Lithium batteries and alternator protection.

[N6WT]

The six 6 volt lead-acid house batteries in my class A DP have gone bad. I am looking to replace them with 6 Battleborn 100Ah 12v LiFePO batteries. Eventually I will be adding solar.

I am not looking for recommendations on what batteries and components to buy, I have made up my mind so please don't try and change it.

The reason for this post is, I am reading that in class A motorhome when you switch batteries you should install a DC to DC charger to protect the alternator of the motorhome from overheating. I would like to know if anyone here has done this to their motorhome, what did you use to do it and where inline did you install it?

[otrfun]

Tom/Barb wrote:

otrfun wrote:

Bottom line, if you don't know the voltage/current readings at all your critical I/O points, then you haven't accomplished the minimum due diligence necessary to determine whether your system is truly operating as designed or not.

It's all on my iPad./phone. (Bluetooth)

Care to share all the voltage/current readings (battery/alternator, charger input, charger output, and battery terminals) for your Victron dc2dc charger install. Charger output current/voltage readings alone reveal very little.

[LittleBill]

deltabravo wrote:
I went with a Victron Orion TR Smart 12-12-30 DC to DC Charger. It was much smaller than the Renogy unit I first bought and was going to install. With the Victron unit, I can control and monitor it with the Victron Connect app.

Here's a video of the project.

do you have a side by side of the two?

[deltabravo]

I went with a Victron Orion TR Smart 12-12-30 DC to DC Charger. It was much smaller than the Renogy unit I first bought and was going to install. With the Victron unit, I can control and monitor it with the Victron Connect app.

Here's a video of the project.

[Tom_M1]

time2roll wrote:

Tom_M wrote:
I have had my Renogy 170ah lithium battery for 2 years and have had no issues with it hooked directly to the alternator.

Any chance a measurement of the charging amps was noted? Please post if available.

Had a couple of days of clouds and rain and battery shut down on me so decided to check while charging from alternator.

I'm measuring current with clamp meter at battery. When battery isolator kicked in, current started at 100 amps and within 10 seconds started ramping down. After about 5 minutes the current was down to about 30 amps and dropped down to about 15 amps after 15 minutes.

I couldn't easily get to the alternator feed so the initial current surge may have come from my chassis battery. Engine was running at idle.

[3_tons]

The smart alternator feature is intended to save fuel by allowing your engine starting battery to achieve only about 80% of it’s full capacity…In most cases this amount is quite sufficient for engine starting, and is achieved by the premature lowering of it’s output voltage, thus the ‘potential need’ (post evaluation…) for a dc-to-dc charger to provide continuous, regulated current and voltage (to prevent alternator overload) to the house battery…

3 tons

[N6WT]

N6WT wrote:
The reason for this post is, I am reading that in class A motorhome when you switch batteries you should install a DC to DC charger to protect the alternator of the motorhome from overheating. I would like to know if anyone here has done this to their motorhome, what did you use to do it and where inline did you install it?

This was my original question. I have learned I am going to use a DC to DC charger(probably Victron). It is recommended by the battery maker. I just need to figure out where I am going to put it.

[Tom_Barb]

BFL13 wrote:
otrfun, this is his approach:

"....save the opinions for some one who wants to do the engineering, ,Victron already has done it."

Meanwhile we don't know what the OP has learned from all this, if anything.

the one thing that the OP can glean from all is simple.

choose good equipment, follow the manufacturers directions.

That is what I did, and it has worked for me. not what some yahoo internet provider with a better theory.

[BFL13]

otrfun, this is his approach:

"....save the opinions for some one who wants to do the engineering, ,Victron already has done it."

Meanwhile we don't know what the OP has learned from all this, if anything.

[StirCrazy]

S Davis wrote:

theoldwizard1 wrote:

CA Traveler wrote:
Also 13.2V would not be a issue for me as it indicates a charged battery and the alternator is only supplying chassis and converter loads. A higher voltage indicates the chassis battery is drawing amps so at least the DC-DC converter has less conversion losses.

Almost all vehicles for the past 15-20 years or so, use some kind of a smart charging system. The voltage from the alternator is controlled by the engine computer and can vary over a wide range.

Not on 2009, 2013, 2019 GM 2500HD diesels, my last three trucks all have had steady voltage at about 14.2 no matter what. They must be in the almost none category.

One of my Redarc 50 amp chargers pulls 50 amps from the alternator and output is about 46 amps to the batteries, so on Redarc it looks like the rating is what is pulled from the alternator.

Im not sure when GM started doing it but your 2013 and 2019 should have smart altanators, but may not. you would have to look for the shunt as GM did it differently and it should be part of your negitive batery post atachment.

GM uses a shunt system whil ford uses a two wire bus.. as well other things might be different as in the voltage setting and such but ventualy when your battery is full in your truck and if your not using a ton of other power hungry stuff it will go down to a maintance voltage. this is to both give longer life to the altanator and the batteries. as for dc to dc chargers a lot of the input output power descrepencies are from wire size also.

[Tom_Barb]

otrfun wrote:

Bottom line, if you don't know the voltage/current readings at all your critical I/O points, then you haven't accomplished the minimum due diligence necessary to determine whether your system is truly operating as designed or not.

