Keeping batteries topped up

[gary955]

My single 80w solar panel has kept up with the modest draw on my old 330ah domestic bank up to now, but a combination of shorter duller days and slightly more frequent use of 12v power means it's slowly losing the battle. Given that it often trickles in just an amp to keep me topped up, would a crappy car battery charger be able to supplement or replace it during winter?

[nicknorman]

My single 80w solar panel has kept up with the modest draw on my old 330ah domestic bank up to now, but a combination of shorter duller days and slightly more frequent use of 12v power means it's slowly losing the battle. Given that it often trickles in just an amp to keep me topped up, would a crappy car battery charger be able to supplement or replace it during winter?

A modest car battery charger should supply enough current especially since it can be left on 24 hrs (I am presuming you have access to shore power?). However the thing to be careful of is that a "crappy car battery charger" may not have any regulation, thus as the batteries become fully charged the voltage can rise to 16v or more, causing gassing. This is OK for a few hours but you wouldn't want to leave it indefinitely like this. In other words if the charger has no regulation, you will need to be careful not to overcharge the batteries.

[sleigh]

My old Mobitronic charger expired about a year ago, ive a decent pair of solar panels that keep me fully sufficient for 8 months of the year.

When looking for a replacement, i came across this ring charger. http://www.warmstrong.co.uk/shop/accessories/ring-battery-chargers/ring-smartcharge-pro-12v-35a-battery-charger-rscpr35

Great build sturdy quality, cracking functions, and bonus of a plug in remote display, its mounted in the engine compartment, directly behind the baulkhead where i lay my weary head, and can say the fan assembly is totally silent, well recommended.

[Phil Ambrose]

Or you could look at Electroquest 30amp charger for 1/2 the price.

I live aboard and reccomend them

Phil

[gary955]

Thank you chaps. I've given my batteries a little drink and plugged in my "happy shopper" 4amp car battery charger. Batteries at 12.6v at 5:00pm now showing 13v at about 10:00pm so going in the right direction. I think my volt meter over reads a little as it sometimes shows the bank at 13.2v in the evening after a sunny day and will show 14.2v with the engine on.

I've only replaced one of the three batteries in the five years that I've owned the boat and for half of that time it's been my four nights a week home. I've never owned a proper charger and very rarely had to run the engine just for charging. Perhaps the bank is getting towards the end of it's useful life but it's done me proud!

[MtB]

My single 80w solar panel has kept up with the modest draw on my old 330ah domestic bank up to now, but a combination of shorter duller days and slightly more frequent use of 12v power means it's slowly losing the battle. Given that it often trickles in just an amp to keep me topped up, would a crappy car battery charger be able to supplement or replace it during winter?

 

 

I'm impressed that you're getting 1A from an 80W panel! I tend to get about 0.1A this time of year.

[gary955]

 

 

I'm impressed that you're getting 1A from an 80W panel! I tend to get about 0.1A this time of year.

Sunny days only, not this time of year........think I once saw 3A on a blazing hot day with the sun overhead, but I may have imagined that!

In any event enough, until now, for my copious LED lighting, water pump, bath pump and radio

[blackrose]

Thank you chaps. I've given my batteries a little drink and plugged in my "happy shopper" 4amp car battery charger. Batteries at 12.6v at 5:00pm now showing 13v at about 10:00pm so going in the right direction. I think my volt meter over reads a little as it sometimes shows the bank at 13.2v in the evening after a sunny day and will show 14.2v with the engine on.

I've only replaced one of the three batteries in the five years that I've owned the boat and for half of that time it's been my four nights a week home. I've never owned a proper charger and very rarely had to run the engine just for charging. Perhaps the bank is getting towards the end of it's useful life but it's done me proud!

When you get a new bank get yourself a small 3 stage charger at the same time. You only need 10 or 20amp output if your DC power consumption is low. If you're on shore power most of the time then with a charger on 24/7 it's like running your DC system from the mains and it maintains the batteries.

Edited November 4, 2015 by blackrose

[gary955]

When you get a new bank get yourself a small 3 stage charger at the same time. You only need 10 or 20amp output if your DC power consumption is low. If you're on shore power most of the time then with a charger on 24/7 it's like running your DC system from the mains and it maintains the batteries.

I left the 4A charger on overnight. Batteries this morning showing 13.3v with the charge rate down from 4A to 2A.

Perhaps this charger is enough, what do you think? given the longevity of my existing bank under my current lack of a proper charging regime, what would be the advantage of a more sophisticated charger?

[craftycarper]

I left the 4A charger on overnight. Batteries this morning showing 13.3v with the charge rate down from 4A to 2A.

Perhaps this charger is enough, what do you think? given the longevity of my existing bank under my current lack of a proper charging regime, what would be the advantage of a more sophisticated charger?

