Lithium LifePo4 12v Batteries - Time For An Upgrade?

[Stay Frosty]

My Renogy experiences ie. flexible solar panels, DCC50S b2b/mppt, 1000watt inverter and smart shunt battery display have been spot on.
The Roamer battery is a beast but a 100A Renogy version would actually be adequate here as the solar input from two 175 watt panels outstrips the demand from the fridge even on a dull summer day.
If you're going to take your MIG welder or two post lift on holiday then battery and inverter size will call the shots, roughly 100Ah of battery per each 1kw of 230V goodness needed and bear in mind a 2kw output inverter will pull close to 200A at 13Vdc so big fat 0 gauge wires from the battery to the inverter.

 

[Northern Soul Gal]

Thanks for your replies....
If I went for the Roamer, does that also work with the CTEK250SE?
Thanks

 

[Stay Frosty]

Have you already got the CTEK and does it combine an mppt too so you can add solar?

 

[Stay Frosty]

Rather than edit that post as long as the CTEK has a lifePO4 charging profile then you'll be good.
In my case I bought a smart charger for use on hook up but have used it once only this year to put the initial charge in the Roamer seatbase battery subsequently all charging has been from driving or driving and solar or solar only.The Renogy DCC50S providing 25A and the solar bunging in anything up to 16A with the solar on at the same time while driving or 50A driving with the solar turned off or the 16A parked up and solar only... blimey.

 

[Northern Soul Gal]

Hi yes already got the CTEK and we have a renogy solar panel, however in winter etc it doesn't give enough to keep everything going, hence the need to upgrade
Thanks

 

[Dellmassive]

Thanks for your replies....
If I went for the Roamer, does that also work with the CTEK250SE?
Thanks

Yes.

The d250Se has a lithium profile.

Checkout the Roamer here:

Roamer - Premium LiFePO4 Leisure Batteries for off grid

For continuous power for non-stop adventures, say hello to Roamer – the next generation in SMART 12v and 24V LiFePO4 leisure batteries for campervans, boats and off grid life. Equal parts power, intelligence and reliability - managed with a smartphone app that puts the power in your hands. 10...

roamer.com

.

 

[RunDSG]

Stacks of amazing advice is in this thread. Took me a long time to arrive at the conclusions shared here. Like many of you, I have a Renogy Lithium battery and CTEK charger.

I had to read deep into the documentation to spot that the ‘smart’ version has double the charge cycles, as pointed out by @Dellmassive. I’ve gone with the heated version for peace of mind. We get below zero degrees a fair bit in Cambridgeshire, and I would worry too much about charging the battery when it’s too cold.

And I’m using the D250SE, having switched the wire over to trigger the lithium charging profile. (So far, seems to charge at 20A initially when driving, settling down to 16A.)

Someone a few pages back mentioned longevity with fridge, phones, TV, etc. We don’t have a TV, but we run a fridge (on setting 4 of 5), charge phones, run lights, fans, charging bricks, watches, diesel heater, etc. First proper camping trip was to Latitude last weekend.
- 100Ah fully charged to start
- 5 nights / 5 full days without running the engine
- moderate weather with some sun and cloud most days, but then fully overcast and raining for at least 1.5 days. At most, we seemed to get maybe up to 10Ah off solar per day.
- battery capacity seemed to drop 10-15Ah per day
- we hit 38% when we finally set off on the Monday.
- charged at 16-20A on the way home. Hit 90% when we got home 3 hours or so later.

In conclusion, very pleased with my setup. 100Ah lithium and 100 watt (ish) flexible panel. I had thought I should buy a second battery and a larger solar panel but (sadly) there’s no need! Yes, I’ll get little or no solar in winter. I’ll run the diesel heater more, but then the fridge won’t have to work as hard. And I also won’t be camping for 5 days without running the engine in winter. We generally wild camp and move on every day, or camp somewhere and do the odd drive.

Anyone who comes across this thread will be well-informed. The power of the forum!

 

[RunDSG]

Now a question!

I’m away for three weeks. Van on drive while we’re away.

Do I put battery into shelf mode?

Manual says to disconnect everything. I don’t care to do that. I could isolate by removing fuses however.

Why do it? Everything is off, so should be no concern of running low. But don’t want the solar continually pushing battery to 100%. I believe constantly charging a full battery can be damaging. Am I right?

