Can you combine two chargers to get 50A?

[twistedtree]

I’m still unclear what problem you are trying to solve.

Do you have inverter loads that are greater than the 30A that the inverter can pass through, and want to be able to power up to the 50A that your shore connection can supply? Presumably you have other loads that do not go through the inverter, like a hot water heater, HVAC, and perhaps others? These will all consume part of the shore’s 50A capacity without impacting the inverters capacity.

Or do you have inadequate charge capacity and want to add more? By all indications you have pretty good charge capacity now, but if the goal is to get more, for whatever reason, we can focus on solving that.

Or do you want to prevent whatever caused your inverter to shutdown that one time? I would argue that you really don’t what caused the overload, and need to before attempting a fix. Otherwise it’s just guessing about the problem, and guessing about the fix.

It’s hard to provide a useful recommendation without being clear what problem you are trying to solve.

 

[Bmarler]

I’m still unclear what problem you are trying to solve.

Do you have inverter loads that are greater than the 30A that the inverter can pass through, and want to be able to power up to the 50A that your shore connection can supply? Presumably you have other loads that do not go through the inverter, like a hot water heater, HVAC, and perhaps others? These will all consume part of the shore’s 50A capacity without impacting the inverters capacity.

Or do you have inadequate charge capacity and want to add more? By all indications you have pretty good charge capacity now, but if the goal is to get more, for whatever reason, we can focus on solving that.

Or do you want to prevent whatever caused your inverter to shutdown that one time? I would argue that you really don’t what caused the overload, and need to before attempting a fix. Otherwise it’s just guessing about the problem, and guessing about the fix.

It’s hard to provide a useful recommendation without being clear what problem you are trying to solve.

Completely agree. It could be that he’s exceeding the capacity of the transfer switch, or the charger is over max output and shutting down for thermal or other protective reasons. Should be easy enough to solve either way without new hardware, just changing settings or shifting loads off the transfer switch.

 

[LeoKa]

Our Victron MultiPlus 24-3000-70-50-120 sorta kinda has Bluetooth... but it's via BMV-712 or a VE.Direct "Smart Dongle".



But that maybe what you meant about additional parts...



-Chris

Yes. I also have one of those. I use it with a Victron MPPT. Works well, but I need it there, so I can monitor the panels behavior.

The Renogy I have listed earlier checks out all the boxes, so I will go for it as a replacement and hopefully solve my 50A problem. The MasterVolt will stay as a backup, as it is fully functional at 30A.

 

[SailorGreg]

At my marina I have 50A shore-power available. My inverter/charger is 30A max. (Mastervolt CombiMaster 12/3000-160 120V). I wanted to buy 50A model but it was on back order forever.
Recently, testing my solar system charging, my lithium bank (680 AH total) was depleted to 55% purposely. When I reconnected the shore-power the draw was too much for the MasterVolt and kept shutting down and back on, till the battery level was back to 65%. After that, the charging went on smoothly. The 160A max from the charger was not enough juice for the batteries.
The 50A MasterVolt model can do 200A charging, but I will need to buy one and get rid of the 30A model I have.
What if I buy just a regular charger from MasterVolt and combine it with my existing 30A charger/inverter? Is this possible? Will I get the 50A from shore? If yes, how would you do it?
MasterVolt chargers can be networked with Masterbus, but there is no instructions on how to combine two chargers and how to wire them?
Thanks.

I am still trying to figure out your set-up. With the Combimaster you now have, the input V is 120. So are you now plugged into a 30A 120v Shore plug or a 50A 240V and using just one leg?
If you want to increase your battery charging capacity you could add another Combimaster and put one on each leg of the 50A/240 from shore.
A lot depends on how the rest of your boat is set up. You say you are equipped for 50A, but are your non- inverted loads 240v or 120v? Balancing power draw on the two legs can be challenging.
Mastervolt service is provided through dealers. Find a local Mastervolt dealer and establish a relationship with a knowledgeable tech there. Better than dealing with the factory.
The Mastervolt Easyview screen/ control panel is useful and you can plug your laptop into it, running MasterAdjust.
For what it is worth, my boat is 24v and 50a/240 with 120v loads supported from the inverter. I have two 100A chargers plus a third 100A charger with the inverter and 900Ahrs of battery capacity (@24v) I can run all three chargers at once.
That said, not sure why you would be having issues with your single charger. Your batteries can accept more than your charger can pump out, at least when the SOC is down. But batteries don't " suck on the pipe" meaning they don't try and draw more than the charger is capable of.
Conjecture on my part, but the shut downs may be that you are maxing out the input current (28a) for the unit to support the charger while also asking for power for the inverter loads. The settings may be prioritizing inverter loads . You may be able to adjust the loads and priorities through masteradjust.
My first assumption would be that the unit is operating as designed. Deciphering those design parameters can be a challenge with the documentation that comes with these units but a close reading may explain what is going on. With this unit you can also set up various alarms for high/ low A and V etc. and then look in the logs to see if any parameters are being exceeded.

 

[LeoKa]

No.
I have 50A/120V shore power coming on board. The distribution panel is wired for this. My previous inverter/charger was 50A but died. I wanted a better brand and picked MasterVolt. They only had 30A models for several months, so I bought one after long wait in 2021.

