2021 Thor Hurricane 29M - House batteries died quickly

[rrtwis]

A few weeks ago had a tech check the batteries in my rig and they cleaned the terminals and said the batteries were sitting I believer around 12.6 volts which was good.
I was at the rig yesterday installing some items so the house batteries were on and I also had the inverter on. Within a little more then an hour the lights dimed and the panel was showing the house batteries at 11.6 volts. I had to start the rig to get the generator started and I let it charge for about 4 minutes then turned the generator off. The batteries were showing 12.6 again.
There is no way there was enough time to charge the batteries in that little time, any ideas on what may have caused this?

 

[ducksface]

Surface charge in a battery is when a battery checks as fully charged due to a charge buildup on the surface of the plates. This causes correct voltage test results even though your battery is bad.


buy new lithiums.

 

[rrtwis]

That makes sense. I want to go Lithium but I need to figure out what's needed so I don't fry an alternator. I see a BIM in the compartment but I'm assuming it's not a LI-BIM so I'm thinking that's all I need to change out.
I might just have a RV tech take a look and I'll buy the parts and he can install.

 

[ducksface]

We've pretty well wiped the alternator fable off of the map.
New lith batteries have computers in them that regulate input.

 

[Lt Keefer]

We've pretty well wiped the alternator fable off of the map.
New lith batteries have computers in them that regulate input.

Really?

 

[16ACE27]

Really?

No.
The BMS limits charging for each individual battery.
Nothing limits the current for the entire bank. A large LFP bank can easily overtax an alternator if the bank is low.

 

[ducksface]

You don't really truly believe the op is going to put a 1100ah bank in do you?

What's large?
What WILL work?

You are falling back to the simca alternator under-ran in a lab make believe adv.

Even battleborn has changed their mind about just about everything.

Show the cutoff where it's not safe for an alternator.
I'm running 400ah of liths that have 100a bms each and the alternator has never dumped 80a into them.

Others here have said the same.

 

[Chateau_Nomad]

We've pretty well wiped the alternator fable off of the map.
New lith batteries have computers in them that regulate input.

But Duck... new alternators don't have computers in them that regulate OUTPUT, and that's the issue. A lithium battery will suck as much juice as it's given (to a point)... not really an issue with one or even two batteries. Stick in a bank of 4 LiPO batteries and that alternator might be crying uncle.

It's been hashed many times that a single, or even two100Ah LiPO charging at 50 amps won't harm most modern alternators. The problem is the battery BMS will shut down charging before the battery is full. Won't harm the battery OR the alternator, but if you only need about 80% use of the battery capacity... no harm.

Most solar charge controllers have battery profile settings which alter the charge rate based on battery type, usually lowering the amperage as the battery tops off.

Ideally every device which has "charging permission" should have a method of setting a charging profile specific to the battery type being charged.

Enter DC-DC chargers which can be programmed. A Li-BIM simply uses a basic ON/OFF timing sequence to allow alternator cooling... not as efficient, but it works.

Bottom line... small LiPO banks can be used without any other mods... IF attention is paid to how many amps are being drawn while charging... albeit with the topping off penalty. Those doing extended untethered boondocking using large banks of LiPO batteries would likely overtax their alternator.

 

[ducksface]

My alternator, for whatever reason, does not dump more than 80a into those batteries.
Others here have said similar.

I'm not sure I've read anywhere, (except those sad, dual alternator no generator, certain conflagration, c class whatever they are, )that rvs are REALLY burning out alternators.

Do we have recent real proofs of such?
Please use real cases not the
'Gee I think" type of you tube vids.

AI quote:
"Yes, a Ford alternator does regulate its amperage output, but not directly at the alternator itself. The alternator produces a voltage, and a voltage regulator controls the amount of current flowing to the battery and electrical system, according to Autoelectro. In modern vehicles, the Powertrain Control Module (PCM) often manages the alternator's output by controlling the current to the rotor's field coil,"

 

[16ACE27]

My alternator, for whatever reason, does not dump more than 80a into those batteries.
Others here have said similar.

