Auxiliary Battery Charging
- Thread starter 525rider
- Start date
autostaretx
Erratic Member
That's what the MB "Auxiliary Battery Package" does ... an "isolation relay" (under the US driver's seat) pulls in when the engine is running and joins the two batteries.
They use a 100 amp -rated relay, and a 150 amp fuse.
Their *manual* says to keep the load on the alternator down to 40 amps, and that may be what their 100AH battery self-limits to.
How much actually gets drawn will depend upon how "flat" the battery is.
What model year Sprinter? (there are differences in the system logic between T1N, NCV3 and VS30)
If an NCV3, which engine?
--dick
They use a 100 amp -rated relay, and a 150 amp fuse.
Their *manual* says to keep the load on the alternator down to 40 amps, and that may be what their 100AH battery self-limits to.
How much actually gets drawn will depend upon how "flat" the battery is.
What model year Sprinter? (there are differences in the system logic between T1N, NCV3 and VS30)
If an NCV3, which engine?
--dick
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autostaretx
Erratic Member
Precisely *what* battery? (a web link would be nice so we can read the specs) ... that limit sounds like a Gel Cell.
You can get "battery-to-battery" units which would limit the current. Sterling makes a bunch (not cheap).
You can get solar controllers which accept an alternator's input too, and then which meter the charge to the battery.
An AGM appreciates a higher charging voltage than the Sprinter's alternator will produce, so unless you have solar (which can provide the "top it off" voltages), the B-to-B route might be the way to go.
Another approach to "B to B" is to actually use an inverter (to 110vac) and then a plug-in-the-wall charger (back to battery levels) to create your own "B to B" with the handy provision of 110vac for other things.
--dick
You can get "battery-to-battery" units which would limit the current. Sterling makes a bunch (not cheap).
You can get solar controllers which accept an alternator's input too, and then which meter the charge to the battery.
An AGM appreciates a higher charging voltage than the Sprinter's alternator will produce, so unless you have solar (which can provide the "top it off" voltages), the B-to-B route might be the way to go.
Another approach to "B to B" is to actually use an inverter (to 110vac) and then a plug-in-the-wall charger (back to battery levels) to create your own "B to B" with the handy provision of 110vac for other things.
--dick
https://www.batteriesplus.com/battery/sla-sealed-lead-acid/12/wkdc12=100p
I am considering this one, have been thinking about solar panels in the future.
I am considering this one, have been thinking about solar panels in the future.
autostaretx
Erratic Member
The sheets for that battery family (specs, applications) don't flat-out say they're gel cells, but both sheets have a little image with the comment that "gel cells want 13.8 to 14.1 volts for charging".
Since these batteries do want more careful handling than "normal" AGMs, you might look at "general purpose deep cycle AGMs" instead (or in addition). The extra cost/care of babying the gel cells might outweigh the battery's cost advantage. (if any).
What you're planning for *loads* now becomes an important question.
(for example: we use a microwave ... that's a 75 amp draw from our battery. A general purpose (starting/deep-cycle) AGM battery is happy with that. The matches-the-battery shore-power charger pushes 40 amps, and the battery's instructions did not warn about using it as a starter battery in a car.)
--dick
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autostaretx
Erratic Member
The same kind as the starter battery. Usually flooded lead acid. Same part number.
If you ordered an AGM as either Aux or starter, the other battery was changed to match that, too.
Your "datacard" (enter your VIN to https://www.datamb.com/ ) would mention if it was AGM.
--dick
p.s. perhaps i should say "a better breed of flooded lead acid" ... the Varta that came standard in my 2005 Sprinter was probably the best battery i ever had in a vehicle.
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autostaretx
Erratic Member
???
Did you mean to say 20 amps? Or *where* are those 20 volts coming from or going to?
Remember that your readers (i.e. us) have dozens of people's systems bouncing in our heads, so a short comment like that may not be easily translated. Please spend a few more words and/or add a diagram.
Hmmm... on re-reading it a third time: you're probably speaking of having the Sprinter's electric system (i.e. alternator) feed the 30A converter, then set the converter to 20v output, which you then feed into an MPPT controller whose output will finally feed the House battery.
Well, the only fly in that ointment is that the MPPT will be trying to *adjust* its "solar input" in an attempt to achieve the "maximum power point" ... so i don't know what sort of hissy-fits the two lumps (coverter versus controller) will get into.
SOME controllers *have* a secondary input channel for non-solar sources (wind power, alternators, generators).
