LifePO4 battery not charged from alternator

[Orca]

Hello,

Anyone able to provide an explanation for this?

Van was at the repair garage for 2 weeks and during this time the leisure battery ran out - understandable as I had two trackers, WiFi router and a camera running and it was parked under trees so no solar!
When I picked up the van and drove it home (30 minutes) I assumed the battery would have started to charge but it didn't.
When I got home and plugged in the EHU it started charging perfectly normally (Victron IP65 12/15).
At 30% I went for a short drive and it charged up to 35% so the alternator was charging normally.
I assume the battery had gone into "sleep" mode but I'm surprised the alternator (via CTEK D250SE) didn't wake it up.

Is this to be expected?

Thanks

 

[yossarian]

It's very much a function of the programmed characteristics of the battery's BMS not the battery's chemistry.

 

[Dellmassive]

Most likely the battery went under voltage and entered sleep mode for protection.

The ctek needs to see a voltage on the house battery terminal before it applies charge power.... A safety feature apparently?

Anyway that's most likely why the ctek didn't charge via the engine running.

Other chargers like Victron and Renogy have a "lithium activation" mode than will wake a sleeping lifepo4. Basically a posh was of saying they alway output power, that will allow a shutdown lifepo4 to start charging and recover itself.

The battery BMS will deal with the restart.... Basically a very low current charge until the internal cells reach a certain voltage..... Then the BMS will allow full charge power.


This has happened before with people on holiday or camping.... The only solution is to connect a separate charger until the battery "wakes up" then will accept charge from the engine DC-DC charger. ( might only need 10mins on a 240v charger )

the worst one i saw was they guy had to remove the battery and take it to a shop for a 8hour charge on the bench - then refit !!!

So yes , normal and to be expected with some chargers.


CTEK should take note and improve there lithium based performance.

 

[Orca]

Thanks Dellmassive for clarifying

 

[Dellmassive]

example:


victron Blue Smart IP65 Charger

Recovery of deeply-discharged 'dead' batteries​

Unlike other brands, the Blue Smart IP65 Charger will attempt to recharge a deeply-discharged battery by force-feeding it with a low current. Normal charging will then be resumed as soon as there is sufficient voltage across the battery terminals.




++++++++++++++++++++++++++

Renogy DCC50S




Lithium Battery Activation

The charge controller has a reactivation feature to awaken a sleeping lithium battery. Theprotection circuit of lithium battery will typically turn the battery off and make it unusable ifover-discharged. This can happen when storing a lithium battery pack in a dischargedstate for any length of time as self-discharge would gradually deplete the remainingcharge. Without the wake-up feature to reactivate and recharge batteries, these batterieswould become unserviceable and the packs would be discarded. The charge controllerwill apply a small charge current to activate the protection circuit and if a correct cellvoltage can be reached, it starts a normal charge.


++++++++++++

this is another example of why im not keen on the CTEK D250SE


++++++++++++

 

[Dellmassive]

my advice, swap the CTEK D250SE out for a more lithium suitable dc-dc charger.

my preferred choice ATM is the RENOGY DCC50S: (can set current limiter 20/30/40/50A)

https://amzn.to/3JZub7e

plus the BT adapter:

https://amzn.to/44MpJAU

+++++++++++++


heres my testing on the 250SE with lithium:

and the Renogy DCC50S

• DC-DC:
• Dc-dc Charger (for Leisure Battery) -- How I Done It --
• Charging Starter and Leisure batteries with same charger - Victron
• DC-DC Charger - AUTO VSR - feature testing
• Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?
• Victron 12/12/30 DC-DC Charger
• Renogy DC50S DC-DC charger
• Redarc BCDC1250D DC-DC charger
• Votronic DC-DC standby charger - or not !
• Renogy Bt-2 Monitor
• Renogy 20A DC-DC Charger (no solar)
• CTEK D250SE DC-DC Charger

+++



and FWIW:

Renogy so a 30A version too:

https://amzn.to/3PT64ek

++++++++++++++++++++

12V DC-DC Solar Battery Charger|Renogy UK

Battery chargers charge and maintain the batteries in your RV or van. The battery charger can be used as a back-up charging source for the battery bank.

uk.renogy.com

+++++++++++++++++++++

 

[Dellmassive]

@Orca

out of interest what lifepo4 are you running?

can you post some pics of your setup?

 

[Orca]

The battery's a TNPower TN-LFP12100 bought from TravelVolts in 2019

You helped me 3 years ago with an issue I had with the shunt which has been fine ever since I carried out your suggestions.
Leisure Battery Monitoring
The battery has switched off a few times in the past but because I always reconnected the EHU (with the Victron) it always charged back up without an issue.
This was the first time it went to sleep away from home.

I quite liked the CTEK as, when it's nice and sunny, and the leisure battery is charged, the solar tops up the starter battery.
Would the Renogy do the same?
I assume the 30A version would be suitable?

 

[Orca]

Think I've answered my own question:

 

[Dellmassive]

yes - the Renogy DCC30/50S are dual chargers with Solar MPPT.

and will reverse charge the starter battery from solar (just a slow trickle charge though)

get the BT2 adapter to add bluetooth and APP support. - shown above.

 

[dieselsnorter]

Jumping in on the thread as my leisure battery has dropped too low for the CTEK for similar reasons! Without removing the driver's seat where the battery is located on this conversion (so no obvious terminals), can a battery charger be hooked up to the output terminal on the CTEK D250SE itself (which feeds to the lb)...?

 

[roadtripper]

Do you have a 12v socket powered by the LB? If you have a maintenance charger with quick connect you can probably get a 12v plug adapter to charge that way.

I wouldn't expect having another charger connected would give the CTEK an issue as many have that exact situation with a second charger fitted as part of EHU.

 

[Dellmassive]

Jumping in on the thread as my leisure battery has dropped too low for the CTEK for similar reasons! Without removing the driver's seat where the battery is located on this conversion (so no obvious terminals), can a battery charger be hooked up to the output terminal on the CTEK D250SE itself (which feeds to the lb)...?

Yes, no probs.

Provided the fuse hasn't blown.

The ctek LB terminal should be direct to the LB battery's via a fuse.

So all good.

Choose any chassis point for the ground.

Got a few pics just to make sure all is good?

Don't too mad with the charge rate.... keep it low and slow.