Dual Battery System with CTEK D250 not charging battery over 12 volts.

coolfeet

Mark Keeler
Or...you mean will it charge from the alternator with the engine battery unhooked? That would probably work fine but shouldn't be necessary.

I will disconnect the alternator power going to d250s and charge only with solar. This is referred to as split testing. The d250s can be used as a stand alone solar charge controller.


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DiploStrat

Expedition Leader
Here is Part of Your Problem

...
I have a Lifeline AGM 80 ah battery connected to the CTEK D250s battery isolater and charger. I connected the Ford auxiliary 12 volt charging circuit directly to the CTEK D250. Additionally, I have a 160 W solar panel connected to the D250s.

The system worked fine for 3 days while parked. ...

OK, reread your original post, again.

-- You probably do not have the CTEK connected properly. Not sure what the "Ford auxiliary 12v charging circuit" is, but I would suspect that it has very small wires and may have a relay or some other form of isolator. To work properly, the CTEK should be connected directly to the positive terminal of the starter battery. (And fused for safety.) Reread the manual and recheck the recommended wire sizes.

-- "The system worked when parked." Of course, this was only running on the solar panel and not was not dependent on power from the alternator.

-- And nothing will work if your grounds are not good.

Still don't think the CTEK is a good idea for your Ford, but it will not perform as advertised (and I have never read a bad review of the D250S) if not connected properly.

N.B. The D250S will perform even better, that is, charge your batteries faster, when paired with the SmartPass. This also has the advantage of allowing your solar panel to charge your starter battery.

Happy rewiring!
 
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coolfeet

Mark Keeler
OK, reread your original post, again.

-- You probably do not have the CTEK connected properly. Not sure what the "Ford auxiliary 12v charging circuit" is, but I would suspect that it has very small wires and may have a relay or some other form of isolator. To work properly, the CTEK should be connected directly to the positive terminal of the starter battery. (And fused for safety.) Reread the manual and recheck the recommended wire sizes.

-- "The system worked when parked." Of course, this was only running on the solar panel and not was not dependent on power from the alternator.

-- And nothing will work if your grounds are not good.

Still don't think the CTEK is a good idea for your Ford, but it will not perform as advertised (and I have never read a bad review of the D250S) if not connected properly.

N.B. The D250S will perform even better, that is, charge your batteries faster, when paired with the SmartPass. This also has the advantage of allowing your solar panel to charge your starter battery.

Happy rewiring!
Why do you think the CTEK is not a good idea for the my Ford? I am open to all suggestions. You are correct that the D250S will not function properly if not connected to the battery. My batteries are located on the frame rail and it's a PITA to get at them. I will make a fused cable from the battery to the CTEK. I need about 12 feet of cable to route it to the battery box. What gauge do you suggest and what amp fuse?
 

coolfeet

Mark Keeler
The CTEK is designed to boost the voltage of your alternator up to the voltage that it already produces. There is a very legitimate question as to why you paid for the CTEK vs. a simple relay. But, we digress ...


My bet would be that the CTEK is working properly and that you have a flaw in your wiring.

READ THIS:
http://smartercharger.com/wp-content/uploads/2010/11/D250S-DUAL_EN.pdf
My wiring is flawed.
 

coolfeet

Mark Keeler
OK, reread your original post, again.

-- You probably do not have the CTEK connected properly. Not sure what the "Ford auxiliary 12v charging circuit" is, but I would suspect that it has very small wires and may have a relay or some other form of isolator. To work properly, the CTEK should be connected directly to the positive terminal of the starter battery. (And fused for safety.) Reread the manual and recheck the recommended wire sizes.

The Ford auxilliary 12 volt charging circuit is a 12 or 14 awg wire connected to a relay.
 

DiploStrat

Expedition Leader
Cure for Which There May Not be a Disease

Why do you think the CTEK is not a good idea for the my Ford? I am open to all suggestions. You are correct that the D250S will not function properly if not connected to the battery. My batteries are located on the frame rail and it's a PITA to get at them. I will make a fused cable from the battery to the CTEK. I need about 12 feet of cable to route it to the battery box. What gauge do you suggest and what amp fuse?

The CTEK D250S (and other B2B's or DC-DC chargers from Sterling, Redarc, et al) are designed to boost the charging voltage of a vehicle that runs at, say, 13.9v or less, up to 14.4v, which is a better voltage for modern AGM batteries. The D250S has the added advantage of being a small, MPPT solar controller.

The "disadvantages" of the D250S are only that:

-- It has a maximum output of only 20A. Thus recharging a 100Ah battery, 50% discharged, will take a minimum of five hours. (A lot more, actually, but that is another discussion.)

-- Most modern vehicles already charge at over 14v, so there is little advantage to the D250S. (And there are often less expensive ways of boosting your voltage.)

All of that said, everyone that I know who has installed a D250S has loved it. Particularly if they have a Toyota that charges at 13.9v.

