Ram Promaster Forum banner
41 - 60 of 102 Posts

·
Premium Member
Joined
·
1,542 Posts
Reading this, a past item came to my mind. Like @proeddie I am an AGM guy so I have no experience with Lithium in my vans. The past item that twigged my mind was the 14.7 volts & the Maxxair fan voltage sensitivity. I contacted the manufacturer directly & was told nothing over 14 volts.

So now I am wondering for those who have had Maxxair fan “beep of circuitboard death” occur what type of batteries are they - Lithium??

I have had 2 vans bith with Maxxair fans and AGMs and no solar (another possible source of above 14volts while charging), but so far no issues with the roof fans failing.

Good Luck with your changes @proeddie I do not have Renogy anything, but when I buy electrical equipment now I try to make sure it is compatible with 12v & 24v and FLA, AGM, & Lithium. I prefer user programable equipment where I can set the charge profiles up.
If you think about it, the max charge voltage of an AGM battery can actually easily reach 15 volts in the winter if the charging system is temperature compensated correctly, and fall well below 12 volts when under load trying to power the heater at night if the van interior is very cold. Both scenarios are kind of a pain.

This was one of the driving forces for me to build 24 volt (and higher) systems and use regulated 13 volt for the 12 volt appliances.

There are more reports of the circuit board issue happening in the "auto turn on" versions of the fans then in the more simplistic models if that helps any.
 

·
Registered
2019 Promaster 3500 Silver high top 159"
Joined
·
606 Posts
The manual doesn't say anything about a fuse on the small red wire... is that the shunt's power lead to which you are referring?
I was being somewhat tongue in cheek. All the talk of protection would dictate that a power lead connect to the battery should be protected at the battery terminal.

The logic the dictates a 200 amp fuse at the battery terminal to protect the 2/0 wire should apply to the 16 gauge wire powering the shunt electronics.

Tongue and cheek because I'm the guy who doesn't put fuses or protection on wires so that I feel are sufficiently protected against accidental shorts.

Edit: our messages crossed in the airwaves. There is a fuse. But not at the battery terminal somewhere in the middle.
 

·
Registered
Van #2 2021 EXT
Joined
·
4,830 Posts
If you think about it, the max charge voltage of an AGM battery can actually easily reach 15 volts in the winter if the charging system is temperature compensated correctly, and fall well below 12 volts when under load trying to power the heater at night if the van interior is very cold. Both scenarios are kind of a pain.

This was one of the driving forces for me to build 24 volt (and higher) systems and use regulated 13 volt for the 12 volt appliances.

There are more reports of the circuit board issue happening in the "auto turn on" versions of the fans then in the more simplistic models if that helps any.
That helps 👍

I never use the “auto turn on”

Maxxair were very interested in knowing if I had solar. IIRC the voltage parameters they told me were between 10.6v & 14.0v.

My Rolls AGMs work out to 24mv per C temperature off the standard 25C

My Van AGMs see above 14v when charging from the PM alternator (direct cable from the started battery). I almos exclusively charge my van AGMs by alternator. Fully charged & a rest & disconnected from the van alternator I would expect them to sit around 13v.

I have thought about it in regards to the Maxxair & above 14v of the van alternator & I cncluded it would ge a very weird operation for me to be driving down the highway alternator charging with the Maxxair fan hood up with the fan turned on & running. 😳. It is possible, I just do not use my van/fan in this manner.

Thus I concluded, why Maxxair asked me about “solar” - which I do not have on my van. If I had solar & the magic of set it & forget it I can totally see running my Maxxair & the solar “kicking in” @ 14.7volts. And then the systems voltage is over the 14v max while the Maxxair fan is running.

I’m a believer in the 24v system and converter to run 12v 😁. I currently am doing ok with the 12v setups I have, but if buying electrical components now the 12v or 24v (like the Victron MPPT controlled is user set & capable of both) are more attractive to me as are equipment that is user programable that can handle all types of battery chemistries. This way if I am in @proeddie position of swapping things out I can keep my “multi voltage or chemistry” equipment. I think the key is in user programable.

It is why I like the Kisae DMT1250. I believe @GaryBIS purchased one of these

 

·
Premium Member
Joined
·
1,542 Posts
That helps 👍

I never use the “auto turn on”

Maxxair were very interested in knowing if I had solar. IIRC the voltage parameters they told me were between 10.6v & 14.0v.

My Rolls AGMs work out to 24mv per C temperature off the standard 25C

My Van AGMs see above 14v when charging from the PM alternator (direct cable from the started battery). I almos exclusively charge my van AGMs by alternator. Fully charged & a rest & disconnected from the van alternator I would expect them to sit around 13v.

I have thought about it in regards to the Maxxair & above 14v of the van alternator & I cncluded it would ge a very weird operation for me to be driving down the highway alternator charging with the Maxxair fan hood up with the fan turned on & running. 😳. It is possible, I just do not use my van/fan in this manner.