It's all on my iPad./phone. (Bluetooth)

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwj-7MyJ58b2AhX7JDQIHb5uDKQQFnoECAMQAQ&url=https%3A%2F%2Fwww.victronenergy.com%2Fpanel-systems-remote-monitoring%2Fvictronconnect&usg=AOvVaw2mNjx7W6V9flhROLTVvOrP

[otrfun]

Tom/Barb wrote:

otrfun wrote:
You haven't been particularly forthcoming with the current/voltage at your battery/alternator, charger input, charger output, and battery terminals. Having this information clarifies exactly you're Victron is doing---no smokescreens. The hundred dollar question: is your charging current purposely limited based on the use of lower charging voltages, or is your charging current limited due to excessive voltage drop due to undersized wiring?

As for high duty cycles, we've pulled the maximum rated charge current from our 40a Renogy dc to dc charger for up to 3-4 hours at a time, at least 50 times over the last year, with zero issues. Renogy is far from an upper-tier product like Victron. I would suspect you'd have zero issues doing the same with your Victron.

my questions/answers are directed to the Victron 12-12 30 DCtoDC charger.

The main inverter/charger in the coach is a Victron 3000W wired to a 50 AMP chord plugged into our house or camp ground post.
Managed by a 50 amp progressive Electrical management system.

Not sure if you're trying to be obtuse, or your reply was meant for another post.

Bottom line, if you don't know the voltage/current readings at all your critical I/O points, then you haven't accomplished the minimum due diligence necessary to determine whether your system is truly operating as designed or not.

[Tom_Barb]

otrfun wrote:
You haven't been particularly forthcoming with the current/voltage at your battery/alternator, charger input, charger output, and battery terminals. Having this information clarifies exactly you're Victron is doing---no smokescreens. The hundred dollar question: is your charging current purposely limited based on the use of lower charging voltages, or is your charging current limited due to excessive voltage drop due to undersized wiring?

As for high duty cycles, we've pulled the maximum rated charge current from our 40a Renogy dc to dc charger for up to 3-4 hours at a time, at least 50 times over the last year, with zero issues. Renogy is far from an upper-tier product like Victron. I would suspect you'd have zero issues doing the same with your Victron.

my questions/answers are directed to the Victron 12-12 30 DCtoDC charger.

The main inverter/charger in the coach is a Victron 3000W wired to a 50 AMP chord plugged into our house or camp ground post.
Managed by a 50 amp progressive Electrical management system.

[Tom_Barb]

CA Traveler wrote:
OK Apparentlly you choose to set the unit to 20A output so no need for further comment on that subject.

With 400AH batteries and 380AH usable I would definitely set the limit to the max provided there was not a alternator or wiring issue. For my MH there would have to be a very significant house DC usage before a 30A+ draw would be a concern.

So yes I would operate the unit at max at times. For me the pros of getting the battery fully charged initially or for short runs would be the deciding factor.

I respect what you choose to do and I think that I better understand your posts.

Cheers

We usually run 8 hour days when traveling so why charge at a high rate.

Alternator heat was a primary reason for the thread. (High amperage = higher heat)
(note) when traveling both of us are up front, house/couch power is very low. most all electronics are running on 12 vdc chassis power. the only inverted power would be the freezer. the couch refer would be running LP gas.
This is why I choose to set the DC-DC charger at a low setting, the engine alternator is providing 90 %.. so we simply don't need it.

[BFL13]

time2roll wrote:
OK to delete all the search, tracking, referral and marketing codes after the "?" question mark.

https://www.amazon.com/Orion-Tr-12-30A-Isolated-Charger-Booster/dp/B07ZKG396Y/ref=sxin_15_pa_sp_sear...

So they have isolating and non-isolating ones.

https://www.victronenergy.com/dc-dc-converters/orion-tr-smart-non-isolated

[otrfun]

Tom/Barb wrote:

CA Traveler wrote:
Tom/Barb From the Victron specs it does not have the ability to display amps. Did you determine the 20A from say a battery monitor? Then the Victron could be supplying 10A to house loads plus 20A to the battery or 30A on it's output. This is how charging systems work - amps supply house loads and what is left charges the battery.

Your 30A unit is spec'd for 30A output not input. I didn't read the manuals but wondering if it can be downgraded to 20A. The voltage can be adjusted and that could reduce the amps.

At 10% efficiency your unit would draw 33A on the input at 36A for 20%. However the unit can be wired (and should be) to sense the actual battery voltage (both batteries). That means that wiring losses are a factor and the input amps could be larger drawing more input amps but IF your wiring (size and length) is per Victrons specs then wiring losses would be limited.

Just trying to see if we can get a better understanding of your system.

You can set any parameters you like, would you operate your equipment at max capacity at times?
Just because you can, should you?
when I installed my Victron equipment I was in contact with the Victron and set the parameters IAW direction.
and yes I have a AMP meter installed in the couch.

You haven't been particularly forthcoming with the current/voltage at your battery/alternator, charger input, charger output, and battery terminals. Having this information clarifies exactly you're Victron is doing---no smokescreens. The hundred dollar question: is your charging current purposely limited based on the use of lower charging voltages, or is your charging current limited due to excessive voltage drop due to undersized wiring?

As for high duty cycles, we've pulled the maximum rated charge current from our 40a Renogy dc to dc charger for up to 3-4 hours at a time, at least 50 times over the last year, with zero issues. Renogy is far from an upper-tier product like Victron. I would suspect you'd have zero issues doing the same with your Victron.