DC-DC charger

[climbing coastie]

After frying one house battery I’m planning on getting a DC-DC charger instead of just hooking it up to my alternator. I’m looking at getting a Redarc charger. Any thoughts/concerns with this charger?

Charger

 

[Trebor English]

After frying one house battery 

What went wrong with the first battery?  Did it get overcharged, undercharged?  What kind of battery was it?  

What kind of battery do you want to use with the dc dc charger?

 

[highdesertranger]

I have never heard of a battery getting fried from being connected to an alternator, unless the alternator was bad. highdesertranger

 

[Canine]

Were you by chance charging an AGM or a Gel cell? I'm curious why it fried.

 

[climbing coastie]

The website for the old battery said it was an AGM, not sure that was actually the case. It might have been my solar charge controller that did it, but can’t afford to chance it again.

All I know is that sulfuric acid leaked out the top and there was sloshing sounds when moving the battery.

Now I have a FullRiver battery that I’ve set my charge controller to their specs. The rep said that a DC-DC charger would be best due to the three stage charging, but the alternator shouldn’t hurt it unless the battery was extremely low.

The voltmeter in my van routinely says its putting out 15v+ which is over FullRiver’s recommendation.

 

[Canine]

AGMs are fussy. I don't really agree with the rep on that one, not for longevity anyway. Maybe a few years it will be OK, but then into the 4th year- poof! A tiny bit of off gassing from a very slight overcharge every day will add up. A DC to DC charger that has 3 charging stages that match the specs for your FullRiver battery would be perfect and worth the money. It may take a few years for it to pay for itself, though. There's no way I would charge an AGM with anything but the manufacturers specs. My AGMs are 7 years old and still working well for a reason (hint: it isn't luck).

 

[John61CT]

Yes the purpose of a DCDC charger is to precisely deliver the right voltage from an imprecise source, also to overcome voltage drop over long runs when fat wires are impractical.

My only problem with Redarc is their setpoints aren't user adjustable like Sterling's BB series, and lower amp limits.

 

[Weight]

I have not seen alternators put out over 15 volts. Upward 14+ is normal.

 

[Canine]

John61CT, I, too, was concerned about the 20 amp charge. 40 feet of 12 AWG wire isn't quite enough for 20 amps. Definitely going to have some voltage drop, although, I don't know if it would get too hot or not. 10 amps would by nice- plenty of juice to give a good start to the charging process while a 100 watt solar panel could take care of what little is left.

 

[Trebor English]

The website for the old battery said it was an AGM, not sure that was actually the case. It might have been my solar charge controller that did it, but can’t afford to chance it again.

All I know is that sulfuric acid leaked out the top and there was sloshing sounds when moving the battery.

AGM batteries don't make sloshing sounds.  It may have been a maintenance free calcium alloy flooded battery.  

How long did it last?  During that time did the starter battery have a problem?

AGM batteries can be mounted sideways.  Was it upright?  

If you haven't diagnosed what went wrong with the first battery spending $300 for the Redarc is just blindly throwing money at the problem.