Thus I concluded, why Maxxair asked me about “solar” - which I do not have on my van. If I had solar & the magic of set it & forget it I can totally see running my Maxxair & the solar “kicking in” @ 14.7volts. And then the systems voltage is over the 14v max while the Maxxair fan is running.

I’m a believer in the 24v system and converter to run 12v 😁. I currently am doing ok with the 12v setups I have, but if buying electrical components now the 12v or 24v (like the Victron MPPT controlled is user set & capable of both) are more attractive to me as are equipment that is user programable that can handle all types of battery chemistries. This way if I am in @proeddie position of swapping things out I can keep my “multi voltage or chemistry” equipment. I think the key is in user programable.

It is why I like the Kisae DMT1250. I believe @GaryBIS purchased one of these

AFAIK, it does not matter if you use the "auto turn on" feature or not, what matters is that the circuit board used in that version of the fan is more sensitive to higher voltages than the lesser version.

It could also be as simple as voltage spikes caused by people who are connecting / disconnecting substantial loads from 12 volt systems without sufficient buffer. (batteries)

User programmability is very useful, but if fully charging a battery is important, then under charging to accommodate a fan that seems - like dealing with a spoiled brat.

Can you think of any other mechanical or electrical item used in a van that is being operated beyond the max of it's spec routinely? It is not so different than someone trying to run an 1800 watt blow dryer off of a 1500 watt inverter, using one battery and wondering why sometimes it shuts down.
 

·
Premium Member
Joined
·
1,542 Posts
My Rolls AGMs work out to 24mv per C temperature off the standard 25C

My Van AGMs see above 14v when charging from the PM alternator (direct cable from the started battery). I almos exclusively charge my van AGMs by alternator. Fully charged & a rest & disconnected from the van alternator I would expect them to sit around 13v.
( -30 C) is a common winter temperature in Canada and many parts of the US.

(55 C) x ( 24 mv) ~ 1.3 volts over the spec charge parameters at 25 C.

That puts many AGM and FLA batteries above 15 volt charge voltage peaks.

As far as the fan guys - they are probably just looking for a reason to cut off your warranty.

____

Example - I had a local sprinter owner call me on Saturday morning (Memorial day weekend ) with an electrical problem - 12 volt fridge would not run for more than 8 hrs.

He told me that while the van builder offered a 2 year warranty, he wasn't available to do any warranty work for a few months. :cautious:

I didn't feel like mowing the yard, so I had him come to the house after lunch.

We checked everything out, including making sure that one of the 2 Lifelines Battle born LiFe batteries wired in parallel had not tripped a BMS.

Most of it looked fine except for some reason a lot of the 12 volt (+) was 12 awg and the black was 14 awg - plus some long runs.

We ran a dedicated 10 awg wire pair from the fuse block to the fridge and I showed him how to crimp on pro grade, panduit terminals so that he can really understand his system. The wiring that I added is all military spec, as are the connectors and heat shrink.

Fridge has run great ever since, zero issues, and he is happy. For the first time, he really understand what the components are and how it all works.
__

I called up the shop owner that did the build on Tuesday, told him that his setup looked great and offered to do some work for him in the future if he wanted.

His response - since the electrical system had been "changed", the warranty was now void. :rolleyes:

I tried to explain what I did and how - finally just hung up on him.

In my mind - it is similar - people just trying to get out of warranty for every possible reason.
 

·
Registered
2018 3500 EXT Camper Conversion in CT (TX for now due to Covid)
Joined
·
1,258 Posts
I have multiple Maxxair fans. I only charge my lithium batteries with 14.2 volts through the solar controller, inverter, and battery to battery charger. By the time the power goes through the circuit breaker panel, wiring, terminals, etc, I am pretty sure my maxxair fan never sees over 14 volts.

I think that one more way controlled battery to battery charging is better than having an alternator charging relay. Some electronics are sensitive.
 

·
Registered
Joined
·
16 Posts
Check eBay as well as Prime. My best deals on Renogy were via eBay. Amazon for most of the other stuff (or if I needed the part yesterday).

I went all Renogy (not the solar panels) and regret picking the inverter/charger since I rarely use shore power. I don't regret going with 2kw inverter as I don't use propane. I slightly regret not going with a third battery and 3kw, but in practice 2kw does it all including running my power tools as I built out the van.

A single 200ah lithium (not Renogy) might be cheaper that 3xAGM and a whole lot easier to wire and stash somewhere in your van.

W/regard to parallel vs. series, do a little more research on the internet, maybe pay a visit to "Diysolar.com"

Finally, that combo Renogy charge controller will float charge the service batteries when the house is full. But you are right, it does cut the alternator current 50% when solar is present. Easy enough to bypass with a relay on the solar feed in. You say you will be driving a lot and then staying put for 2+ days. Seems like the combo will work fine for you if 50A output were sufficient for your needs.
Thanks!

