LeadAcid replace with Lifepo4 in campervan - split charging.

Puiumeu

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Aug 5, 2021
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I am building a 12v 280ah lifepo4 battery as detailed in this forum.
I currently have Lead Acid Deap Cycle Batteries connected to a CBE charge controller and MPPT (set for Lead Acid).
The battery will charge from the van, shore power or solar. Most of the time it's full from solar alone.
When I replace the battery with a Lifepo4 with JBD/Overkill BMS, I should change the MPPT controller to Lithium but do I need to change the shore and van charging to a system that supports lithium or will the BMS be able to manage the charge from the CBE charging even though it does not support lithium.

If not should I just replace the MPPT with the DC-DC unit Will recommends for an alternator system as to date I have never used the shore power.

Thanks in advance and sorry for what is possibly a silly question...
 

mikefitz

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I guess you are in the UK or EU.
A few questions.
What amount of solar panels and what solar controller?
Is the existing engine charging via the CBE internal relay?
Is the vehicle professional build or diy? What vehicle?
What is the model number of the CBE mains charger?
What existing high current fuses do you have at the engine and service battery and what is the cable size?

I suggest you consider b2b chargers from the Victron, Votronic, or Sterling Power. Renogy units have poor support in Europe and from reported issues seem unreliable.

It's possible cables, fuses, need upgrading and modification to the CBE units

The BMS is a last resort protection device not a charge control .

Mike
 

Puiumeu

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Aug 5, 2021
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I guess you are in the UK or EU.
A few questions.
What amount of solar panels and what solar controller?
Is the existing engine charging via the CBE internal relay?
Is the vehicle professional build or diy? What vehicle?
What is the model number of the CBE mains charger?
What existing high current fuses do you have at the engine and service battery and what is the cable size?

I suggest you consider b2b chargers from the Victron, Votronic, or Sterling Power. Renogy units have poor support in Europe and from reported issues seem unreliable.

It's possible cables, fuses, need upgrading and modification to the CBE units

The BMS is a last resort protection device not a charge control .

Mike
Hi Mike,

Thank you so much for your reply.

Yes in Edinburgh UK.

With respect to your questions.

What amount of solar panels and what solar controller? 2*150w flexible, spark 40A MPPT.

Is the existing engine charging via the CBE internal relay? As far as I am aware, I would need to check, see later comment. The CBE stuff all looks a little "toy" to me and the battery always appears to be fully charged by solar...

Is the vehicle professional build or diy?
It was supposed to be professional but is a bit of a mess to be honest, was the personal vehicle of a van conversion company but sold privately, having now had time to look under the hood we appear to have been sold a busmans holiday. The vehicle was only really used for campsites and the owner "converted it for us for off grid before we purchased"

What vehicle? VW Crafter LWB 2011.

What is the model number of the CBE mains charger? Its a CBE PC180 System with CB-516 Charger. I believe the Ds300

What existing high current fuses do you have at the engine and service battery and what is the cable size? Still reverse engineering the mess but planning to rewire and add circuit breakers.

I will look at the b2b solutions you listed and would appreciate any advice you could give me to making this more usable and safe.

Thanks in advance.

Al
 

mikefitz

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859
Travelling about at the moment so will 'drip feed' info over the next few days.

The solar controller and panels you have, are unfortunately, not the best. The spark 40A is not a mppt, is is a fake, just a low cost pwm. (£12)
Not the best for lithium as the settings may not be optimum.
I suggest changing for a quality mppt controller, Victron Smart 100/20 is OK for 300 watts of panel.
Although the panels are working at the moment unless you're very lucky they will fail within 24 months.
Sorry for the negative comment but your converter did not do you any favours fitting this solar setup.

The connections from the batteries to ds300 the should be via a 50A fuse ar the battery end of the cable. Do not consider dc breakers, most of the breakers available in the UK are poor quality, keep over current protection using fuses, more on this later.

On a 2011 crafter use a 30 amp b2b for engine charging. Victron or Votronics

Useful 'shop' for everything you may need is 12vplanet.

The ds300 has a built in combining relay that allows engine charging.

The lithium setup you intend to fit will need modifications to the ds300.

More suggestions in a day or two.
Note much on this forum is relative to USA RVs that tend to use significantly more battery energy than Euro vans.

Mike
 

Puiumeu

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Aug 5, 2021
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@mikefitz,

Thank you so much I look forward to your additional posts and insight.

I was under the impression that the spark mppt 5040 was a voltronic copy and was a true mppt.


I am in total agreement that the supplier did us no favours.

I would be interested in what would be my best, short term and safe solution for making this as usable as possible and ready for the Lifepo4 with BMS when it arrives.

I am reasonably competent but need your expertise so I have the safest solution.

There is currently no isolation of the cells or battery so your advice is appreciated.

Thanks in advance.

Al.
 

mikefitz

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Joined
May 28, 2020
Messages
859
spark mppt 5040
Sorry , you are correct, I was looking at a different model. The unit in your link is a MPPT.

The CBE PC180 and DS300 is a common install in professional built motorhome and although the PC display panel now has updated versions, the basic DS 300 is still used. Its quite a good system and is adequate for the majority of users who will stay most of the time on campsites.

The battery charger is designed for lead acid and GEL batteries. The lead acid setting could be used for lithium if you accept the longish absorption time.
It operates as follows, charges to target volts, (max current 16 amps), 14.1 volt, has a fixed absorption time of 90 mins, drops to float, 13.5 volts for 10 hours then goes to standby until the volts drop below 13 volts.
I think this is usable for lithium on an infrequent basis, the absorption duration is perhaps a little long.

Engine charging is controlled by a relay in the DS300.The engine battery is connected to the +B1 terminal, the service battery to the +B2 terminal and the common negative to the -B2 terminal. The DS300 detects that when ignition is active and the engine battery volts are over 13 volts and switches the internal relay, connecting +B2 to +B1.
This is usable for lead acid batteries but replacing the service battery with lithium may/will cause issues,
there is nothing to limit the high current the lithium batteries may take, ( perhaps damaging the internal relay)
the starter battery voltage may not be suitable,
there is no termination of charge when the lithium battery is full.

When up dating the system, connecting the b2b and solar charger direct to the service battery via suitable fuses is preferable to using the DS300 relay. The relay activation can be disables by cutting out the resistor, 2, in the picture ( resistor R37).

On the DS300 the terminal +B2 will still be connected to the service battery and + B1 to the engine battery but solar and engine charging are now direct to the service battery.

Suitable b2b chargers are the Victron Orion12 12 30, the Votronics VCC121230 or the121250, Sterling Pro 121230 or 121260

You may need to update cables and fuses, the instructions for the chargers will advise.

General diagram showing connections of chargers ( the CBE mains charger is connected via the DS300, replace with an alternative charger as shown if required). The Victron shunt or equivalent is for an optional battery monitor.

ds300mod.jpg
diy solar8.jpg

Mike
 

Puiumeu

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Aug 5, 2021
Messages
26

Puiumeu

New Member
Joined
Aug 5, 2021
Messages
26
@mikefitz, all done working great, thank you so much could not have done it without you.
Stirling B2B works great, just wish I can trickle charge the van as the battery always shows low on the PC180.. Noticed the new Stirling b2b's support vehicle charging...
 
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