Solar Charging Lithium and Starter Battery

I have a 2011 Sprinter that is getting 300ah of lithium batteries and a 315 watt solar panel with Victron controller. I am connecting to the alternator via a Victron Cyrix-Li ACR and it will be controlled by the 712 battery monitor to shut off charging when the batteries are below freezing and when they are roughly 80% charged. I imagine some will say that the alternator can't handle this but Ive seen several reports that the factory wiring can only support about 80 amps from the alternator and thus will act as a regulator to keep the batteries from cooking the alternator if they are low on charge.

My question relates to the starter battery and the lithium programming in the solar controller. Victron sells two different Cyrix models that will work, the CT and the Charge. The CT will connect when either of its terminals sees over 13.4V and the Charge will connect only when the input terminal sees 13.7V. My choice would be the CT as it has a built in Start Assist feature and also would help keep the starter battery charged via solar (the CT will connect when solar power is present) but Im not sure if the programming of the solar controller ( higher voltage and no trickle) will hurt the starter battery more than it will help, plus the different chemistry's mingling during the day when there is no load may be problematic.

I can easily add a manual bypass as a jump start option but in my previous van the solar charging on the starter battery was handy during periods of inactivity, though it had AGM house batteries and was straight forward. Thanks for any input.
 

john61ct

Active member
Victron in general makes top notch products.

The Cyrix line is not one.

A Sterling BB series DC-DC would be my reco. Set a 60A limit explicitly on the current pulled by your LFP bank rather than letting your charge system get stressed

Will actually charge faster by maintaining the V setpoint. And even then in hot ambients watch out, a V/A meter on the DCDC input can be informative.
 

OrioN

2008 2500 170" EXT
Victron in general makes top notch products.

The Cyrix line is not one.

A Sterling BB series DC-DC would be my reco. Set a 60A limit explicitly on the current pulled by your LFP bank rather than letting your charge system get stressed

Will actually charge faster by maintaining the V setpoint. And even then in hot ambients watch out, a V/A meter on the DCDC input can be informative.
What makes the Cyrix inferior?
 

john61ct

Active member
Poor build quality,

subject to faster corrosion, not potted

brass studs rather than plated, uncovered

no blinky light, local much less remote

no remote override

no starting isolation

Even if some features since added, they have a much higher reported failure rate than Blue Sea ACRs which are pretty much bulletproof
 

JIB

Well-known member
John61ct, as long as you know Victron and recommend them as well as the Stirling BB. What are your thoughts of the Sterling vs. the 60 amp Victron Buckboost potentially throttled down to 40 Amps? This would be for a smart alternator VS30.

Apology to the OP and thanks in advance,

Jack
 

john61ct

Active member
Have not used nor researched that buckboost to use as a charger, so reco Sterling BB series.

Thought it was just a DCDC converter / OSU style.

Does it have

current derating?
user-custom setpoint adjustment?
remote switch ability?

What sort of stop-charge algorithms?
 

wankel7

Active member
Poor build quality,

subject to faster corrosion, not potted

brass studs rather than plated, uncovered

no blinky light, local much less remote

no remote override

no starting isolation

Even if some features since added, they have a much higher reported failure rate than Blue Sea ACRs which are pretty much bulletproof
Can you expand on starting isolation and what failure modes / symptoms you have seen?
 

Sunny&75

Active member
I think this is related, sorry if I'm hijacking! I'll move it to a new thread if it is.

