DC-to-DC + Isolator

[reilym]

Originally Posted by Rlum

Very interesting! Will wait to see what you find out. Thanks everyone. Great ideas and input!

I posed the questions below to the Mastervolt tech support and got the responses that follow. Basically, they are suggesting the DC-DC charger as the best solution and suggest using more than one in parallel to get a higher rate of charge than a single unit can provide.

My email to Mastervolt:
I have a few questions about the chargemate pro 90. My application is an RV that originally came with an under hood solenoid battery separator, which I replaced with a 60 amp DC-DC charger. I have 200 Ah of LiFePO4 batteries in the coach and an AGM starter battery in the Promaster 3500 chassis.

Can this unit be mounted under the hood? If not, where would a suitable external location be for mounting?
Will the unit automatically shut off if temperature exceed the maximum operating temperature?
It appears that this unit will pass 90 amps, with priority to the starter battery, with the balance going to the second battery bank. As this starter battery becomes fully charged, more current will go to the second battery bank. Do I have this correct?
What is the efficiency? In other words, if the output is 90 amps, what is the input current?

Response from Mastervolt:
You have two different battery chemistries, and most likely have two different charge rates for each type of battery. The preferred method of charging would be to use multiple Mac Plus [DC-DC charger] units in parallel instead of the Chargemate 90.

It is recommended to install a Chargemate in a well ventilated area to reduce heat. If the temp under the hood does not exceed the temp spec of the Chargemate or does not maintain temps close the max. spec’d temp, you can mount the device under the hood.

The Chargemate will not automatically shut off it exceeds the maximum operating temperature. The unit could be damaged is the temp exceeds the spec.

When the start battery is full, any available current up to 90 amps will be passed through to the house battery.

I do not have a spec for efficiency, but the reduction in current would be minimal. Any difference between the input and output current should be less than 1 amp. The circuit board consumes mA to operate the components on the board. Let me know if this is a critical piece of information that you need, and I will contact the Engineers in Amsterdam. The max. voltage drop is 0.2V

[Rlum]

Originally Posted by reilym

I posed the questions below to the Mastervolt tech support and got the responses that follow. Basically, they are suggesting the DC-DC charger as the best solution and suggest using more than one in parallel to get a higher rate of charge than a single unit can provide.

My email to Mastervolt:
I have a few questions about the chargemate pro 90. My application is an RV that originally came with an under hood solenoid battery separator, which I replaced with a 60 amp DC-DC charger. I have 200 Ah of LiFePO4 batteries in the coach and an AGM starter battery in the Promaster 3500 chassis.

Can this unit be mounted under the hood? If not, where would a suitable external location be for mounting?
Will the unit automatically shut off if temperature exceed the maximum operating temperature?
It appears that this unit will pass 90 amps, with priority to the starter battery, with the balance going to the second battery bank. As this starter battery becomes fully charged, more current will go to the second battery bank. Do I have this correct?
What is the efficiency? In other words, if the output is 90 amps, what is the input current?

Response from Mastervolt:
You have two different battery chemistries, and most likely have two different charge rates for each type of battery. The preferred method of charging would be to use multiple Mac Plus [DC-DC charger] units in parallel instead of the Chargemate 90.

It is recommended to install a Chargemate in a well ventilated area to reduce heat. If the temp under the hood does not exceed the temp spec of the Chargemate or does not maintain temps close the max. spec’d temp, you can mount the device under the hood.

The Chargemate will not automatically shut off it exceeds the maximum operating temperature. The unit could be damaged is the temp exceeds the spec.

When the start battery is full, any available current up to 90 amps will be passed through to the house battery.

I do not have a spec for efficiency, but the reduction in current would be minimal. Any difference between the input and output current should be less than 1 amp. The circuit board consumes mA to operate the components on the board. Let me know if this is a critical piece of information that you need, and I will contact the Engineers in Amsterdam. The max. voltage drop is 0.2V

Thanks! Very good information. Anyone connect two Victron DC to DC chargers in parallel to get 60amp charging? Maximum on Victron DC chargers is currently 30amps. I really like their products. Easy to use with bluetooth and very robust!

[@Michael]

Originally Posted by Rlum

Thanks! Very good information. Anyone connect two Victron DC to DC chargers in parallel to get 60amp charging? Maximum on Victron DC chargers is currently 30amps. I really like their products. Easy to use with bluetooth and very robust!

I have two Victron MPPT solar controllers, IP-22 one charger/converter, and one Orion B2B charger in parallel, all charging the same AGM bank at the same time. As long as the settings are identical, they'll work.

[Rlum]

Originally Posted by @Michael

I have two Victron MPPT solar controllers, IP-22 one charger/converter, and one Orion B2B charger in parallel, all charging the same AGM bank at the same time. As long as the settings are identical, they'll work.

How many amps for the Orion? Does it get really hot?

Thanks

[@Michael]

Originally Posted by Rlum

How many amps for the Orion? Does it get really hot?

Thanks

I have the 18 amp version Orion mounted in a fairly tight enclosure. It hasn't gotten hot enough that I noticed, but I've not actually measured its temperature.

Just to make sure, I checked the Orion docs:

"All models are short circuit proof and can be paralleled to increase output current" ... "An unlimited number of units can be connected in parallel."

[Rlum]

Originally Posted by @Michael

I have the 18 amp version Orion mounted in a fairly tight enclosure. It hasn't gotten hot enough that I noticed, but I've not actually measured its temperature.

Just to make sure, I checked the Orion docs:

"All models are short circuit proof and can be paralleled to increase output current" ... "An unlimited number of units can be connected in parallel."

Thanks for update and information!

[booster]

Originally Posted by @Michael

I have two Victron MPPT solar controllers, IP-22 one charger/converter, and one Orion B2B charger in parallel, all charging the same AGM bank at the same time. As long as the settings are identical, they'll work.

Have you ever watched the stages on all the sources when then were running?



I find highly unlikely that different brands would have the same style or charge control and/or the same timer settings or algorithm.


That said, they will not likely hurt each other, and they wouldn't even if the settings were slightly different, which the probably are at least sometimes but probably more often anyway.


All the really happens is that there will be one dominant source doing a majority of the charging with the others running at reduced output, so you would almost never see a charge rate that was the actual sum of sources max output.



Most of us have similar setups without issue. We have a shore charger, solar controller and remote regulator running alternator charging. All are different brands and I actually have them set at somewhat different voltages for various reasons.

[@Michael]

Originally Posted by booster

Have you ever watched the stages on all the sources when then were running?

I find highly unlikely that different brands would have the same style or charge control and/or the same timer settings or algorithm.

I don't have each metered individually and only the MPPT controllers have current measuring built in, so no, I can't tell exactly how much each source is contributing. I also only have 220Ah of AGM, so the batteries don't accept at a rate high enough to max out all the charge sources for more than a few minutes anyway.

On my lithium battery, I have a 40A Redarc B2B, which I occasionally have run in parallel with the two Victron MPPT's. The result was a rate of charge higher than 40A, with both solar controllers contributing.

Some Victron devices (the 'Smart' MPPT controllers and some of the chargers, but not the Orion B2B's) participate in a Bluetooth mesh network that synchronizes the charge profiles between devices. This is a nice feature.

[rowiebowie]

Originally Posted by ovsa

To those that have replace their 4 post chevy RT isolators with the Renogy DC2DC charger, what do u do with the extra wires coming of the relay and the two switches on top?

I don't have a Roadtrek, but a fairly similar (to the 190) Airstream Avenue on the Chevy Express chassis. I did a lithium/inverter/dc to dc Renogy upgrade and my isolator looked like this. Don't know if it's the same as yours.