I'm not sure I've read anywhere, (except those sad, dual alternator no generator, certain conflagration, c class whatever they are, )that rvs are REALLY burning out alternators.

Do we have recent real proofs of such?
Please use real cases not the
Gee I think type you tube vids.

AI quote:
"Yes, a Ford alternator does regulate its amperage output, but not directly at the alternator itself. The alternator produces a voltage, and a voltage regulator controls the amount of current flowing to the battery and electrical system, according to Autoelectro. In modern vehicles, the Powertrain Control Module (PCM) often manages the alternator's output by controlling the current to the rotor's field coil,"

When I had two 100 AH LFP batteries I saw my alternator output at 170 amps shortly after starting. 70 of that was normal post SU load. The other 100 was the LFPs. That's why I installed a Trombetta cut-off switch to hold off the LFP charging until the chassis battery was topped off. I also noticed that the alternator output voltage had dropped from a normal 14.4 - 14.6 VDC down to 14.1 VDC when at 170 amps.

 

[Lt Keefer]

One of the problems van dwellers have is the frequency with which their alternators fail.

 

[Chateau_Nomad]

This video shows Duck's smoking alternator demo... a Victron propaganda piece. BUT... it does present many excellent considerations one should make as to how to effectively charge LiFePO4 batteries. Each user case is different... so there's no "one size fits all" fix.

 

[rrtwis]

So will the LI-BIM 225 control the charging amperage? From what I'm reading it doesn't control the amperage but will connect the house batteries for 15 minutes then disconnect for 15 minutes so the alternator cools down.

 

[16ACE27]

So will the LI-BIM 225 control the charging amperage? From what I'm reading it doesn't control the amperage but will connect the house batteries for 15 minutes then disconnect for 15 minutes so the alternator cools down.

https://battlebornbatteries.com/wp-content/uploads/2019/01/BIM-LI225-Quick-Guide.pdf

 

[Chateau_Nomad]

Think of the Li-BIM 225 as operating like a resetting thermal fuse... but it works from an internal (non-adjustable) timing sequence. An engineer at Precision Circuits evidently settled on a one size fits all timer. However on my setup it works fine... Probably not as efficient as a DC-DC charger, but it works.

I installed a Li-BIM 225 when I switched to my 300Ah (3 100Ah) LiFePO4 batteries. It works fine in my setup.

I have 3 options for charging...
"Always on" 600 watts rooftop solar
Alternator through Li-BIM 225
Shore power through 3k watt inverter/charger

The generator also charges via the 3k inverter/charger.

 

[ducksface]

I think of li-bim as something that doubles my charge time due to ridiculously long shut off times.

I have one but it is tertiary in my charging scheme.

There can't be anyone who believes it takes that long for a modern alternator with an integral fan and road speed air travelling through the engine bay to cool itself
And
That if it takes that long to cool it's safe to run for that long.

I believe them to be dinosaur legacy stuff.

 

[rrtwis]

Sounds good! I already have a BIM 160 so it should be a simple swap, then I just got to deal with the converter. I only have one 100w solar which came from the factory but the controller can handle one more 100w so I'm adding that.
I also have a 340w portable solar panel so can put out if necessary.

 

[rrtwis]

I hear what you say about dinosaur but I want to keep this simple so the swap out is the easiest. I'm more of a weekend warrior or state park camper but want to do some off grid.

 

[ducksface]

Ford smart alternator regulates output current by the vehicle's PCM.

Regulates
Output
Current
So
As
To
Not
Fry
Itself

 

[ducksface]

Sounds good! I already have a BIM 160 so it should be a simple swap, then I just got to deal with the converter. I only have one 100w solar which came from the factory but the controller can handle one more 100w so I'm adding that.
I also have a 340w portable solar panel so can put out if necessary.

Yes.
It's just a swap out.

The folks who say it isn't just swappable are the same folks who two years ago said you couldn't mix battery types or even battery age.
Old facts become new lies as progress progresses.