I want to build a 120v DC power supply with 20 amps power capability for up to about an hour (2400 amp/hours).
,
120vDC nominal (134v DC fully charged) is easy enough to do with ten 12v lead-acid batteries in series, but finding 120v DC lead-acid "battery string" chargers is extremely difficult and uncommon.
Is there any problem with just using commonly available 12v batteries and 12v chargers, and wiring them together in a series/parallel circuit?
Basically each charger is connected across the terminals of a single battery, so each battery can be charged separately.
Then the positive terminal of one battery/charger group is connected to the negative terminal of the next group, until we have ten in a row and 120v DC nominal output.
For safety and short protection, I would put a 20 amp circuit breaker or fuse between each charger/battery group, so ten 20 amp breakers, limiting the overall wattage to 2400 watts at 120v DC. To remove batteries or chargers for service, any of the breakers can be opened to disable the string power.
The main safety concern would be just covering up or insulating the tops of the battery terminals so there isn't a high-voltage risk of accidentally bridging across different group terminals, while working on the battery string.
,
Should there also be separate breakers/fusing for each of the battery-to-charger connections, like this?
If the chargers have enough supply capacity, they can help supply the 120v DC output while also charging.
- Dale Mahalko
,
120vDC nominal (134v DC fully charged) is easy enough to do with ten 12v lead-acid batteries in series, but finding 120v DC lead-acid "battery string" chargers is extremely difficult and uncommon.
Is there any problem with just using commonly available 12v batteries and 12v chargers, and wiring them together in a series/parallel circuit?
Basically each charger is connected across the terminals of a single battery, so each battery can be charged separately.
Then the positive terminal of one battery/charger group is connected to the negative terminal of the next group, until we have ten in a row and 120v DC nominal output.
For safety and short protection, I would put a 20 amp circuit breaker or fuse between each charger/battery group, so ten 20 amp breakers, limiting the overall wattage to 2400 watts at 120v DC. To remove batteries or chargers for service, any of the breakers can be opened to disable the string power.
The main safety concern would be just covering up or insulating the tops of the battery terminals so there isn't a high-voltage risk of accidentally bridging across different group terminals, while working on the battery string.
,
Should there also be separate breakers/fusing for each of the battery-to-charger connections, like this?
If the chargers have enough supply capacity, they can help supply the 120v DC output while also charging.
- Dale Mahalko
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