24V to 12V split charger?

[surfer4life]

i must have confused you somewhat pierre,

i have the sterling battery to battery 30A charger 24v to 24v.

my understanding is that if you have a 55 amp alternator that is the max it will put in, the 80A alternator to battery charger just means that it is capable of handling 80A, if your alternator only puts outs out 55A then the max it can possibly put in in 55A, this will not happen though as the vehicle will be using the some of the alternators power to run.

are you sure your alternator is 55A? seems a bit low, i thought vario's came in at 80A and 120A

the 30A B2B charger is fine for me as i have 200W solar at 24v, and a 240v to 24v charger, seems to keep everything topped up and i've never needed to use the 240V to 24v charger.

 

[Stuartag]

the 30A B2B charger is fine for me as i have 200W solar at 24v, and a 240v to 24v charger, seems to keep everything topped up and i've never needed to use the 240V to 24v charger.

Sorry to resurrect an old thread, but I am looking at the Sterling 24v to 24v BtoB charger for my soon-to-be Mog. Looking at the manual for my compressor fridge, it says to unplug when using a fast charger (over 5 amps). I have heard of people, and you seem to be one of them, that use this with a fridge without any problems. I assume that you are using it with the fridge running? Any problems that anyone can see with this. I also will have about 200W of solar.

 

[ianc]

Stuartag - What model of fridge do you have?

 

[Stuartag]

ARB MT35F-AL previous generation. The truck currently has an old Engel.

 

[surfer4life]

Sorry to resurrect an old thread, but I am looking at the Sterling 24v to 24v BtoB charger for my soon-to-be Mog. Looking at the manual for my compressor fridge, it says to unplug when using a fast charger (over 5 amps). I have heard of people, and you seem to be one of them, that use this with a fridge without any problems. I assume that you are using it with the fridge running? Any problems that anyone can see with this. I also will have about 200W of solar.

I couldnt comment on your specific fridge, but mine is an auto switching 12v/24v shoreline fridge, its always on, and my solar system runs at over 5 amps and is on most the day, it would make the fridge un usable if i had to switch it off in daylight hours. No issues at all with my shoreline being on all the time.

I cant see how using a charger effects the fridge as it only drawing what current it needs from the battery bank, the only thing that changes is the voltage of the leisure batteries, it goes upto 29.1 v when the sterling B2B is on and my fridge can handle that range, so no issues.

 

[Stuartag]

Surfer, Thanks for the reply. I wonder if the fast charging could possibly effect the long term life of the fridge, or if it is a case of ARB cya, or both.

 

[nick disjunkt]

Stuart, the fridge recommendation surely has more to do with voltage than amps. Fast chargers can put out a pretty high voltage to help get the current into the batteries quickly. Over 15v/30v is not uncommon, and it is probably this that the fridge objects to. I cannot see how the fridge would even know the batteries were receiving a >5a charge unless the voltage rose. Where possible I have tried to stick with equipment in my truck which is happy at up to 32v, but some of the equipment (led lights particulalrly) specify 28v max and so I will just accept a shorter life on these components.

If you are likely to exceed the recommended max voltage of the fridge when you are running high power chargers such as solar regulators, sterling B2B chargers, or mains chargers, you might like to fit a voltage regulator in the power feed to the fridge. Studer make some extremely good low voltage electrical equipment, including voltage regulators for 12v and 24v supplies; the 12v versions take any voltage between 9v and 15v and give a stable 12.5v. To the fridge, the supply looks like the battery is fully charged but not actually being charged. There is of course an inherent inefficiency in the voltage conversion but the Studer units achieve around 90%

 

[pier1234]

wiring the Sterling A to B charger

Hi all,

I bought the Sterling Alternator to Battery charger, 24V 80A. Now I have to connect it.

Sterling says I should connect it directly to the alternator, to the starter battery and to the house battery. I suppose the idea is to force the current charging the starter battery and the house battery through the Sterling charger.

First question:
Actually the alternator and the starter are connected, this is the connection betwen the alternator and the starting battery. Should I remove this connection? If not, the starting battery will be connected directly to the alternator and the charging current wouldn't have to go through the Sterling charger.

Second question:
If I remove the connection between the alternator and the starter, then all electric equipment which is connected to the alternator would not work when the motor (and the alternator) is not running. Shoud I now connect this Equipment to the starter (and the starting battery) instead of the alternator?

Thanks for your input.

Pierre

 

[ianc]

Pierre,
There should be a detailed wiring diagram with the unit and you should follow that. On your specific questions:
1) I would not break any connections unless the instructions explicitly tell you to do so and I'm sure you should not be removing the connection between the alternator and the starting battery.
EDIT - I've just downloaded the installation guide and it does appear to break the Alternator<->Start battery connection and I see how that makes sense now (I'd mistakenly read that you had a battery to battery charging system). Call the guys in Sterling to confirm. This is the diagram I was looking at: http://www.shop.sterling-power.com/acatalog/AB.pdf

2) You won't be removing that cable so Q2 is not necessary.
EDIT - I think this should still not be a problem - But what do you think might be just connected to the Alternator and will become isolated?

Also - the Sterling help phone number is pretty good. The guy can be a little abrupt but he can explain how to connect it up.

 

[Joe917]

I have a 3 stage Dometic Perfect Charge that puts out charge voltage for 12 and 24 volts at the same time set up for house and starter batteries. My 100 amp alternator also charges both banks although I have not checked how it is wired. I have not owned the vehicle long enough to recommend the Dometic.
T105's are the best bang for the buck although they are taller than 8d batteries and may not fit.

 

[killowatt]

The way its done on Large Power generators

I build large Co-gens and Generator packages and some sensors and the wireless routers we use are 12vdc the best way we have found is using a DC to DC transformer. SDC30 converter is used to drop a 24 volt DC source to a regulated 12 volt DC source. Its made by Samlex I use http://chargingchargers.com/converters/sdc30.html

good luck