Is this charger right for my battery?

[jiminwatford]

I have a 130ah leisure battery and I read that chargers should at least match the amperage of the battery. So a 50ah battery would need a 5amp charger

With this in mind I found a 20amp charger for my battery

Now it has arrived i'm concerned to check it's right

This chart confirms my theory



But this dial only goes up to 120ah



Should I turn it to 120ah?

Will this charger be right for my battery?

(Sorry for the large pics)

[slater]

Connect it up and see if it will put out the current you want. I think the 1amp per 10ah is probably an old wives tail in the first place tbh.. maybe they don't like a trickle charge from flat but i doubt it matters if you're an amp or two off.

[jiminwatford]

Thanks, I chaarged them until the green light came on and they got to 13.1 volts

I have two of these batteries in parallel connected to 300 watts of solar panel. In full sunlight I've seen them reach 13.8 so on that I'm assuming it can't fully charge them

However, it only took 1h20m to charge each one from 12.6v to 13,1 so at least it can be used to boost them up

[chris y]

I cant see why the charger wouldnt work given time.

You need to charge at 14v or a bit more, but it looks like your charger does that, you just need to give it more time, I'd be leaving it at the very least overnight.
Once you disconnect the charger and wait for an hour or so the battery should be at least 12.6, maybe nearer 13 if very healthy. If it drops off too low its the battery getting tired not the charger.

[jiminwatford]

It's just that green 'charged' light comes on and the fan goes off the charger so i assume it's stopped

In theory i could leave it connected overnight but i am using a generator to power the charger

The batteries do stay at around 13 as they're only a month old

[ChasR]

Jan 3, 2019 9:42:44 GMT chris y said:

I cant see why the charger wouldnt work given time.

You need to charge at 14v or a bit more, but it looks like your charger does that, you just need to give it more time, I'd be leaving it at the very least overnight.
Once you disconnect the charger and wait for an hour or so the battery should be at least 12.6, maybe nearer 13 if very healthy. If it drops off too low its the battery getting tired not the charger.

I've had batteries give 12V before and be tired.

The only way to really get a better idea for the average Joe is to get a Capacitance tester. Halfords do these but you can get home ones alot cheaper than you could. Sealey do one as do Foxwell, in their case it is the BT-100). I've confirmed a few dead batteries with those, and it's what we use at work (well, both a home one and a pricey Yuasa tester).

[rwdrules]

Jan 3, 2019 8:32:50 GMT jiminwatford said:

Thanks, I chaarged them until the green light came on and they got to 13.1 volts

I have two of these batteries in parallel connected to 300 watts of solar panel. In full sunlight I've seen them reach 13.8 so on that I'm assuming it can't fully charge them

However, it only took 1h20m to charge each one from 12.6v to 13,1 so at least it can be used to boost them up

solar will charge bateries to 100percent, battery charger will only ever charge to 80/85 percent,

[ChasR]

Jan 4, 2019 16:05:08 GMT rwdrules said:

Jan 3, 2019 8:32:50 GMT jiminwatford said:

Thanks, I chaarged them until the green light came on and they got to 13.1 volts

I have two of these batteries in parallel connected to 300 watts of solar panel. In full sunlight I've seen them reach 13.8 so on that I'm assuming it can't fully charge them

However, it only took 1h20m to charge each one from 12.6v to 13,1 so at least it can be used to boost them up

solar will charge bateries to 100percent, battery charger will only ever charge to 80/85 percent,

It's the first I've heard of that. Do you have any proof?

Normally, a decent smart charger will charge a battery to 100% of its useful capacity from what I've seen, and other decent chargers will come close to that. My CTEK normally charges at 13.8V unless put into the RECOND function, where it will charge for quite some time at 16V.


Most solar chargers I have seen have been near useless. Sure, they can be the difference between starting a car and not starting it, but I've not seen them fully charge a battery up before.

[rwdrules]

LOL Can understand where you are thinking,however solar panel at 160 watts through a mppt controller will charge batteries to maximum capacity,this set up will produce just over 10amps,

Battery chargers work on resistance, which gets higher as the battery takes a charge and it then gives up or switches off thinking the unit is full,
mppt controller will continue charging until it is full, plwnty of info around about solar an battery storage,

case in point on my camper i have a large battery charger built in and its great for when the battery is flat, however if i charge the battery up with it, it will charge them to 128/9
I then connect it to the solar it looks at the state of charge and then continues charging even though theBUILT IN 8 amp charger says its full,

only when the battery is at max capacity does it stop charging,
solar panel and controller keep my batteries at 13.7v even when checked after standing for a week they are still at 13.7,
I just had my raptor battery desulphated as it was brand new but had been left standing for 18 months,it only read 3v so thought it was dead and it now holds at 12.8, which is great, but to get the full charge it will go on the solar when the sun is out probably march time

[ChasR]

While I hear your point, and can see it, I'll agree to disagree.

As I've said before, Voltage isn't an indication of the power o the battery ; the cold cranking amps are part of that. After all, Power = Current * Voltage.

As for my proof?

My RS Turbo would go flat quite a bit when I bought it. When left on the charger, the battery would kick the car into life very quickly, and it got to the stage that I really didn't need to charge it anymore. I tried a solar charger on that, as the car was then stored where I had no electric present, but it went in the bin; it really didn't do alot, and after it had gone, I didn't notice much difference anyway.

M3 is the same. Despite driving it for 2 hours, it will always crank over faster once I'd charged it off my CTEK.

My dad's Mondeo had a battery floating at 12.8V, but it wouldn't start the car in winter. With a fresh battery, it's around 12.6V but it starts the car every time. The difference? The cranking voltage. The old battery had 420CCA left in a 700A battery. Going to Huddersfield and back, or charging it made very little difference to it, but it was a very old battery by then. The new one? 700CCA was still there.

But we all have different experiences.