I'm using a Sterling b2b charger(60amp) between my Lithium house bank(200 amp) and my AGM starter batt, wired as per Sterling. I also have solar panels(400 watts) with a Victron MPPT controller(50/100). All above commonly wired to + and - Blue Sea Power bars.
My question is; At rest, will my starter batt receive a charge from my solar without any additional hardware? Do I need some kind of additional combiner? The two banks are connected via the power bars and the Sterling b2b wiring. Will the b2b act as the combiner?
Magnum Energy makes a combiner, ME-SBC Smart Battery Combiner, i was thinking of using. I currently am using their hybrid 3000 inverter/charger and related components(batt monitor and display).
Thanks!
 

autostaretx

Erratic Member
(Dang... can't find my local copy of a Sterling manual ... so i'll guess):
((the manual confirms my "guess" ... they even speak of "shore power" as being applied to the *starter* battery then reaching through to charge the "domestic" (house) battery))

Sunny: I would be stunned if the Sterling acted as a "reverse joiner" ... it's really a one-way (very complicated) device.

It's only the far simpler (in essence) voltage-sensitive relays that will join the two systems if *either* side appears to have charging voltages (such as solar on the house side and/or alternator on the starter side) appearing at its terminals. BlueSea ACR for example.
BUT: don't just throw an ACR "across" the Sterling without additional "lock-out" wiring/logic, otherwise you'll trigger a loop of "solar fires up ACR which puts charging voltage on starter battery which convinces Sterling it can fire up and charge house battery which is already getting solar which..."


--dick (who'll correct/update this when he finds/re-fetches a Sterling manual)((but i'm 99.95% confident in my "guess"))
Step One: the 1260's current manual: http://www.sterling-power-usa.com/library/2017-06-29_BB1260_30_Ultra_InstructionsEng_GerV60.pdf
from: https://www.sterling-power-usa.com/SterlingPower12volt-12volt-60ampbatterytobatterycharger.aspx
 
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marklg

Well-known member
(Dang... can't find my local copy of a Sterling manual ... so i'll guess):
((the manual confirms my "guess" ... they even speak of "shore power" as being applied to the *starter* battery then reaching through to charge the "domestic" (house) battery))

Sunny: I would be stunned if the Sterling acted as a "reverse joiner" ... it's really a one-way (very complicated) device.

It's only the far simpler (in essence) voltage-sensitive relays that will join the two systems if *either* side appears to have charging voltages (such as solar on the house side and/or alternator on the starter side) appearing at its terminals. BlueSea ACR for example.

--dick (who'll correct/update this when he finds/re-fetches a Sterling manual)((but i'm 99.95% confident in my "guess"))
Step One: the 1260's current manual: http://www.sterling-power-usa.com/library/2017-06-29_BB1260_30_Ultra_InstructionsEng_GerV60.pdf
from: https://www.sterling-power-usa.com/SterlingPower12volt-12volt-60ampbatterytobatterycharger.aspx
The Sterling is one way only. I have mine connected with the input from the starter battery and the output to the house batteries. Since the house batteries are Lithium, they have a completely different charging characteristic which the Sterling takes care of. I installed a manual relay with a big red guarded switch to connect the house batteries to the starter battery in case the starter battery runs down. The switch should only be used when the Sterling is off, so I have the running signal from the Sprinter enabling the Sterling and only use the switch when the motor is not running.

The new "green stripe" Sterling works better with the low alternator voltage and higher voltage requirements of the Lithiums, but it needs good ventilation or it will get hot and cut back to half power until it cools. Right now in AZ it cuts back about 1/2 the time. I'm working on a bilge blower cooling solution to move more air through the Sterling and will post it when it is done.

Regards,

Mark
 

OrioN

2008 2500 170" EXT
The Sterling is one way only. I have mine connected with the input from the starter battery and the output to the house batteries. Since the house batteries are Lithium, they have a completely different charging characteristic which the Sterling takes care of. I installed a manual relay with a big red guarded switch to connect the house batteries to the starter battery in case the starter battery runs down. The switch should only be used when the Sterling is off, so I have the running signal from the Sprinter enabling the Sterling and only use the switch when the motor is not running.

The new "green stripe" Sterling works better with the low alternator voltage and higher voltage requirements of the Lithiums, but it needs good ventilation or it will get hot and cut back to half power until it cools. Right now in AZ it cuts back about 1/2 the time. I'm working on a bilge blower cooling solution to move more air through the Sterling and will post it when it is done.