I suspect that if you rewire your D250S directly to the positive terminal of your starter battery, and size your wires according to the chart on the last pages of the D250S manual, you will get great performance within the limits of a 20A charger. (And do make sure that your base wiring, grounds, etc. are all good.)

See page 19 of the manual for the correct wiring. Page 20 for what I would recommend, and Page 24 for the MINIMUM wire sizes by length. When in doubt, go at least one size larger or double up the wires.

If you are bored, go to the "Documents" page of my website, get an adult beverage, and settle in for a long, pedantic read.

Good luck!

 

coolfeet

Mark Keeler
The CTEK D250S (and other B2B's or DC-DC chargers from Sterling, Redarc, et al) are designed to boost the charging voltage of a vehicle that runs at, say, 13.9v or less, up to 14.4v, which is a better voltage for modern AGM batteries. The D250S has the added advantage of being a small, MPPT solar controller.

The "disadvantages" of the D250S are only that:

-- It has a maximum output of only 20A. Thus recharging a 100Ah battery, 50% discharged, will take a minimum of five hours. (A lot more, actually, but that is another discussion.)

-- Most modern vehicles already charge at over 14v, so there is little advantage to the D250S. (And there are often less expensive ways of boosting your voltage.)

All of that said, everyone that I know who has installed a D250S has loved it. Particularly if they have a Toyota that charges at 13.9v.

I suspect that if you rewire your D250S directly to the positive terminal of your starter battery, and size your wires according to the chart on the last pages of the D250S manual, you will get great performance within the limits of a 20A charger. (And do make sure that your base wiring, grounds, etc. are all good.)

See page 19 of the manual for the correct wiring. Page 20 for what I would recommend, and Page 24 for the MINIMUM wire sizes by length. When in doubt, go at least one size larger or double up the wires.

If you are bored, go to the "Documents" page of my website, get an adult beverage, and settle in for a long, pedantic read.

Good luck!

I am looking for an alternative to the D250S. As you mentioned, it takes 5 hours to charge my camper battery when discharged 50%. I rarely drive anywhere for 5 hours straight. Apparently, the D250 works better with the SmartPass attached. That means forking out another $250! There has to be a less expensive way.

As I am writing this, I have my vehicle parked in full sun shining on the 160 watt solar panel. The battery was at 12.75 volts before I started charging with the solar panel. After 5 hours of charging, it's at 13.2 volts. I do not have any appliances connected to the service battery.
 

DiploStrat

Expedition Leader
I am looking for an alternative to the D250S. As you mentioned, it takes 5 hours to charge my camper battery when discharged 50%. I rarely drive anywhere for 5 hours straight. Apparently, the D250 works better with the SmartPass attached. That means forking out another $250! There has to be a less expensive way.

As I am writing this, I have my vehicle parked in full sun shining on the 160 watt solar panel. The battery was at 12.75 volts before I started charging with the solar panel. After 5 hours of charging, it's at 13.2 volts. I do not have any appliances connected to the service battery.

Go read up on this subject on my website.

-- The D250S/SmartPass combo works well because it combines an intelligent relay with the voltage boost of a B2B.

-- Less expensive? Well, I like the Blue Sea ACR, but then you would have to spring for a solar controller. And, if your voltage really stays below 14v, some form of voltage adjustment device, about $100 for something plug and play.

Given that you already have the D250S and solar panels, your best bet might well be to simply add the SmartPass.

Some notes about voltage as a means of determining state of charge (aka SOC). There are lots of charts, like this one, that will give you a guesstimated state of charge from the battery voltage.

12-v-Battery-State-Of-Charge-website.jpg


But they are generally not very accurate because they only work with resting voltage, that is the voltage of the battery about two hours AFTER being disconnected from either a charge source or a load:

-- When connected to a charger, the voltage at the battery terminals is generally that of the charge source. (Unless the load is much greater than the charge.)

-- Disconnected from a charger, but under load, the voltage will be drawn down by the load. Lights or even a small refrigerator won't matter much, put a hair dryer or microwave on there and even a large battery bank will show an appallingly low voltage.

Sooooo, if your batteries were at 12.7v when you started, then they were "fully" charged. If they now show 13.2v, connected to the solar controller with sunlight on the panels (expect about 5A for every 100w of panel in good sun), then they have probably completed the absorb stage and are floating nicely.

If you are really concerned, and you probably should be if you have a large battery bank, call it larger than 200Ah, then you are in the market for a real battery monitor. But that too is another, long discussion. But remember, it is less important that YOU know the state of charge and more important that your electrical system know it and respond correctly.

With lead acid batteries, time is your friend and that means that you want as much solar as you can cram on there.

Final note: Charging lead acid batteries is not something that you decide to do, or start or stop. The old statement, "I need to idle the engine for a few minutes to "top off" the batteries." is a prescription for turning expensive batteries into paper weights. You want a system that puts the batteries on charge automatically, every time there is even a single ray of sun or that your engine is running. And no, you will never run your engine long enough to fully charge your batteries. A full charge requires shore power or solar. Fortunately, you already have the latter and it will make all of the difference.
 
