My Cheapo exercise with Battery Charging

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Some may recall - I posted about a £7 Maplin charge splitter I was to try.

Hooked with the Halfords Auto-Float charger it failed to do anything and one posted reply was spot on - The charger didn't like anything between it and the battery - so wouldn't click in.

So tried it with normal non-float charger and BINGO ! Clicked straight in and charger ammeter shows that each battery does receive different charge dependent on its state.
I do believe thtough that the batterys do balance though ... as one was full charged when connected up, second reasonably low charge state .... both are now at reasonably high levels.

So coupled with the timer on the mains input ... it's actually a success. Not high rate charging - so cannot rival the Sterling / Adverc systems ... but for small boat with limited electrical needs - simple, cheap and effective.


Anyone wants any more info on what I did etc. ..... PM me ..
 
Is this a diode or relay type split charger.

On the same maplin page is what is this

I use a unit like this with a non auto battery charger to switch charge on and off on my classic car batterys wich keeps them topped up ready for use.

May be these could be used after the split charger unit to switch charging on and off without using the time switch
 
Roger,
I would guess this is a diode type of splitter. The normal voltage drop associated with silicon diodes would not be a problem with an unregulated mains powered charger. So it would be possible to make something similar from separate diodes
For anyone competant to meddle with the insides of such a charger it would be possible to replace the rectifier with two identical ones, to give two independent outputs for two batteries. Can anyone suggest why this would not be an equally effectve way of achieving the same the same result.

The Maplin solar charge regulator does seem to be some form of electronic switch rather than the more common shunt type regulator. At least that is what is implied by the description. I wonder if it could be used in conjunction with the charge splitter. I guess you would need two of them one in the supply to each battery.

Nigel,
You have put fuses in the connections to the batteries, as close to the batteries as possible and rated to protect the wiring , haven't you. That's in addition to any fuse that the charger may have in its output.
 
Hi Vic
Nice to chat again and thanks for the help last year when I visited you and I still need to get round to the mirror's.

Yes it is a switch on / off regulator as I had 2 on my previous yacht (2 solar panels 75 watt 2 battery banks 400 Ah connected all time) I then increased the solar to 6 , 3 in each bank and replaced regular to a 3 stage, found batteries lost water and then cooked then selves due to last water so I dont like permantally connected "smart" chargers.

On my new yacht I plan to have 2 - 75watt solar panels connected permanitally to 2 battery banks with switch on/off regulators and the other 4 connected to the common side of my off 1 2 both battery switch using a "smart" regulator.

The idea is the 2 panels will trickle charge the 2 battery banks while I am away but when I am on the boat I will have 5 of the panels charging the batery in use and the other topping the battery not in use.

I have been looking for a split charging unit for the engine alternator and wind generator and this one looked nice and cheep.

PS have a look at my URL in my profile to see the progress on the lavranos 50

Thanks again Vic
 
The two Maplin units have only relatively low current ratings. The regulator is only rated at 5A so will only be good for solar panels or wind turbines up to 60 watts. The split charge device is only rated at 8A continuous or 20A for 5 seconds max so although it will be OK for solar panels or wind turbines upto just under 100 watts. It won't be man enough for the alternator output.

I wondered if you had done anything with the Mirrors but they are still on the "to do" list then. I'll have a look at your website later as I think it is going to take a long while to down load on a dial up connection.
 
Thanks Vic
You are correct the maplin units will not be man eough for most of my application.

I was thinking last night as to how a voltage switch works and I wondered is it a volatge compariator using on op amp like a 741 driving a big relay if so it could be very easy to make for people who can handle a soldering iron.

I think when you look at my web site you will see why the mirrors are still on my to do list (very big to do list !!!)

Go will Vic

Kind Regards
Roger
 
Update on use ....

This splitter has proven to do the job very well.

I was under impression that the splitter allowed batterys to balance out when charger was off. I am pretty sure that this is not the case now ... as I made an error and left a light on in the boat draining the domestic "Full charged" battery. This brought it down to similar to start battery ... where it then had divided charge from the splitter. As info I have is that the splitter will not swap due to "load" on the battery .. but due to charge state .... ok - that's in my lay-mans terms, borne out by observation so far.

I think for any boat that sits on shore power basically systems switched for a few days between use ..... this splitter allied with simple charger and timer - can be a simple answer. It has certainly worked on my boat ....

My boat sits for long periods not used and before was without charge to batterys during. I would return to boat with batterys flat. I would then have to charge up at least one as soon as I arrived and then think about using boat next day or at least reasonable time after starting charge. I then tried the Float charger and timer ....... but that only fed one battery - the float charger didn't like two batterys connected. I was against parrelelling them ... This has given an option .... Maybe "against Experts" advice .... but let's be honest there are many things that don't follow experts / technical instructions ... as long as it's safe - why not ?

I know of boats that sit on shore power on "boost chargers and auto float ......." Having a timer and no boost charge - I consider possibly a safer way ?? Leaving a boat with possible high ampage being pumped in .... ?? My charger is max 4A .... with overload / thermal / short cut-outs.
 
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