cheap trickle charger for generator battery?

  • Thread starter Thread starter vas
  • Start date Start date
vas

vas

Well-Known Member
Joined
21 Jun 2011
Messages
8,200
Location
Volos-Athens
Visit site
hello,

got this:
https://www.ebay.co.uk/itm/1-1000A-...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
for less than four quid.
Didn't realise how small it was...
4quidtricklecharger.jpg


I'll feed it with starter engines 24V output in order to charge a 90Ah flooded led acid generator battery.
Prior to that I didn't use a dedicated gen battery and was nicking 12V out of the 2X12V engine start batteries and managed to destroy both, so lesson learnt (almost) and got three new batteries.
Alternatively I could buy a 220V->10-30adj output dropper and hook it up there so it only works when the generator is on, but since generator may be off duty for months, I'd rather have some sort of freshening up...
I'm thinking of not having it on permanently and only run it a couple of days a week with a timer or something.

Before someone asks, yes, yanmar 2GM on my Mase 8KW generator didn't have an alternator but was using the generator second coil or something like that to provide 12V. Problem is that this output is dead now and not planning on taking the generator apart to fix it, nor paying 50+ to get an alternator for it.

anyone tried something like that?
Generator battery is used only for starting up (so consumes whatever the starter needs) and then does nothing till next start (even oil/temp sensors are fed from the NMEA2K supply)

cheers

V.
 
I know some will cry ... UGH .... but for years I have a used a Splitter sold by Maplins. Its designed for caravans and RV to monitor and charge batterys from either a charger or engine alternator.

Its solid state - so no moving parts at all ... you connect supply and then it divides of to each battery ... if battery is full - it basically reduces to near zero ... but maintains charge to the other battery if needed.

They did two versions ... one that was more suited to a charger at max 8A ... and another that was more suited to engine alternator at far higher output.

My 8A unit is over 20yrs old and still works perfect supplied by a basic charger.
 
These look like useful little units, but I'd be cautious about how I used one.
At a max charge of 3A, a decent size 12V battery is going to be in some danger of overcharge to get it to the 14.8V 'switch to float' point.
Might not be ideal if the system is being cycled a lot. (sounds like not a problem for the OP).
Can we read the part number from the ICs?
 
thanks for the replies, as I said, I'll thread carefully on that, don't want to loose another battery!

the centrally placed ic is: CN3768 https://datasheet4u.com/datasheet-pdf/CONSONANCE/CN3768/pdf.php?id=1257624
the other one is: GA7S13 / 4435 https://www.mouser.com/datasheet/2/149/FDS4435-1008306.pdf
system is definitely NOT going to be cycled a lot, once a day for the summer (and if that) hopefully once I identify the recurring air leak in the circuit, cranking will be minimal...

will have a good look at their specs later, doing some home maintenance atm and slightly stuck :(

cheers

V.
 
Looking at the CN3768 datasheet, no chance to tweak the thresholds.
But I'd only want to do that if there was a risk of spending too many hours at 'overcharge voltage' wHich I can only see happening with a big battery bank that gets the charger cycled a lot.
 
just an update, to note that the thing died on me midsummer. Died as in doesn't output a thing!
Not a big issue, got a victron 12V 10A charger and I hooked it up on the battery a few times when generator was running, but will try and remove it and see what really happened.
Batteries are all happy and hold their charge/do their job nicely.
 
er, looking for something else, came across this old thread...
Well, I had placed it in a tiny plastic box together with a buck converter to drop the 24V to whatever it wanted to be fed - don't remember now!
Heat and working close to it's limits, the buck converter popped its central IC.
So, new buck converter in heatsink on the IC, back in the box in Sept. Now March, touch wood still works fine.

when I get bored, I'll get it in a larger box with some air circulation.

cheers

V.
 
me again :rolleyes:

Hack still working, but checking on my service vs engine start battery bank voltages (both 24V) through signalk/grafana noticed that engine bank was dropping to alarming levels overnight and only next morning with solar power would go up to 26V for a while and drop down to 24.5 overnight.
Tonight had a chance to check what's happening there, nothing strange tbh, case is warm, not alarming so, but will have to investigate further with an amp clamp. For now, disconnected it from the engine start battery bank and bank voltage recovered. Will see how it goes - seems that I shouldn't have it on all the time, but on a timer for say couple of hours every afternoon or something like that (when solar is wasted as batteries are already topped up). Will be added to the winter to-do list :cool:

cheers

V
 
You must log in or register to reply here.

Share this page

Top