Small Inverter/Charger Recommendations

dragonfly

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I have a requirement for a small inverter charger, to be basically used as a UPS, for a pump. However I have a few special requirements,so i hoping to get some recommendations. I'm perfectly aware I could buy a UPS locally however they have a terrible reputation for either killing batteries or burning out.

First of all the pump is approx 50w, and needs to run for 24hrs on battery. Ofcourse I would guess startup power is a little over 50w.

The pump is part of a wood burning heating solution, so most likely lay dormant for most of the year, and only be actively used for 4/5 months. However I don't want the batteries to be killed by overcharging from the charger, or left to self discharge over summer.

My electric is about half the cost at night, than it is during the day, so it makes sense to charge for 6hrs at night, and use the battery during the day, even when grid power is on. Which is part of my reason for wanting24hrs battery supply.

Where we are, grid power is readily available and cheap, however isn't the most reliable, 4hr to 12hr power cuts aren't uncommon especially in winter.

Ideally I'm thinking of a charger that properly chargers and floats batteries, I've seen so many that just kill batteries over 1 to 2 years. So My thoughts are a couple of deep cycle lead acid batteries, and an inverter with a proper charger.

Anybody got any recommendations.
 
What Voltage of Batteries? What voltage of Mains. Where are you. What kind of batteries do you want to use.

Lots of questions
 
jdeadman said:
What Voltage of Batteries? What voltage of Mains. Where are you. What kind of batteries do you want to use.

Lots of questions

What are the pump / power specs? what kind of 'power spike' will it need?
 
In Bulgaria, so mains is 230vac, haven't yet bought the batteries but I'm thinking 12v lead acid. Pump is rated at 35w and I assume will power spike on startup, but I have no measure of exactly what it will be.
 
If you plan on lead acid, then there's no problem with most chargers and over charging the batteries. That's what most chargers are designed to work with. Even a cheap UPS with marine/deep-cycle batteries attached to it would do just fine.

If you absolutely want the pump to run on solar, then going with a good inverter and mppt charge controller would be fine, too. You could even get away with Reliable inverter and a cheap MPPT controller. It's not like you are demanding a huge load for long durations in this particular application.
 
Having done the maths over here solar panels at current prices would take something like 30years to pay for, so probably not a worthwhile investment really, which surprised me, however if either price moves by much that could easily change.

If you ups are okay with lead acid batteries why do so many kill the batteries in a couple of years. I've had a couple myself do it. Is it that they are using cheap car type batteries??

My take was that they were over charging, rather than maintenance charging and that was either warping plates or evaporating electrolyte off?
 
Consumer grade UPS units use seal lead acid batteries. These are also cheaply made. They aren't designed to last a long time, just like lawn mower batteries. The UPS doesn't overcharge. They only charge when the battery voltage is low. I know this because I've done some test with a voltage meter clamped onto the battery through a few cycles of use. Once the battery was charged, the charging portion from the UPS stopped. It would trickle charge, yeah, but wouldn't over charge.

That's why I said to replace the SLA with a marine/deep-cycle battery instead as those are designed to last years, even under heavy loads.
 
That makes sense, so I potentially have choice of 2 dead ups to play with a no-brand 800w cheapo job, or the sua2200 that I still need to collect from the UK. I reckon the sua2200 is overkill for this, maybe start with the 800w with decent batteries and some battery monitoring. First job cut the damn buzzer off the circuit board lol
 
Now, if you plan to use the UPS in constant battery mode, for consumer units you want to pull as little power as possible. They aren't designed for continuous battery inversion. However, the sua2200 is a beefier unit and can handle the continuous loads.

For consumer units, I'd recommend running them about 1/2 their rated wattage. And, if possible, add a few fans inside to help keep things cool.
 
Korishan said:
For consumer units, I'd recommend running them about 1/2 their rated wattage. And, if possible, add a few fans inside to help keep things cool.

The no-brand if I remember correctly is rated at 800w for 20mins. The pump is rated at 35w on it's lowest setting, 75w on full power. It is normally used on low. So intheory all should be golden. Fingers Crossed
 
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