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Hello,
I'm planning to have an alternator charging of my leisure LiFePO4 battery in my camper van. I have standard Lead Acid starter battery connected to an old van alternator from the 80'.
What would be more safe for my LiFePO4 Victron 150ah battery and for my old van alternator (I don't want to overheat the alternator).
Would Cyric Li-Ct would be a safe solution or should I go with the DC-DC charger?
Thanks for answers!
Tom
The Cyrix is basically a glorified relay so it won't limit current draw in any way.
The Orion will limit the current drawn from the charging system but only in a roundabout way. What these things do is they will attempt to charge the batteries at a given amperage and output voltage; the implication here is that the output power is fixed. The issue this may present is that if the output power is fixed, then the input power is also fixed. But what's not fixed are the input voltage and current. Because there will be voltage drop between the vehicle's charging system and the Orion's input terminals, the input current may far exceed the unit's specified max output current. I know this from experience because my Orion 12/30 charger will try to maintain 14.2V when bulk charging my batteries, but the input voltage drops precipitously and of course to maintain the voltage*current on the output side the input current must increase dramatically thus increasing the voltage drop and creating a vicious cycle and cascading failure. In practice what happens is that it blows the 30A input fuse within seconds.
In my application the Orion is in a trailer being charged from the truck's 12V auxiliary power circuit which has to run through somewhere between 35 and 45 feet of 10 AWG wire before it gets to the Orion (including the truck/trailer interface which is full of corrosion and resistance), so 30-40 percent voltage drops are not out of the question at all. If you can position the Orion so that it's close to the charging system you may be able to avoid this, but then you have the problem of the Orion's output voltage not matching the batteries' voltage (due to the voltage drop between the Orion and the batteries).
You can set an input voltage cutoff such that the charger turns off if the input voltage drops below some level; I can do this with my 12/30 but what winds up happening is that it charges for a few seconds, the voltage cutoff kicks in, and the charger turns off. Then the input voltage comes back to its open-circuit value and the charger turns on again. But it only spends about 25-50% of the time actually charging. The solution in my case is to just get a lower amperage Orion, but a better solution would be for Victron to allow users to specify an input current limit for these devices.
@Jersey Dirtbag, please note that the manual specifies a 50A input fuse.
@SlowJoe, the Cyrix is not current-limiting, so it won't protect your alternator at all; to ensure alternator protection, a DC-DC charger is the only option - in your case, with an old and likely low-output alternator, the Orion-Tr Smart 12/12-18A is likely your best bet.
Thank you for the advice. I have two more questions.
If I will instal the Orion-Tr will I need still some battery separator or the Orion would do the job?
Would I have any option for jump starting the engine in the DC-DC configuration?
For information, I checked that my alternator rating is 55A.
Thx for all the suggestions and help!
Hi @SlowJoe, the Orion will isolate the batteries from each other, you don't need an additional isolator.
Unfortunately, there is no "jump-start" feature in the Orion, but of course you could always just run a set of jumper cables between the two batteries if you needed a jump.
For a 55A alternator, you have realistically around 25A that you can safely pull continuous. Since the Orion-Tr Smart 12/12-18 will pull ~21A from the start battery, it would work fine so long as you have NO chassis loads (ie, headlights, heater blower, etc). As soon as you turn on a few chassis loads, you start running the risk of overloading the alternator. Personally I would look into getting a higher-current alternator installed prior to installing any kind of DC-DC charging system.
