Power Charge controller from 24v Power supply?

[sfpcservice]

Hi everyone,

I just got some batteries in our RV that require a bit higher voltage than usual to charge. So far it looks like the best charging option I have is a morningstar ts-45 because you can specify the charging voltages. One little glich, I don't have solar panels... I was wondering if I can feed it with a 24v DC 700 watt power supply? If not, can someone explain why it wouldn't work?

Thanks everyone!

[Logan005]

NO. You need a good AC to DC charger like Samlex or IOTA. you can not feed a solar charge controller with a 24 volt power supply.

[Logan005]

the solar CC is not made to have a constant power source, in my case the combo I used created feedback into power supply blowing transistor before blowing the charge controller. power supply easy fix with a solder gun. CC not so much.

[sfpcservice]

Is the feedback a result of two PWM circuits fighting each other?

[Logan005]

IDK, I have read details of why it will not work since. I did not read long enough to learn why. I do remember it had to do with current feedback due to the amount of time the PWM was in off condition. but I am no electronics major.

[inetdog]

IDK, I have read details of why it will not work since. I did not read long enough to learn why. I do remember it had to do with current feedback due to the amount of time the PWM was in off condition. but I am no electronics major.

The most common reason why it will not work is that a PWM CC acts like a hard connection to the battery terminal during the time that the pulse is on. That means that there is no limit except the internal resistance of the battery to keep from drawing too much current from the power supply output.
The two most likely results of this are:
1. Burn out power supply or blow fuse, or
2. The power supply shuts down because of the overcurrent on its output and has to be power cycled or otherwise reset before it can deliver power again.
An MPPT CC on the other hand will try to draw as much current as it can from the power supply to find the maximum power point. Since the PS, unlike PV panels, is a voltage source rather than a current source the result will again be either overloading the power supply or the MPPT CC input circuit.

[Sunking]

No it takes 29 volts to charge a 24 volt battery. End of story

[sfpcservice]

No it takes 29 volts to charge a 24 volt battery. End of story

I am trying to charge a 12 volt system, 2 golf cart batteries.

[inetdog]

No it takes 29 volts to charge a 24 volt battery. End of story

Other than the use of "batteries", plural, I do not see any indication that the OP has a 24V battery bank.
Most RVs come from the factory with 12V, either two 6V batteries or 12s in parallel.

[Sunking]

my bad, assumed 24 volt battery from title. Does not change things, not going to happen with a Solar Controller.

Other than the use of "batteries", plural, I do not see any indication that the OP has a 24V battery bank.
Most RVs come from the factory with 12V, either two 6V batteries or 12s in parallel.

[sfpcservice]

The most common reason why it will not work is that a PWM CC acts like a hard connection to the battery terminal during the time that the pulse is on. That means that there is no limit except the internal resistance of the battery to keep from drawing too much current from the power supply output.
The two most likely results of this are:
1. Burn out power supply or blow fuse, or
2. The power supply shuts down because of the overcurrent on its output and has to be power cycled or otherwise reset before it can deliver power again.
An MPPT CC on the other hand will try to draw as much current as it can from the power supply to find the maximum power point. Since the PS, unlike PV panels, is a voltage source rather than a current source the result will again be either overloading the power supply or the MPPT CC input circuit.

Doesn't the ts-45 have an adjustible amp setting? If it did, couldn't you set that to not over draw the power supply?

[Sunking]

Doesn't the ts-45 have an adjustible amp setting? If it did, couldn't you set that to not over draw the power supply?

No.

[sfpcservice]

Ok so just to clarify, the reason this won't work is because it wold have a similar effect on the power supply as if you hooked the power supply directly up to the batteries?

[sfpcservice]

Just heard back from Morningstar and they confirm not to use their PWM controllers with an external power supply, but their MPPT controllers can be used in this manner.

[inetdog]

Just heard back from Morningstar and they confirm not to use their PWM controllers with an external power supply, but their MPPT controllers can be used in this manner.

They may not have mentioned it, but that advice is conditioned on the power supply having a higher maximum output than the maximum rating of the CC or the supply having built in soft current limiting.