20amp or 30amp Charger?

[canals are us?]

I'm going to be purchasing a mains powered 12 volt battery charger to charge my 4x 110amp/h batteries while I'm on shorepower.

 

I'm currently running the engine for 2 hours a day to charge the batteries, mainly for the 12 volt fridge and usual 12 volt water pump etc.

 

At the moment there isn't sufficient power to run the fridge for more than 6 hours even charging for 2 hours.

 

The TV and living light is all 240 volt as is the laptop use. I just need a charger to keep up with the power requirements of the 12 volt fridge, water pump, shower drain pump and the occasional short usage of 12 volt led lighting.

 

What charger amperage would you buy? Plan to leave it permanently connected.

 

This was the 30 amp version I was thinking of, on a tight budget £100 max.http://electroquestuk.co.uk/index.php?main_page=product_info&cPath=2_36&products_id=318

 

Thanks James.

Edited May 26, 2013 by canals are us?

[ditchcrawler]

To maintain a 12 volt fridge and pump 10 Amps would be more than enough on 24/7. I would however suggest that you have been under charging your batteries and they may well be past their sell by date.

[bottle]

What Brian (ditchcrawler) said but how are you monitoring your batteries to know that they are fully charged?

 

Are you running the engine at about 1,000 rpm, assuming it is a 'modern' one

 

After all that, getting and fitting a charger would be ideal but please remove the 'crocodile clips' and use correct terminations for connection to the batteries.

 

ps. if you know all this just ignore me.

[mrsmelly]

I'm going to be purchasing a mains powered 12 volt battery charger to charge my 4x 110amp/h batteries while I'm on shorepower.

 

I'm currently running the engine for 2 hours a day to charge the batteries, mainly for the 12 volt fridge and usual 12 volt water pump etc.

 

At the moment there isn't sufficient power to run the fridge for more than 6 hours even charging for 2 hours.

 

The TV and living light is all 240 volt as is the laptop use. I just need a charger to keep up with the power requirements of the 12 volt fridge, water pump, shower drain pump and the occasional short usage of 12 volt led lighting.

 

What charger amperage would you buy? Plan to leave it permanently connected.

 

This was the 30 amp version I was thinking of, on a tight budget £100 max.http://electroquestuk.co.uk/index.php?main_page=product_info&cPath=2_36&products_id=318

 

Thanks James.

Hi

 

I am a liveaboard with many years experience. I am at present a saddo plugged in to mains leccy. i have an electroquest 20 amp charger and it is more than enough and works spot on.

 

Tim

[canals are us?]

Thanks everyone

Unfortunately I have no idea of the current charge of the batteries as there is no quage to monitor them, the same as the engine rpm. So at a quess above 1000rpm

Any cheap battery monitor available? My engine is a beta 1305 with just a basic panel. Temp, oil, and 2 battery pictures with warning light and buzzer.

When I had the boat surveyed the surveyor said the batteries were 50% through their life, so probably pretty bad now.

Great to hear the 20 amp electroquest charger has been adequate, think I will buy the same. Now back in stock, arrived from China.

I'm in a Marina too but plan to get out exploring this Summer.

Crocodile clips will be binned as I want to wire it permanantly and croc clips dont seem a very good way. No doubt I'll have some Q's as how to wire it eg, wire size and fuse size from charger to batteries.

 

James

Edited May 26, 2013 by canals are us?

[ditchcrawler]

Thanks everyone

Unfortunately I have no idea of the current charge of the batteries

I'm in a Marina too but plan to get out exploring this Summer.

 

James

Then you will be back to square one

[canals are us?]

Then you will be back to square one

Hence me asking about a cheap battery monitor.

 

James

[Arthur Brown]

The cheapest battery monitor is a cheap digital multimeter from Maplin or the like. £5 should get one £10 will get you a choice. Then you must read the resting battery voltage at say first thing in the morning each day and plot volts against state of charge.

 

For more money the Smartgauge monitor will do all you want and has a visual display.

 

Easiest solution is to buy a decent solar array and a good controller with battery monitor built in.

[blackrose]

Canals are us, I wouldn't worry about your batteries too much at the moment.Once you've installed your mains charger it won't actually matter if your batteries are knackered. If they are wet lead/acid batteries just keep them topped up with distilled or de-ionised water.

 

There are hundreds of people living on boats with knackered batteries on charge from shore power and I think I may be one of them! You will only really have to start thinking about monitoring the batteries and whether to replace them once you switch the charger off, disconnect from shore power and go for a cruise. Then you will need a battery monitor to know when to charge and stop charging (to save fuel once they're fully charged).

 

And as Tim said, a 20 amp charger should be fine because it's left on permanently and the demands are small. The only caveat to that is if you ever wanted to run the charger from a generator while out on the move, in which case you'd want a larger output charger in order to reduce generator running times. In that case you can always add additional chargers - I've got a 30 amp and 40 amp charger. I use the 30 amp on shore power but if I'm away from shore power I can run both from the generator at the same time.

Edited May 27, 2013 by blackrose

[canals are us?]

