Deep cycle battery charging tech.

[Redfin]

I have a large Odessy deep cycle battery which I use to power an inverter for some small ac jobs. I'm wanting to use this large battery to charge my two smaller group 24 deep cycle trolling batts on my boat while I'm at camp, which does not have ac power.

Iirc my smaller 24 group batts have a siemans rating of around 350g at full capacity and the larger Odessy is rated at 1300g. I am aware that not all batterys are going to have the same ratings due to the manufactures formulas used to rate the batterys. I don't feel there is a need to try to convert excactly the seiman value between these batterys to accomplish what I'm trying to do.

I'm wondering what will give me better results.

1. Connect all three batterys in parrell so they will equalize. (This being the large Odessy being fully charged and the group 24 batts partially discharged from a day of trolling)

2. Connect my inverter to the larger fully charged battery and run my battery charger from that.

Lets just assume (to get me in the ballpark) all three batts are from the same manufacture and the g value is derived from the same formula. My thinking is if I have depeleted my two group 24 batts 50% which would give me 350g and I parralell connect them to my 1300g batt, they should equalize giving me a full charge on my small batts. Is my thinking way off? Or should I just use the inverter and charger?

[Redfin]

Wow almost four hours and not so much as one smart ass comment. Slackers

[xmptsunami]

Generally, don't you have to get up to around 14 volts to properly charge a battery?

Using the inverter should work, however you'd be losing with all the inverting/rectifing, easy enough to test to see if you could charge the smaller ones more than once.

I'll ask the obvious question though, why don't you just bring the big batt in the boat with you?


Interesting question.

[Brutpwr]

You will be better off using an inverter off the larger Odessey to run your battery charger I'm guessing. It will charger your boat batteries to a higher level. You will need to measure the output voltage to make sure the battery charger works properly with the inverter. Most battery chargers are very dependant on A/C voltage levels. If the input voltage is lower than normal charging output will often be reduced greatly slowing battery charging ability.
Putting the Odessey in parrallel with the Group 24's would be extremely slow even though static voltage levels on an Odessey are usually a good 1/2 volt higher than most Marine batteries.

Jason

[chevy_man]

Why not just put a solar trickle charger on your boat?

[Halogrinder]

what composition are they? wetcell/drycell/AGM?


if you had a wet cell, and hooked up an AGM in parallel to help "equalize", you may end up with blown up batteries.......

[Redfin]

Originally Posted by chevy_man

Why not just put a solar trickle charger on your boat?

I was only at camp for the weekend, I'm afraid a solar trickle would take entirely to long.

Originally Posted by Halogrinder

what composition are they? wetcell/drycell/AGM?


if you had a wet cell, and hooked up an AGM in parallel to help "equalize", you may end up with blown up batteries.......

They are a combo of agm and wet cells. I did not even think of this possibilty. I'm a bit confused though, my trolling motor doesn't care what type they are. Regardless, I tried wiring the inverter and using charger when I got back to camp sat night. I don't think the inverter is large enogh, the charger was not happy and would not charge batteries.

I didn't have a volt meter with me to check incoming ac, I'm going to check. It may not have been high enough.

[87manche]

http://ludens.cl/Electron/12Vcharger/12Vcharger.html

you need something like that.


or, if you're not too handy with the sodlering iron and being a nerd.

http://www.hobbyking.com/hobbyking/s...1_8_Cells.html

input voltage 10-18V.
charges lead acid battereis up to 36V.
downside is 7A current limit, but there are larger battery chargers out there, you're just going to have to pay more. Also charges just about anything you can think of. Discharges and storage charges things too.

[Halogrinder]

Originally Posted by Redfin

my trolling motor doesn't care what type they are.

and it shouldnt....... but that doesnt mean that the charger and/or batteries will enjoy re-charging