Critique my solar charger/battery monitor setup?

[Bayou Boy]

The solar will do a good job is there is sun. But there isn't always sun, especially in the shoulder seasons, or in the far north. Sometimes you need a bit of a boost, and 20A from a short idle can be a big deal.

You would be hard pressed to get even 10A through a 8 or 6AWG run over that distance. Especially with connectors etc.

Hopefully he will test the converter well. Assuming he doesn't run the unit at the max output, it could live a long life. I have used many products in that price range with good results. Just take the ratings as the max, not the continuous. If it does fail, he can source a better unit. Or just revert to the previous wiring scheme.

Have you tested that? I bet not.

I see 30+ amps at idle through 6awg and Anderson connectors with my Ram and 5th wheel.


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[luthj]

Have you tested that? I bet not.

I see 30+ amps at idle through 6awg and Anderson connectors with my Ram and 5th wheel.


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Have you tested on the OPs config and vehicle? I bet not. /sarcasm


For how long though? And at what SOC? With what sized battery bank? Whats your alternator voltage? There are lots of variables, and any of them can drastically reduce charge rates.

30A for ~10 minutes at 20% SOC which tapers to 15A thereafter will still be slower overall.

Lead batteries are very sensitive to charge voltage with regards to current rates. 0.1V can nearly double the rate in some cases. I am guessing your ram outputs around 14.4V at the alternator. Not all vehicles do this, and most will drop 0.1-0.2V once the alternator is hot.


Going DC-DC removes all of this from the equation.


I think part of the disconnect is that I am talking about average currents (over 30-60 minutes) while you may be talking about peak currents. Kinda like the MPG discussions where folks talk about fuelly records, and some are talking about their best tank.

 

[john61ct]

On some setups it’ll only be 15 or 20 amp hours. I’ve watched it on actual shunt based monitors on multiple campers.

Obviously I'm not talking about replicating a silly setup like that, those issues need to be resolved.

My point is, put the focus on doing that, not much of a challenge getting plenty of amps at the right voltage from a 200A alternator to the posts of the bank at the right voltage.

Ignoring the solar for now frees up plenty of budget for that.

 

[Bayou Boy]

Obviously I'm not talking about replicating a silly setup like that, those issues need to be resolved.

My point is, put the focus on doing that, not much of a challenge getting plenty of amps at the right voltage from a 200A alternator to the posts of the bank at the right voltage.

Ignoring the solar for now frees up plenty of budget for that.

Gotcha. We are on the same page then.


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[john61ct]

Why are we arguing over wire gauge?

Even if you need 1/0 or higher, just do that!

It's not a subjective decision, plug the numbers into Blue Sea Circuit Wizard and voila.

Putting in **solar** for a once off **road trip** to Alaska fer Chrissakes makes no sense **at all**!

Unless OP says that's what they want for future off grid staying put.

Meantime the alternator sourcing needs doing anyway, provides 20times the energy much more reliably with much less futzing around.

Let's get back to making that work not waste time arguing things that are obvious.

 

[Alloy]

Why are we arguing over wire gauge?

Even if you need 1/0 or higher, just do that!

It's not a subjective decision, plug the numbers into Blue Sea Circuit Wizard and voila.

Putting in **solar** for a once off **road trip** to Alaska fer Chrissakes makes no sense **at all**!

Unless OP says that's what they want for future off grid staying put.

Meantime the alternator sourcing needs doing anyway, provides 20times the energy much more reliably with much less futzing around.

Let's get back to making that work not waste time arguing things that are obvious.

The OP did say that there will be trips once they get there which is why solar would be bennificail and from our experice a 2nd way of charging to back up the solar. Idling the truck or a cheap generator its the OP choice....but I'd be carrying a 2nd 12-36 offshore converter.

 

[john61ct]

To be clear, I don't see solar as needed at all here, certainly not "primary" in an Alaskan winter without spending megabucks or drastically cutting Ah/day consumption.

Yes of course if OP thinks they need off-grid stay-put living capability beyond the alternator charging rig, NP

but I infer the road trip is the priority with living off mains input once they get there.

If not, and off-grid stay-put living capability is desired now not just the road trip

**then** solar is needed, but won't be sufficient.

Idling the truck is not as good as a small inverter genset, and both really would benefit from thousand$ more spent on LFP.

But let's get the road trip settled, relying on drivetime for 100% of input is an easy and relatively inexpensive issue to solve, requires no compromises for energy efficiency or reducing consumption.

I'd be carrying a 2nd 12-36 offshore converter.

Haven't even looked at that level of detail yet, best IMO to settle the broad brush strokes first.

 

[Buddha.]

To be clear, I don't see solar as needed at all here, certainly not "primary" in an Alaskan winter without spending megabucks or drastically cutting Ah/day consumption.

Summer*

 

[Buddha.]

What is the rating of your solar charger? If its rated for ~30A output, then you should be fine with the 36V supply at 540W. I would feel comfortable pulling ~350W from that unit.

Do you have a generator? If so, a 30A shore power charger could be a good backup. For just a few weeks of traveling, you should be fine. I would suggest doing a bit of testing to see how much power the heater uses to keep the unit warm.

My solar charger is rated 30 amps and 100volts.
"~350w" I can limit what the solar charger pulls? How do I do that?
I have a 3000w Yamaha inverter generator that I can use if needed. I was trying to limit it's use. We've stayed at some national parks where generators aren't allowed.
Yes I plan on testing.

 

[luthj]

Some solar controllers allow you to specific an output limit (other than your max). I don't recall what controller you are using though. If you have that option, I would set the max output to 25A, just to give you a bit of margin. Worst case it doesn't work, and you have to take another approach.

 

[Buddha.]

If the converter is a WAFCO it is a pcs of junk. It's a power supply not a battery charger. When on shore power it is best to disconnect the batteries or the WAFCO will ruin the batteries

The wire from the main breaker/disconnect to the batteries needs to be size for combined input of the converter and the solar controller.

The converter I have is the Progressive dynamics PD9160A.
"Once the battery reaches 90% of full charge, the Charge Wizardautomatically selects the NORMAL Mode (13.6V) to safely complete the charge. The STORAGE Mode (13.2V) is automatically selected after 30 hours of non-use of the 12-volt RV electrical systems. The lower charging voltage in the STORAGE Mode of operation reduces battery gassing and water usage, while maintaining the charge. Every 21 hours when the system is operating in the STORAGE Mode, the Charge Wizard will automatically switch to the EQUALIZATION Mode of operation. The EQUALIZATION Mode increases the charging voltage up to 14.4 volts for 15 minutes. This increased voltage mixes up the battery electrolyte and prevents battery stratification and the resulting problems of battery sulfation."

 

[luthj]

Another option is to get a small inverter, and run an extension cord to your converter/charger. That would get the job done as well, just need to take a bit more care with the 120V runs.

 

[john61ct]

Not every SC will handle non-panel inputs.

I know Victron MPPT Smartsolar are very often used this way as DCDC converters, and have excellent monitoring/logging capabilities you can view from a smartphone over BT.

 

[Buddha.]

Some solar controllers allow you to specific an output limit (other than your max). I don't recall what controller you are using though. If you have that option, I would set the max output to 25A, just to give you a bit of margin. Worst case it doesn't work, and you have to take another approach.

Victron smart solar 100/30. 100v/30a.

 

[Buddha.]

Another option is to get a small inverter, and run an extension cord to your converter/charger. That would get the job done as well, just need to take a bit more care with the 120V runs.

You're talking about putting an inverter on the tow rig and run a 120v extension cord back to my factory installed converter/charger? Would I mount the inverter under the hood? What size ~500w?