there was some snow or debris, or shadow on the array. Is having both as an option worthwhile or is that getting to the point of overly complex?

Yes, you can have any number of chargers on the same bank. I have three, the alternator though a REDARC, a solar controller, and shore power. Lead acid batteries do not have BMS. Each controller measures the battery voltage and tries to meet its own criteria. Each will come on or shut off depending on its individual profile (If you look under "Documents" on my web page, you will find several slide decks which deal with all of this. You may find them helpful.)

I am a total REDARC phanboi. That said, I would not plan on using a REDARC B2B as my primary solar controller.

-- In my case, my truck came with a low quality PWM controller that was already at its maximum input.
-- I wanted the REDARC to charge a 12v battery from a 24v truck.
-- I wanted more solar.
-- Running 160w of solar through the REDARC spared my alternator a bit as it was approaching its maximum.

Sooo, adding another panel and plugging it into the REDARC was an easy fix.

But, in a clean new design, I would go with an MPPT controller that is large enough to handle all the panels that I could ever fit AND, if I were using lead acid batteries, would allow me to program a full absorb stage. E.G., Blue Sky, Victron, and others. (I would have to reread the REDARC literature to see how they handle the absorb stage.)

Part of the value of solar is that most of us never drive long enough to fully charge our batteries. Having even 100-200w of solar can go a long way towards completing the L O N G absorb stage that is so necessary to avoid partial charge and the resulting sulfation. And yes, the REDARC has a maximum voltage of 32v, which precludes its use for large series arrays. It was really designed to provide options for typical Australian rigs, e.g. Toyota Land Cruisers with smaller alternators putting out 13.9v and not a lot of room to install things.

BUT, as noted previously, building today, I would go with lithium iron batteries and a B2B, right from the start. In this case, the REDARC units are more compact, and the Sterling units are more adjustable. Sterling also makes a larger unit.

Your money - spend it wisely!

 

[SteevsyWeevsy92]

Yes, you can have any number of chargers on the same bank. I have three, the alternator though a REDARC, a solar controller, and shore power. Lead acid batteries do not have BMS. Each controller measures the battery voltage and tries to meet its own criteria. Each will come on or shut off depending on its individual profile (If you look under "Documents" on my web page, you will find several slide decks which deal with all of this. You may find them helpful.)

I am a total REDARC phanboi. That said, I would not plan on using a REDARC B2B as my primary solar controller.

-- In my case, my truck came with a low quality PWM controller that was already at its maximum input.
-- I wanted the REDARC to charge a 12v battery from a 24v truck.
-- I wanted more solar.
-- Running 160w of solar through the REDARC spared my alternator a bit as it was approaching its maximum.

Sooo, adding another panel and plugging it into the REDARC was an easy fix.

But, in a clean new design, I would go with an MPPT controller that is large enough to handle all the panels that I could ever fit AND, if I were using lead acid batteries, would allow me to program a full absorb stage. E.G., Blue Sky, Victron, and others. (I would have to reread the REDARC literature to see how they handle the absorb stage.)

Part of the value of solar is that most of us never drive long enough to fully charge our batteries. Having even 100-200w of solar can go a long way towards completing the L O N G absorb stage that is so necessary to avoid partial charge and the resulting sulfation. And yes, the REDARC has a maximum voltage of 32v, which precludes its use for large series arrays. It was really designed to provide options for typical Australian rigs, e.g. Toyota Land Cruisers with smaller alternators putting out 13.9v and not a lot of room to install things.

BUT, as noted previously, building today, I would go with lithium iron batteries and a B2B, right from the start. In this case, the REDARC units are more compact, and the Sterling units are more adjustable. Sterling also makes a larger unit.

Your money - spend it wisely!

Gotchya, thanks for running through that. I feel like the curtain has been lifted on somethings I hadn’t previously thought of as viable. I have a Lithium battery bank so your comments have reaffirmed that purchase. I’m going to hit the drawing board again with regard to my solar arrays but I’m thinking something like what you described could be the key I’m looking for. And I’m not sure what it is but I too am drawn to REDARC. I saw one in person at the local overland shop the other day and it just seems like a solid unit, and the more I’ve read about it the more I think they’re cool.