 

[Stoatie_weasel]

Just adding my experience.. Having moved from lead acid to lithium I originally purchased the renogy 100ah BT but found it way too heavy and not very user friendly.. Over cell voltage alarms and to be honest crap at cell balancing. Still have it but using it for my portable power box project.
Purchased a fogstar drift 105ah and wow what a difference.. Very light.. Small.. Now I have more space in my battery compartment. Added built in heating at sub zero temps charging.. I use it with a CTEK 250d se and whilst it's not the best I haven't had a problem in over 3 months of regular use.. Reason I kept the CTEK is I only have 6mm2 cable from starter to charger.. I was worried initially about upgrading to lithium with my setup but it's been absolutely the right way to go..

 

[Dellmassive]

No need for shelf mode for three weeks.

Lifepo4 like to be stored at 40-80% for long term, (longer than three months)

Don't leave permanently connected to a charger for long term storage.

Best thing to do is to just run the battery down a bit, say to 80%, then leave the isolator off.

It's recommended to check the battery every couple of months for soc.

And to fully recharge to 100% evey 3months or so to reset the BMS, which will reset any BMS drift soc error.

To be fair all the batteries still self discharge 1-3% per month as the BMS still uses some power even when sleeping.

 

[Stoatie_weasel]

Respective of what battery and charge you have it's the BMS that calls the shots.. I just didn't have very good experience with renogy

 

[RunDSG]

No need for shelf mode for three weeks.

Lifepo4 like to be stored at 40-80% for long term, (longer than three months)

Don't leave permanently connected to a charger for long term storage.

Best thing to do is to just run the battery down a bit, say to 80%, then leave the isolator off.

It's recommended to check the battery every couple of months for soc.

And to fully recharge to 100% evey 3months or so to reset the BMS, which will reset any BMS drift soc error.

To be fair all the batteries still self discharge 1-3% per month as the BMS still uses some power even when sleeping.

Thanks. Very reassuring.

Embarrassed to admit… I don’t believe I have any isolation for my solar!! Fitted by Skyline with my pop top. I can’t find any way to isolate bar removing from positive terminal.

 

[Stoatie_weasel]

The BMS on the renogy BT battery is not very good.. To be polite..even on their own forums. The Foster drift uses a tried and tested and user adjustable JBD BMS..

 

[Dellmassive]

Most people should have a main isolation switch that disconnects the battery completly. (For storage, safety and maintenance purposes)

So.

Lifepo4 battery --> master fuse (eg 100A midi) --> battery isolator --> positive busbar, or fusebox.


Example:

https://amzn.to/3OwzMoh

.


Basically it's not recommended to have loads of wires connected to the battery pos post, you should have one main fused, switched feed that connects to the sub fusebox that runs all your various circuits.




.

 

[Stoatie_weasel]

Another negative for the renogy BT.. Not to be confused with the Smart range.. It only has a passive balancer which is more or less useless.. Fogstar drift has active balancing and ithe most my cells have a differential of 3mv.. Which is pretty good..

 

[RunDSG]

Most people should have a main isolation switch that disconnects the battery completly. (For storage, safety and maintenance purposes)

So.

Lifepo4 battery --> master fuse (eg 100A midi) --> battery isolator --> positive busbar, or fusebox.


Example:

https://amzn.to/3OwzMoh

Basically it's not recommended to have loads of wires connected to the battery pos post, you should have one main fused, switched feed that connects to the sub fusebox that runs all your various circuits.

Good advice. I'll not have time to do this before I head off, but it's something to work on later in the summer. All makes good sense.

(I can't believe there's no isolator for the solar... but the more I learn the more I realise the 'pros' made some really daft decisions on my conversion.)

 

[Stay Frosty]

I've got a conventional domestic 30A double pole switch in a plastic surface box screwed into the top of the wardrobe where the solar live and neutral wires come through the pop top, might work for you if you've got enough slack on them?

 

[RunDSG]

I've got a conventional domestic 30A double pole switch in a plastic surface box screwed into the top of the wardrobe where the solar live and neutral wires come through the pop top, might work for you if you've got enough slack on them?

Interesting. I need to take apart the panel behind my top/rear cabinet and have another look at the wiring.

Frustratingly, a lot of the wiring is behind my cabinets and fully inaccessible, before emerging at the battery underneath the rear RIB seat.

 

[Stay Frosty]

I bunged my own solar panels on and they're practical rather than pretty but I placed the switch as close to where the feeds came in so that there weren't any wires that might be live floating around, not so much to a 21volt shock more so I didn't short them out and bugger the panels up.
Another advantage is turning off the solar means the Renogy DCC50S then pumps 50A instead of 25A from the vehicle battery/alternator.

 

[Northern Soul Gal]

Hi again
Thanks to everyone for their input on my query.
I went for the Renogy 200ah with Bluetooth and they have the Renogy One offer again for £1 just in case anyone is interested.
Used the 6% discount also so all done paid 752
Thanks again much appreciated