Using one of them would reduce the hissy-fit potential.
On the other hand, the MPPT may well see that 600 watts (30A * 20V) is its best shot, and live with it.
--dick
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The controller is going to receive voltage and amperage within its parameters, so I think it shouldn't matter from what source. Yes that's what I meant: you're probably speaking of having the Sprinter's electric system (i.e. alternator) feed the 30A converter, then set the converter to 20v output, which you then feed into an MPPT controller whose output will finally feed the House battery.
Many SCs especially MPPT will only work with panels as input.
Kludgey workarounds may be fun science projects but rarely result in a reliable robust setup for production use.
Please write a single detailed post about the specific goals, volts and amps desired, and links to the specific devices and batteries involved.
Or, likely get a better result posting your general goals, and ask the members here for recommendations as to specific quality products.
Kludgey workarounds may be fun science projects but rarely result in a reliable robust setup for production use.
Please write a single detailed post about the specific goals, volts and amps desired, and links to the specific devices and batteries involved.
Or, likely get a better result posting your general goals, and ask the members here for recommendations as to specific quality products.
Thanks,
controller: https://www.amazon.com/dp/B07MM4CG9D/ref=twister_B07LCCTXS4?_encoding=UTF8&psc=1
converter: https://www.amazon.com/gp/product/B078RLDBPS/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
Battery: https://www.amazon.com/Vmaxtanks-Vm...coding=UTF8&psc=1&refRID=46ZX2FK969420YEPW2Y0
I received an answer from another website: "Yes it will accept any DC voltages from 14V to 100V"
controller: https://www.amazon.com/dp/B07MM4CG9D/ref=twister_B07LCCTXS4?_encoding=UTF8&psc=1
converter: https://www.amazon.com/gp/product/B078RLDBPS/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
Battery: https://www.amazon.com/Vmaxtanks-Vm...coding=UTF8&psc=1&refRID=46ZX2FK969420YEPW2Y0
I received an answer from another website: "Yes it will accept any DC voltages from 14V to 100V"
4wheeldog
2018 144" Tall Revel
Charging current and draw are two different things.
A battery will not draw more than it can handle, as long as the current (Voltage) is not excessive.
I doubt a flat battery would draw more than 40 amps as long as current did not exceed what a Sprinter alternator puts out...….Which is generally about 14volts in my experience.
If you need a sealed battery, then go proper deep cycling AGM, like Lifeline or Odyssey, call them for a local dealer, avoid buying big batts online if possible.
Quality FLA would be much better value.
Do not use a SC until you add panels, it goes between them and the battery only.
If you're OK regulating the charge cycle manually may not need anything at all, get the appropriate wiring in place first and test alt output there with a cheap battery you already have using a clamp ammeter.
If voltage is too low for the AGM, check out Deka GEL, they can go over a decade if coddled.
For convenience, better to just get a proper staged DC-DC charger to put between the alt output and your House bank, ideally one you can adjust to user-custom setpoints rather than just choosing a canned profile.
Quality FLA would be much better value.
Do not use a SC until you add panels, it goes between them and the battery only.
If you're OK regulating the charge cycle manually may not need anything at all, get the appropriate wiring in place first and test alt output there with a cheap battery you already have using a clamp ammeter.
If voltage is too low for the AGM, check out Deka GEL, they can go over a decade if coddled.
For convenience, better to just get a proper staged DC-DC charger to put between the alt output and your House bank, ideally one you can adjust to user-custom setpoints rather than just choosing a canned profile.
A **lead** battery will not draw more than it can handle, as long as the current (Voltage) is not excessive.
FTFY
It is true you can't hurt a lead bank by making more amps available than it will accept.
But a big enough bank of high-CAR chemistry - even AGM - will try to draw lots more current than the alt can supply, and if that doesn't damage the alt, it likely interferes with the VR maintaining proper voltage output.
Another case where a good DCDC charger is called for.
FTFY
It is true you can't hurt a lead bank by making more amps available than it will accept.
But a big enough bank of high-CAR chemistry - even AGM - will try to draw lots more current than the alt can supply, and if that doesn't damage the alt, it likely interferes with the VR maintaining proper voltage output.
Another case where a good DCDC charger is called for.
4wheeldog
2018 144" Tall Revel
A single 100AH battery is what the OP asked about.
No way a single battery that size will overdraw what is available from the alternator.
A dc/dc programmable charger is definitely superior. But is overkill, for most of us.