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coolfeet

Mark Keeler
Go read up on this subject on my website.

-- The D250S/SmartPass combo works well because it combines an intelligent relay with the voltage boost of a B2B.


With lead acid batteries, time is your friend and that means that you want as much solar as you can cram on there.

Final note: Charging lead acid batteries is not something that you decide to do, or start or stop. The old statement, "I need to idle the engine for a few minutes to "top off" the batteries." is a prescription for turning expensive batteries into paper weights. You want a system that puts the batteries on charge automatically, every time there is even a single ray of sun or that your engine is running. And no, you will never run your engine long enough to fully charge your batteries. A full charge requires shore power or solar. Fortunately, you already have the latter and it will make all of the difference.

Thanks! I went to your website and got absorbed by all the great info. The Smart pass sounds like a good idea since I own the D250S.

Mark
 

DiploStrat

Expedition Leader
I believe that all of the information is correct; it is based on two years of long term experience. I hope that you find some of it helpful.
 

coolfeet

Mark Keeler
I let the service battery charge all day through the solar panel. It got up to 13.3 volts and held steady all day. I drove the van for 2 hours yesterday and observed the service battery going down to 12.7 volts without anything connected to it.

I have not rewired anything yet. Even though the Ford auxiliary trailer battery charging circuit is not directly connected to the starting battery, it's still considered the "battery" as far as how CTEK D250S sees. It's a charging 12 awg fused circuit with a built in relay to separate the starting batteries from the service battery.

Something is causing the service battery to drain when it's supposed to charge. I think it's the CTEK. It worked beautiful 2 years ago on my first month long trip. I did not have solar connected. Thinks started going awry when I connected solar. However, I don't think it's the solar that's the problem.
 

john61ct

Adventurer
All charge sources should be directly connected to the House bank.

The B2B charger should charge the smaller, hardly depleted Reserve/Starter, which takes hardly any current, no SmartPass needed.

A proper alt VR like Balmar MC-614 and any quality solar controller will be very programmable for voltage setpoints, how long to hold Absorb etc.

Ideally use a shunt-based BM / AH counter to allow using endAmps to determine when to call it Full, and only then go to Float.
 

DiploStrat

Expedition Leader
… I have not rewired anything yet. Even though the Ford auxiliary trailer battery charging circuit is not directly connected to the starting battery, it's still considered the "battery" as far as how CTEK D250S sees. It's a charging 12 awg fused circuit with a built in relay to separate the starting batteries from the service battery. ...

Do the maths on a long 12 AWG wire. Compare with the CTEK recommended wire gauge. Then add in the resistance of your relay. I suspect that you could drive both ways around the world and never get a charge, even with the CTEK boosting the voltage.

Wire the D250S according to the factory instructions (getting rid of the relay) and let us know what you see. If that doesn't work, then you may have a dud unit. As you are getting a charge from your solar panels, you know that the base charger unit works.

The other alternative is a properly gauged, relay based system and simply using the D250S as a solar charger. (Not my recommended solution, but it will work.)
 

dwh

Tail-End Charlie
SYMPTOM:

I let the service battery charge all day through the solar panel. It got up to 13.3 volts and held steady all day. I drove the van for 2 hours yesterday and observed the service battery going down to 12.7 volts without anything connected to it.


DIAGNOSIS:

Something is causing the service battery to drain when it's supposed to charge.


I'm not convinced that this diagnosis is quite correct.

If the battery were fully charged and being held in float by the solar (at say 13.3v), then all charging was shut off, the battery would slowly dissipate its "surface charge" and after a couple of hours would eventually settle down at its proper fully charged "resting voltage" of (for most lead-acid batteries) 12.7v-12.8v.

This would happen normally and naturally and doesn't require any loads to be draining the battery.

So it doesn't seem correct to say "something is draining the battery when it should be charging". I think perhaps it's a case of, "nothing is charging the battery when it should be".


I'm not familiar with the intimate details of the 250s' internal operation, so all I can do is take a guess that seems to fit the symptom. So here's one guess...

When the unit senses rising voltage on the engine battery input (engine is running), it switches the input of its internal battery charger from solar to engine battery (disconnecting the solar).

Then perhaps when it loads the engine battery input, the input voltage drops below whatever it needs to see, so it isn't charging the house battery from the engine either.

Thus no charging from either solar or engine, and without any charging or loads on the house battery, the house battery is allowed to dissipate its surface charge and drop to its resting voltage.


Another alternative - still assuming that the solar is disconnected when the engine is running - is that the battery is fully charged, so when the internal battery charger is powered from the engine, the amps flowing is low enough that the charger knows the battery is full and just doesn't bother to charge it.

Still, in that situation, I would normally expect to see it holding the battery at a float voltage. But perhaps the amp flow is low enough that when the engine was started the charger never went into bulk stage, so it doesn't run through the normal "charge profile" and never has a chance to "drop to float stage".



Dunno. Just guessing here.

I'm still thinking there's likely a voltage drop issue to the unit's engine battery input.
 

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