I do have EasyView, MasterShunt, software. The setting options are very limited and most of it locked down. MasterVolt does not support other brand lithiums. Only theirs. Yes, the Events section in the software could give a clue what happened, but it only occurred once. I plan to figure out, why my batteries were down to 55% SOC, while my solar panels were charging the bank? But that is another story. I do not want my batteries to be depleted this much, when I am away from the boat for few months.

 

[SteveK]

I recently switched to Lithium for the ability to draw down to 0% if needed. Your 55% causing charging shutdown concerns me as that also limits your use of the battery type.
Why the charger exceeded the max rate of 160A to 165A and then shut down is the real issue that should not be happening.
A second Mastervolt charger idea may work if both chargers combined output the max the batteries are willing to take in. If that is above 320A then I would expect both to shut down.
Why the charger went above the max rating and then shutdown needs to be solved. Your 680A bank might accept 340A max. before a BMS shutdown.

 

[SailorGreg]

No.
I have 50A/120V shore power coming on board. The distribution panel is wired for this. My previous inverter/charger was 50A but died. I wanted a better brand and picked MasterVolt. They only had 30A models for several months, so I bought one after long wait in 2021.

I do have EasyView, MasterShunt, software. The setting options are very limited and most of it locked down. MasterVolt does not support other brand lithiums. Only theirs. Yes, the Events section in the software could give a clue what happened, but it only occurred once. I plan to figure out, why my batteries were down to 55% SOC, while my solar panels were charging the bank? But that is another story. I do not want my batteries to be depleted this much, when I am away from the boat for few months.

The 50A/120v explains it for me. I missed that earlier in the thread.
The 160A @ 12 v delivered is using about 19 of your available 50A at the pedestal. You could add a Chargemaster, say 100A and still stay inside your limits. Chargemasters are not very expensive.
I would work with a local Mastervolt dealer and have them assist you in choosing the correct unit and provide instructions on wiring. Just another load on your ac panel. The dc wiring may take some doing, depending on how your shunt is set up.
As to the unit cutting out, either over temp or over current and tripping the fuse. How quickly it resets, and how often will define what type of overage happened. The manual describes such, and the event log will capture. The fuse limits are programmable.

 

[JDCAVE]

LeoKa: I can see only two reasons why you would want another charger. 1) you desire redundancy in the event of a failure of the existing charger. 2) you have under-utilized generator capacity and want to reduce generator runtime. Both of these are reasonable goals. However, I still believe your existing charging capacity while on shore power is entirely adequate, based on the size of your LFP bank. It doesn’t really matter if it recharges in 2 hours or 4 hours or even longer while on shore power as the house loads should be passed on to the charger. If the issue you identified recurs, as TT said, either get to the bottom of it with Mastervolt, or simply change the charge settings to throttle down the charger, so the house loads can be carried by the charger.

Jim

 

[READY]

Ok. I think we can put this thread into the "well beaten dead horse category".

 

[LeoKa]

Ok. I think we can put this thread into the "well beaten dead horse category".

Agreed. Thanks for all the clues.
I think we can conclude this now with the following.

- No need to worry about charging the lithiums, even if it takes longer. There is no need for another charger.
- The shut down of my charger was possibly due to high draw from the batteries and the house load.
- Mastervolt charger might have a protection built in.

Here is what I will do;
- reduce the max charge to 100A on the Mastervolt
- turn off inverter, when shorepower
- consider buying another inverter/charger for 50A transfer

Although, I have not mentioned, but I am still puzzled, why my battery bank’s SOC goes down, when on solar charging? This is what caused the 55% depletion during my solar charging test. But I will start another thread on this issue.

 

[Don L]

OP are you sure it isn't just that your charger is getting hot and shutting down and cycling?

I added a vent and fan to the locker my charger is is in.

 

[Darlin]

Noco makes a nice solid state sealed, marine compatible 10 amp charger with a lithium setting for supplemental charging and a lead acid desulfating/ recondition setting. I have one connected to my 200 ah lithium / solar charged battery. This is a supplemental charger used exclusively with my Starlink and chest freezer system when I have shore power or run the genset. When on the hook with solely solar power I shut down the Starlink and freezer overnight. Combined draw for the lithium system as shown on the inverter is intermittent 200 watts as the freezer compressor cycles with momentary peak of 450w when the compressor starts. It is fed by 4x 150 watt panels that generate about 1,200 watts per day for freezer. I have another 4 panels and controller for the house AGM bank. Peak output 330 watts on 30 amp Victron controller for freezer. House bank also has a 50 amp Charles Marine AC charger with AGM setting.

I am frequently surprised by battery SOC voltage readings. My ER buddy advises much of the variance is caused by my Victron controllers and the BMS system in the lithium battery.

I have successfully used the recondition setting to restore life to my failing Optima AGM batteries.

 

[L Erie Tugger]

Do you actually ever draw more than 30 amps AC ex the battery charging? If not, then it seems to me that the easy solution is to fuse the AC for 30 amps and add a 50 amp battery charger to handle the batteries, not using the charger on the inverter. That will protect the inverter relay at 30 amps. The battery charger would be wired in after the existing 50 amp breaker and before the new 30 amp breaker.