Samlex SSW 2000 W Inverter Over Voltage after switching to Blue Sea 7610 from Diode

[Bikersmurf]

'97 Crestline Ambulance
215 Amp Mitsubishi Alternator
Samlex SSW 2000 W Sine Wave Inverter

Originally Equipped with a Vanier 250 Amp Alternator to isolate the House and Starting banks.

A couple days ago, I upgraded to an ACR. Alternator is wired directly to house batteries to ensure the ACR doesn't melt down if I use the Inverter to it's potential. The Blue Sea 7610 is rated for 120 amps continuous and 210 amps for 5 minutes. The starting batteries won't draw enough juice to cook the ACR. Blue Sea Tech support agrees the house batters should be wired direct.

Initial results are positive. 14.7 Volts at both banks of batteries. (12 v flooded lead acid batteries)
- House batteries <1 week old
- Starting +/- 10 months

- Alternator was new a couple years ago and has <1000 hrs on it.


Where things get funny:
- At initial cold startup, when the starting batteries are Isolated, there is a momentary peak of about 15.1-15.2 V for <20 seconds.
- The voltage is slightly high and the Alternator output seems limited to about 20 amps.
- There is then an audible click and the voltage then drops to about 14.7 V and alternator output swings up to about 100 ish amps.

The problem:
- Samlex SSW 2000 Watt Sine wave inverter has a high voltage limit of 15.3 ± 0.3 V
- In my case it shuts down the inverter for about 20 seconds or so until the electronics are satisfied the over voltage situation has passed.

Samlex Solution:
- Buy a different inverter that has a 16.5 V kick out
- Somehow limit the voltage to the inverter (potentially 300A / 4000 watt surge)

Anyone have any thoughts?

 

[Bikersmurf]

I've considered that. It would address the high voltage symptom... However there'd be a lot lost to heat and the inverter would shut off at .7 V higher on the lower end... although it'd still be 11.2 V left in the Battery.

One shop indicated that the Mitsubishi VR shouldn't be allowing it to reach much more than 14.5 V. Which brings into question how the VR is getting its input. How is something I'm trying to figure out.

Are there high amperage solenoids that are normally closed? If so, the diode could be bypassed when the engine is off which would allow full Voltage to the Inverter without extra drain.

 

[DaveInDenver]

Is the alternator still sensing the starting battery? Just basing that on the "click" to combine followed by voltage regulation. The Blue Sea 7610 is dual sensing, so it will combine when either side is greater than 13.6V for 30 seconds, which is the case with the alternator at its rail supplying the house battery.

 

[comptiger5000]

Is the alternator still sensing the starting battery? Just basing that on the "click" to combine followed by voltage regulation. The Blue Sea 7610 is dual sensing, so it will combine when either side is greater than 13.6V for 30 seconds, which is the case with the alternator at its rail supplying the house battery.

This is quite likely. The alternator sees the house battery voltage being lower than the target, so the regulator cranks up the field until it hits max output, driving the voltage too high on the house side. Once the ACR closes the relay, the regulator senses voltage correctly and everything works as normal.

 

[Bikersmurf]

This is quite likely. The alternator sees the house battery voltage being lower than the target, so the regulator cranks up the field until it hits max output, driving the voltage too high on the house side. Once the ACR closes the relay, the regulator senses voltage correctly and everything works as normal.

I did find that if the ground wire of the ACR is disconnected (constant disconnect), that the voltage remained at the 15.1-15.2 V. If Dave's theory is correct, the issue should go away (or be reduced) if I jumped across the ACR with a Jumper (cable). This would then either prove or disprove the theory.

Once I have know, I could then rewire the VR connections so that it reads off the House battery rather than the OEM Ford circuits (Starting Battery). I would make a lot of sense if that was the issue.

On a related (or less likely unrelated) note, pre ACR if the House batteries were run flat, the alternator wouldn't charge at all until made a momentary connection between the two battery banks. Then the inoperative alternator would be energized and start pumping out gobs of power to recharge the Starting batteries and House batteries. And I'm not talking when the House batteries were down, I mean dead (6 V) because I left the house powered when I dropped it at the shop for a 2 hour job, and things went sideways causing a week long delay. The house would have stayed on till the Main House solenoid shut off due to low voltage ie. 6 V.


This is why Forums are good... since I can't have a group meeting with the Mitsubishi engineer, Ford engineer, and Crestline engineer who designed the setup to understand all of the eccentricities of how all three systems work together.

 

[dwh]

There is no reason to run the alternator to the house batteries except that the ACR you bought is too small to handle the full load.

I'd ugrade to the 500a rated ACR and run the alternator back to the engine battery where it belongs.

That doesn't guarantee to prevent the voltage spike, but at least the alternator field coil will be fed by the correct battery.

 

[Bikersmurf]

DWH, you're correct. I hindsight that's what I should have done. Despite even Blue Sea's tech support advising me to to run it this way, that would have been a better way.

 

[Bikersmurf]

And the Beer goes to DaveInDenver. By momentarily jumping the House and Starting banks, I was able to make the problem vanish.

With the two banks connected, the VR is able to sense the Alternator output and the peak is now only 14.7 V.

I suspect the 15.2 V limit @ 20 amp is some sort of Mitsubishi VR Limit for when the VR isn't getting proper input.

Now I could spend $220 on another ACR or wire in a manual combiner switch (A, B, or A&B) to switch where the Alternator is connected on the rare occasions I want to use the rig as a 2000 W pure sine generator.

 

[Bikersmurf]

Crunched some numbers. And I've decided to hook the alternator to the Starting batteries.

With the rig running the Inverter can put out roughly 14.5 A @ 120v without overloading the ACR. If the house batteries are significantly drained and I want to run something thirsty for more than 5 minutes, I can add a switch to engage the 'Sure Start' which will connect the House Batteries to the Starting Batteries.

 

[DaveInDenver]

Crunched some numbers. And I've decided to hook the alternator to the Starting batteries.

With the rig running the Inverter can put out roughly 14.5 A @ 120v without overloading the ACR. If the house batteries are significantly drained and I want to run something thirsty for more than 5 minutes, I can add a switch to engage the 'Sure Start' which will connect the House Batteries to the Starting Batteries.

So any barley pops are therefore split with dwh. The solution is to leave the charging system intact and wire things in the ways that have been proved to work countless times. There's ways to make it work, parallel relays or moving sense wires around but unless you want to do more work than is necessary just do what works in a thousand other vehicles: leave the stock system alone, add an ACR to parallel in a house battery and enjoy the journey.

 

[Bikersmurf]

So any barley pops are therefore split with dwh. The solution is to leave the charging system intact and wire things in the ways that have been proved to work countless times. There's ways to make it work, parallel relays or moving sense wires around but unless you want to do more work than is necessary just do what works in a thousand other vehicles: leave the stock system alone, add an ACR to parallel in a house battery and enjoy the journey.

That's what I've done. In my case, it was more difficult to what stock was since none of the wiring is stock. It already has paralleled solenoids in the 'Sure Start' circuit... all it needs is a switch in parallel to the momentary switch to keep them on. I'd only need to
Do this if I, for some reason, had a sustained load of more than 15 amps.