I have checked eBay too. So far only one potential “deal” (I want to avoid refurbished units, and simply saving a few bucks makes me uncomfortable as we are talking about rather sophisticated electronics).

It might turn out otherwise, but I do anticipate having access to shore power a reasonable percentage of the time, so I want the flexibility to have a charger.

I have looked at 200ah lithium batteries, but I can get 3 Renogy 100ah AGMs for less money, unless I take a risk with a lesser known brand (which I don’t want to do). Yes, I know this means 150 vs effectively 180 usable amp hours, but 150 is plenty for my needs (no power tools, microwave, induction cooktop, etc.). In addition, like I said, I’d have to upside the inverter/charger to support Li batteries, which would offset any cost savings…or, I’d have to sacrifice the charger capability, which I don’t want to do. Yes, I know I could go with a non-Renogy charger unit, but I don’t want to “engineer“ this configuration, and I’d rather stay with all Renogy products. Bottom line, as I said, 3 100ah AGMs is not at all an issue for me given how I plan to use the van.

Thanks for the link. I have looked at this site.

Unless I’m missing something, I don’t see a need to float charge the service (van) battery. And, it doesn’t make sense to me to isolate the solar panels. If anything, I’d rather have the ability to isolate the DC-DC charger in situations where the alternator is being taxed (stop & go traffic, AC running on high, etc) or when house batteries are topped off. As such, I plan to put a switch in the D+ circuit for this. I may also do same for LC wire, if I even run that (not sure yet if I see value in this).

Thanks again!
 

·
Registered
Joined
·
16 Posts
Current options are the Renogy 20A plug in charger (cut off the clips and use lugs), the Powermax PM4 55A
Hmmm….food for thought! I previously stated I didn’t want to “engineer” system with separate charger, but the Renogy option might work. Cost would only be slightly more if I went with 1 or 2 Li batteries (and a standard inverter), but overall might be a good option.

Question: how would the system handle the AC current? I assume the higher voltage would “win”, correct? Any other issues/concerns?
 

·
Registered
2014-159 HR in CT
Joined
·
4,355 Posts
Discussion Starter · #52 ·
At this point I have most of my setup planned out. The only item under consideration is the shore power charger...

It seems like it will be a less-needed component on the charging side, with a 40A B2B doing most of the charging. I haven't had lithiums before but it seems like I won't be plugging in to shore power at home as often as I did with the AGMs (although I did plug in if I wasn't taking the van out for a few days, which I believe gave me over 6 years out of my AGMs)

So I'm thinking, maybe a simple Renogy 20A AC charger will suffice when I plug in. Worst case, if 300Ah of lithiums are down to 20% (down 240Ah), it would only take 12 hours to fill 'em up. So at a CG overnight tthey'll be back to full in the morning.

Other option would be a fixed voltage 55A Powermax Lithium converter/charger. I have the AGM version now but it has no setting for LI batteries.

Decisions...

Mr B, I think the LC wire would be useful to limit the load when in traffic, idling, etc...

I am amazed that the most power hungry unit in the van is the dual cooling fan, rated at 65A, which are often on in stop and go and idling situations...
 

·
Registered
2014-159 HR in CT
Joined
·
4,355 Posts
Discussion Starter · #53 ·
Hmmm….food for thought! I previously stated I didn’t want to “engineer” system with separate charger, but the Renogy option might work. Cost would only be slightly more if I went with 1 or 2 Li batteries (and a standard inverter), but overall might be a good option.

Question: how would the system handle the AC current? I assume the higher voltage would “win”, correct? Any other issues/concerns?
I used a non Pure Sine Wave (Harbor Freight 2000W) inverter for 6 years... microwave was a bit noisy but worked fine.. Keurig coffeemaker was happy, induction cooktop was a no-go (but I usually use butane).

On this rebuild, I'm thinking a PSW inverter for some other more electronic low power AC loads, so I'm switching from the MSW inverter (which work great for most items).

Not sure about your high voltage would win comment...

As far as batteries, The Renogy 100Ah Bluetooth batteries are on sale at $499 plus another 5% off... 100Ah AGMs are about $300... (They were $150 when I got mine in 2015)
 

·
Registered
2014-159 HR in CT
Joined
·
4,355 Posts
Discussion Starter · #56 ·
WillProwse coupon code gives you 10% off renogy batteries.
I could find no way to get 10% off with the willprowse coupon codes... I did see 5% at one point, currently no willprowse discount apples (maybe because it's on sale (up from $499 to $519))
 

·
Registered
Joined
·
3,354 Posts
That’s what I was thinking. Easy enough to wire up while I’m at it, and it gives me another option with an extra switch (100%, 50% & 0% output).
Yes, installing switches on both D+ and LC wires gives you max control, which is always a good thing. I did that to mine and I use them both.
 
41 - 60 of 102 Posts
Top