antiguasky
New Member
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- Apr 17, 2020
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Destroyed $4K of alternator & regulator with a good Fuse
- Thread starter me3
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antiguasky
New Member
- Joined
- Apr 17, 2020
- Messages
- 2
I'm a little bit late to this thread but thought I'd comment in the event anyone is still working the problem. My solution was to bypass the internal BMS and connect an external Batrium BMS to the cells. The Batrium has a number of relays that can be used to react to the environment in and around the battery. I used four of them. The first simply turns on/off the regulator (which turns off the alternator) based on sensory input from the alternator or battery (charge state, temperature, c-rate, etc.). The second controls a contactor that will disconnect the battery if any parameter reaches a critical state. Another turns on some tank heaters under the batteries at a set temp. The last turns on a CPU fan to cool the cell balancer sink at a set temp. Other charging sources (shore and solar) are controlled by a Victon Cerbo GX in ESS mode that is also controlled by the Batrium through a CAN bus connection. The BMS is always in charge so the alternator and other charging sources always turn off before the BMS removes the battery from the circuit. As a final fail safe I installed two Sterling 24V alternator protect devices in series.
HarryN
Solar Enthusiast
WS and alternator companies like to blame the installer, end user and the BMS for these problems.
While those are always possibilities, in our case we determined the real challenge is that a WS + alternator simply cannot operate in real time to manage the field current, even though WS like to claim that they can.
What happens is that at modest engine / alternator rpms, the WS (and others) drive a large field current into the alternator to push out the amps.
When you push on the gas to increase vehicle speed, the engine rpm rapidly rises and the actual alternator output will substantially exceed the official alternator rating - by a lot. Think in terms of 2x +
If you think about the field current as the "signal" and the rotational energy of the alternator as the gain of an amplifier, it sort of makes sense. When the rpms change, it is like someone really turning up the gain during a particularly loud part of a song is playing.
We used a similar setup to the OP in terms of alternator and WS and set it for 60 amps to try to keep it under control. Dual parallel battery packs with charge settings so that it will never shut off the bms due to voltage. Current projects at > 2x. (yes you do need some way to deal with very high power packs )
Anyway, during acceleration it can still go way past the ratings and set points, but it does help to have the current set point lower just because it does limit the max field current some.
So if you are going to put protection devices such as fuses, breakers, etc in, plan to use ones that are at least 2x the rating of the alternator, maybe more, because if they pop during operation, it will blow everything out with a big power spike.
Working on another solution but not tested yet.
We didn't find WS to be helpful other than try to tell us that even though we did exactly what we had shown them in a diagram and following their directions we were still wrong.
More or less, if you go down this path, you are buying parts with no warranty, so just keep that in mind.
While those are always possibilities, in our case we determined the real challenge is that a WS + alternator simply cannot operate in real time to manage the field current, even though WS like to claim that they can.
What happens is that at modest engine / alternator rpms, the WS (and others) drive a large field current into the alternator to push out the amps.
When you push on the gas to increase vehicle speed, the engine rpm rapidly rises and the actual alternator output will substantially exceed the official alternator rating - by a lot. Think in terms of 2x +
If you think about the field current as the "signal" and the rotational energy of the alternator as the gain of an amplifier, it sort of makes sense. When the rpms change, it is like someone really turning up the gain during a particularly loud part of a song is playing.
We used a similar setup to the OP in terms of alternator and WS and set it for 60 amps to try to keep it under control. Dual parallel battery packs with charge settings so that it will never shut off the bms due to voltage. Current projects at > 2x. (yes you do need some way to deal with very high power packs )
Anyway, during acceleration it can still go way past the ratings and set points, but it does help to have the current set point lower just because it does limit the max field current some.
So if you are going to put protection devices such as fuses, breakers, etc in, plan to use ones that are at least 2x the rating of the alternator, maybe more, because if they pop during operation, it will blow everything out with a big power spike.
Working on another solution but not tested yet.
We didn't find WS to be helpful other than try to tell us that even though we did exactly what we had shown them in a diagram and following their directions we were still wrong.
More or less, if you go down this path, you are buying parts with no warranty, so just keep that in mind.
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RCinFLA
Solar Wizard
- Joined
- Jun 21, 2020
- Messages
- 3,560
I would think that it would work if the clamping voltage is a few volts higher than the voltage setting of the regulator. Just there to catch the runaway voltage of an open circuit, not so much the current.
Edit, they already make them. “Alternator protector” pricy for just a diode
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JeepHammer
Solar Wizard
- Joined
- Nov 15, 2019
- Messages
- 1,149
Respectfully, this sounds a lot like the rectifier diodes went first.
I run a 300 amp, 48 volt Lecce Neville, did this myself. Had to double up rectifiers to keep them from overheating.
Locomotive application and common case, isolated negative, I picked it for the ease of adding an extra set of rectifiers on the back of the case, but that one I ran it out of the box... My mistake.
When the rectifier diodes go, you get unregulated AC output and things fry QUICKLY.
When you are making 300 Amps at 48 volts (56 actual) that's 16,800 Watts, 16.8 kW, and that's a LOT of heat and power to smoke weak links.
I run a 300 amp, 48 volt Lecce Neville, did this myself. Had to double up rectifiers to keep them from overheating.
Locomotive application and common case, isolated negative, I picked it for the ease of adding an extra set of rectifiers on the back of the case, but that one I ran it out of the box... My mistake.
When the rectifier diodes go, you get unregulated AC output and things fry QUICKLY.
When you are making 300 Amps at 48 volts (56 actual) that's 16,800 Watts, 16.8 kW, and that's a LOT of heat and power to smoke weak links.
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