Regards,

Mark
Li's require lower voltages than Lead Acid.
 

marklg

Well-known member
Li's require lower voltages than Lead Acid.
To clarify, after a few minutes the alternator voltage drops down below that needed to fully charge the lithiums, to less than 13V. The Sterling keeps the voltage up as high as 13.6 to fully charge the house batteries. So yes, lead acid requires higher voltage to fully charge, but I don't see that from my alternator at least.

Regards,

Mark
 

OrioN

2008 2500 170" EXT
To clarify, after a few minutes the alternator voltage drops down below that needed to fully charge the lithiums, to less than 13V. The Sterling keeps the voltage up as high as 13.6 to fully charge the house batteries. So yes, lead acid requires higher voltage to fully charge, but I don't see that from my alternator at least.

Regards,

Mark
Ah.... you need the Sterling to resolve your alternator issues. Unfortunately, this appears to be an isolated issue and for you as a properly functioning 2011 alternator will give out 13.6-14.2 volts.
 

marklg

Well-known member
Ah.... you need the Sterling to resolve your alternator issues. Unfortunately, this appears to be an isolated issue and for you as a properly functioning 2011 alternator will give out 13.6-14.2 volts.
Mine is a 2006, but it may very well be an issue with the alternator. Since an alternator is expensive and it does seem to keep the starter battery charged, and the Sterling is completely configurable, I went that way.

Some very recent vehicles have smart alternators and regenerative braking that produce wild swings in voltage and the Sterling handles that.

Regards,

Mark
 
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autostaretx

Erratic Member
The 2006 alternator should put out over 14 volts immediately after starting, and later drop to 13.7 or .8 without extra loads.

--dick (at least, that's what my 115 amp alternator manages)
 

wankel7

Active member
To clarify, after a few minutes the alternator voltage drops down below that needed to fully charge the lithiums, to less than 13V. The Sterling keeps the voltage up as high as 13.6 to fully charge the house batteries. So yes, lead acid requires higher voltage to fully charge, but I don't see that from my alternator at least.

Regards,

Mark
Is the less than 13 volts measured at the alternator or the house batteries?

What is the distance between them? What wire size?
 

marklg

Well-known member
Is the less than 13 volts measured at the alternator or the house batteries?

What is the distance between them? What wire size?
At the starter battery. I posted some results and a long research and discussion a while back. My "green stripe" Sterling is installed and done with two AWG 4 wires in each leg, low voltage drop.

Regards,

Mark
 

Sunny&75

Active member
The Sterling is one way only. I have mine connected with the input from the starter battery and the output to the house batteries. Since the house batteries are Lithium, they have a completely different charging characteristic which the Sterling takes care of. I installed a manual relay with a big red guarded switch to connect the house batteries to the starter battery in case the starter battery runs down. The switch should only be used when the Sterling is off, so I have the running signal from the Sprinter enabling the Sterling and only use the switch when the motor is not running.

The new "green stripe" Sterling works better with the low alternator voltage and higher voltage requirements of the Lithiums, but it needs good ventilation or it will get hot and cut back to half power until it cools. Right now in AZ it cuts back about 1/2 the time. I'm working on a bilge blower cooling solution to move more air through the Sterling and will post it when it is done.

Regards,

Mark
If I get an ACR, will i be able to charge my starting batt with my solar?
 

marklg

Well-known member
If I get an ACR, will i be able to charge my starting batt with my solar?
If the batteries are the same chemistry, it will work. In my case they are not. I have a manual switch and relay to connect the house batteries to the starter battery. So, solar charges the house batteries and I can flip the switch to charge the starter battery from the house batteries.

The house batteries are charged via Solar, Inverter / Charger from shore power and the alternator via the Sterling.

Regards,

Mark
 

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