 

I think what people are trying to tell you is that you risk cooking your battery,s if the crappy charger keeps on and on charging,with out a built in regulator, if you don't want the expense of a new super intelligent charger, why not stick one of those timer switch,s in the socket and limit the charger to a few hours each day when your not on board, that should keep battery's topped up without cooking them, I would be very reluctant to just leave a cheap unregulated charger running 24/7 if I was not there to keep an eye on it, lastly I bought a regulated charger with a digi display from aldi a few years back for around a tenner, it keeps the battery on my old car topped up and has lasted at least 4 years now so does not have to break the bank

[Top cat]

If your charger does end up boiling your batteries it isn't just a case of refilling them , in a bad case you could do a lot of damage to the rest of the boat and there are safety implications too. When batteries "boil" what is actually happening is the water in them is being broken down into oxygen and hydrogen, a very explosive combination. If the process goes further out of control and the batteries heat up further so they really boil then a mist of sulphuric acid droplets gets released, very unhealthy for you and the boat I believe a boat called Oakapple had that happen while unattended which wrecked the internal fitout big time.

 

So seriously spend the money to get a properly reguated charger, I have done well with Cteks.

 

Top Cat

[by'eck]

I left the 4A charger on overnight. Batteries this morning showing 13.3v with the charge rate down from 4A to 2A.

Perhaps this charger is enough, what do you think? given the longevity of my existing bank under my current lack of a proper charging regime, what would be the advantage of a more sophisticated charger?

 

Whilst I endorse all the suggestions to use a multi-stage charger, in this particular instance it seems the batteries are still not fully charged. Suggest leaving it on for maybe another 24 hours but monitor volts regularly. When/if they reach something over 14 volts with the very modest charge current, they can be considered fully charged.

[bottle]

Just to mention also your voltage readings are not of the battery voltage but the charge source.

 

by'eck was up earlier than me and so mentioned the batteries are not fully charged, no matter what their capacity is.

 

Fit an 'intelligent' charger and all will be solved and you will not have to worry about that, the charger will do it for you.

ps. for intelligent read three stage

[sleigh]

The Ring (8 stage) one i suggested on thread #3 was nowhere near the advertised price, i got it from a local motor factors in Newark for about 50% of the advertised price, and the seperate remote display for about 16 quid

[bottle]

Three's enough, Bulk, Absorption, Float any more are just decoration.

[Dave Payne]

I have one of these across my domestic bank of 3 x 110ah batteries, its plugged into the shore line 24/7. works a treat!

 

http://www.halfords.com/workshop-tools/garage-equipment/car-battery-chargers/halfords-fully-automatic-battery-charger

[sleigh]

Bottle i know 3's enough, but great to top trump people by 5

[bottle]

I know, you know, well I hoped you did. Hence smilie

 

My point is that with people that do not know may think they are getting a slightly inferior charger just because it does not have bells and whistles.

 

When a basic three stage one will do.

[by'eck]

I know, you know, well I hoped you did. Hence smilie

 

My point is that with people that do not know may think they are getting a slightly inferior charger just because it does not have bells and whistles.

 

When a basic three stage one will do.

 

I suppose you could claim that all three stage chargers are in fact four stage. This being when a load on batteries whilst charger is on float and acting as a power pack, exceeds the max current available from charger returning it to bulk or absorb mode when batteries drop to something like 12.5 volts. Some manufacturers claim such others don't.

[sleigh]

Clarke CB09-12 8A Auto Battery Charger/Maintainer 9 Stage WOW. Even top trumped myself. 9 stager. Makes my 8 weedy

Clarke CB09-12 8A Auto Battery Charger/Maintainer 9 Stage WOW. Even top trumped myself. 9 stager. Makes my 8 weedy

[gary955]

Been looking for replacement battery's. There are some good offers around but few suppliers seem to know whether their amp hour ratings are 20hr or 100hr!

The helpful chaps in Halfords for instance look at you as if you're speaking a foreign language if you ask them, and even Adverc seemed unsure! A post on the forum recently suggested that it was now a requirement for suppliers to quote an EU standardised 20hr rating but I've found several battery's for sale from reputable suppliers quoted at 100hr rating.

Should I assume that the battery's at the cheaper end of the market have their Ah ratings to a 100hr standard?

[Dinz]

Some refer to it as C rating.
If you see C20 = 20hrs
C5 = 5hrs etc.
Dunno why just have this in the back of my mind so could be totally wrong

Edited November 5, 2015 by Dinz

[Top cat]

I think you should assume that any battery is rated at the 100hr rate unless labelled differently regardless of price. There are lies , damn lies and battery specs. The difference between the cheap and expensive brands is the higher the price the more likely it is that the lies wont be as outrageous ( but not guaranteed). As for warranty they are generally not worth the paper they are written on.

 

Top Cat

[bottle]

I would say that 99% of the batteries sold by Halfords are start batteries and so the AH is not the important figure but he CCA (Cold Cranking Capacity) is. Not whant you want if looking for 'domestic' batteries

 

If you want decent batteries then buy from the specialists, they do lots of different types , makes, specifications and prices.

 

A lot of the on-line specialists have links to the manufacturers sites.

 

Search the internet for battery makes and check specifications on their web sites.

Edited November 6, 2015 by bottle