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Auxillary battery: install, charge with DC-Dc charger XH-M603?


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unn
Novice

Mar 31, 2021, 8:50 AM

Post #1 of 10 (513 views)
  post locked   Auxillary battery: install, charge with DC-Dc charger XH-M603?  

I am thinking of installing an auxillary battery in my van. The usual split charging systems or the DC-Dc devices are quite expensive. I thought of using the below charge controller module XH-M603, only $5 for this purpose. What do you think?
Link deleted
Here is how I plan to connect it: + & - (or body ground) from the starter battery will give the input to the XH-M603. Output will be connected to the auxillary battery. The board will be set to turn the charge on at 13.6v (means when the alternator is on) and turn off at 12.6v. This way the starter battery will not drop below 12.6v.

Does this sound right?
A second question: how to wire the battery from an unused fuse socket inside the vehicle? Can this be done instead of pulling wires all the way from the starter battery? How?

Thanks.


(This post was edited by Hammer Time on Mar 31, 2021, 9:05 AM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 31, 2021, 9:05 AM

Post #2 of 10 (509 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

That board is going to do nothing for the issues you will have.

You cannot charge 2 batteries at the same time with a factory alternator. It will overload it and burn it out. What you need is a battery switch commonly used in boats to give you control of which batteries you are operating on at any given time. You can choose between battery 1, 2 or both.

I also had to delete your Ebay link as they are not allowed here.





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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 31, 2021, 10:40 AM

Post #3 of 10 (497 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

Marine stuff like Hammer just posted is superior - full and real connections without making a spark.

Question I have is why do you want or need 2 batteries? Voltage drop from a normal good battery should show maybe 10.5V in reasonable temps outside and of battery really.

If you want a back up do the switch thing as shown just beware if you choose two at once and one has a dead short internally you'll take them both out if not fast enough using both.

I've dealt with yachts using as many as 6 marine deep cycles batteries never all of them at once I think just two at once for twin engines no need to start both at the same time just seconds apart if some emergency to move but you can with one engine - been there done that,

T



unn
Novice

Apr 1, 2021, 6:55 AM

Post #4 of 10 (468 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

The second battery is for accessories, 12v fan, USB chargers etc. All those "auxiliary battery install kits" that are available in the market never mention that alternator cannot handle charging two batteries. Most of the times the primary battery is full any way and the alternator is just idle unless one does frequent starts and stops like the door to door delivery people. two battery scenario also exists when one "jumps a dead battery from a good running battery and alternator". My limited understanding of electronics is that all that the kits do is put the two batteries in parallel and prevent charging of auxiliary from the primary while the engine is off. Thanks.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Apr 1, 2021, 8:27 AM

Post #5 of 10 (464 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

? You'd have to do tons of 1 minute or less stops (engine) and starts before a problem. How about getting a jumper box with up to 1000 AMPS comes with power ports and USB ports some with air compressors you can fill tires or whatevers with?


I have tons of those surprised but Harbor Freight has decent ones last years. Recharge can be by the van or bring it to plug in it is a charger too inside.
Low watt cig lighter size inverters small things can run quite a bit - power goes out where I am too much have some things going in no time - lights if LED a lot of them.
If that's what you wanted think about it, lots easier, cheaper and can take it with you in any other vehicle or home - handy suckers,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 1, 2021, 9:14 AM

Post #6 of 10 (460 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  


Quote
two battery scenario also exists when one "jumps a dead battery from a good running battery and alternator".


Yes and I can't tell you how many times I've replaced alternators for people that have done that.
Replacement alternators these days come with instructions to charge your battery manually before starting the engine as you can burn out the new alternator. Today's alternators are designed to simply "maintain" a charged battery, not charge one from dead or charge more than one. They are not designed to charge at full capacity for any period of time.

Jump starting cars has been advised against for a good period of time now for this same reason. This is why they have designed these small, compact jump tools that can be carried around.

I will not use my vehicle to jump another car. Old school rules don't apply any more.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



unn
Novice

Apr 2, 2021, 7:44 PM

Post #7 of 10 (440 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

Thank you.
Just curious about some thing. For years now, we have had those "always on headlights" cars. I don't know exactly how many amps head lights draw but i understand those are the highest consuming part of the car. Does that mean the "always on headlights" cars are putting extra load on the alternator? What if one was using the same amps that would have been used by the headlights to charge the auxiliary battery (with the lights off)?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Apr 3, 2021, 12:38 AM

Post #8 of 10 (429 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

Biggest draw on a battery is the starter motor for most. Headlights or DRLs may or may not use many AMPs if LED or halogen something each if new the package should say what they consume.
Alternator does power that and just keeping a spare battery charged don't need to if isolated would last many weeks or more? If installed to be dual battery that's another thing.


unn: There are many different items that place by place MUST be on and others optional. The high consumption items include blower motors, electric window defoggers/defrosters, all I've know self shut off by time.
The other is aftermarket items and how power ports are used.
mal
Alternators should be doing the work after engines are running and puts battery back to full charge if normal but does cover sudden spikes of use. Power windows for example, high use but not for long is while running.
Other fuels and now electric only use and follow each ones suggestions.
RVs and or other machines and vehicles you may need to be more attentive one by one only.
Add plain "Common Sense" (that died years ago) one issue at a time.


This thread has about run its course of value IMO will be locked for archives soon I hope or may do start new issued on your own,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 3, 2021, 4:34 AM

Post #9 of 10 (426 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

As a rule DRLs are not full headlamps. I know there are exceptions. They are not designed to light up the road ahead. They are designed to be seen by other vehicles so most consume far less current than regular headlamps.

Still the max most headlamps consume is 15-20 amps. The alternator can safely put out 30-40 amps consistently. Although many new alternators are rated to output 100-130 amps, anything over 80 really stresses them. Even 40-50 for an extended period can be a problem.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



unn
Novice

Apr 3, 2021, 10:35 AM

Post #10 of 10 (413 views)
  post locked   Re: Auxillary battery: install, charge with DC-Dc charger XH-M603?  

Thank you very much every one. Definitely, this thread can be closed.






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