Can I maintain my starter battery with my dc distribution panel?

[Justdeansd]

I'm putting in 800W solar with a Growatt 3000LVM 24v charge controller/inverter. I'm changing to a 24V system so now my generator is going to be relying on just the starting battery. I already have problems keeping if fully charged when I'm out because I keep my dashcams recording while I'm camping, so I know I need to keep the starting battery fully charged. I don't want to run a junction to the generator & starter battery by tapping into one of the 12V batteries because they will become unbalanced (but I will have a battery 'normally off' battery switch split between my 2 house batts to use to start the generator in case the starting battery ends up dead somehow).

I will be installing a stepdown DC converter from the house 24V converter in order to power the house lights & refrigerator, but I'm thinking that if I just run a wire from that to a battery isolator that goes to the starting battery it may draw more than the rated 40 amps every time I start the RV.(?) But I also think that maybe if the starting battery is fully charged all of the time then maybe it won't draw much current.(?)

The easiest way I can think of to do this is to just use my house AC to power a 12v 3A trickle charger? Would it kill the trickle charger?

Other questions I have: When my starter battery has dies in the past all I had to do is start my generator and that would jump start my starter battery. So is the DC power panel what did that? If so, is my 40amp step down converter going to handle it anyhow? The wires are definitely too small I think they are 10ga at best. I'm stuck, please tell me what I am missing.
Thanks,
Dean

 

[Substrate]

The easiest way I can think of to do this is to just use my house AC to power a 12v 3A trickle charger? Would it kill the trickle charger?

Wow, there is a lot there, but this seems the most prudent way to do it, *provided* your starter battery is already at or near full charge.

Because consumers don't know the difference between a trickle/maintainer, and a true higher-amperage battery charger, many batts are killed by trying to use them. So many, that in recent years, manufacturers have provided guidelines as how to differentiate between the two.

Here are the rules:
1) A low amperage trickle / maintainer is to be used AFTER your battery has already been charged by another source to near full.

2) If the battery is heavily discharged, then a higher-amperage charger must be used FIRST, and then you can apply the maintainer charger.

Many a good battery that has been heavily or moderately discharged, and then the consumer uses a low-amperage trickler to charge it for like 3 days, is killing that battery chemically. A superficial "surface charge" develops which may eventually trigger the "battery full / 100%" light, but the superficial charge gets blown away as soon as a dome-light comes on.

Worse still is that using a maintainer to fully charge a large battery is so inefficient that it is chemically damaging - even heating and warping plates - even though YOU can't feel it - the plates do.

Long moral: know the difference between a maintainer and a charger. Maintainer is applied AFTER a full charge.

In your case, since you have jump-started the battery so many times, there may be other issues that a maintainer won't band-aid. Get your starter battery tested and see if a replacement is the best option. Then use the maintainer.

Just notes for the notebook ....

 

[Justdeansd]

Thank you for all of that. After reading more about the Trik-L-Start posted on other threads I think it would be best to just go with that since it has the build-in current limiter and over current protection. Thank you for your time and information, it actually helped me figure out why one of my trickle chargers doesn't work anymore. I won't make that mistake again.

 

[Substrate]

No problem - common mistake. You'll see vids of guys charging a big battery with a Battery Tender, and when it times out the safety timers, unplug and do it all over again for 3 days.

Usually this a quickie attempt on some discard old trash battery, but I've seen guys do it on brand-new ones. Ouch.