Charging Batteries in Parallel

[Noelm]

It is very hard to explain in home handy man terms what you spent years learning from text books and teachers, and you know inside out in your mind, putting into text just muddles things sometimes.

[aussiebasser]

Buy two little C-Tek chargers to maintain the batteries when stored.

[scottar]

It is very hard to explain in home handy man terms what you spent years learning from text books and teachers, and you know inside out in your mind, putting into text just muddles things sometimes.

I don't know about that Noel - this bloke does a good job LOL

http://www.bing.com/videos/search?q=...3F7&FORM=VIRE6

[The Mad Cat]

TMC

Unsure which Optima's you are running , however 10 Amps is not required. Optima recommend 4 Amps constant with a time period subject to state of charge.

Red Top (34 type) - 12-45 to 12-55 V 4Amps / 4 hrs. Yellow Top (34 type) - same voltage range 4 A / 6 hrs.

Blue Top (D34M) - Same as Yellow Top. Yellow Top (D31A , D27F) Blue Top (D27M , D31M) - same voltage

range 4 A / 9 hrs.

I don't believe that the charger that you would be using would put out a constant charge , but would be 1 that will decrease the rate of charge as batteries approach full charge going into float at completion of charge.

Voltages after 24 hrs. stand should be 12-8V for Red Top or 13-1V for others. Just check Voltages before charging & charge in parallel if similar state of discharge.

As to mixing & matching of batteries types during charging NOT recommended. You can get away with it as Scottar stated (trickle charges being used by most). Just not on my boat or in my vicinity.

Cheers Kevin.

HI Kevin,
This is off the Optima site.
https://www.optimabatteries.com/en-u...-care/charging
I am running 4 blue tops, 2 as house and 2 as start. The blue tops are hybrid like the yellow tops and was trying to look after them by following Optimas recommendations. I really don't understand as much about all of this as i would like, hence the original question and thanks to everyone for there reply's.

TMC
Battery Charger:

• 13.8 to 15.0 volts, 10 amps maximum, approximately for 6-12 hours.

Battery Charger:

[Kevin Ferguson]

TMC

Apologies for not replying sooner. Had a look at Optima site via your link. I think that this would be for general public & the chargers that they would have normal access to. Specs I have provided are from Optima but relate to commercial charging applications. I top up charge Optima's on a regular basis using either 4 channel - 70Amps per channel or single channel 270 Amp output rectifiers. Constant current for the entire charge time allocated.

Your blue tops are usually charged in 6 banks of 6 (36 per channel) @ 4 Amps (total input 24 amps). As mentioned on their site heat build up is an important issue. Should not be a problem for you. I have a laser temp gauge to monitor 'on charge' product to avoid overheating with resultant venting thru the valve.

I can appreciate you wanting to keep them in prime condition as they are an expensive product. I rate them highly & see virtually nil warranty claims unless from abuse. As per your original post re keeping them on a constant float charge consider this , commercial battery manufacturers / wholesalers do not keep their stock on a continual charge. I would be charging them to full capacity , disconnecting all cables & would have no problems leaving them sit for the 1 to 2 months you mentioned.

Cheers Kevin.

[Noelm]

Any battery that can't sit for a few months and still be OK is near shagged.

[Fed]

It would probably help to know exactly what batteries & charger you have TMC.

[The Mad Cat]

It would probably help to know exactly what batteries & charger you have TMC.

Hey Fed,
I think it was mentioned somewhere. Optima Blue Tops 2 house and 2 start. I only have a smaller Ctek 3.5 amps I think it is, so was looking for something more suitable to run off a small gen set when/if needed when we are away for longer trips and something to top up batteries when at home. Batteries will be running a fridge and freezer plus lights, fans etc.

TMC

[Fed]

There is 2 types of blue tops mentioned in the link but looking more carefully the charging is much the same for both.

I'd be looking for a charger big enough to do the job under the flattest conditions (20A) that also has a built in Voltmeter & Ammeter.
Then get to 'know' your batteries & stop charging when they're full, I have to say I've never been a fan of leaving batteries on trickle/float charge simply because I think it can mask a problem.

FWIW there seems to be heaps of stand alone digital Voltmeter/Ammeters available on the net, cheap as chips.

[The Mad Cat]

http://www.ctek.com/au/en/Product/Ca...egory=sailboat

The Ctek M300 is my choice so far. Other opinions welcomed.

TMC

[juggernaut]

I have the M300 and a Redarc SBC1205.

http://www.redarc.com.au/products/pr...attery-charger

The M300 does put some heat into the batteries and certainly need to vent the area where you are charging due to the gasses the batteries gives off. For this reason I prefer the Redarc. Both great chargers. The M300 does have the recondition mode for dead batteries which I have used from time to time for mine and friends batteries and works a treat to bring batteries back to life.