Current limiter for DC-DC charger ?

Hey Folks,

I do have a 30 Amp DC-DC charger for camper battery already in place, connected directly to the starter battery. Works fine, but the problem is the alternator is rated 60 Amp, running Taco takes 44 Amp already, leaving only 16 Amp available for the Dc-Dc charger.

Is there a way to limit the current able to reach the Dc-DC charger ? something

$50 Car Voltage Stabilizer, DC 12V Regulator 12V Surge Protector 144W Heavy Duty for Car Battery Auto Truck Vehicle Boat Motor Solar System Protection (DC 10-36V Input, DC 12V Output)

like that maybe ?

Of course when I ask Victron they tell me to buy the 18 Amp version ...

I don't want to overload my alternator and run into issues while off-roading with no service !

 

does the DC-DC charger subtract that much?

Ive had a 25 amp dcdc charger for a year with no ill effects. Does it work like that?

 

The real solution is a more powerful alternator, or to take victrons suggestion.


Where did you they 44A to run the truck? Is that everything on?

 

You should put your money towards a better alternator, the OEM alternator from the tow package puts out 130A and there are aftermarket alternators that go up to 350A. Another option would be to add an MPPT controller and some solar to the house battery. There are DC-DC MPPT all in one's that will dynamically keep both your house battery and starter battery charged.

 

@fatfurious2, @0xDEADBEEF : I used a clampmeter, running truck with all accessories on (lights, stereo, AC) = 44 amp. Same goes when I clamp the cable to the DC charger , 35->38 Amp (89% efficient so I guess it needs more than 30 Amps.

@Glazed_Ham : agreed, from the literature I could find here, the factory alternator is only 60 A. But I am not a mechanic, I'll have to ask my mechanic to do that for me $$$... and yes I also explore the renogy solution that does MPPT and DC-DC under the same device, shame it is a 30 Amp as well, won't make the problem go away

So I gather a current limiter option does not even exist ?

 

That option might exist but it's silly. Let me make it simple: you are never going to subtract electrical loads now that you are opening pandoras box on having even more power. Upgrade your alternator as it would be more logical and better in the long-run. Or buy the 18A version of the Victron.

My qualifications to say these things: I have owned the 30A Victron DC-DC and have the 130A alternator in my '15 Offroad. Upgrade the alternator.

 

Ok I’ll figure out how much it is going to cost me to get the alt replaced, or if I. An do it myself …

 

Not sure where you are getting 60amps from? From what I can see even the 2.7L gets an 80amp alt, non towing package v6's get 100amp and the towing package is 130.

 

Can you put your reference please ? Ok got mine from here : https://www.tacomaworld.com/threads/alternator-output.285202/

i have the V6 4.0l

thx

 

Thats for the 1st gen taco. Just looking on rock auto the replacement stock alts for our 2nd gen trucks to get numbers.

 

Arg this is so hard and confusing to get right numbers I'll see if I can find any reference on the alternator itself as the internet is giving me all kind of results !

 

Based on your profile it looks like you have a 2nd gen. What year do you have, and what trim (i.e. SR5, Offroad, etc) do you have? I didn't catch that before but like @nd4spdbh says you probably have at least the 100A version at minimum. If you have the towing package you have the 130A and either of those should be fine to run the 30A charger.

 

Yes it is a 2nd gen, 2014 Toyota Tacoma 4WD 6 Cylinders 4.0L MFI DOHC 241 CID. Trim is not TRD, I would say SR5, access cab. Thanks !!

 

Cool, then you should by all accounts have at least the 100A alternator already. Unless you are running the HVAC fan at full blast with every single light and electrical load on at the same time you are probably just fine to run the 30A charger.

 

Im just curious as to why you would need to use one of these chargers? The stock 7 pin towing harness simply connects the main battery to the trailer battery via a relay when the truck is running to charge things. Wouldnt be too hard to rig up the same on a non tow package setup.

 

Voltage drop is one reason. That long a run might not have enough voltage to properly charge the camper's house battery, especially if it's an AGM that already needs higher voltage than a Tacoma puts out without mods.

 

@nd4spdbh : It is a lithium battery, Lifepo4, It is not recommended to charge it directly :

Can an alternator damage a lithium battery?

While not being the best for the battery, the charge voltage should not destroy it. The risk is on the alternator side. The lithium battery has a very low internal resistance that forces the alternator to deliver as much current as possible.​

 

Looks like you got some sort of truck camper on there. Lets get some more pics of that thing!

 

Hehe going off topic here, but here are the few pictures I could find :

100% homemade, 800 pounds, wood + fabric + lots of wood glue (waterproof) + paint (uv and waterproof). We use it in the winter in Alaska / Yukon, up to -25 F no problem. Lithium battery is self heating if cold before charging, it is fantastic. (30 minutes to go from -20 F to 45 F, then it charges the battery)