Canals are us, I wouldn't worry about your batteries too much at the moment.Once you've installed your mains charger it won't actually matter if your batteries are knackered. If they are wet lead/acid batteries just keep them topped up with distilled or de-ionised water.

 

There are hundreds of people living on boats with knackered batteries on charge from shore power and I think I may be one of them! You will only really have to start thinking about monitoring the batteries and whether to replace them once you switch the charger off, disconnect from shore power and go for a cruise. Then you will need a battery monitor to know when to charge and stop charging (to save fuel once they're fully charged).

 

And as Tim said, a 20 amp charger should be fine because it's left on permanently and the demands are small. The only caveat to that is if you ever wanted to run the charger from a generator while out on the move, in which case you'd want a larger output charger in order to reduce generator running times. In that case you can always add additional chargers - I've got a 30 amp and 40 amp charger. I use the 30 amp on shore power but if I'm away from shore power I can run both from the generator at the same time.

 

Thanks for your reply, makes perfect sence. Basically the 20 amp is fine on shore power, but if cruising then buy a battery monitor to check the voltage in the morning etc and monitor it. When I recharge off shorepower I will need a larger charger or an additional one to reduce charging time from a generator.

I will buy a basic maplin digital multimeter for when I'm away from shore power.

I will gradually like to buy a solar panel but as I'm mostly in a Marina is there much point, unless the setup would be the same cost as a smartquage (but built in monitor) which aren't cheap. A whole new discussion!!

 

Ordered my charger today, back in stock.http://electroquestuk.co.uk/index.php?main_page=product_info&cPath=2_36&products_id=372

 

Thanks James

Edited May 27, 2013 by canals are us?

[blackrose]

 

 

Basically don't let your batteries fall below about 50% capacity. If you don't have a battery monitor you can just use a voltmeter. 50% equates to about 12.2v but you have to test this with no charge or discharge - so ideally several hours after stopping the engine (morning is good) and all lights, fridge, etc. off. The other "golden rule of charging" is to always charge to 100% or as near as possible. I'm not sure how you can check that without a battery monitor. Someone here must know.

Edited May 27, 2013 by blackrose

[canals are us?]

Basically don't let your batteries fall below about 50% capacity. If you don't have a battery monitor you can just use a voltmeter. 50% equates to about 12.2v but you have to test this with no charge or discharge - so ideally several hours after stopping the engine (morning is good) and all lights, fridge, etc. off. The other "golden rule of charging" is to always charge to 100% or as near as possible. I'm not sure how you can check that without a battery monitor. Someone here must know.

 

Once again thank you blackrose Great to get the info that 12.2volt is roughly 50% state of charge and should go no lower. I have a multimeter and I have also bought a plug in lighter type digital voltage meter just now. It will give a very basic idea of charge.

 

James

[bottle]

To know when, batteries are fully charged, can be achieved by reading the amps going into the battery bank when being charged.

 

When the amps read about 1% to 2% of the battery bank (ie bank size 300 amp.hr then 3 to 6 amps on the gauge) they are about fully charged.

 

but

 

To get to that reading (3 to 6 amp) will take an inordinate amount of time, so the 'norm' is to charge to about 95% SOC and then once a week do a long charge (hours and hours) to 100%

 

Now if you want to really get into batteries and battery charging etc. some reading for you.

 

http://www.batteryfaq.org/

 

http://www.smartgauge.co.uk/ Click on 'Technical info'

 

and of our Tony Brooks site for this and all boaty things.

 

http://www.tb-training.co.uk/

[blackrose]

To know when, batteries are fully charged, can be achieved by reading the amps going into the battery bank when being charged.

 

When the amps read about 1% to 2% of the battery bank (ie bank size 300 amp.hr then 3 to 6 amps on the gauge) they are about fully charged.

 

I thought he didn't have an ammeter?

[bottle]

I didn't say he did.

[blackrose]

I didn't say he did.

 

No, but since this thread is about a member without a battery monitor and my preceeding question asked how one would know when to stop charging without a battery monitor, your advice seemed to imply he had an ammeter.

 

Unless of course you weren't replying to either of us and just supplying random advice... In which case carry on by all means.

Edited May 27, 2013 by blackrose

[bottle]

It was a general answer but also it was in refernce to your

 

The other "golden rule of charging" is to always charge to 100% or as near as possible. I'm not sure how you can check that without a battery monitor. Someone here must know.

 

The voltage measurement that you mentioned is correct but can be only done after charging and the batteries have 'rested' as you said.

 

The ampere measurement can be used whilst charging.

 

or

 

Specific Gravity measurement is a very good method but again the batteries have to be 'rested'

[smileypete]

If the OP isn't confident about wiring in a digital ammeter and shunt, or waiting for one of the £10 ones to arrive from Asia, then a £30 clamp meter with DC current capability could be very helpful for current measurements:

 

http://www.ebay.co.uk/itm/New-MASTECH-MS2108A-Digital-Clamp-Meter-Multimeter-AC-DC-Current-Volt-Tester-/221121783212

 

But bear in mind a lot of clamp meters especially the cheap ones can only measure AC current which isn't much use on a boat.

 

cheers, Pete.

~smpt~