Limiting amperage

[Rebalaje]

Hello, I am changing to Lifepo4 12v. I have a standard alternator of 50 amp. but the dc dc charger (it is a combined Dc Dc charger and a mppt) is 60 amp. I am afraid that with that combination will damage the alternator. How could I reduce the flow to solve that? Is there anything that would reduce the amperage draw from the alternator?
Thank you. Fair winds.

[Emmalina]

An external regulator such as a balmar.

[hjohnson]

Originally Posted by Rebalaje

Hello, I am changing to Lifepo4 12v. I have a standard alternator of 50 amp. but the dc dc charger (it is a combined Dc Dc charger and a mppt) is 60 amp. I am afraid that with that combination will damage the alternator. How could I reduce the flow to solve that? Is there anything that would reduce the amperage draw from the alternator?
Thank you. Fair winds.

You will either need to modify your alternator and get an external regulator (balmar or Wakespeed, both expensive) or get yourself a smaller DCDC charger, such as the 18A victron.

[RaymondR]

Or just put a resistance in the line to the battery and use a regulator with a voltage sensing terminal connected to the alternator side of the resistance.

[smac999]

Replace the 60a with a 30a victron Orion smart.

Get a victron mppt well you are at it.

[zurk]

Originally Posted by Rebalaje

Hello, I am changing to Lifepo4 12v. I have a standard alternator of 50 amp. but the dc dc charger (it is a combined Dc Dc charger and a mppt) is 60 amp. I am afraid that with that combination will damage the alternator. How could I reduce the flow to solve that? Is there anything that would reduce the amperage draw from the alternator?
Thank you. Fair winds.

get a WS500. ditch the DC to DC charger portion and use it just as an MPPT.

[rgleason]

What you need to do is reduce the field current and disconnect it if the alternater heats up too much.

That is only part of the job that a good external regulator does.

In addition, you will want to manage your lifepo properly.

[donradcliffe]

Originally Posted by RaymondR

Or just put a resistance in the line to the battery and use a regulator with a voltage sensing terminal connected to the alternator side of the resistance.

What Raymond says. If you want to limit current from the alternator, just don't put massive wires from the output to the battery. See what current the alternator is actually putting out before you go crazy with fixes for a problem that doesn't exist.

[goboatingnow]

Originally Posted by RaymondR

Or just put a resistance in the line to the battery and use a regulator with a voltage sensing terminal connected to the alternator side of the resistance.

Huh this is effectively a cabin heater. Work out the watts

[Rebalaje]

Thank you for the replies. Its true that I am fixing a problem that may no exist. I am afraid I have little idea about regulators and electric stuff, and I understand that another DC DC with lower amperage would be the simpler and maybe cheaper solution.
I think I will implement the system as it is, with a breaker between the alternator and the DC DC so I will control how is the amperage going thru the system. I understand that I have to be careful that in low rpm the alternator may no have enough cooling, but in higher rpm should cool ok. Another concern is that as noted, maybe if the wiring is not up to the task, it will be enough to keep the amperage down, but I guess I should keep an eye in that they don't fry up.
Fair winds and Watts to spare.

[smac999]

Originally Posted by Rebalaje

I think I will implement the system as it is, with a breaker between the alternator and the DC DC so I will control how is the amperage going thru the system. .

the alt goes to the engine battery, the dc- dc goes between engine battery and lith batt so you could breaker between the engine battery and dc-dc (you have to anyways) but putting a smaller breaker in to control is a horible way to do it.

if you connected alt direct to to dc to dc with a breaker as you posted. and the breaker blew, you would blow up the alt too

[T1 Terry]

Does the DC to DC have any sort of adjustments as regards to voltage, start battery charge stop and recovery and charging current. If it is a Victron Smart model, you should be able to communicate with it via an app and cell phone to set the parameters avoid cooking the alternator. If you set higher start battery voltage for instance, it will draw the start battery down and then shut the DC to DC down until the start battery recovers, this will give the alternator and DC to DC charger a chance to cool a bit between DC to DC load cycles ......

The resistor/small cable idea will just drop the voltage being supplied to the DC to DC charger making it work harder and you just move the over loading problem from the alternator to the DC to DC charger.

T1 Terry

[SOLAR SUPPORT]

Originally Posted by Rebalaje

Hello, I am changing to Lifepo4 12v. I have a standard alternator of 50 amp. but the dc dc charger (it is a combined Dc Dc charger and a mppt) is 60 amp. I am afraid that with that combination will damage the alternator. How could I reduce the flow to solve that? Is there anything that would reduce the amperage draw from the alternator?
Thank you. Fair winds.

http://balmar.net/products/digital-duo-charge/

Balmar's "Digital Duo Charger". I guess it's not a new product. With DDC, you can charge different types of battery groups using a standard alternator. The diagram below is from Balmar's website. Consider the LFP battery bank connected at the Engine battery location shown in the diagram. The engine battery is connected where the house battery is shown in the diagram. When such a connection is applied, the LFP bank receives a limited charging current of 30A. It is possible to increase this current with an optional solenoid control, says Balmar. No need to use DcDc charger, APD, Smart External Regulator.